is MCU dependent.
Supported data-types are
\emph on
-short (8 bits, 1 byte), char (8 bits, 1 byte), int (16 bits, 2 bytes ),
- long (32 bit, 4 bytes) & float (4 byte IEEE).
+char (8 bits, 1 byte), short and int (16 bits, 2 bytes ), long (32 bit,
+ 4 bytes)
+\emph default
+and
+\emph on
+ float (4 byte IEEE).
\emph default
The compiler also allows
\series medium
SDCC binaries are commonly installed in a directory arrangement like this:
+\series default
+
+\newline
+
\layout Standard
\end_inset
-\layout Standard
+\newline
+\newline
\series medium
Make sure the compiler works on a very simple example.
Type in the following test.c program using your favorite editor:
-\layout Standard
+\series default
+\newline
\emph on
-main()
+
\newline
-{ int i;
+
+\family typewriter
+\emph default
+main()
\newline
+{
+\layout Standard
+
+
+\family typewriter
+int i;
+\layout Standard
+
+
+\family typewriter
i = 0;
-\newline
+\layout Standard
+
+
+\family typewriter
i += 10;
\newline
}
-\series medium
-\emph default
+\family default
+\emph on
\newline
\series medium
The final test is to ensure sdcc can use the standard header files and libraries.
Edit test.c and change it to the following:
-\layout Standard
+\series default
+\newline
-\emph on
+\newline
+
+\family typewriter
#include <string.h>
\newline
main()
\newline
-{ char str1[10];
-\newline
+{
+\layout Standard
+
+
+\family typewriter
+char str1[10];
+\layout Standard
+
+
+\family typewriter
strcpy(str1,
\begin_inset Quotes eld
\end_inset
\end_inset
);
+\newline
+
\newline
}
+\family default
+\emph on
+
+\newline
+
\layout Standard
SDCC does not compile correctly.
\layout Standard
-A things to try is starting from scratch by unpacking the .tgz source package
+A thing to try is starting from scratch by unpacking the .tgz source package
again in an empty directory.
Confure it again and build like:
\layout Standard
SDCDB - Source Level Debugger
\layout Standard
-SDCDB is the companion source level debugger .
+SDCDB is the companion source level debugger.
The current version of the debugger uses Daniel's Simulator S51, but can
be easily changed to use other simulators.
\layout Section
\size footnotesize
sourcefile.ihx - The load module in Intel hex format (you can select the
Motorola S19 format with --out-fmt-s19)
+\layout Itemize
+
+sourcefile.cdb - An optional file (with --debug) containing debug information.
\layout Subsubsection
Projects with Multiple Source Files
Generate code for the Toshiba TLCS-900H processor(In development, not complete).
\layout Subsubsection
-Path and Define Options
+Preprocessor Options
\layout List
\labelwidthstring 00.00.0000
\series bold
-\bar under
-I<path>
\series default
-\bar default
The additional location where the pre processor will look for <..h> or
\begin_inset Quotes eld
\end_inset
\series bold
+-D<macro[=value]>
+\series default
+ Command line definition of macros.
+ Passed to the pre processor.
+\layout List
+\labelwidthstring 00.00.0000
+
+
+\series bold
+--compile-only(-c)
+\series default
\size large
-\bar under
---lib-path(-L)
+
\size default
+ will compile and assemble the source, but will not call the linkage editor.
+\layout Subsubsection
+
+Linker Options
+\layout Standard
+
+
+\series bold
+--lib-path(-L)
+\bar under
\series default
\bar default
<absolute path to additional libraries> This option is passed to the linkage
- editor, additional libraries search path.
+ editor's additional libraries search path.
The path name must be absolute.
- Additional library files may be specified in the command line .
- See section Compiling programs for more details
+ Additional library files may be specified in the command line.
+ See section Compiling programs for more details.
+\layout Standard
+
+
+\series bold
+--xram-loc
+\series default
+<Value> The start location of the external ram, default value is 0.
+ The value entered can be in Hexadecimal or Decimal format, e.g.: --xram-loc
+ 0x8000 or --xram-loc 32768.
\layout List
\labelwidthstring 00.00.0000
\series bold
-\size large
-\bar under
--D<macro[=value]>
+--code-loc
\series default
-\size default
-\bar default
- Command line definition of macros.
- Passed to the pre processor.
+<Value> The start location of the code segment , default value 0.
+ Note when this option is used the interrupt vector table is also relocated
+ to the given address.
+ The value entered can be in Hexadecimal or Decimal format, e.g.: --code-loc
+ 0x8000 or --code-loc 32768.
+\layout List
+\labelwidthstring 00.00.0000
+
+
+\series bold
+--stack-loc
+\series default
+<Value> The initial value of the stack pointer.
+ The default value of the stack pointer is 0x07 if only register bank 0
+ is used, if other register banks are used then the stack pointer is initialized
+ to the location above the highest register bank used.
+ eg.
+ if register banks 1 & 2 are used the stack pointer will default to location
+ 0x18.
+ The value entered can be in Hexadecimal or Decimal format, eg.
+ --stack-loc 0x20 or --stack-loc 32.
+ If all four register banks are used the stack will be placed after the
+ data segment (equivalent to --stack-after-data)
+\layout List
+\labelwidthstring 00.00.0000
+
+
+\series bold
+--stack-after-data
+\series default
+ This option will cause the stack to be located in the internal ram after
+ the data segment.
+\layout List
+\labelwidthstring 00.00.0000
+
+
+\series bold
+--data-loc
+\series default
+<Value> The start location of the internal ram data segment, the default
+ value is 0x30.The value entered can be in Hexadecimal or Decimal format,
+ eg.
+ --data-loc 0x20 or --data-loc 32.
+\layout List
+\labelwidthstring 00.00.0000
+
+
+\series bold
+--idata-loc
+\series default
+<Value> The start location of the indirectly addressable internal ram, default
+ value is 0x80.
+ The value entered can be in Hexadecimal or Decimal format, eg.
+ --idata-loc 0x88 or --idata-loc 136.
\layout Subsubsection
MCS51 Options
\series bold
-\size large
--model-large
\series default
-\size default
Generate code for Large model programs see section Memory Models for more
details.
If this option is used all source files in the project should be compiled
\series bold
-\size large
-\bar under
--model-small
\series default
+\size large
\emph on
-\bar default
\size default
\emph default
\series bold
-\size large
-\bar under
--stack-auto
\series default
+\size large
\emph on
-\bar default
\size default
\emph default
\series bold
-\size large
-\bar under
--xstack
\series default
-\size default
-\bar default
Uses a pseudo stack in the first 256 bytes in the external ram for allocating
variables and passing parameters.
See section on external stack for more details.
\series bold
-\size large
-\bar under
--nogcse
\series default
-\size default
-\bar default
Will not do global subexpression elimination, this option may be used when
the compiler creates undesirably large stack/data spaces to store compiler
temporaries.
\series bold
-\size large
-\bar under
--noinvariant
\series default
-\size default
-\bar default
Will not do loop invariant optimizations, this may be turned off for reasons
- explained for the previous option .
+ explained for the previous option.
For more details of loop optimizations performed see section Loop Invariants.It
recommended that this option NOT be used , #pragma NOINVARIANT can be used
to turn off invariant optimizations for a given function only.
