* device/lib/_memset.c: assembler version for mcs51

git-svn-id: https://sdcc.svn.sourceforge.net/svnroot/sdcc/trunk/sdcc@4766 4a8a32a2-be11-0410-ad9d-d568d2c75423

diff --git a/ChangeLog b/ChangeLog
index 67eb9964078f3e6a93e392e73591ce9de15eec0f..086630bf521ef97e404a4a3db169861593884447 100644 (file)
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+2007-04-23 Frieder Ferlemann <Frieder.Ferlemann AT web.de>
+
+       * device/lib/_memset.c: assembler version for mcs51
+
 2007-04-22 Borut Razem <borut.razem AT siol.net>
 
        * support/scripts/listerr.c: program to create the list of errors and

diff --git a/device/lib/_memset.c b/device/lib/_memset.c
index 9bd603edf3e42eb4566dc5c837376f569e1ebe6f..5b9202e7b16778b68544aec9ab046ed7df845c83 100644 (file)
--- a/device/lib/_memset.c
+++ b/device/lib/_memset.c
@@ -2,6 +2,7 @@
   _memset.c - part of string library functions
 
              Written By -  Sandeep Dutta . sandeep.dutta@usa.net (1999)
+                           mcs51 assembler by Frieder Ferlemann (2007)
 
    This library is free software; you can redistribute it and/or modify it
    under the terms of the GNU Library General Public License as published by the
@@ -23,18 +24,151 @@
 -------------------------------------------------------------------------*/
 #include "string.h" 
 
-void * memset (
-       void * buf,
-       unsigned char ch ,
-       size_t count) 
-{
-       register unsigned char * ret = buf;
+#if defined (_SDCC_NO_ASM_LIB_FUNCS) || !defined (SDCC_mcs51) || \
+    (!defined (SDCC_MODEL_SMALL) && !defined (SDCC_MODEL_LARGE)) || \
+     (defined (SDCC_STACK_AUTO) || defined (SDCC_PARMS_IN_BANK1) )
 
-       while (count--) {
-               *(unsigned char *) ret = ch;
-               ret = ((unsigned char *) ret) + 1;
-       }
+  void * memset (
+          void * buf,
+          unsigned char ch ,
+          size_t count) 
+  {
+          register unsigned char * ret = buf;
 
-       return buf ;
-}
+          while (count--) {
+                  *(unsigned char *) ret = ch;
+                  ret = ((unsigned char *) ret) + 1;
+          }
 
+          return buf ;
+  }
+
+#else
+
+  /* assembler implementation for mcs51 */
+  static void dummy(void) __naked
+  {
+    __asm
+
+  /* assigning function parameters to registers.
+     SDCC_PARMS_IN_BANK1 or SDCC_STACK_AUTO not yet implemented. */
+  #if defined (SDCC_MODEL_SMALL)
+
+    #if defined(SDCC_NOOVERLAY)
+        .area DSEG    (DATA)
+    #else
+        .area OSEG    (OVR,DATA)
+    #endif
+        _memset_PARM_2::
+              .ds 1
+        _memset_PARM_3::
+              .ds 2
+
+        .area CSEG    (CODE)
+
+        _memset::
+
+        ;   Assign buf (b holds memspace, no need to touch)
+                mov     r4,dpl
+                mov     r5,dph
+                ;
+        ;   Assign count
+                mov     r6,_memset_PARM_3
+                mov     r7,(_memset_PARM_3 + 1)
+                ;
+        ;   if (!count) return buf;
+        ;   check for count != 0 intermangled with gymnastic
+        ;   preparing djnz instructions
+                cjne    r6,#0x00,COUNT_LSB_NOT_ZERO
+                mov     a,r7
+                jz      MEMSET_END
+                dec     r7
+        COUNT_LSB_NOT_ZERO:
+                inc     r7
+                ;
+                ; This was 8 byte overhead for preparing
+                ; the count argument for an integer loop with two
+                ; djnz instructions - it might make sense to
+                ; let SDCC automatically generate this when
+                ; it encounters a loop like:
+                ; for(i=0;i<j;i++){...}
+                ; (at least for option --opt-code-speed)
+                ;
+
+        ;   Assign ch
+                mov     a,_memset_PARM_2
+
+  #else
+
+        .area XSEG    (XDATA)
+
+        _memset_PARM_2::
+                .ds 1
+        _memset_PARM_3::
+                .ds 2
+
+        .area CSEG    (CODE)
+
+        _memset::
+
+        ;   Assign buf (b holds memspace, no need to touch)
+                mov     r4,dpl
+                mov     r5,dph
+                ;
+        ;   Assign count
+                mov     dptr,#_memset_PARM_3
+                movx    a,@dptr
+                mov     r6,a
+                inc     dptr
+                movx    a,@dptr
+                mov     r7,a
+                ;
+        ;   if (!count) return buf;
+        ;   check for count != 0 intermangled with gymnastic
+        ;   preparing djnz instructions
+                cjne    r6,#0x00,COUNT_LSB_NOT_ZERO
+        ;   acc holds r7
+                jz      MEMSET_END
+                dec     r7
+        COUNT_LSB_NOT_ZERO:
+                inc     r7
+                ;
+        ;   Assign ch
+                mov     dptr,#_memset_PARM_2
+                movx    a,@dptr
+        ;   acc is precious now
+                ;
+        ;   Restore dptr
+                mov     dpl,r4
+                mov     dph,r5
+
+  #endif
+
+        /* now independent of the parameter passing everything
+           should be in registers by now and the loop may start */
+        ;   _memset.c do {
+
+        MEMSET_LOOP:
+        ;   _memset.c *p = ch;
+                lcall   __gptrput
+
+        ;   _memset.c p++;
+                inc     dptr
+
+        ;   _memset.c } while(--count) ;
+                djnz    r6,MEMSET_LOOP
+                djnz    r7,MEMSET_LOOP
+                ;
+
+        MEMSET_END:
+        ;   _memset.c return buf ;
+                ; b was unchanged
+                mov     dpl,r4
+                mov     dph,r5
+                ;
+                ret
+
+    __endasm;
+  }
+
+#endif