+\begin_layout Description
+-
+\begin_inset ERT
+status collapsed
+
+\begin_layout Standard
+
+
+\backslash
+/
+\end_layout
+
+\end_inset
+
+-optimize-goto Try to use (conditional) BRA instead of GOTO.
+\end_layout
+
+\begin_layout Description
+-
+\begin_inset ERT
+status collapsed
+
+\begin_layout Standard
+
+
+\backslash
+/
+\end_layout
+
+\end_inset
+
+-optimize-cmp Try to optimize some compares.
+\end_layout
+
+\begin_layout Description
+-
+\begin_inset ERT
+status collapsed
+
+\begin_layout Standard
+
+
+\backslash
+/
+\end_layout
+
+\end_inset
+
+-optimize-df Analyze the dataflow of the generated code and improve it.
+\end_layout
+
+\begin_layout Subsubsection
+Assembling Options
+\end_layout
+
+\begin_layout Description
+-
+\begin_inset ERT
+status collapsed
+
+\begin_layout Standard
+
+
+\backslash
+/
+\end_layout
+
+\end_inset
+
+-asm= Sets the full path and name of an external assembler to call.
+\end_layout
+
+\begin_layout Description
+-
+\begin_inset ERT
+status collapsed
+
+\begin_layout Standard
+
+
+\backslash
+/
+\end_layout
+
+\end_inset
+
+-mplab-comp MPLAB
+\begin_inset LatexCommand \index{PIC16!MPLAB}
+
+\end_inset
+
+ compatibility option.
+ Currently only suppresses special gpasm directives.
+\end_layout
+
+\begin_layout Subsubsection
+Linking Options
+\end_layout
+
+\begin_layout Description
+-
+\begin_inset ERT
+status collapsed
+
+\begin_layout Standard
+
+
+\backslash
+/
+\end_layout
+
+\end_inset
+
+-link= Sets the full path and name of an external linker to call.
+\end_layout
+
+\begin_layout Description
+-
+\begin_inset ERT
+status collapsed
+
+\begin_layout Standard
+
+
+\backslash
+/
+\end_layout
+
+\end_inset
+
+-preplace-udata-with=[kword] Replaces the default udata keyword for allocating
+ unitialized data variables with [kword].
+ Valid keywords are: "udata_acs", "udata_shr", "udata_ovr".
+\end_layout
+
+\begin_layout Description
+-
+\begin_inset ERT
+status collapsed
+
+\begin_layout Standard
+
+
+\backslash
+/
+\end_layout
+
+\end_inset
+
+-ivt-loc=n Place the interrupt vector table at address
+\emph on
+n
+\emph default
+.
+ Useful for bootloaders.
+\end_layout
+
+\begin_layout Description
+-
+\begin_inset ERT
+status collapsed
+
+\begin_layout Standard
+
+
+\backslash
+/
+\end_layout
+
+\end_inset
+
+-nodefaultlibs Do not link default libraries when linking.
+\end_layout
+
+\begin_layout Description
+-
+\begin_inset ERT
+status collapsed
+
+\begin_layout Standard
+
+
+\backslash
+/
+\end_layout
+
+\end_inset
+
+-use-crt= Use a custom run-time module instead of the defaults.
+\end_layout
+
+\begin_layout Description
+-
+\begin_inset ERT
+status collapsed
+
+\begin_layout Standard
+
+
+\backslash
+/
+\end_layout
+
+\end_inset
+
+-no-crt Don't link the default run-time modules
+\end_layout
+
+\begin_layout Subsubsection
+Debugging Options
+\end_layout
+
+\begin_layout Standard
+Debugging options enable extra debugging information in the output files.
+\end_layout
+
+\begin_layout Description
+-
+\begin_inset ERT
+status collapsed
+
+\begin_layout Standard
+
+
+\backslash
+/
+\end_layout
+
+\end_inset
+
+-debug-xtra Similar to -
+\begin_inset ERT
+status collapsed
+
+\begin_layout Standard
+
+
+\backslash
+/
+\end_layout
+
+\end_inset
+
+-debug
+\begin_inset LatexCommand \index{-\/-debug}
+
+\end_inset
+
+, but dumps more information.
+\end_layout
+
+\begin_layout Description
+-
+\begin_inset ERT
+status collapsed
+
+\begin_layout Standard
+
+
+\backslash
+/
+\end_layout
+
+\end_inset
+
+-debug-ralloc Force register allocator to dump <source>.d file with debugging
+ information.
+ <source> is the name of the file being compiled.
+\end_layout
+
+\begin_layout Description
+-
+\begin_inset ERT
+status collapsed
+
+\begin_layout Standard
+
+
+\backslash
+/
+\end_layout
+
+\end_inset
+
+-pcode-verbose Enable pcode debugging information in translation.
+\end_layout
+
+\begin_layout Description
+-
+\begin_inset ERT
+status collapsed
+
+\begin_layout Standard
+
+
+\backslash
+/
+\end_layout
+
+\end_inset
+
+-calltree Dump call tree in .calltree file.
+\end_layout
+
+\begin_layout Description
+-
+\begin_inset ERT
+status collapsed
+
+\begin_layout Standard
+
+
+\backslash
+/
+\end_layout
+
+\end_inset
+
+-gstack Trace push/pops for stack pointer overflow.
+\end_layout
+
+\begin_layout Subsection
+Enviroment Variables
+\end_layout
+
+\begin_layout Standard
+There is a number of enviromental variables that can be used when running
+ SDCC to enable certain optimizations or force a specific program behaviour.
+ these variables are primarily for debugging purposes so they can be enabled/dis
+abled at will.
+\end_layout
+
+\begin_layout Standard
+Currently there is only two such variables available:
+\end_layout
+
+\begin_layout Description
+OPTIMIZE_BITFIELD_POINTER_GET When this variable exists, reading of structure
+ bitfields is optimized by directly loading FSR0 with the address of the
+ bitfield structure.
+ Normally SDCC will cast the bitfield structure to a bitfield pointer and
+ then load FSR0.
+ This step saves data ram and code space for functions that make heavy use
+ of bitfields.
+ (i.e., 80 bytes of code space are saved when compiling malloc.c with this
+ option).
+
+\end_layout
+
+\begin_layout Description
+NO_REG_OPT Do not perform pCode registers optimization.
+ This should be used for debugging purposes.
+ If bugs in the pcode optimizer are found, users can benefit from temporarily
+ disabling the optimizer until the bug is fixed.
+\end_layout
+
+\begin_layout Subsection
+Preprocessor Macros
+\end_layout
+
+\begin_layout Standard
+PIC16
+\begin_inset LatexCommand \index{PIC16}
+
+\end_inset
+
+ port defines the following preprocessor macros while translating a source.
+\end_layout
+
+\begin_layout Standard
+\align center
+\begin_inset Tabular
+<lyxtabular version="3" rows="6" columns="2">
+<features>
+<column alignment="center" valignment="top" leftline="true" width="0">
+<column alignment="center" valignment="top" leftline="true" rightline="true" width="0">
+<row topline="true" bottomline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+Macro
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+Description
+\end_layout
+
+\end_inset
+</cell>
+</row>
+<row topline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+SDCC_pic16
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+Port identification
+\end_layout
+
+\end_inset
+</cell>
+</row>
+<row topline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+_
+\begin_inset ERT
+status collapsed
+
+\begin_layout Standard
+
+
+\backslash
+/
+\end_layout
+
+\end_inset
+
+_pic16
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+Port identification (same as above)
+\end_layout
+
+\end_inset
+</cell>
+</row>
+<row topline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+pic18fxxxx
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+MCU Identification.
+
+\emph on
+xxxx
+\emph default
+ is the microcontrol identification number, i.e.
+ 452, 6620, etc
+\end_layout
+
+\end_inset
+</cell>
+</row>
+<row topline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+_
+\begin_inset ERT
+status collapsed
+
+\begin_layout Standard
+
+
+\backslash
+/
+\end_layout
+
+\end_inset
+
+_18Fxxxx
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+MCU Identification (same as above)
+\end_layout
+
+\end_inset
+</cell>
+</row>
+<row topline="true" bottomline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+STACK_MODEL_nnn
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+nnn = SMALL or LARGE respectively according to the stack model used
+\end_layout
+
+\end_inset
+</cell>
+</row>
+</lyxtabular>
+
+\end_inset
+
+
+\end_layout
+
+\begin_layout Standard
+In addition the following macros are defined when calling assembler:
+\end_layout
+
+\begin_layout Standard
+\align center
+\begin_inset Tabular
+<lyxtabular version="3" rows="4" columns="2">
+<features>
+<column alignment="center" valignment="top" leftline="true" width="0">
+<column alignment="center" valignment="top" leftline="true" rightline="true" width="0">
+<row topline="true" bottomline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+Macro
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+Description
+\end_layout
+
+\end_inset
+</cell>
+</row>
+<row topline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+__18Fxxxx
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+MCU Identification.
+
+\emph on
+xxxx
+\emph default
+ is the microcontrol identification number, i.e.
+ 452, 6620, etc
+\end_layout
+
+\end_inset
+</cell>
+</row>
+<row topline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+SDCC_MODEL_nnn
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+nnn = SMALL or LARGE respectively according to the memory model used for
+ SDCC
+\end_layout
+
+\end_inset
+</cell>
+</row>
+<row topline="true" bottomline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+STACK_MODEL_nnn
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+nnn = SMALL or LARGE respectively according to the stack model used
+\end_layout
+
+\end_inset
+</cell>
+</row>
+</lyxtabular>
+
+\end_inset
+
+
+\end_layout
+
+\begin_layout Subsection
+Directories
+\end_layout
+
+\begin_layout Standard
+PIC16
+\begin_inset LatexCommand \index{PIC16}
+
+\end_inset
+
+ port uses the following directories for searching header files and libraries.