\series bold
-\size large
-\bar under
--noinduction
\series default
-\size default
-\bar default
Will not do loop induction optimizations, see section Strength reduction
for more details.It recommended that this option NOT be used , #pragma NOINDUCTI
ON can be used to turn off induction optimizations for given function only.
\series bold
+--nojtbound
\size large
\bar under
---nojtbound
+
\series default
\size default
\bar default
\series bold
-\size large
-\bar under
--noloopreverse
\series default
-\bar default
+\size large
\size default
Will not do loop reversal optimization
-\layout List
-\labelwidthstring 00.00.0000
-
-
-\series bold
-\size large
-\bar under
---noregparms
-\series default
-\size default
-\bar default
- By default the first parameter is passed using global registers (DPL,DPH,B,ACC).
- This option will disable parameter passing using registers.
- NOTE: if your program uses the 16/32 bit support routines (for multiplication/d
-ivision) these library routines will need to be recompiled with the --noregparms
- option as well.
\layout Subsubsection
DS390 Options
\layout List
\labelwidthstring 00.00.0000
-
-\size large
-\bar under
--
\series bold
model
\series bold
flat24
\series default
+\size large
\emph on
-\bar default
\size default
\emph default
\series bold
-\size large
-\bar under
--callee-saves function1[,function2][,function3]....
\series default
-\size default
-\bar default
The compiler by default uses a caller saves convention for register saving
across function calls, however this can cause unneccessary register pushing
& popping when calling small functions from larger functions.
If the project consists of multiple source files then all the source file
should be compiled with the same --callee-saves option string.
Also see Pragma Directive CALLEE-SAVES.
- .
\layout List
\labelwidthstring 00.00.0000
\series bold
+--debug
\bar under
---debug
+
\series default
\bar default
When this option is used the compiler will generate debug information ,
\series bold
-\size large
-\bar under
--regextend
-\size default
+\bar under
\series default
\bar default
\series bold
-\size large
-\bar under
---compile-only
+--peep-file
\series default
-\bar default
-(-c)
-\size default
- will compile and assemble the source, but will not call the linkage editor.
+<filename> This option can be used to use additional rules to be used by
+ the peep hole optimizer.
+ See section Peep Hole optimizations for details on how to write these rules.
\layout List
\labelwidthstring 00.00.0000
\series bold
-\size large
-\bar under
---xram-loc
+-E
\series default
-\size default
-\bar default
-<Value> The start location of the external ram, default value is 0.
- The value entered can be in Hexadecimal or Decimal format .eg.
- --xram-loc 0x8000 or --xram-loc 32768.
+ Run only the C preprocessor.
+ Preprocess all the C source files specified and output the results to standard
+ output.
\layout List
\labelwidthstring 00.00.0000
\series bold
-\size large
-\bar under
---code-loc
+-M
\series default
-\size default
-\bar default
-<Value> The start location of the code segment , default value 0.
- Note when this option is used the interrupt vector table is also relocated
- to the given address.
- The value entered can be in Hexadecimal or Decimal format .eg.
- --code-loc 0x8000 or --code-loc 32768.
+ Tell the preprocessor to output a rule suitable for make describing the
+ dependencies of each object file.
+ For each source file, the preprocessor outputs one make-rule whose target
+ is the object file name for that source file and whose dependencies are
+ all the files `#include'd in it.
+ This rule may be a single line or may be continued with `
+\backslash
+'-newline if it is long.
+ The list of rules is printed on standard output instead of the preprocessed
+ C program.
+ `-M' implies `-E'.
+\layout List
+\labelwidthstring 00.00.0000
+
+
+\series bold
+-C
+\series default
+ Tell the preprocessor not to discard comments.
+ Used with the `-E' option.
\layout List
\labelwidthstring 00.00.0000
\series bold
+-MM
\size large
\bar under
---stack-loc
-\series default
-\size default
-\bar default
-<Value> The initial value of the stack pointer.
- The default value of the stack pointer is 0x07 if only register bank 0
- is used, if other register banks are used then the stack pointer is initialized
- to the location above the highest register bank used.
- eg.
- if register banks 1 & 2 are used the stack pointer will default to location
- 0x18.
- The value entered can be in Hexadecimal or Decimal format .eg.
- --stack-loc 0x20 or --stack-loc 32.
- If all four register banks are used the stack will be placed after the
- data segment (equivalent to --stack-after-data)
-\layout List
-\labelwidthstring 00.00.0000
-
-
-\series bold
-\size large
-\bar under
---stack-after-data
-\series default
-\size default
-\bar default
- This option will cause the stack to be located in the internal ram after
- the data segment.
-\layout List
-\labelwidthstring 00.00.0000
-
-
-\series bold
-\size large
-\bar under
---data-loc
-\series default
-\size default
-\bar default
-<Value> The start location of the internal ram data segment, the default
- value is 0x30.The value entered can be in Hexadecimal or Decimal format
- .eg.
- --data-loc 0x20 or --data-loc 32.
-\layout List
-\labelwidthstring 00.00.0000
-
-
-\series bold
-\size large
-\bar under
---idata-loc
-\series default
-\size default
-\bar default
-<Value> The start location of the indirectly addressable internal ram, default
- value is 0x80.
- The value entered can be in Hexadecimal or Decimal format .eg.
- --idata-loc 0x88 or --idata-loc 136.
-\layout List
-\labelwidthstring 00.00.0000
-
-
-\series bold
-\size large
-\bar under
---peep-file
-\series default
-\size default
-\bar default
-<filename> This option can be used to use additional rules to be used by
- the peep hole optimizer.
- See section Peep Hole optimizations for details on how to write these rules.
-\layout List
-\labelwidthstring 00.00.0000
-
-
-\series bold
-\size large
-\bar under
--E
-\series default
-\size default
-\bar default
- Run only the C preprocessor.
- Preprocess all the C source files specified and output the results to standard
- output.
-\layout List
-\labelwidthstring 00.00.0000
-
-
-\series bold
-\size large
-\bar under
--M
-\series default
-\size default
-\bar default
- Tell the preprocessor to output a rule suitable for make describing the
- dependencies of each object file.
- For each source file, the preprocessor outputs one make-rule whose target
- is the object file name for that source file and whose dependencies are
- all the files `#include'd in it.
- This rule may be a single line or may be continued with `
-\backslash
-'-newline if it is long.
- The list of rules is printed on standard output instead of the preprocessed
- C program.
- `-M' implies `-E'.
-\layout List
-\labelwidthstring 00.00.0000
-
-
-\series bold
-\size large
-\bar under
--C
-\series default
-\size default
-\bar default
- Tell the preprocessor not to discard comments.
- Used with the `-E' option.
-\layout List
-\labelwidthstring 00.00.0000
-
-
-\series bold
-\size large
-\bar under
--MM
+
\series default
\size default
\bar default
\series bold
-\size large
-\bar under
-Aquestion(answer)
\series default
-\size default
-\bar default
Assert the answer answer for question, in case it is tested with a preprocessor
conditional such as `#if #question(answer)'.
`-A-' disables the standard assertions that normally describe the target
\series bold
-\size large
-\bar under
-Aquestion
\series default
-\size default
-\bar default
(answer) Assert the answer answer for question, in case it is tested with
a preprocessor conditional such as `#if #question(answer)'.