+\end_layout
+
+\begin_layout Standard
+\align center
+\begin_inset Tabular
+<lyxtabular version="3" rows="3" columns="4">
+<features>
+<column alignment="center" valignment="top" leftline="true" width="0">
+<column alignment="center" valignment="top" leftline="true" rightline="true" width="0">
+<column alignment="center" valignment="top" width="0">
+<column alignment="center" valignment="top" leftline="true" rightline="true" width="0">
+<row topline="true" bottomline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+Directory
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+Description
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+Target
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+Command prefix
+\end_layout
+
+\end_inset
+</cell>
+</row>
+<row topline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+PREFIX/sdcc/include/pic16
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+PIC16 specific headers
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+Compiler
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+-I
+\end_layout
+
+\end_inset
+</cell>
+</row>
+<row topline="true" bottomline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+PREFIX/sdcc/lib/pic16
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+PIC16 specific libraries
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+Linker
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+-L
+\end_layout
+
+\end_inset
+</cell>
+</row>
+</lyxtabular>
+
+\end_inset
+
+
+\end_layout
+
+\begin_layout Subsection
+Pragmas
+\begin_inset LatexCommand \label{sub:PIC16_Pragmas}
+
+\end_inset
+
+
+\end_layout
+
+\begin_layout Standard
+The PIC16
+\begin_inset LatexCommand \index{PIC16}
+
+\end_inset
+
+ port currently supports the following pragmas:
+\end_layout
+
+\begin_layout Description
+stack
+\begin_inset LatexCommand \index{PIC16!Pragmas!\#pragma stack}
+
+\end_inset
+
+ This forces the code generator to initialize the stack & frame pointers
+ at a specific address.
+ This is an ad hoc solution for cases where no STACK directive is available
+ in the linker script or gplink is not instructed to create a stack section.
+\newline
+The
+ stack pragma should be used only once in a project.
+ Multiple pragmas may result in indeterminate behaviour of the program.
+\begin_inset Foot
+status open
+
+\begin_layout Standard
+The old format (ie.
+ #pragma stack 0x5ff) is deprecated and will cause the stack pointer to
+ cross page boundaries (or even exceed the available data RAM) and crash
+ the program.
+ Make sure that stack does not cross page boundaries when using the SMALL
+ stack model.
+\end_layout
+
+\end_inset
+
+
+\newline
+The format is as follows:
+\newline
+
+\end_layout
+
+\begin_layout LyX-Code
+#pragma stack bottom_address [stack_size]
+\newline
+
+\end_layout
+
+\begin_layout Standard
+
+\emph on
+bottom_address
+\emph default
+ is the lower bound of the stack section.
+ The stack pointer initially will point at address (bottom_address+stack_size-1).
+\end_layout
+
+\begin_layout LyX-Code
+Example:
+\end_layout
+
+\begin_layout LyX-Code
+
+\end_layout
+
+\begin_layout LyX-Code
+/* initializes stack of 100 bytes at RAM address 0x200 */
+\end_layout
+
+\begin_layout LyX-Code
+#pragma stack 0x200 100
+\end_layout
+
+\begin_layout Standard
+If the stack_size field is omitted then a stack is created with the default
+ size of 64.
+ This size might be enough for most programs, but its not enough for operations
+ with deep function nesting or excessive stack usage.
+\end_layout
+
+\begin_layout Description
+code
+\begin_inset LatexCommand \index{PIC16!Pragmas!\#pragma code}
+
+\end_inset
+
+ Force a function to a static FLASH address.
+\end_layout
+
+\begin_layout LyX-Code
+Example:
+\end_layout
+
+\begin_layout LyX-Code
+
+\end_layout
+
+\begin_layout LyX-Code
+/* place function test_func at 0x4000 */
+\end_layout
+
+\begin_layout LyX-Code
+#pragma code test_func 0x4000
+\end_layout
+
+\begin_layout LyX-Code
+
+\end_layout
+
+\begin_layout Description
+library instructs the linker to use a library module.
+\newline
+Usage:
+\end_layout
+
+\begin_layout LyX-Code
+#pragma library module_name
+\end_layout
+
+\begin_layout Standard
+
+\emph on
+module_name
+\emph default
+ can be any library or object file (including its path).
+ Note that there are four reserved keywords which have special meaning.
+ These are:
+\end_layout
+
+\begin_layout Standard
+\align center
+\begin_inset Tabular
+<lyxtabular version="3" rows="6" columns="3">
+<features>
+<column alignment="center" valignment="top" leftline="true" width="0">
+<column alignment="block" valignment="top" leftline="true" width="20page%">
+<column alignment="left" valignment="top" leftline="true" rightline="true" width="0">
+<row topline="true" bottomline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+Keyword
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+Description
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+Module to link
+\end_layout
+
+\end_inset
+</cell>
+</row>
+<row topline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+
+\series bold
+ignore
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+ignore all library pragmas
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+
+\emph on
+(none)
+\end_layout
+
+\end_inset
+</cell>
+</row>
+<row topline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+
+\series bold
+c
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+link the C library
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+
+\emph on
+libc18f
+\emph default
+.lib
+\end_layout
+
+\end_inset
+</cell>
+</row>
+<row topline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+
+\series bold
+math
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+link the Math libarary
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+
+\emph on
+libm18f
+\emph default
+.lib
+\end_layout
+
+\end_inset
+</cell>
+</row>
+<row topline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+
+\series bold
+io
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+link the I/O library
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+
+\emph on
+libio18f*
+\emph default
+.lib
+\end_layout
+
+\end_inset
+</cell>
+</row>
+<row topline="true" bottomline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+
+\series bold
+debug
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+link the debug library
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+
+\emph on
+libdebug
+\emph default
+.lib
+\end_layout
+
+\end_inset
+</cell>
+</row>
+</lyxtabular>
+
+\end_inset
+
+
+\newline
+* is the device number, i.e.
+ 452 for PIC18F452 MCU.
+\end_layout
+
+\begin_layout Standard
+This feature allows for linking with specific libraries withoug having to
+ explicit name them in the command line.
+ Note that the
+\noun on
+ignore
+\noun default
+ keyword will reject all modules specified by the library pragma.
+\end_layout
+
+\begin_layout Description
+udata The pragma udata instructs the compiler to emit code so that linker
+ will place a variable at a specific memory bank.
+\end_layout
+
+\begin_layout LyX-Code
+Example:
+\end_layout
+
+\begin_layout LyX-Code
+
+\end_layout
+
+\begin_layout LyX-Code
+/* places variable foo at bank2 */
+\end_layout
+
+\begin_layout LyX-Code
+#pragma udata bank2 foo
+\end_layout
+
+\begin_layout LyX-Code
+char foo;
+\end_layout
+
+\begin_layout Standard
+In order for this pragma to work extra SECTION directives should be added
+ in the .lkr script.
+ In the following example a sample .lkr file is shown:
+\end_layout
+
+\begin_layout LyX-Code
+
+\end_layout
+
+\begin_layout LyX-Code
+// Sample linker script for the PIC18F452 processor
+\end_layout
+
+\begin_layout LyX-Code
+LIBPATH .
+\end_layout
+
+\begin_layout LyX-Code
+CODEPAGE NAME=vectors START=0x0 END=0x29 PROTECTED
+\end_layout
+
+\begin_layout LyX-Code
+CODEPAGE NAME=page START=0x2A END=0x7FFF
+\end_layout
+
+\begin_layout LyX-Code
+CODEPAGE NAME=idlocs START=0x200000 END=0x200007 PROTECTED
+\end_layout
+
+\begin_layout LyX-Code
+CODEPAGE NAME=config START=0x300000 END=0x30000D PROTECTED
+\end_layout
+
+\begin_layout LyX-Code
+CODEPAGE NAME=devid START=0x3FFFFE END=0x3FFFFF PROTECTED
+\end_layout
+
+\begin_layout LyX-Code
+CODEPAGE NAME=eedata START=0xF00000 END=0xF000FF PROTECTED
+\end_layout
+
+\begin_layout LyX-Code
+ACCESSBANK NAME=accessram START=0x0 END=0x7F
+\end_layout
+
+\begin_layout LyX-Code
+
+\end_layout
+
+\begin_layout LyX-Code
+DATABANK NAME=gpr0 START=0x80 END=0xFF
+\end_layout
+
+\begin_layout LyX-Code
+DATABANK NAME=gpr1 START=0x100 END=0x1FF
+\end_layout
+
+\begin_layout LyX-Code
+DATABANK NAME=gpr2 START=0x200 END=0x2FF
+\end_layout
+
+\begin_layout LyX-Code
+DATABANK NAME=gpr3 START=0x300 END=0x3FF
+\end_layout
+
+\begin_layout LyX-Code
+DATABANK NAME=gpr4 START=0x400 END=0x4FF
+\end_layout
+
+\begin_layout LyX-Code
+DATABANK NAME=gpr5 START=0x500 END=0x5FF
+\end_layout
+
+\begin_layout LyX-Code
+ACCESSBANK NAME=accesssfr START=0xF80 END=0xFFF PROTECTED
+\end_layout
+
+\begin_layout LyX-Code
+
+\end_layout
+
+\begin_layout LyX-Code
+SECTION NAME=CONFIG ROM=config
+\end_layout
+
+\begin_layout LyX-Code
+
+\end_layout
+
+\begin_layout LyX-Code
+SECTION NAME=bank0 RAM=gpr0 # these SECTION directives
+\end_layout
+
+\begin_layout LyX-Code
+SECTION NAME=bank1 RAM=gpr1 # should be added to link
+\end_layout
+
+\begin_layout LyX-Code
+SECTION NAME=bank2 RAM=gpr2 # section name 'bank?' with
+\end_layout
+
+\begin_layout LyX-Code
+SECTION NAME=bank3 RAM=gpr3 # a specific DATABANK name
+\end_layout
+
+\begin_layout LyX-Code
+SECTION NAME=bank4 RAM=gpr4
+\end_layout
+
+\begin_layout LyX-Code
+SECTION NAME=bank5 RAM=gpr5
+\end_layout
+
+\begin_layout Standard
+The linker will recognise the section name set in the pragma statement and
+ will position the variable at the memory bank set with the RAM field at
+ the SECTION line in the linker script file.
+\end_layout
+
+\begin_layout Subsection
+Header Files
+\begin_inset LatexCommand \label{sub:PIC16_Header-Files}
+
+\end_inset
+
+
+\end_layout
+
+\begin_layout Standard
+There is one main header file
+\begin_inset LatexCommand \index{PIC16!Header files}
+
+\end_inset
+
+ that can be included to the source files using the pic16
+\begin_inset LatexCommand \index{PIC16}
+
+\end_inset
+
+ port.
+ That file is the
+\series bold
+pic18fregs.h
+\series default
+.
+ This header file contains the definitions for the processor special registers,
+ so it is necessary if the source accesses them.
+ It can be included by adding the following line in the beginning of the
+ file:
+\end_layout
+
+\begin_layout LyX-Code
+#include <pic18fregs.h>
+\end_layout
+
+\begin_layout Standard
+The specific microcontroller is selected within the pic18fregs.h automatically,
+ so the same source can be used with a variety of devices.
+\end_layout
+
+\begin_layout Subsection
+Libraries
+\end_layout
+
+\begin_layout Standard
+The libraries
+\begin_inset LatexCommand \index{PIC16!Libraries}
+
+\end_inset
+
+ that PIC16
+\begin_inset LatexCommand \index{PIC16}
+
+\end_inset
+
+ port depends on are the microcontroller device libraries which contain
+ the symbol definitions for the microcontroller special function registers.
+ These libraries have the format pic18fxxxx.lib, where
+\emph on
+xxxx
+\emph default
+ is the microcontroller identification number.
+ The specific library is selected automatically by the compiler at link
+ stage according to the selected device.
+\end_layout
+
+\begin_layout Standard
+Libraries are created with gplib which is part of the gputils package
+\begin_inset LatexCommand \url{http://sourceforge.net/projects/gputils}
+
+\end_inset
+
+.
+\end_layout
+
+\begin_layout Subsubsection*
+Building the libraries
+\end_layout
+
+\begin_layout Standard
+Before using SDCC/pic16 there are some libraries that need to be compiled.
+ This process is not done automatically by SDCC since not all users use
+ SDCC for pic16 projects.
+ So each user should compile the libraries separately.
+\end_layout
+
+\begin_layout Standard
+The steps to compile the pic16 libraries under Linux and Mac OS X are:
+\end_layout
+
+\begin_layout LyX-Code
+cd device/lib/pic16
+\end_layout
+
+\begin_layout LyX-Code
+./configure
+\end_layout
+
+\begin_layout LyX-Code
+make
+\end_layout
+
+\begin_layout LyX-Code
+cd ..
+\end_layout
+
+\begin_layout LyX-Code
+make model-pic16
+\end_layout
+
+\begin_layout LyX-Code
+su -c 'make install' # install the libraries, you need the root password
+\end_layout
+
+\begin_layout Standard
+If you need to install the headers too, do:
+\end_layout
+
+\begin_layout LyX-Code
+cd device/include
+\end_layout
+
+\begin_layout LyX-Code
+su -c 'make install' # install the headers, you need the root password
+\end_layout
+
+\begin_layout Standard
+There exist a special target to build the I/O libraries.
+ This target is not automatically build because it will build the I/O library
+ for
+\emph on
+every
+\emph default
+ supported device.
+ This way building will take quite a lot of time.
+ Users are advised to edit the
+\series bold
+device/lib/pic16/pics.build
+\series default
+ file and then execute:
+\end_layout
+
+\begin_layout LyX-Code
+make lib-io
+\end_layout
+
+\begin_layout Subsection
+Adding New Devices to the Port
+\end_layout
+
+\begin_layout Standard
+Adding support for a new 16
+\begin_inset ERT
+status open
+
+\begin_layout Standard
+
+
+\backslash
+,
+\end_layout
+
+\end_inset
+
+bit PIC MCU requires the following steps:
+\end_layout
+
+\begin_layout Enumerate
+Create picDEVICE.c and picDEVICE.h from pDEVICE.inc using
+\newline
+
+\family typewriter
+perl /path/to/sdcc/support/scripts/inc2h-pic16.pl /path/to/gputils/header/pDEVICE.
+inc
+\end_layout
+
+\begin_layout Enumerate
+
+\family typewriter
+mv picDEVICE.h /path/to/sdcc/device/include/pic16
+\end_layout
+
+\begin_layout Enumerate
+
+\family typewriter
+mv picDEVICE.c /path/to/sdcc/device/lib/pic16/libdev
+\end_layout
+
+\begin_layout Enumerate
+Add DEVICE to
+\family typewriter
+/path/to/sdcc/device/lib/pics.all
+\family default
+ (and
+\family typewriter
+.build
+\family default
+).
+\newline
+Note: No 18f prefix here!
+\end_layout
+
+\begin_layout Enumerate
+Adjust
+\family typewriter
+/path/to/sdcc/device/lib/pic16/libio/*.ignore
+\family default
+
+\newline
+Add your DEVICE if it does not compile in
+\family typewriter
+adc
+\family default
+,
+\family typewriter
+i2c
+\family default
+, or
+\family typewriter
+usart
+\family default
+.
+\end_layout
+
+\begin_layout Enumerate
+Edit
+\family typewriter
+/path/to/sdcc/device/include/pic16/pic18fregs.h
+\family default
+.
+ The file format is self-explanatory, just add
+\newline
+
+\family typewriter
+#elif defined(picDEVICE)
+\newline
+# include <picDEVICE.h>
+\family default
+
+\newline
+at the right place (keep it sorted).
+\end_layout
+
+\begin_layout Enumerate
+Edit
+\family typewriter
+/path/to/sdcc/src/pic16/devices.inc
+\family default
+.
+ Copy and modify an existing entry and insert it at the correct place (keep
+ the file sorted).
+ The file is hardly documented, look at the entries for the 18f2221...
+\end_layout
+
+\begin_layout Enumerate
+Recompile SDCC, including the pic16 libraries.
+\end_layout
+
+\begin_layout Subsection
+Memory Models
+\end_layout
+
+\begin_layout Standard
+The following memory models are supported by the PIC16 port:
+\end_layout
+
+\begin_layout Itemize
+small model
+\end_layout
+
+\begin_layout Itemize
+large model
+\end_layout
+
+\begin_layout Standard
+Memory model affects the default size of pointers within the source.
+ The sizes are shown in the next table:
+\end_layout
+
+\begin_layout Standard
+\align center
+\begin_inset Tabular
+<lyxtabular version="3" rows="3" columns="3">
+<features>
+<column alignment="center" valignment="top" leftline="true" rightline="true" width="0">
+<column alignment="center" valignment="top" leftline="true" width="0">
+<column alignment="center" valignment="top" leftline="true" rightline="true" width="0">
+<row topline="true" bottomline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+Pointer sizes according to memory model
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+small model
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+large model
+\end_layout
+
+\end_inset
+</cell>
+</row>
+<row topline="true" bottomline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+code pointers
+\end_layout
+
+\end_inset
+</cell>
+<cell multicolumn="1" alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+16-bits
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+24-bits
+\end_layout
+
+\end_inset
+</cell>
+</row>
+<row topline="true" bottomline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+data pointers
+\end_layout
+
+\end_inset
+</cell>
+<cell multicolumn="1" alignment="center" valignment="top" topline="true" bottomline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+16-bits
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+16-bits
+\end_layout
+
+\end_inset
+</cell>
+</row>
+</lyxtabular>
+
+\end_inset
+
+
+\end_layout
+
+\begin_layout Standard
+It is advisable that all sources within a project are compiled with the
+ same memory model.
+ If one wants to override the default memory model, this can be done by
+ declaring a pointer as
+\series bold
+far
+\series default
+ or
+\series bold
+near
+\series default
+.
+ Far selects large memory model's pointers, while near selects small memory
+ model's pointers.
+\end_layout
+
+\begin_layout Standard
+The standard device libraries (see
+\begin_inset LatexCommand \ref{sub:PIC16_Header-Files}
+
+\end_inset
+
+) contain no reference to pointers, so they can be used with both memory
+ models.
+\end_layout
+
+\begin_layout Subsection
+Stack
+\end_layout
+
+\begin_layout Standard
+The stack
+\begin_inset LatexCommand \index{PIC16!stack}
+
+\end_inset
+
+ implementation for the PIC16 port uses two indirect registers, FSR1 and
+ FSR2.
+\end_layout
+
+\begin_layout Description
+FSR1 is assigned as stack pointer
+\end_layout
+
+\begin_layout Description
+FSR2 is assigned as frame pointer
+\end_layout
+
+\begin_layout Standard
+The following stack models are supported by the PIC16 port
+\end_layout
+
+\begin_layout Itemize
+
+\noun on
+small
+\noun default
+ model
+\end_layout
+
+\begin_layout Itemize
+
+\noun on
+large
+\noun default
+ model
+\end_layout
+
+\begin_layout Standard
+
+\noun on
+Small
+\noun default
+ model means that only the FSRxL byte is used to access stack and frame,
+ while
+\emph on
+\noun on
+large
+\emph default
+\noun default
+ uses both FSRxL and FSRxH registers.