`-A-' disables the standard assertions that normally describe the target
\series bold
-\size large
-\bar under
-Umacro
\series default
-\size default
-\bar default
Undefine macro macro.
`-U' options are evaluated after all `-D' options, but before any `-include'
and `-imacros' options.
\series bold
-\size large
-\bar under
-dM
\series default
-\size default
-\bar default
Tell the preprocessor to output only a list of the macro definitions that
are in effect at the end of preprocessing.
Used with the `-E' option.
\series bold
-\size large
-\bar under
-dD
\series default
-\size default
-\bar default
Tell the preprocessor to pass all macro definitions into the output, in
their proper sequence in the rest of the output.
\layout List
\series bold
+-dN
\size large
\bar under
--dN
+
\series default
\size default
\bar default
\series bold
+-S
\size large
\bar under
--S
+
\series default
\size default
\bar default
\series bold
-\bar under
-Wa_asmOption[,asmOption]
\series default
-\bar default
...
Pass the asmOption to the assembler.
\layout List
\series bold
-\bar under
-Wl_linkOption[,linkOption]
\series default
-\bar default
- ..
+...
Pass the linkOption to the linker.
\layout List
\labelwidthstring 00.00.0000
\series bold
-\size large
-\bar under
--int-long-reent
\series default
-\bar default
+\size large
\size default
Integer (16 bit) and long (32 bit) libraries have been compiled as reentrant.
\series bold
-\size large
-\bar under
--cyclomatic
-\size default
+\bar under
\series default
\bar default
\series bold
-\size large
-\bar under
--float-reent
-\size default
+\bar under
\series default
\bar default
\series bold
-\size large
-\bar under
--out-fmt-ihx
-\size default
+\bar under
\series default
\bar default
\series bold
-\size large
-\bar under
--out-fmt-s19
-\size default
+\bar under
\series default
\bar default
\series bold
-\size large
-\bar under
--nooverlay
\series default
-\size default
-\bar default
The compiler will not overlay parameters and local variables of any function,
see section Parameters and local variables for more details.
\layout List
\series bold
-\size large
-\bar under
--main-return
\series default
-\size default
-\bar default
This option can be used when the code generated is called by a monitor
program.
The compiler will generate a 'ret' upon return from the 'main' function.
The default option is to lock up i.e.
- generate a 'ljmp .' .
+ generate a 'ljmp '.
\layout List
\labelwidthstring 00.00.0000
\series bold
-\size large
-\bar under
--no-peep
\series default
-\size default
-\bar default
Disable peep-hole optimization.
\layout List
\labelwidthstring 00.00.0000
\series bold
-\size large
-\bar under
--peep-asm
\series default
-\size default
-\bar default
Pass the inline assembler code through the peep hole optimizer.
This can cause unexpected changes to inline assembler code, please go through
the peephole optimizer rules defined in the source file tree '<target>/peeph.def
\series bold
-\size large
-\bar under
--iram-size
\series default
-\size default
-\bar default
<Value> Causes the linker to check if the interal ram usage is within limits
of the given value.
\layout Subsubsection
\layout Standard
The following options are provided for the purpose of retargetting and debugging
- the compiler .
+ the compiler.
These provided a means to dump the intermediate code (iCode) generated
by the compiler in human readable form at various stages of the compilation
process.
\series bold
-\size large
-\bar under
--dumpraw
\series default
-\size default
-\bar default
This option will cause the compiler to dump the intermediate code into
a file of named
\emph on
\series bold
-\size large
-\bar under
--dumpgcse
\series default
-\size default
-\bar default
Will create a dump of iCode's, after global subexpression elimination,
into a file named
\emph on
\series bold
-\size large
-\bar under
--dumpdeadcode
\series default
-\size default
-\bar default
Will create a dump of iCode's, after deadcode elimination, into a file
named
\emph on
\series bold
-\size large
-\bar under
--dumploop
\series default
-\bar default
+\size large
\size default
Will create a dump of iCode's, after loop optimizations, into a file named
\series bold
-\size large
-\bar under
--dumprange
\series default
-\bar default
+\size large
\size default
Will create a dump of iCode's, after live range analysis, into a file named
\series bold
-\size large
-\bar under
+--dumlrange
+\series default
+ Will dump the life ranges for all symbols
+\layout List
+\labelwidthstring 00.00.0000
+
+
+\series bold
--dumpregassign
-\size default
+\bar under
\series default
\bar default
\layout List
\labelwidthstring 00.00.0000
---dumplrange Will create a dump of the live ranges of iTemp's
+
+\series bold
+--dumplrange
+\series default
+ Will create a dump of the live ranges of iTemp's
\layout List
\labelwidthstring 00.00.0000
\series bold
+--dumpall
\size large
\bar under
---dumpall
+
\series default
\size default
\bar default
\series bold
default
\series default
- storage class for Large Memory model .
-\layout Standard
+ storage class for Large Memory model, e.g.:
+\newline
+\newline
-\size footnotesize
-eg.
-
-\emph on
+\family typewriter
xdata unsigned char xduc;
\layout Subsubsection
\series default
storage class for Small Memory model.
Variables declared with this storage class will be allocated in the internal
- RAM.
-\layout Standard
-
+ RAM, e.g.:
+\newline
-\size footnotesize
-eg.
+\newline
-\emph on
- data int iramdata;
+\family typewriter
+data int iramdata;
\layout Subsubsection
idata
\layout Standard
Variables declared with this storage class will be allocated into the indirectly
- addressable portion of the internal ram of a 8051 .
-\layout Standard
+ addressable portion of the internal ram of a 8051, e.g.:
+\newline
+\newline
-\size footnotesize
-eg.
-\emph on
+\family typewriter
idata int idi;
\layout Subsubsection
This is a data-type and a storage class specifier.
When a variable is declared as a bit , it is allocated into the bit addressable
- memory of 8051.
-\layout Standard
+ memory of 8051, e.g.:
+\newline
-eg.
-\emph on
+\newline
+
+\family typewriter
bit iFlag;
\layout Subsubsection
sfr / sbit
\emph default
signifies both a data-type and storage class, they are used to describe
- the special function registers and special bit variables of a 8051.
-
-\layout Standard
-
-eg.
-
-\emph on
-
-\layout Standard
-
-
-\emph on
-sfr at 0x80 P0;
-\emph default
-\noun on
-/* special function register P0 at location 0x80 */
-\layout Standard
+ the special function registers and special bit variables of a 8051, eg:
+\newline
+\newline
-\emph on
-sbit at 0xd7 CY; /*
-\noun on
-CY (Carry Flag) */
+\family typewriter
+sfr at 0x80 P0; /* special function register P0 at location 0x80 */
+\newline
+sbit at 0xd7 CY; /* CY (Carry Flag) */
\layout Subsection
Pointers
_generic
\emph default
class of pointers which can be used to point to any of the memory spaces.
-
-\layout Standard
+\newline
+\newline
Pointer declaration examples.