+ The following table shows the stack/frame pointers sizes according to stack
+ model and the maximum space they can address:
+\end_layout
+
+\begin_layout Standard
+\align center
+\begin_inset Tabular
+<lyxtabular version="3" rows="3" columns="3">
+<features>
+<column alignment="center" valignment="top" leftline="true" rightline="true" width="0">
+<column alignment="center" valignment="top" leftline="true" width="0">
+<column alignment="center" valignment="top" leftline="true" rightline="true" width="0">
+<row topline="true" bottomline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+Stack & Frame pointer sizes according to stack model
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+small
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+large
+\end_layout
+
+\end_inset
+</cell>
+</row>
+<row topline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+Stack pointer FSR1
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+8-bits
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+16-bits
+\end_layout
+
+\end_inset
+</cell>
+</row>
+<row topline="true" bottomline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+Frame pointer FSR2
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+8-bits
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+16-bits
+\end_layout
+
+\end_inset
+</cell>
+</row>
+</lyxtabular>
+
+\end_inset
+
+
+\end_layout
+
+\begin_layout Standard
+
+\noun on
+Large
+\noun default
+stack model is currently not working properly throughout the code generator.
+ So its use is not advised.
+ Also there are some other points that need special care:
+\newline
+
+\end_layout
+
+\begin_layout Enumerate
+Do not create stack sections with size more than one physical bank (that
+ is 256 bytes)
+\end_layout
+
+\begin_layout Enumerate
+Stack sections should no cross physical bank limits (i.e.
+ #pragma stack 0x50 0x100)
+\end_layout
+
+\begin_layout Standard
+These limitations are caused by the fact that only FSRxL is modified when
+ using SMALL stack model, so no more than 256 bytes of stack can be used.
+ This problem will disappear after LARGE model is fully implemented.
+\end_layout
+
+\begin_layout Subsection
+Functions
+\end_layout
+
+\begin_layout Standard
+In addition to the standard SDCC function keywords, PIC16
+\begin_inset LatexCommand \index{PIC16}
+
+\end_inset
+
+ port makes available two more:
+\end_layout
+
+\begin_layout Description
+wparam
+\begin_inset LatexCommand \index{PIC16!wparam}
+
+\end_inset
+
+ Use the WREG to pass one byte of the first function argument.
+ This improves speed but you may not use this for functions with arguments
+ that are called via function pointers, otherwise the first byte of the
+ first parameter will get lost.
+ Usage:
+\end_layout
+
+\begin_layout LyX-Code
+void func_wparam(int a) wparam
+\end_layout
+
+\begin_layout LyX-Code
+{
+\end_layout
+
+\begin_layout LyX-Code
+ /* WREG hold the lower part of a */
+\end_layout
+
+\begin_layout LyX-Code
+ /* the high part of a is stored in FSR2+2 (or +3 for large stack model)
+ */
+\end_layout
+
+\begin_layout LyX-Code
+...
+\end_layout
+
+\begin_layout LyX-Code
+}
+\end_layout
+
+\begin_layout Description
+shadowregs
+\begin_inset LatexCommand \index{PIC16!shadowregs}
+
+\end_inset
+
+ When entering/exiting an ISR, it is possible to take advantage of the PIC18F
+ hardware shadow registers which hold the values of WREG, STATUS and BSR
+ registers.
+ This can be done by adding the keyword
+\emph on
+shadowregs
+\emph default
+ before the
+\emph on
+interrupt
+\emph default
+ keyword in the function's header.
+\end_layout
+
+\begin_layout LyX-Code
+void isr_shadow(void) shadowregs interrupt 1
+\end_layout
+
+\begin_layout LyX-Code
+{
+\end_layout
+
+\begin_layout LyX-Code
+...
+\end_layout
+
+\begin_layout LyX-Code
+}
+\end_layout
+
+\begin_layout Standard
+
+\emph on
+shadowregs
+\emph default
+ instructs the code generator not to store/restore WREG, STATUS, BSR when
+ entering/exiting the ISR.
+\end_layout
+
+\begin_layout Subsection
+Function return values
+\end_layout
+
+\begin_layout Standard
+Return values from functions are placed to the appropriate registers following
+ a modified Microchip policy optimized for SDCC.
+ The following table shows these registers:
+\end_layout
+
+\begin_layout Standard
+\align center
+\begin_inset Tabular
+<lyxtabular version="3" rows="6" columns="2">
+<features>
+<column alignment="center" valignment="top" leftline="true" width="0">
+<column alignment="center" valignment="top" leftline="true" rightline="true" width="0">
+<row topline="true" bottomline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+size
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+destination register
+\end_layout
+
+\end_inset
+</cell>
+</row>
+<row topline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+8 bits
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+WREG
+\end_layout
+
+\end_inset
+</cell>
+</row>
+<row topline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+16 bits
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+PRODL:WREG
+\end_layout
+
+\end_inset
+</cell>
+</row>
+<row topline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+24 bits
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+PRODH:PRODL:WREG
+\end_layout
+
+\end_inset
+</cell>
+</row>
+<row topline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+32 bits
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+FSR0L:PRODH:PRODL:WREG
+\end_layout
+
+\end_inset
+</cell>
+</row>
+<row topline="true" bottomline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+>32 bits
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+on stack, FSR0 points to the beginning
+\end_layout
+
+\end_inset
+</cell>
+</row>
+</lyxtabular>
+
+\end_inset
+
+
+\end_layout
+
+\begin_layout Subsection
+Interrupts
+\end_layout
+
+\begin_layout Standard
+An interrupt
+\begin_inset LatexCommand \index{PIC16!interrupt}
+
+\end_inset
+
+ service routine (ISR) is declared using the
+\emph on
+interrupt
+\emph default
+ keyword.
+\end_layout
+
+\begin_layout LyX-Code
+void isr(void) interrupt
+\emph on
+n
+\end_layout
+
+\begin_layout LyX-Code
+{
+\end_layout
+
+\begin_layout LyX-Code
+...
+\end_layout
+
+\begin_layout LyX-Code
+}
+\end_layout
+
+\begin_layout Standard
+
+\emph on
+n
+\emph default
+ is the interrupt number, which for PIC18F devices can be:
+\end_layout
+
+\begin_layout Standard
+\align center
+\begin_inset Tabular
+<lyxtabular version="3" rows="4" columns="3">
+<features>
+<column alignment="center" valignment="top" leftline="true" width="0">
+<column alignment="center" valignment="top" leftline="true" width="0">
+<column alignment="center" valignment="top" leftline="true" rightline="true" width="0">
+<row topline="true" bottomline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+
+\emph on
+n
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+Interrupt Vector
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+Interrupt Vector Address
+\end_layout
+
+\end_inset
+</cell>
+</row>
+<row topline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+0
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+RESET vector
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+0x000000
+\end_layout
+
+\end_inset
+</cell>
+</row>
+<row topline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+
+\family roman
+\series medium
+\shape up
+\size normal
+\emph off
+\bar no
+\noun off
+\color none
+1
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+
+\family roman
+\series medium
+\shape up
+\size normal
+\emph off
+\bar no
+\noun off
+\color none
+HIGH priority interrupts
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+0x000008
+\end_layout
+
+\end_inset
+</cell>
+</row>
+<row topline="true" bottomline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+2
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+LOW priority interrupts
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+0x000018
+\end_layout
+
+\end_inset
+</cell>
+</row>
+</lyxtabular>
+
+\end_inset
+
+
+\end_layout
+
+\begin_layout Standard
+When generating assembly code for ISR the code generator places a
+\noun on
+goto
+\noun default
+instruction at the
+\emph on
+Interrupt Vector Address
+\emph default
+ which points at the genetated ISR.
+ This single GOTO instruction is part of an automatically generated
+\emph on
+interrupt entry point
+\emph default
+ function.
+ The actuall ISR code is placed as normally would in the code space.
+ Upon interrupt request, the GOTO instruction is executed which jumps to
+ the ISR code.
+ When declaring interrupt functions as _naked this GOTO instruction is
+\series bold
+not
+\series default
+ generated.
+ The whole interrupt functions is therefore placed at the Interrupt Vector
+ Address of the specific interrupt.
+ This is not a problem for the LOW priority interrupts, but it is a problem
+ for the RESET and the HIGH priority interrupts because code may be written
+ at the next interrupt's vector address and cause undeterminate program
+ behaviour if that interrupt is raised.
+\begin_inset Foot
+status open
+
+\begin_layout Standard
+This is not a problem when
+\end_layout
+
+\begin_layout Enumerate
+this is a HIGH interrupt ISR and LOW interrupts are
+\emph on
+disabled
+\emph default
+ or not used.
+\end_layout
+
+\begin_layout Enumerate
+when the ISR is small enough not to reach the next interrupt's vector address.
+\end_layout
+
+\end_inset
+
+
+\end_layout
+
+\begin_layout Standard
+
+\emph on
+n
+\emph default
+ may be omitted.
+ This way a function is generated similar to an ISR, but it is not assigned
+ to any interrupt.
+\end_layout
+
+\begin_layout Standard
+When entering an interrupt, currently the PIC16
+\begin_inset LatexCommand \index{PIC16}
+
+\end_inset
+
+ port automatically saves the following registers:
+\end_layout
+
+\begin_layout Itemize
+WREG
+\end_layout
+
+\begin_layout Itemize
+STATUS
+\end_layout
+
+\begin_layout Itemize
+BSR
+\end_layout
+
+\begin_layout Itemize
+PROD (PRODL and PRODH)
+\end_layout
+
+\begin_layout Itemize
+FSR0 (FSR0L and FSR0H)
+\end_layout
+
+\begin_layout Standard
+These registers are restored upon return from the interrupt routine.
+\begin_inset Foot
+status open
+
+\begin_layout Standard
+NOTE that when the _naked attribute is specified for an interrupt routine,
+ then NO registers are stored or restored.
+\end_layout
+
+\end_inset
+
+
+\end_layout
+
+\begin_layout Subsection
+Generic Pointers
+\end_layout
+
+\begin_layout Standard
+Generic pointers are implemented in PIC16 port as 3-byte (24-bit) types.
+ There are 3 types of generic pointers currently implemented data, code
+ and eeprom pointers.
+ They are differentiated by the value of the 7th and 6th bits of the upper
+ byte:
+\end_layout
+
+\begin_layout Standard
+\align center
+\begin_inset Tabular
+<lyxtabular version="3" rows="5" columns="5">
+<features>
+<column alignment="center" valignment="top" leftline="true" rightline="true" width="0">
+<column alignment="center" valignment="top" width="0">
+<column alignment="center" valignment="top" leftline="true" rightline="true" width="0">
+<column alignment="center" valignment="top" width="0">
+<column alignment="left" valignment="top" rightline="true" width="0">
+<row topline="true" bottomline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+pointer type
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+7th bit
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+6th bit
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+rest of the pointer
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+description
+\end_layout
+
+\end_inset
+</cell>
+</row>
+<row topline="true" bottomline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+data
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+1
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+0
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+
+\family typewriter
+\shape slanted
+\emph on
+uuuuuu uuuuxxxx xxxxxxxx
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+a 12-bit data pointer in data RAM memory
+\end_layout
+
+\end_inset
+</cell>
+</row>
+<row bottomline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+code
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+0
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+0
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+
+\family typewriter
+\shape slanted
+\emph on
+uxxxxx xxxxxxxx xxxxxxxx
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+a 21-bit code pointer in FLASH memory
+\end_layout
+
+\end_inset
+</cell>
+</row>
+<row bottomline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+eeprom
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+0
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+1
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+
+\family typewriter
+\shape slanted
+\emph on
+uuuuuu uuuuuuxx xxxxxxxx
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+a 10-bit eeprom pointer in EEPROM memory
+\end_layout
+
+\end_inset
+</cell>
+</row>
+<row bottomline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+(unimplemented)
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+1
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+1
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+
+\family typewriter
+\shape slanted
+\emph on
+xxxxxx xxxxxxxx xxxxxxxx
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+unimplemented pointer type
+\end_layout
+
+\end_inset
+</cell>
+</row>
+</lyxtabular>
+
+\end_inset
+
+
+\end_layout
+
+\begin_layout Standard
+Generic pointer are read and written with a set of library functions which
+ read/write 1, 2, 3, 4 bytes.
+\end_layout
+
+\begin_layout Subsection
+PIC16 C Libraries
+\end_layout
+
+\begin_layout Subsubsection
+Standard I/O Streams
+\end_layout
+
+\begin_layout Standard
+In the
+\emph on
+stdio.h
+\emph default
+ the type FILE is defined as:
+\end_layout
+
+\begin_layout LyX-Code
+typedef char * FILE;
+\end_layout
+
+\begin_layout Standard
+This type is the stream type implemented I/O in the PIC18F devices.
+ Also the standard input and output streams are declared in stdio.h:
+\end_layout
+
+\begin_layout LyX-Code
+extern FILE * stdin;
+\end_layout
+
+\begin_layout LyX-Code
+extern FILE * stdout;
+\end_layout
+
+\begin_layout Standard
+The FILE type is actually a generic pointer which defines one more type
+ of generic pointers, the
+\emph on
+stream
+\emph default
+pointer.
+ This new type has the format:
+\end_layout
+
+\begin_layout Standard
+\align center
+\begin_inset Tabular
+<lyxtabular version="3" rows="2" columns="7">
+<features>
+<column alignment="center" valignment="top" leftline="true" rightline="true" width="0">
+<column alignment="center" valignment="top" width="0">
+<column alignment="center" valignment="top" leftline="true" width="0">
+<column alignment="center" valignment="top" leftline="true" width="0">
+<column alignment="center" valignment="top" leftline="true" rightline="true" width="0">
+<column alignment="center" valignment="top" width="0">
+<column alignment="left" valignment="top" rightline="true" width="0">
+<row topline="true" bottomline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+pointer type
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+<7:6>
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+<5>
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+<4>
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+<3:0>
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+rest of the pointer
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+descrption
+\end_layout
+
+\end_inset
+</cell>
+</row>
+<row topline="true" bottomline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+stream
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+00
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+1
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+0
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+nnnn
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+
+\family typewriter
+\shape slanted
+\emph on
+uuuuuuuu uuuuuuuu
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+upper byte high nubble is 0x2n, the rest are zeroes
+\end_layout
+
+\end_inset
+</cell>
+</row>
+</lyxtabular>
+
+\end_inset
+
+
+\end_layout
+
+\begin_layout Standard
+Currently implemented there are 3 types of streams defined:
+\end_layout
+
+\begin_layout Standard
+\align center
+\begin_inset Tabular
+<lyxtabular version="3" rows="4" columns="4">
+<features>
+<column alignment="center" valignment="top" leftline="true" width="0">
+<column alignment="center" valignment="top" leftline="true" width="0">
+<column alignment="center" valignment="top" leftline="true" width="0">
+<column alignment="center" valignment="top" leftline="true" rightline="true" width="0">
+<row topline="true" bottomline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+stream type
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+value
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+module
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+description
+\end_layout
+
+\end_inset
+</cell>
+</row>
+<row topline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+STREAM_USART
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+
+\family typewriter
+0x200000UL
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+USART
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+Writes/Reads characters via the USART peripheral
+\end_layout
+
+\end_inset
+</cell>
+</row>
+<row topline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+STREAM_MSSP
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+
+\family typewriter
+0x210000UL
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+MSSP
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+Writes/Reads characters via the MSSP peripheral
+\end_layout
+
+\end_inset
+</cell>
+</row>
+<row topline="true" bottomline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+STREAM_USER
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+
+\family typewriter
+0x2f0000UL
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+(none)
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+Writes/Reads characters via used defined functions
+\end_layout
+
+\end_inset
+</cell>
+</row>
+</lyxtabular>
+
+\end_inset
+
+
+\end_layout
+
+\begin_layout Standard
+The stream identifiers are declared as macros in the stdio.h header.
+\end_layout
+
+\begin_layout Standard
+In the libc library there exist the functions that are used to write to
+ each of the above streams.
+ These are
+\end_layout
+
+\begin_layout Description
+_
+\begin_inset ERT
+status collapsed
+
+\begin_layout Standard
+
+
+\backslash
+/
+\end_layout
+
+\end_inset
+
+_stream_usart_putchar writes a character at the USART stream
+\end_layout
+
+\begin_layout Description
+_
+\begin_inset ERT
+status collapsed
+
+\begin_layout Standard
+
+
+\backslash
+/
+\end_layout
+
+\end_inset
+
+_stream_mssp_putchar writes a character at the MSSP stream
+\end_layout
+
+\begin_layout Description
+putchar dummy function.
+ This writes a character to a user specified manner.
+\end_layout
+
+\begin_layout Standard
+In order to increase performance
+\emph on
+putchar
+\emph default
+is declared in stdio.h as having its parameter in WREG (it has the wparam
+ keyword).
+ In stdio.h exists the macro PUTCHAR(arg) that defines the putchar function
+ in a user-friendly way.
+
+\emph on
+arg
+\emph default
+ is the name of the variable that holds the character to print.
+ An example follows:
+\end_layout
+
+\begin_layout LyX-Code
+#include <pic18fregs.h>
+\newline
+#include <stdio.h>
+\newline
+
+\newline
+PUTCHAR( c )
+\end_layout
+
+\begin_layout LyX-Code
+{
+\end_layout
+
+\begin_layout LyX-Code
+ PORTA = c; /* dump character c to PORTA */
+\end_layout
+
+\begin_layout LyX-Code
+}
+\newline
+
+\newline
+void main(void)
+\end_layout
+
+\begin_layout LyX-Code
+{
+\end_layout
+
+\begin_layout LyX-Code
+ stdout = STREAM_USER; /* this is not necessary, since stdout points
+\end_layout
+
+\begin_layout LyX-Code
+ * by default to STREAM_USER */
+\end_layout
+
+\begin_layout LyX-Code
+ printf (
+\begin_inset Quotes sld
+\end_inset
+
+This is a printf test
+\backslash
+n
+\begin_inset Quotes srd
+\end_inset
+
+);
+\end_layout
+
+\begin_layout LyX-Code
+}
+\end_layout
+
+\begin_layout LyX-Code
+
+\end_layout
+
+\begin_layout Subsubsection
+Printing functions
+\end_layout
+
+\begin_layout Standard
+PIC16 contains an implementation of the printf-family of functions.
+ There exist the following functions:
+\end_layout
+
+\begin_layout LyX-Code
+extern unsigned int sprintf(char *buf, char *fmt, ...);
+\end_layout
+
+\begin_layout LyX-Code
+extern unsigned int vsprintf(char *buf, char *fmt, va_list ap);
+\end_layout
+
+\begin_layout LyX-Code
+
+\end_layout
+
+\begin_layout LyX-Code
+extern unsigned int printf(char *fmt, ...);
+\end_layout
+
+\begin_layout LyX-Code
+extern unsigned int vprintf(char *fmt, va_lista ap);
+\end_layout
+
+\begin_layout LyX-Code
+
+\end_layout
+
+\begin_layout LyX-Code
+extern unsigned int fprintf(FILE *fp, char *fmt, ...);
+\end_layout
+
+\begin_layout LyX-Code
+extern unsigned int vfprintf(FILE *fp, char *fmt, va_list ap);
+\end_layout
+
+\begin_layout Standard
+For sprintf and vsprintf
+\emph on
+buf
+\emph default
+should normally be a data pointer where the resulting string will be placed.
+ No range checking is done so the user should allocate the necessery buffer.
+ For fprintf and vfprintf
+\emph on
+fp
+\emph default
+ should be a stream pointer (i.e.
+ stdout, STREAM_MSSP, etc...).
+\end_layout
+
+\begin_layout Subsubsection
+Signals
+\end_layout
+
+\begin_layout Standard
+The PIC18F family of microcontrollers supports a number of interrupt sources.