-\layout Standard
-
+\newline
\size small
+
+\newline
+
+\family typewriter
+\size default
/* pointer physically in xternal ram pointing to object in internal ram
*/
\newline
data unsigned char * xdata p;
\newline
-\layout Standard
-
-
-\size small
+\newline
/* pointer physically in code rom pointing to data in xdata space */
\newline
xdata unsigned char * code p;
\newline
-\layout Standard
-
-
-\size small
+\newline
/* pointer physically in code space pointing to data in code space */
\newline
code unsigned char * code p;
/* the folowing is a generic pointer physically located in xdata space */
\newline
char * xdata p;
-\layout Standard
+\family default
+\size small
+
+\newline
+
+\newline
+\size default
Well you get the idea.
For compatibility with the previous version of the compiler, the following
- syntax for pointer declaration is also supported.
- Note the above examples will be portable to other commercially available
- compilers.
-\layout Standard
+ syntax for pointer declaration is still supported but will disappear int
+ the near future.
+
+\newline
+\newline
-\size small
+\family typewriter
unsigned char _xdata *ucxdp; /* pointer to data in external ram */
\newline
unsigned char _data \SpecialChar ~
\newline
unsigned char _idata *uccp; \SpecialChar ~
/* pointer to upper 128 bytes of ram */
-\layout Standard
+\family default
+\size small
+
+\newline
-All unqualified pointers are treated as 3-byte (4-bytes for the ds390) '_generic
-' pointers.
+\newline
+
+\size default
+All unqualified pointers are treated as 3-byte (4-byte for the ds390) '_generic'
+ pointers.
These type of pointers can also to be explicitly declared.
-\layout Standard
+\newline
+\newline
-\size small
+\family typewriter
unsigned char _generic *ucgp;
-\layout Standard
+\family default
+\size small
+
+\newline
+\newline
+
+\size default
The highest order byte of the generic pointers contains the data space informati
on.
Assembler support routines are called whenever data is stored or retrieved
\emph on
--stack-auto
\emph default
- compiler option or by using the 'reentrant' keyword in the function declaration.
-\layout Standard
-
+ compiler option or by using the 'reentrant' keyword in the function declaration
+, e.g.:
+\newline
-\family typewriter
-\size scriptsize
-eg
-\layout Standard
+\size small
+\newline
-\size small
-unsigned short foo( short i) reentrant {
+\family typewriter
+\size default
+unsigned char foo( char i) reentrant
+\newline
+{
\newline
...
\newline
}
-\layout Standard
+\newline
+
+\family default
+\newline
Note that when the parameters & local variables are declared in the internal/ext
ernal ram the functions are non-reentrant.
Since stack space on 8051 is limited the
When compiled with the default option (i.e.
non-reentrant ), local variables can be assigned storage classes and absolute
- addresses.
-
+ addresses, e.g.: (jwk: pending: this is obsolete and need a rewrite)
+\newline
+
+\newline
+
+\family typewriter
+unsigned char foo() {
+\layout Standard
+
+
+\family typewriter
+xdata unsigned char i;
\layout Standard
-(jwk: pending: this is obsolete and need a rewrite)
+
+\family typewriter
+bit bvar;
\layout Standard
\family typewriter
-\size scriptsize
-eg
+data at 0x31 unsiged char j;
\layout Standard
-\size small
-unsigned short foo() {
-\newline
-\SpecialChar ~
- \SpecialChar ~
-xdata unsigned short i;
-\newline
-\SpecialChar ~
- \SpecialChar ~
-bit bvar;
-\newline
-\SpecialChar ~
- \SpecialChar ~
-data at 0x31 unsiged short j;
-\newline
+\family typewriter
...
\newline
Parameters and Local variables of functions that contain 16 or 32 bit multiplica
tion or division will NOT be overlayed since these are implemented using
- external functions.
-\layout Standard
-
-eg.
-\layout Standard
+ external functions, e.g.:
+\newline
+\newline
-\size small
+\family typewriter
#pragma SAVE
\newline
#pragma NOOVERLAY
\newline
-void set_error( unsigned short errcd)
-\newline
-{
+void set_error( unsigned char errcd)
\newline
-\SpecialChar ~
- \SpecialChar ~
- P3 = errcd;
+{
+\layout Standard
+
+
+\family typewriter
+P3 = errcd;
\newline
}
\newline
\newline
void some_isr () interrupt 2 using 1
\newline
-{
-\newline
-\SpecialChar ~
- \SpecialChar ~
- ...
-
-\newline
-\SpecialChar ~
- \SpecialChar ~
- set_error(10);
-\newline
-\SpecialChar ~
- \SpecialChar ~
- ...
-
-\newline
-}
+{
\layout Standard
-In the above example the parameter
-\emph on
-errcd
-\emph default
- for the function
-\emph on
-set_error
-\emph default
- would be assigned to the overlayable segment (if the #pragma NOOVERLAY
- was not present) , this could cause unpredictable runtime behavior.
- The pragma NOOVERLAY ensures that the parameters and local variables for
- the function are NOT overlayed.
-\layout Subsection
-Critical Functions
+\family typewriter
+...
\layout Standard
-A special keyword may be associated with a function declaring it as '
-\emph on
-critical
-\emph default
-'.
- SDCC will generate code to disable all interrupts upon entry to a critical
- function and enable them back before returning .
- Note that nesting critical functions may cause unpredictable results.
-\layout Standard
-eg
+\family typewriter
+set_error(10);
\layout Standard
-\size small
-int foo () critical
-\newline
-{
-\newline
-...
-
-\newline
+\family typewriter
...
\newline
}
\layout Standard
-The critical attribute maybe used with other attributes like
-\emph on
-reentrant.
-\layout Subsection
-
-Absolute Addressing
-\layout Standard
-
-Data items can be assigned an absolute address with the
-\emph on
-at <address>
-\emph default
- keyword, in addition to a storage class.
-\layout Standard
-
-eg.
-
-\layout Standard
-
-
-\size small
-xdata at 0x8000 unsigned char PORTA_8255 ;
-\layout Standard
-
-In the above example the
+In the above example the parameter
\emph on
-PORTA_8255
+errcd
\emph default
- will be allocated to the location 0x8000 of the external ram.
-
-\layout Standard
-
-Note that is this feature is provided to give the programmer access to
+ for the function
\emph on
-memory mapped
+set_error
\emph default
- devices attached to the controller.
- The compiler does not actually reserve any space for variables declared
- in this way (they are implemented with an equate in the assembler), thus
- it is left to the programmer to make sure there are no overlaps with other
- variables that are declared without the absolute address, the assembler
- listing file (.lst) and the linker output files (<filename>.rst) and (<filename>.m
-ap) are a good places to look for such overlaps.
-\layout Standard
-
-Absolute address can be specified for variables in all storage classes.
-\layout Standard
-
-
-\size small
-eg.
-\layout Standard
-
-
-\size small
-bit at 0x02 bvar;
-\layout Standard
-
-The above example will allocate the variable at offset 0x02 in the bit-addressab
-le space.
- There is no real advantage to assigning absolute addresses to variables
- in this manner , unless you want strict control over all the variables
- allocated.
+ would be assigned to the overlayable segment (if the #pragma NOOVERLAY
+ was not present) , this could cause unpredictable runtime behavior when
+ called from an ISR.
+ The pragma NOOVERLAY ensures that the parameters and local variables for
+ the function are NOT overlayed.
\layout Subsection
Interrupt Service Routines
The 'using' keyword is used to tell the compiler to use the specified register
bank (8051 specific) when generating code for this function.
Note that when some function is called from an interrupt service routine
- it should be preceded by a #pragma NOOVERLAY (if it is not reentrant) .
+ it should be preceded by a #pragma NOOVERLAY (if it is not reentrant).
A special note here, int (16 bit) and long (32 bit) integer division, multiplic
ation & modulus operations are implemented using external support routines
developed in ANSI-C, if an interrupt service routine needs to do any of
8051 are listed below.
SDCC will automatically adjust the interrupt vector table to the maximum
interrupt number specified.
+\newline
+
\layout Standard
\end_inset
+\newline
+
\layout Standard
-If the interrupt service routine is defined without a register bank or with
- register bank 0 (using 0), the compiler will save the registers used by
- itself on the stack (upon entry and restore them at exit), however if such
- an interrupt service routine calls another function then the entire register
- bank will be saved on the stack.
+If the interrupt service routine is defined without
+\emph on
+'using'
+\emph default
+ a register bank or with register bank 0 (using 0), the compiler will save
+ the registers used by itself on the stack (upon entry and restore them
+ at exit), however if such an interrupt service routine calls another function
+ then the entire register bank will be saved on the stack.
This scheme may be advantageous for small interrupt service routines which
have low register usage.
\layout Standard
avoid it if possible.
\layout Subsection
-Startup Code
+Critical Functions
+\layout Standard
+
+A special keyword may be associated with a function declaring it as '
+\emph on
+critical
+\emph default
+'.
+ SDCC will generate code to disable all interrupts upon entry to a critical
+ function and enable them back before returning.
+ Note that nesting critical functions may cause unpredictable results.
+\newline
+
+\newline
+eg:
+\newline
+
+\size small
+
+\newline
+int foo () critical
+\newline
+{
+\newline
+...
+
+\newline
+...
+
+\newline
+}
+\newline
+
+\size default
+
+\newline
+The critical attribute maybe used with other attributes like
+\emph on
+reentrant.
+\layout Subsection
+
+Naked Functions
+\layout Standard
+
+A special keyword may be associated with a function declaring it as
+\emph on
+'_naked'.
+
+\emph default
+The
+\emph on
+'_naked'
+\emph default
+ function modifier attribute prevents the compiler from generating prologue
+ and epilogue code for that function.
+ This means that the user is entirely responsible for such things as saving
+ any registers that may need to be preserved, selecting the proper register
+ bank, generating the
+\emph on
+'return'
+\emph default
+ instruction at the end, etc.
+ Practically, this means that the contents of the function must be written
+ in inline assembler.
+ This is particularly useful for interrupt functions, which can have a large
+ (and often unnecessary) prologue/epilogue.
+ For example, compare the code generated by these two functions:
+\newline
+
+\newline
+data unsigned char counter;
+\newline
+void simpleIterrupt(void) interrupt 1
+\newline
+{
+\layout Standard
+
+counter++;
+\newline
+}
+\newline
+
+\newline
+void nakedInterrupt(void) interrupt 2 _naked
+\newline
+{
+\layout Standard
+
+_asm
+\layout Standard
+
+\SpecialChar ~
+\SpecialChar ~
+ inc\SpecialChar ~
+ _counter
+\layout Standard
+
+\SpecialChar ~
+\SpecialChar ~
+ reti\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+ ; MUST explicitly include ret in _naked function.
+\layout Standard
+
+_endasm;
+\newline
+}
+\newline
+
+\newline
+For an 8051 target, the generated simpleInterrupt looks like:
+\newline
+
+\newline
+_simpleIterrupt:
+\layout Standard
+
+push\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+ acc
+\layout Standard
+
+push\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+ b
+\layout Standard
+
+push\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+ dpl
+\layout Standard
+
+push\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+ dph
+\layout Standard
+
+push\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+ psw
+\layout Standard
+
+mov\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+ psw,#0x00
+\layout Standard
+
+inc\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+ _counter
+\layout Standard
+
+pop\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+ psw
+\layout Standard
+
+pop\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+ dph
+\layout Standard
+
+pop\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+ dpl
+\layout Standard
+
+pop\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+ b
+\layout Standard
+
+pop\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+ acc
+\layout Standard
+
+reti
+\newline
+
+\newline
+whereas nakedInterrupt looks like:
+\newline
+
+\newline
+_nakedInterrupt:
+\layout Standard
+
+inc\SpecialChar ~
+ _counter
+\layout Standard
+
+reti\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+ ; MUST explicitly include ret(i) in _naked function.
+\newline
+
+\newline
+While there is nothing preventing you from writing C code inside a _naked
+ function, there are many ways to shoot yourself in the foot doing this,
+ and is is recommended that you stick to inline assembler.
+\layout Subsection
+
+Functions using private banks
+\layout Standard
+
+The
+\emph on
+'using'
+\emph default
+ attribute (which tells the compiler to use a register bank other than the
+ default bank zero) should only be applied to 'interrupt' functions (see
+ note A below).
+ This will in most circumstances make the generated ISR code more efficient
+ since it will not have to save registers on the stack.
+\layout Standard
+
+The
+\emph on
+'using'
+\emph default
+ attribute will have no effect on the generated code for a
+\emph on
+non-'interrupt'
+\emph default
+ function (but may occasionally be useful anyway
+\begin_float footnote
+\layout Standard
+
+possible exception: if a function is called ONLY from 'interrupt' functions
+ using a particular bank, it can be declared with the same 'using' attribute
+ as the calling 'interrupt' functions.
+ For instance, if you have several ISRs using bank one, and all of them
+ call memcpy(), it might make sense to create a specialized version of memcpy()
+ 'using 1', since this would prevent the ISR from having to save bank zero
+ to the stack on entry and switch to bank zero before calling the function
+\end_float
+).
+\newline
+(jwk: todo: I don't think this has been done yet)
+\layout Standard
+
+An 'interrupt' function using a non-zero bank will assume that it can trash
+ that register bank, and will not save it.
+ Since high-priority interrupts can interrupt low-priority ones on the 8051
+ and friends, this means that if a high-priority ISR 'using' a particular
+ bank occurs while processing a low-priority ISR 'using' the same bank,
+ terrible and bad things can happen.
+ To prevent this, no single register bank should be 'used' by both a high
+ priority and a low priority ISR.
+ This is probably most easily done by having all high priority ISRs use
+ one bank and all low priority ISRs use another.
+ If you have an ISR which can change priority at runtime, you're on your
+ own: I suggest using the default bank zero and taking the small performance
+ hit.
+\layout Standard
+
+It is most efficient if your ISR calls no other functions.
+ If your ISR must call other functions, it is most efficient if those functions
+ use the same bank as the ISR (see note A below); the next best is if the
+ called functions use bank zero.
+ It is very inefficient to call a function using a different, non-zero bank
+ from an ISR.
+
+\layout Subsection
+
+Absolute Addressing
+\layout Standard
+
+Data items can be assigned an absolute address with the
+\emph on
+at <address>
+\emph default
+ keyword, in addition to a storage class.
+\layout Standard
+
+eg.