+ A list of these interrupts is shown in the following table:
+\end_layout
+
+\begin_layout Standard
+\align center
+\begin_inset Tabular
+<lyxtabular version="3" rows="11" columns="4">
+<features>
+<column alignment="left" valignment="top" leftline="true" width="0">
+<column alignment="center" valignment="top" leftline="true" rightline="true" width="0">
+<column alignment="left" valignment="top" leftline="true" width="0">
+<column alignment="center" valignment="top" leftline="true" rightline="true" width="0">
+<row topline="true" bottomline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+signal name
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+description
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+signal name
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+descritpion
+\end_layout
+
+\end_inset
+</cell>
+</row>
+<row topline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+SIG_RB
+\end_layout
+
+\end_inset
+</cell>
+<cell multicolumn="1" alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+PORTB change interrupt
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+SIG_EE
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+EEPROM/FLASH write complete interrupt
+\end_layout
+
+\end_inset
+</cell>
+</row>
+<row topline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+SIG_INT0
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+INT0 external interrupt
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+SIG_BCOL
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+Bus collision interrupt
+\end_layout
+
+\end_inset
+</cell>
+</row>
+<row topline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+SIG_INT1
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+INT1 external interrupt
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+SIG_LVD
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+Low voltage detect interrupt
+\end_layout
+
+\end_inset
+</cell>
+</row>
+<row topline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+SIG_INT2
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+INT2 external interrupt
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+SIG_PSP
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+Parallel slave port interrupt
+\end_layout
+
+\end_inset
+</cell>
+</row>
+<row topline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+SIG_CCP1
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+CCP1 module interrupt
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+SIG_AD
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+AD convertion complete interrupt
+\end_layout
+
+\end_inset
+</cell>
+</row>
+<row topline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+SIG_CCP2
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+CCP2 module interrupt
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+SIG_RC
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+USART receive interrupt
+\end_layout
+
+\end_inset
+</cell>
+</row>
+<row topline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+SIG_TMR0
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+TMR0 overflow interrupt
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+SIG_TX
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+USART transmit interrupt
+\end_layout
+
+\end_inset
+</cell>
+</row>
+<row topline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+SIG_TMR1
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+TMR1 overflow interrupt
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+SIG_MSSP
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+SSP receive/transmit interrupt
+\end_layout
+
+\end_inset
+</cell>
+</row>
+<row topline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+SIG_TMR2
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+TMR2 matches PR2 interrupt
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+
+\end_layout
+
+\end_inset
+</cell>
+</row>
+<row topline="true" bottomline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+SIG_TMR3
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+TMR3 overflow interrupt
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+
+\end_layout
+
+\end_inset
+</cell>
+</row>
+</lyxtabular>
+
+\end_inset
+
+
+\end_layout
+
+\begin_layout Standard
+The prototypes for these names are defined in the header file
+\emph on
+signal.h
+\emph default
+ .
+\end_layout
+
+\begin_layout Standard
+In order to simplify signal handling, a number of macros is provided:
+\end_layout
+
+\begin_layout List
+\labelwidthstring 00.00.0000
+DEF_INTHIGH(name) begin the definition of the interrupt dispatch table for
+ high priority interrupts.
+
+\emph on
+name
+\emph default
+ is the function name to use.
+\end_layout
+
+\begin_layout List
+\labelwidthstring 00.00.0000
+DEF_INTLOW(name) begin the definition of the interrupt dispatch table fo
+ low priority interrupt.
+
+\emph on
+name
+\emph default
+ is the function name to use.
+\end_layout
+
+\begin_layout List
+\labelwidthstring 00.00.0000
+DEF_HANDLER(sig,handler) define a handler for signal
+\emph on
+sig.
+\end_layout
+
+\begin_layout List
+\labelwidthstring 00.00.0000
+END_DEF end the declaration of the dispatch table.
+\end_layout
+
+\begin_layout Standard
+Additionally there are two more macros to simplify the declaration of the
+ signal handler:
+\end_layout
+
+\begin_layout List
+\labelwidthstring 00.00.0000
+
+\series medium
+SIGHANDLER(handler)
+\series default
+this declares the function prototype for the
+\emph on
+handler
+\emph default
+ function.
+\end_layout
+
+\begin_layout List
+\labelwidthstring 00.00.0000
+SIGHANDLERNAKED(handler) same as SIGHANDLER() but declares a naked function.
+\end_layout
+
+\begin_layout Standard
+An example of using the macros above is shown below:
+\end_layout
+
+\begin_layout LyX-Code
+#include <pic18fregs.h>
+\end_layout
+
+\begin_layout LyX-Code
+#include <signal.h>
+\newline
+
+\newline
+DEF_INTHIGH(high_int)
+\end_layout
+
+\begin_layout LyX-Code
+DEF_HANDLER(SIG_TMR0, _tmr0_handler)
+\end_layout
+
+\begin_layout LyX-Code
+DEF_HANDLER(SIG_BCOL, _bcol_handler)
+\end_layout
+
+\begin_layout LyX-Code
+END_DEF
+\newline
+
+\newline
+SIGHANDLER(_tmr0_handler)
+\end_layout
+
+\begin_layout LyX-Code
+{
+\end_layout
+
+\begin_layout LyX-Code
+ /* action to be taken when timer 0 overflows */
+\end_layout
+
+\begin_layout LyX-Code
+}
+\newline
+
+\newline
+SIGHANDLERNAKED(_bcol_handler)
+\end_layout
+
+\begin_layout LyX-Code
+{
+\end_layout
+
+\begin_layout LyX-Code
+ _asm
+\end_layout
+
+\begin_layout LyX-Code
+ /* action to be taken when bus collision occurs */
+\end_layout
+
+\begin_layout LyX-Code
+ retfie
+\end_layout
+
+\begin_layout LyX-Code
+ _endasm;
+\end_layout
+
+\begin_layout LyX-Code
+}
+\end_layout
+
+\begin_layout Standard
+
+\series bold
+NOTES:
+\series default
+ Special care should be taken when using the above scheme:
+\end_layout
+
+\begin_layout Itemize
+do not place a colon (;) at the end of the DEF_* and END_DEF macros.
+\end_layout
+
+\begin_layout Itemize
+when declaring SIGHANDLERNAKED handler never forget to use
+\emph on
+retfie
+\emph default
+ for proper returning.
+\end_layout
+
+\begin_layout Subsection
+PIC16 Port -- Tips
+\end_layout
+
+\begin_layout Standard
+Here you can find some general tips for compiling programs with SDCC/pic16.
+\end_layout
+
+\begin_layout Subsubsection
+Stack size
+\end_layout
+
+\begin_layout Standard
+The default stack
+\begin_inset LatexCommand \index{PIC16!stack}
+
+\end_inset
+
+ size (that is 64 bytes) probably is enough for many programs.
+ One must take care that when there are many levels of function nesting,
+ or there is excessive usage of stack, its size should be extended.
+ An example of such a case is the printf/sprintf family of functions.
+ If you encounter problems like not being able to print integers, then you
+ need to set the stack size around the maximum (256 for small stack model).
+ The following diagram shows what happens when calling printf to print an
+ integer:
+\end_layout
+
+\begin_layout LyX-Code
+printf () --> ltoa () --> ultoa () --> divschar ()
+\end_layout
+
+\begin_layout Standard
+It is should be understood that stack is easily consumed when calling complicate
+d functions.
+ Using command line arguments like -
+\begin_inset ERT
+status collapsed
+
+\begin_layout Standard
+
+
+\backslash
+/
+\end_layout
+
+\end_inset
+
+-fommit-frame-pointer might reduce stack usage by not creating unnecessery
+ stack frames.
+ Other ways to reduce stack usage may exist.
+\end_layout
+
+\begin_layout Subsection
+Known Bugs
+\end_layout
+
+\begin_layout Standard
+The PIC16 Port currently does not pass SDCC's regression test
+\begin_inset LatexCommand \index{Regression test (PIC16)}
+
+\end_inset
+
+ suite (see section
+\begin_inset LatexCommand \ref{sec:Quality-control}
+
+\end_inset
+
+) and thus the snapshot build regression tests for the PIC16 target are
+ currently disabled for all hosts
+\emph on
+.
+\end_layout
+
+\begin_layout Chapter
+Debugging
+\end_layout
+
+\begin_layout Standard
+There are several approaches to debugging your code.
+ This chapter is meant to show your options and to give detail on some of
+ them:
+\newline
+
+\newline
+When writing your code:
+\end_layout
+
+\begin_layout Itemize
+write your code with debugging in mind (avoid duplicating code, put conceptually
+ similar variables into structs, use structured code, have strategic points
+ within your code where all variables are consistent, ...)
+\end_layout
+
+\begin_layout Itemize
+run a syntax-checking tool like splint
+\begin_inset LatexCommand \index{splint (syntax checking tool)}
+
+\end_inset
+
+
+\begin_inset LatexCommand \index{lint (syntax checking tool)}
+
+\end_inset
+
+ (see -
+\begin_inset ERT
+status collapsed
+
+\begin_layout Standard
+
+
+\backslash
+/
+\end_layout
+
+\end_inset
+
+-more-pedantic
+\begin_inset LatexCommand \ref{lyx:more-pedantic-SPLINT}
+
+\end_inset
+
+) over the code.
+\end_layout
+
+\begin_layout Itemize
+for the high level code use a C-compiler (like f.e.
+ GCC) to compile run and debug the code on your host.
+ See (see -
+\begin_inset ERT
+status collapsed
+
+\begin_layout Standard
+
+
+\backslash
+/
+\end_layout
+
+\end_inset
+
+-more-pedantic
+\begin_inset LatexCommand \ref{lyx:more-pedantic-SPLINT}
+
+\end_inset
+
+) on how to handle syntax extensions like __xdata, __at(), ...
+
+\end_layout
+
+\begin_layout Itemize
+use another C-compiler to compile code for your target.
+ Always an option but not recommended:) And not very likely to help you.
+ If you seriously consider walking this path you should at least occasionally
+ check portability of your code.
+ Most commercial compiler vendors will offer an evaluation version so you
+ can test compile your code or snippets of your code.