+
+\layout Standard
+
+
+\size small
+xdata at 0x8000 unsigned char PORTA_8255 ;
+\layout Standard
+
+In the above example the
+\emph on
+PORTA_8255
+\emph default
+ will be allocated to the location 0x8000 of the external ram.
+
+\layout Standard
+
+Note that is this feature is provided to give the programmer access to
+\emph on
+memory mapped
+\emph default
+ devices attached to the controller.
+ The compiler does not actually reserve any space for variables declared
+ in this way (they are implemented with an equate in the assembler), thus
+ it is left to the programmer to make sure there are no overlaps with other
+ variables that are declared without the absolute address, the assembler
+ listing file (.lst) and the linker output files (<filename>.rst) and (<filename>.m
+ap) are a good places to look for such overlaps.
+\layout Standard
+
+Absolute address can be specified for variables in all storage classes.
+\layout Standard
+
+
+\size small
+eg.
+\layout Standard
+
+
+\size small
+bit at 0x02 bvar;
+\layout Standard
+
+The above example will allocate the variable at offset 0x02 in the bit-addressab
+le space.
+ There is no real advantage to assigning absolute addresses to variables
+ in this manner , unless you want strict control over all the variables
+ allocated.
+\layout Subsection
+
+Startup Code
\layout Standard
The compiler inserts a jump to the C routine
\layout Standard
The inline assembler code can contain any valid code understood by the assembler
- (this includes any assembler directives and comment lines ) .
+ (this includes any assembler directives and comment lines).
The compiler does not do any validation of the code within the
\emph on
_asm ...
Defines Created by the Compiler
\layout Standard
-The compiler creates the following #defines .
+The compiler creates the following #defines.
\layout Itemize
SDCC - this Symbol is always defined.
\layout Standard
Note: the dead stores created by this copy propagation will be eliminated
- by dead-code elimination .
+ by dead-code elimination.
\layout Subsubsection
Loop Optimizations
of the loop.
Because of this preference of the register allocator , loop induction optimizat
ion causes an increase in register pressure, which may cause unwanted spilling
- of other temporary variables into the stack / data space .
+ of other temporary variables into the stack / data space.
The compiler will generate a warning message when it is forced to allocate
extra space either on the stack or data space.
If this extra space allocation is undesirable then induction optimization
\layout Standard
Note djnz instruction can be used for 8-bit values ONLY, therefore it is
- advantageous to declare loop control symbols as either 'char' or 'short',
- ofcourse this may not be possible on all situations.
+ advantageous to declare loop control symbols as either 'char', ofcourse
+ this may not be possible on all situations.
\layout Subsubsection
Algebraic Simplifications
\layout Standard
then both the switch statements will be implemented using jump-tables whereas
- the unmodified switch statement will not be .
+ the unmodified switch statement will not be.
\layout Subsubsection
Bit-shifting Operations.
\layout Standard
Bit shifting is one of the most frequently used operation in embedded programmin
-g .
+g.
SDCC tries to implement bit-shift operations in the most efficient way
possible.
\layout Standard
\size small
-unsigned short i;
+unsigned char i;
\layout Standard
mov _i,a
\layout Standard
-SDCC uses pattern matching on the parse tree to determine this operation
- .Variations of this case will also be recognized as bit-rotation i.e
+SDCC uses pattern matching on the parse tree to determine this operation.Variatio
+ns of this case will also be recognized as bit-rotation i.e
\emph on
i = ((i >> 7) | (i << 1));
\emph default
\layout Standard
It is frequently required to obtain the highest order bit of an integral
- type (int,long,short or char types).
+ type (long, int, short or char types).
SDCC recognizes the following expression to yield the highest order bit
and generates optimized code for it.
\layout Standard
_foo_hob_1_1,a
\layout Standard
-Variations of this case however will NOT be recognized .
+Variations of this case however will NOT be recognized.
It is a standard C expression , so I heartily recommend this be the only
way to get the highest order bit, (it is portable).
Of course it will be recognized even if it is embedded in other expressions.
\layout Standard
The compiler uses a rule based , pattern matching and re-writing mechanism
- for peep-hole optimization .
+ for peep-hole optimization.
It is inspired by '
\emph on
copt'
\series bold
SAVE
\series default
- - this will save all the current options .
+ - this will save all the current options.
\layout Itemize
\series bold
NOINDUCTION
\series default
- - will stop loop induction optimizations .
+ - will stop loop induction optimizations.
\layout Itemize
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
- int
+ short/int
\newline
%ld\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
-short/char
+char
\newline
%x\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
-int
+short/int
\newline
%lx\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
-short/char
+char
\newline
%o\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
-int
+short/int
\newline
%lo\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
-short/char
+char
\newline
%c\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
-char/short
+char
\newline
%s\SpecialChar ~
\SpecialChar ~
very stack intesive
\series default
, --stack-after-data parameter should be used when using this routine, the
- routine also takes about 1K of code space .It also expects an external function
- named
+ routine also takes about 1K of code space.
+ It also expects an external function named
\emph on
putchar(char )
\emph default
\begin_deeper
\layout Standard
-
-\size scriptsize
-//Example:
-\newline
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
- //\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
- #define DYNAMIC_MEMORY_SIZE 0x2000
-\newline
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
- //\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
- .....
-
-\newline
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
- //\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
- unsigned char xdata dynamic_memory_pool[DYNAMIC_MEMORY_SIZE];
-\newline
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
- //\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
- unsigned char xdata * current_buffer;
-\newline
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
- //\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
- .....
-
-\newline
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
- //\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
- void main(void)
-\newline
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
- //\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
- {
-\newline
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
- //\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
- ...
-
-\newline
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-//\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
- init_dynamic_memory(dynamic_memory_pool,DYNAMIC_MEMORY_SIZE);
-\newline
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
- //\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
- //Now it's possible to use malloc.
-
-\newline
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
- //\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
- ...
-
-\newline
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
- //\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
- current_buffer = malloc(0x100);
-\newline
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
- //
-\end_deeper
-\layout Itemize
-
-
-\series bold
-\size large
-serial.h
-\series default
-\size default
- - Serial IO routines are also developed by Dmitry S.
- Obukhov (dso@usa.net).
- These routines are interrupt driven with a 256 byte circular buffer, they
- also expect external ram to be present.
- Please see documentation in file SDCCDIR/sdcc51lib/serial.c .
- Note the header file
-\begin_inset Quotes eld
-\end_inset
-
-serial.h
-\begin_inset Quotes erd
-\end_inset
-
- MUST be included in the file containing the 'main' function.
-\layout Itemize
-
-
-\series bold
-\size large
-ser.h
-\series default
-\size default
-- Alternate serial routine provided by Wolfgang Esslinger <wolfgang@WiredMinds.co
-m> these routines are more compact and faster.
- Please see documentation in file SDCCDIR/sdcc51lib/ser.c
-\layout Itemize
-
-
-\series bold
-\size large
-ser_ir.h
-\series default
-\size default
-- Another alternate set of serial routines provided by Josef Wolf <jw@raven.inka.d
-e> , these routines do not use the external ram.
-\layout Itemize
-
-
-\series bold
-\size large
-reg51.h
-\series default
-\size default
- - contains register definitions for a standard 8051
-\layout Itemize
-
-
-\series bold
-\size large
-reg552.h
-\series default
-\size default
-- contains register definitions for 80C552.
-\layout Itemize
-
-
-\series bold
-\size large
-float.h
-\series default
-\size default
- - contains min, max and other floating point related stuff.
-\layout Standard
-
-All library routines are compiled as --model-small , they are all non-reentrant,
- if you plan to use the large model or want to make these routines reentrant,
- then they will have to be recompiled with the appropriate compiler option.
-\layout Standard
-
-Have not had time to do the more involved routines like printf, will get
- to them shortly.
-\layout Subsection
-
-Interfacing with Assembly Routines
-\layout Subsection
-
-Global Registers used for Parameter Passing
-\layout Standard
-
-By default the compiler uses the global registers
-\begin_inset Quotes eld
-\end_inset
-
-DPL,DPH,B,ACC
-\begin_inset Quotes erd
-\end_inset
-
- to pass the first parameter to a routine, the second parameter onwards
- is either allocated on the stack (for reentrant routines or --stack-auto
- is used) or in the internal / external ram (depending on the memory model).
-
-\layout Subsubsection
-
-Assembler Routine(non-reentrant)
-\layout Standard
-
-In the following example the function
-\series bold
- cfunc
-\series default
- calls an assembler routine
-\series bold
-asm_func
-\series default
-, which takes two parameters.
-\layout Standard
-
-
-\size footnotesize
-extern int asm_func( unsigned short, unsigned short);
-\layout Standard
-
-
-\size footnotesize
-\SpecialChar ~
-
-\newline
-int c_func (unsigned short i, unsigned short j)
-\newline
-{
-\newline
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
- return asm_func(i,j);
-\newline
-}
-\size default
-
-\size scriptsize
-
-\newline
-int main()
-\newline
-{
-\newline
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-return c_func(10,9);
-\newline
-}
-\layout Standard
-
-The corresponding assembler function is:-
-\layout Standard
-
-
-\size scriptsize
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
- .globl _asm_func_PARM_2
-\newline
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
- .globl _asm_func
-\newline
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
- .area OSEG
-\newline
-_asm_func_PARM_2:\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
- .ds\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
- 1
-\newline
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
- .area CSEG
-\newline
-_asm_func:
-\newline
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
- mov\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
- a,dpl
-\newline
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
- add\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
- a,_asm_func_PARM_2
-\newline
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
- mov\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
- dpl,a
-\newline
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
- mov\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
- dpl,#0x00
-\newline
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
- ret
-\layout Standard
-
-Note here that the return values are placed in 'dpl' - One byte return value,
- 'dpl' LSB & 'dph' MSB for two byte values.
- 'dpl', 'dph' and 'b' for three byte values (generic pointers) and 'dpl','dph','
-b' & 'acc' for four byte values.
-\layout Standard
-
-The parameter naming convention is
-\series bold
-_<function_name>_PARM_<n>,
-\series default
- where n is the parameter number starting from 1, and counting from the
- left.
- The first parameter is passed in
-\begin_inset Quotes eld
-\end_inset
-
-dpl
-\begin_inset Quotes erd
-\end_inset
-
- for One bye parameter,
-\begin_inset Quotes eld
-\end_inset
-
-dptr
-\begin_inset Quotes erd
-\end_inset
-
- if two bytes,
-\begin_inset Quotes eld
-\end_inset
-
-b,dptr
-\begin_inset Quotes erd
-\end_inset
-
- for three bytes and
-\begin_inset Quotes eld
-\end_inset
-
-acc,b,dptr
-\begin_inset Quotes erd
-\end_inset
-
- for four bytes, the
-\family typewriter
-\series bold
-\size footnotesize
-varaible name for the second parameter will be _<function_name>_PARM_2.
-\layout Standard
-
-Assemble the assembler routine with the following command.
-\layout Standard
-
-asx8051 -losg asmfunc.asm
-\layout Standard
-
-Then compile and link the assembler routine to the C source file with the
- following command,
-\layout Standard
-
-sdcc cfunc.c asmfunc.rel
-\layout Subsubsection
-
-Assembler Routine(reentrant)
-\layout Standard
-
-In this case the second parameter onwards will be passed on the stack ,
- the parameters are pushed from right to left i.e.
- after the call the left most parameter will be on the top of the stack.
- Here is an example.
-\layout Standard
-
-
-\size footnotesize
-extern int asm_func( unsigned short, unsigned short);
-\layout Standard
-
-
-\size footnotesize
-\SpecialChar ~
-
-\layout Standard
-
-
-\size footnotesize
-int c_func (unsigned short i, unsigned short j) reentrant
-\newline
-{
-\newline
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
- return asm_func(i,j);
-\newline
-}
-\size default
-
-\size scriptsize
-
-\newline
-int main()
-\newline
-{
-\newline
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-return c_func(10,9);
-\newline
-}
-\layout Standard
-
-The corresponding assembler routine is.
-\layout Standard
-
-
-\size scriptsize
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
- .globl _asm_func
-\newline
-_asm_func:
+
+\size scriptsize
+//Example:
\newline
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
+ //\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
- push\SpecialChar ~
- _bp
+ #define DYNAMIC_MEMORY_SIZE 0x2000
\newline
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
+ //\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
- mov\SpecialChar ~
- _bp,sp
+ .....
+
\newline
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
+ //\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
-\SpecialChar ~
-mov\SpecialChar ~
- r2,dpl
+ unsigned char xdata dynamic_memory_pool[DYNAMIC_MEMORY_SIZE];
\newline
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
+ //\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
- mov\SpecialChar ~
- a,_bp
+ unsigned char xdata * current_buffer;
\newline
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
+ //\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
- clr\SpecialChar ~
- c
+ .....
+
\newline
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
+ //\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
- add\SpecialChar ~
- a,#0xfd
+ void main(void)
\newline
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
+ //\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
- mov\SpecialChar ~
- r0,a
+ {
\newline
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
- add\SpecialChar ~
- a,#0xfc
-\newline
+ //\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
- mov\SpecialChar ~
- r1,a
+ ...
+
\newline
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
- mov\SpecialChar ~
- a,@r0
-\newline
+//\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
- add\SpecialChar ~
- a,r2
+ init_dynamic_memory(dynamic_memory_pool,DYNAMIC_MEMORY_SIZE);
\newline
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
+ //\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
- mov\SpecialChar ~
- dpl,a
-\newline
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
+ //Now it's possible to use malloc.
+
+\newline
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
- mov\SpecialChar ~
- dph,#0x00
-\newline
\SpecialChar ~
+ //\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
- mov\SpecialChar ~
- sp,_bp
+\SpecialChar ~
+ ...
+
\newline
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
+ //\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
- pop\SpecialChar ~
- _bp
-\newline
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
+\SpecialChar ~
+ current_buffer = malloc(0x100);
+\newline
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
- ret
+ //
+\end_deeper
+\layout Itemize
+
+
+\series bold
+\size large
+serial.h
+\series default
+\size default
+ - Serial IO routines are also developed by Dmitry S.
+ Obukhov (dso@usa.net).
+ These routines are interrupt driven with a 256 byte circular buffer, they
+ also expect external ram to be present.
+ Please see documentation in file SDCCDIR/sdcc51lib/serial.c.