+\end_layout
+
+\begin_layout Standard
+Debugging on a simulator:
+\end_layout
+
+\begin_layout Itemize
+there is a separate section about SDCDB (section
+\begin_inset LatexCommand \ref{cha:Debugging-with-SDCDB}
+
+\end_inset
+
+) below.
+\end_layout
+
+\begin_layout Itemize
+or (8051 specific) use a freeware/commercial simulator which interfaces
+ to the AOMF
+\begin_inset LatexCommand \index{AOMF, AOMF51}
+
+\end_inset
+
+ file (see
+\begin_inset LatexCommand \ref{OMF file}
+
+\end_inset
+
+) optionally generated by SDCC.
+\end_layout
+
+\begin_layout Standard
+Debugging On-target:
+\end_layout
+
+\begin_layout Itemize
+use a MCU port pin to serially output debug data to the RS232 port of your
+ host.
+ You'll probably want some level shifting device typically involving a MAX232
+ or similar IC.
+ If the hardware serial port of the MCU is not available search for 'Software
+ UART' in your favourite search machine.
+\end_layout
+
+\begin_layout Itemize
+use an on-target monitor.
+ In this context a monitor is a small program which usually accepts commands
+ via a serial line and allows to set program counter, to single step through
+ a program and read/write memory locations.
+ For the 8051 good examples of monitors are paulmon and cmon51 (see section
+
+\begin_inset LatexCommand \ref{sec:Related-open-source-tools}
+
+\end_inset
+
+).
+\end_layout
+
+\begin_layout Itemize
+toggle MCU port pins at strategic points within your code and use an oscilloscop
+e.
+ A
+\emph on
+digital oscilloscope
+\emph default
+
+\begin_inset LatexCommand \index{Oscilloscope}
+
+\end_inset
+
+ with deep trace memory is really helpful especially if you have to debug
+ a realtime application.
+ If you need to monitor more pins than your oscilloscope provides you can
+ sometimes get away with a small R-2R network.
+ On a single channel oscilloscope you could f.e.
+ monitor 2 push-pull driven pins by connecting one via a 10\InsetSpace ~
+k
+\begin_inset Formula $\Omega$
+\end_inset
+
+ resistor and the other one by a 5\InsetSpace ~
+k
+\begin_inset Formula $\Omega$
+\end_inset
+
+ resistor to the oscilloscope probe (check output drive capability of the
+ pins you want to monitor).
+ If you need to monitor many more pins a
+\emph on
+logic analyzer
+\emph default
+ will be handy.
+\end_layout
+
+\begin_layout Itemize
+use an ICE (
+\emph on
+i
+\emph default
+n
+\emph on
+c
+\emph default
+ircuit
+\emph on
+e
+\emph default
+mulator
+\begin_inset LatexCommand \index{ICE (in circuit emulator)}
+
+\end_inset
+
+).
+ Usually very expensive.
+ And very nice to have too.
+ And usually locks you (for years...) to the devices the ICE can emulate.
+
+\end_layout
+
+\begin_layout Itemize
+use a remote debugger.
+ In most 8-bit systems the symbol information is not available on the target,
+ and a complete debugger is too bulky for the target system.
+ Therefore usually a debugger on the host system connects to an on-target
+ debugging stub which accepts only primitive commands.
+
+\newline
+Terms to enter into your favourite search engine could be 'remote debugging',
+ 'gdb stub' or 'inferior debugger'.
+ (is there one?)
+\end_layout
+
+\begin_layout Itemize
+use an on target hardware debugger.
+ Some of the more modern MCUs include hardware support for setting break
+ points and monitoring/changing variables by using dedicated hardware pins.
+ This facility doesn't require additional code to run on the target and
+
+\emph on
+usually
+\emph default
+ doesn't affect runtime behaviour until a breakpoint is hit.
+ For the mcs51 most hardware debuggers use the AOMF
+\begin_inset LatexCommand \index{AOMF, AOMF51}
+
+\end_inset
+
+ file (see
+\begin_inset LatexCommand \ref{OMF file}
+
+\end_inset
+
+) as input file.
+
+\end_layout
+
+\begin_layout Standard
+Last not least:
+\end_layout
+
+\begin_layout Itemize
+if you are not familiar with any of the following terms you're likely to
+ run into problems rather sooner than later:
+\emph on
+volatile
+\emph default
+,
+\emph on
+atomic
+\emph default
+,
+\emph on
+memory map
+\emph default
+,
+\emph on
+overlay
+\emph default
+.
+ As an embedded programmer you
+\emph on
+have
+\emph default
+ to know them so why not look them up
+\emph on
+before
+\emph default
+ you have problems?)
+\end_layout
+
+\begin_layout Itemize
+tell someone else about your problem (actually this is a surprisingly effective
+ means to hunt down the bug even if the listener is not familiar with your
+ environment).
+ As 'failure to communicate' is probably one of the job-induced deformations
+ of an embedded programmer this is highly encouraged.
+\end_layout
+
+\begin_layout Section
+Debugging with SDCDB
+\begin_inset LatexCommand \label{cha:Debugging-with-SDCDB}
+
+\end_inset
+
+
+\begin_inset LatexCommand \index{SDCDB (debugger)}
+
+\end_inset
+
+
+\end_layout
+
+\begin_layout Standard
+SDCC is distributed with a source level debugger
+\begin_inset LatexCommand \index{Debugger}
+
+\end_inset
+
+.
+ The debugger uses a command line interface, the command repertoire of the
+ debugger has been kept as close to gdb
+\begin_inset LatexCommand \index{gdb}
+
+\end_inset
+
+ (the GNU debugger) as possible.
+ The configuration and build process is part of the standard compiler installati
+on, which also builds and installs the debugger in the target directory
+ specified during configuration.
+ The debugger allows you debug BOTH at the C source and at the ASM source
+ level.
+\end_layout
+
+\begin_layout Subsection
+Compiling for Debugging
+\end_layout
+
+\begin_layout Standard
+The -
+\begin_inset ERT
+status collapsed
+
+\begin_layout Standard
+
+
+\backslash
+/
+\end_layout
+
+\end_inset
+
+-debug
+\begin_inset LatexCommand \index{-\/-debug}
+
+\end_inset
+
+ option must be specified for all files for which debug information is to
+ be generated.
+ The compiler generates a .adb file for each of these files.
+ The linker creates the .cdb
+\begin_inset LatexCommand \index{<file>.cdb}
+
+\end_inset
+
+ file from the .adb
+\begin_inset LatexCommand \index{<file>.adb}
+
+\end_inset
+
+ files and the address information.
+ This .cdb is used by the debugger.
+\end_layout
+
+\begin_layout Subsection
+How the Debugger Works
+\end_layout
+
+\begin_layout Standard
+When the -
+\begin_inset ERT
+status collapsed
+
+\begin_layout Standard
+
+
+\backslash
+/
+\end_layout
+
+\end_inset
+
+-debug option is specified the compiler generates extra symbol information
+ some of which are put into the assembler source and some are put into the
+ .adb file.
+ Then the linker creates the .cdb file from the individual .adb files with
+ the address information for the symbols.
+ The debugger reads the symbolic information generated by the compiler &
+ the address information generated by the linker.
+ It uses the SIMULATOR (Daniel's S51) to execute the program, the program
+ execution is controlled by the debugger.
+ When a command is issued for the debugger, it translates it into appropriate
+ commands for the simulator.
+ (Currently SDCDM only connects to the simulator but
+\emph on
+newcdb
+\emph default
+ at
+\begin_inset LatexCommand \url{http://ec2drv.sf.net/}
+
+\end_inset
+
+ is an effort to connect directly to the hardware.)
+\end_layout
+
+\begin_layout Subsection
+Starting the Debugger SDCDB
+\end_layout
+
+\begin_layout Standard
+The debugger can be started using the following command line.
+ (Assume the file you are debugging has the file name foo).
+\newline
+
+\newline
+
+\family sans
+\series bold
+sdcdb foo
+\newline
+
+\family default
+\series default
+
+\newline
+The debugger will look for the following files.
+\end_layout
+
+\begin_layout Itemize
+foo.c - the source file.
+\end_layout
+
+\begin_layout Itemize
+foo.cdb - the debugger symbol information file.
+\end_layout
+
+\begin_layout Itemize
+foo.ihx - the Intel hex format
+\begin_inset LatexCommand \index{Intel hex format}
+
+\end_inset
+
+ object file.
+\end_layout
+
+\begin_layout Subsection
+SDCDB Command Line Options
+\end_layout
+
+\begin_layout Itemize
+-
+\begin_inset ERT
+status collapsed
+
+\begin_layout Standard
+
+
+\backslash
+/
+\end_layout
+
+\end_inset
+
+-directory=<source file directory> this option can used to specify the directory
+ search list.
+ The debugger will look into the directory list specified for source, cdb
+ & ihx files.
+ The items in the directory list must be separated by ':', e.g.
+ if the source files can be in the directories /home/src1 and /home/src2,
+ the -
+\begin_inset ERT
+status collapsed
+
+\begin_layout Standard
+
+
+\backslash
+/
+\end_layout
+
+\end_inset
+
+-directory option should be -
+\begin_inset ERT
+status collapsed
+
+\begin_layout Standard
+
+
+\backslash
+/
+\end_layout
+
+\end_inset
+
+-directory=/home/src1:/home/src2.
+ Note there can be no spaces in the option.
+
+\end_layout
+
+\begin_layout Itemize
+-cd <directory> - change to the <directory>.
+\end_layout
+
+\begin_layout Itemize
+-fullname - used by GUI front ends.
+\end_layout
+
+\begin_layout Itemize
+-cpu <cpu-type> - this argument is passed to the simulator please see the
+ simulator docs for details.
+\end_layout
+
+\begin_layout Itemize
+-X <Clock frequency > this options is passed to the simulator please see
+ the simulator docs for details.
+\end_layout
+
+\begin_layout Itemize
+-s <serial port file> passed to simulator see the simulator docs for details.