+ Note the header file
+\begin_inset Quotes eld
+\end_inset
+
+serial.h
+\begin_inset Quotes erd
+\end_inset
+
+ MUST be included in the file containing the 'main' function.
+\layout Itemize
+
+
+\series bold
+\size large
+ser.h
+\series default
+\size default
+- Alternate serial routine provided by Wolfgang Esslinger <wolfgang@WiredMinds.co
+m> these routines are more compact and faster.
+ Please see documentation in file SDCCDIR/sdcc51lib/ser.c
+\layout Itemize
+
+
+\series bold
+\size large
+ser_ir.h
+\series default
+\size default
+- Another alternate set of serial routines provided by Josef Wolf <jw@raven.inka.d
+e> , these routines do not use the external ram.
+\layout Itemize
+
+
+\series bold
+\size large
+reg51.h
+\series default
+\size default
+ - contains register definitions for a standard 8051
+\layout Itemize
+
+
+\series bold
+\size large
+float.h
+\series default
+\size default
+ - contains min, max and other floating point related stuff.
\layout Standard
-The compiling and linking procedure remains the same, however note the extra
- entry & exit linkage required for the assembler code, _bp is the stack
- frame pointer and is used to compute the offset into the stack for parameters
- and local variables.
+All library routines are compiled as --model-small , they are all non-reentrant,
+ if you plan to use the large model or want to make these routines reentrant,
+ then they will have to be recompiled with the appropriate compiler option.
+\layout Standard
+
+Have not had time to do the more involved routines like printf, will get
+ to them shortly.
+\layout Subsection
+
+Interfacing with Assembly Routines
\layout Subsection
-With --noregparms Option
+Global Registers used for Parameter Passing
\layout Standard
-When the source is compiled with --noregparms option , space is allocated
- for each of the parameters passed to a routine.
+By default the compiler uses the global registers
+\begin_inset Quotes eld
+\end_inset
+
+DPL,DPH,B,ACC
+\begin_inset Quotes erd
+\end_inset
+
+ to pass the first parameter to a routine, the second parameter onwards
+ is either allocated on the stack (for reentrant routines or --stack-auto
+ is used) or in the internal / external ram (depending on the memory model).
+
\layout Subsubsection
-Assembler Routine Non-reentrant
+Assembler Routine(non-reentrant)
\layout Standard
In the following example the function
\size footnotesize
-extern int asm_func( unsigned short, unsigned short);
+extern int asm_func( unsigned char, unsigned char);
\layout Standard
\SpecialChar ~
\newline
-int c_func (unsigned short i, unsigned short j)
+int c_func (unsigned char i, unsigned char j)
\newline
{
\newline
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
-\SpecialChar ~
- .globl _asm_func_PARM_1
-\newline
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
\SpecialChar ~
.globl _asm_func_PARM_2
\newline
\SpecialChar ~
.area OSEG
\newline
-_asm_func_PARM_1:\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
- .ds\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
- 1
-\newline
_asm_func_PARM_2:\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
- a,_asm_func_PARM_1
+ a,dpl
\newline
\SpecialChar ~
\SpecialChar ~
\series default
where n is the parameter number starting from 1, and counting from the
left.
- i.e.
- the
+ The first parameter is passed in
+\begin_inset Quotes eld
+\end_inset
+
+dpl
+\begin_inset Quotes erd
+\end_inset
+
+ for One bye parameter,
+\begin_inset Quotes eld
+\end_inset
+
+dptr
+\begin_inset Quotes erd
+\end_inset
+
+ if two bytes,
+\begin_inset Quotes eld
+\end_inset
+
+b,dptr
+\begin_inset Quotes erd
+\end_inset
+
+ for three bytes and
+\begin_inset Quotes eld
+\end_inset
+
+acc,b,dptr
+\begin_inset Quotes erd
+\end_inset
+
+ for four bytes, the
\family typewriter
\series bold
\size footnotesize
-left-most parameter name will be _<function_name>_PARM_1.
+varaible name for the second parameter will be _<function_name>_PARM_2.
\layout Standard
Assemble the assembler routine with the following command.
Assembler Routine(reentrant)
\layout Standard
-In this case the parameters will be passed on the stack , the parameters
- are pushed from right to left i.e.
+In this case the second parameter onwards will be passed on the stack ,
+ the parameters are pushed from right to left i.e.
after the call the left most parameter will be on the top of the stack.
Here is an example.
\layout Standard
\size footnotesize
-extern int asm_func( unsigned short, unsigned short);
+extern int asm_func( unsigned char, unsigned char);
\layout Standard
\size footnotesize
-int c_func (unsigned short i, unsigned short j) reentrant
+int c_func (unsigned char i, unsigned char j) reentrant
\newline
{
\newline
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
-\SpecialChar ~
- mov\SpecialChar ~
- a,_bp
-\newline
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
- clr\SpecialChar ~
- c
+mov\SpecialChar ~
+ r2,dpl
\newline
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
- add\SpecialChar ~
- a,#0xfd
+ mov\SpecialChar ~
+ a,_bp
\newline
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
- mov\SpecialChar ~
- r0,a
+ clr\SpecialChar ~
+ c
\newline
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
- mov\SpecialChar ~
- a,_bp
+ add\SpecialChar ~
+ a,#0xfd
\newline
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
- clr\SpecialChar ~
- c
+ mov\SpecialChar ~
+ r0,a
\newline
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
add\SpecialChar ~
- a,#0xfc
+ a,#0xfc
\newline
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
add\SpecialChar ~
- a,@r1
+ a,r2
\newline
\SpecialChar ~
\SpecialChar ~
Cyclomatic complexity of a function is defined as the number of independent
paths the program can take during execution of the function.
This is an important number since it defines the number test cases you
- have to generate to validate the function .
+ have to generate to validate the function.
The accepted industry standard for complexity number is 10, if the cyclomatic
complexity reported by SDCC exceeds 10 you should think about simplification
of the function logic.
Use the smallest data type to represent your data-value.
If it is known in advance that the value is going to be less than 256 then
- use a 'short' or 'char' instead of an 'int'.
+ use a 'char' instead of a 'short' or 'int'.
\layout Itemize
Use unsigned when it is known in advance that the value is not going to
\layout Enumerate
Phase five is register allocation.
- There are two parts to this process .
+ There are two parts to this process.
\begin_deeper
\layout Enumerate
-The first part I call 'register packing' (for lack of a better term) .
+The first part I call 'register packing' (for lack of a better term).
In this case several MCU specific expression folding is done to reduce
register pressure.
\layout Enumerate
.cdb
\emph default
file with the address information.
- This .cdb is used by the debugger .
+ This .cdb is used by the debugger.
\layout Subsection
How the Debugger Works
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 .
+ commands for the simulator.
\layout Subsection
Starting the Debugger
& 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 --directory option should be --directory=/home/src1:/home/src2 .
+ the --directory option should be --directory=/home/src1:/home/src2.
Note there can be no spaces in the option.
\layout Itemize
to the installation bin directory [$(prefix)/bin], then enter the following
command
\emph on
-ESC-x load-file sdcdbsrc .
+ESC-x load-file sdcdbsrc.
\emph default
To start the interface enter the following command
projects / fw / sdcc / commitdiff