+\end_layout
+
+\begin_layout Itemize
+-S <serial in,out> passed to simulator see the simulator docs for details.
+\end_layout
+
+\begin_layout Itemize
+-k <port number> passed to simulator see the simulator docs for details.
+\end_layout
+
+\begin_layout Subsection
+SDCDB Debugger Commands
+\end_layout
+
+\begin_layout Standard
+As mentioned earlier the command interface for the debugger has been deliberatel
+y kept as close the GNU debugger gdb, as possible.
+ This will help the integration with existing graphical user interfaces
+ (like ddd, xxgdb or xemacs) existing for the GNU debugger.
+ If you use a graphical user interface for the debugger you can skip this
+ section.
+\end_layout
+
+\begin_layout Subsubsection*
+break [line | file:line | function | file:function]
+\end_layout
+
+\begin_layout Standard
+Set breakpoint at specified line or function:
+\newline
+
+\newline
+
+\family sans
+\series bold
+sdcdb>break 100
+\newline
+sdcdb>break foo.c:100
+\newline
+sdcdb>break funcfoo
+\newline
+sdcdb>break foo.c:funcfoo
+\end_layout
+
+\begin_layout Subsubsection*
+clear [line | file:line | function | file:function ]
+\end_layout
+
+\begin_layout Standard
+Clear breakpoint at specified line or function:
+\newline
+
+\newline
+
+\family sans
+\series bold
+sdcdb>clear 100
+\newline
+sdcdb>clear foo.c:100
+\newline
+sdcdb>clear funcfoo
+\newline
+sdcdb>clear foo.c:funcfoo
+\end_layout
+
+\begin_layout Subsubsection*
+continue
+\end_layout
+
+\begin_layout Standard
+Continue program being debugged, after breakpoint.
+\end_layout
+
+\begin_layout Subsubsection*
+finish
+\end_layout
+
+\begin_layout Standard
+Execute till the end of the current function.
+\end_layout
+
+\begin_layout Subsubsection*
+delete [n]
+\end_layout
+
+\begin_layout Standard
+Delete breakpoint number 'n'.
+ If used without any option clear ALL user defined break points.
+\end_layout
+
+\begin_layout Subsubsection*
+info [break | stack | frame | registers ]
+\end_layout
+
+\begin_layout Itemize
+info break - list all breakpoints
+\end_layout
+
+\begin_layout Itemize
+info stack - show the function call stack.
+\end_layout
+
+\begin_layout Itemize
+info frame - show information about the current execution frame.
+\end_layout
+
+\begin_layout Itemize
+info registers - show content of all registers.
+\end_layout
+
+\begin_layout Subsubsection*
+step
+\end_layout
+
+\begin_layout Standard
+Step program until it reaches a different source line.
+ Note: pressing <return> repeats the last command.
+\end_layout
+
+\begin_layout Subsubsection*
+next
+\end_layout
+
+\begin_layout Standard
+Step program, proceeding through subroutine calls.
+\end_layout
+
+\begin_layout Subsubsection*
+run
+\end_layout
+
+\begin_layout Standard
+Start debugged program.
+\end_layout
+
+\begin_layout Subsubsection*
+ptype variable
+\end_layout
+
+\begin_layout Standard
+Print type information of the variable.
+\end_layout
+
+\begin_layout Subsubsection*
+print variable
+\end_layout
+
+\begin_layout Standard
+print value of variable.
+\end_layout
+
+\begin_layout Subsubsection*
+file filename
+\end_layout
+
+\begin_layout Standard
+load the given file name.
+ Note this is an alternate method of loading file for debugging.
+\end_layout
+
+\begin_layout Subsubsection*
+frame
+\end_layout
+
+\begin_layout Standard
+print information about current frame.
+\end_layout
+
+\begin_layout Subsubsection*
+set srcmode
+\end_layout
+
+\begin_layout Standard
+Toggle between C source & assembly source.
+\end_layout
+
+\begin_layout Subsubsection*
+! simulator command
+\end_layout
+
+\begin_layout Standard
+Send the string following '!' to the simulator, the simulator response is
+ displayed.
+ Note the debugger does not interpret the command being sent to the simulator,
+ so if a command like 'go' is sent the debugger can loose its execution
+ context and may display incorrect values.
+\end_layout
+
+\begin_layout Subsubsection*
+quit
+\end_layout
+
+\begin_layout Standard
+"Watch me now.
+ Iam going Down.
+ My name is Bobby Brown"
+\end_layout
+
+\begin_layout Subsection
+Interfacing SDCDB with DDD
+\end_layout
+
+\begin_layout Standard
+\begin_inset Note Note
+status collapsed
+
+\begin_layout Standard
+The screenshot was converted from png to eps with:
+\begin_inset Quotes sld
+\end_inset
+
+bmeps -c -e8f -p3 ddd_example.png >ddd_example.eps
+\begin_inset Quotes srd
+\end_inset
+
+ which produces a pretty compact eps file which is free from compression
+ artifacts.
+\end_layout
+
+\begin_layout Standard
+The screenshot was included in sdccman.lyx cvs version 1.120 but later removed
+ as this broke the build system on Sourceforge (pdf-file was broken.
+ pdflatex does not accept eps files).
+\end_layout
+
+\end_inset
+
+
+\end_layout
+
+\begin_layout Standard
+The
+\emph on
+p
+\emph default
+ortable
+\emph on
+n
+\emph default
+etwork
+\emph on
+g
+\emph default
+raphics File
+\size footnotesize
+
+\begin_inset LatexCommand \url{http://sdcc.svn.sourceforge.net/viewvc/*checkout*/sdcc/trunk/sdcc/doc/figures/ddd_example.png}
+
+\end_inset
+
+
+\size default
+ shows a screenshot of a debugging session with DDD
+\begin_inset LatexCommand \index{DDD (debugger)}
+
+\end_inset
+
+ (Unix only) on a simulated 8032.
+ The debugging session might not run as smoothly as the screenshot suggests.
+ The debugger allows setting of breakpoints, displaying and changing variables,
+ single stepping through C and assembler code.
+
+\newline
+The source was compiled with
+\family sans
+\series bold
+
+\newline
+
+\newline
+sdcc -
+\family default
+\series default
+
+\begin_inset ERT
+status collapsed
+
+\begin_layout Standard
+
+
+\backslash
+/
+\end_layout
+
+\end_inset
+
+
+\family sans
+\series bold
+-debug ddd_example.c
+\family default
+\series default
+
+\family sans
+\series bold
+
+\newline
+
+\family default
+\series default
+
+\newline
+and DDD was invoked with
+\family sans
+\series bold
+
+\newline
+
+\newline
+ddd -debugger "sdcdb -cpu 8032 ddd_example"
+\end_layout
+
+\begin_layout Standard
+\begin_inset Note Note
+status open
+
+\begin_layout Standard
+Check that the double quotes or an apostroph within the command line survive
+ the LyX tool chain.
+ Previously the apostrophs got slanted in the PDF output so a cut and paste
+ did not work.
+\end_layout
+
+\end_inset
+
+
+\end_layout
+
+\begin_layout Subsection
+Interfacing SDCDB with XEmacs
+\begin_inset LatexCommand \index{XEmacs}
+
+\end_inset
+
+
+\begin_inset LatexCommand \index{Emacs}
+
+\end_inset
+
+
+\end_layout
+
+\begin_layout Standard
+Two files (in emacs lisp) are provided for the interfacing with XEmacs,
+ sdcdb.el and sdcdbsrc.el.
+ These two files can be found in the $(prefix)/bin directory after the installat
+ion is complete.
+ These files need to be loaded into XEmacs for the interface to work.
+ This can be done at XEmacs startup time by inserting the following into
+ your '.xemacs' file (which can be found in your HOME directory):
+\newline
+
+\newline
+
+\family typewriter
+(load-file sdcdbsrc.el)
+\family default
+
+\newline
+
+\newline
+.xemacs is a lisp file so the () around the command is REQUIRED.
+ The files can also be loaded dynamically while XEmacs is running, set the
+ environment variable 'EMACSLOADPATH' to the installation bin directory
+ (<installdir>/bin), then enter the following command ESC-x load-file sdcdbsrc.
+ To start the interface enter the following command:
+\newline
+
+\newline
+
+\family sans
+\series bold
+ESC-x sdcdbsrc
+\family default
+\series default
+
+\newline
+
+\newline
+You will prompted to enter the file name to be debugged.
+
+\newline
+
+\newline
+The command line options that are passed to the simulator directly are
+ bound to default values in the file sdcdbsrc.el.
+ The variables are listed below, these values maybe changed as required.
+\end_layout
+
+\begin_layout Itemize
+sdcdbsrc-cpu-type '51
+\end_layout
+
+\begin_layout Itemize
+sdcdbsrc-frequency '11059200
+\end_layout
+
+\begin_layout Itemize
+sdcdbsrc-serial nil
+\end_layout
+
+\begin_layout Standard
+The following is a list of key mapping for the debugger interface.
+\end_layout
+
+\begin_layout Standard
+\InsetSpace ~
+
+\family typewriter
+
+\newline
+;;\InsetSpace ~
+Current Listing ::
+\newline
+;;key\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+binding\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+Comment
+\newline
+;;---\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+-------\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+-------
+\newline
+;;
+\newline
+;;\InsetSpace ~
+n\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+sdcdb-next-fro
+m-src\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+SDCDB next command
+\newline
+;;\InsetSpace ~
+b\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+sdcdb-back-from-src\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+SDCDB back command
+\newline
+;;\InsetSpace ~
+c\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+sdcdb-cont-f
+rom-src\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+SDCDB continue command
+\newline
+;;\InsetSpace ~
+s\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+sdcdb-step-from-src\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+SDCDB step command
+\newline
+;;\InsetSpace ~
+?\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+sdcdb-w
+hatis-c-sexp\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~