From 7e0f021a9aec35fd8e6725e87e3313b101d26f5e Mon Sep 17 00:00:00 2001
From: Tobias Klauser <tklauser@distanz.ch>
Date: Sun, 27 Jan 2008 11:37:44 +0100
Subject: Initial import (2.0.2-6)

---
 reference/C/CONTRIB/SNIP/strecpy.asm | 92 ++++++++++++++++++++++++++++++++++++
 1 file changed, 92 insertions(+)
 create mode 100755 reference/C/CONTRIB/SNIP/strecpy.asm

(limited to 'reference/C/CONTRIB/SNIP/strecpy.asm')

diff --git a/reference/C/CONTRIB/SNIP/strecpy.asm b/reference/C/CONTRIB/SNIP/strecpy.asm
new file mode 100755
index 0000000..223dad4
--- /dev/null
+++ b/reference/C/CONTRIB/SNIP/strecpy.asm
@@ -0,0 +1,92 @@
+        page    ,132
+        title   STRECPY
+COMMENT $
+        Author: Leslie Satenstein
+        A form of strcpy() where the result returned is the
+        nul terminating character of the first argument. In many cases
+        this function is move efficient than the equivalent
+        strcpy, followed by strcat.
+ 
+        The assembler code does a strlen followed by a memcpy,
+            and makes use of the special string move instructions
+            intrinsic to the intel 8088, 80186, 80286, '386 and '486s.
+ 
+        Use as: strecpy(strecpy(target,"first part"),"Second part");
+        in place of
+                strcat(strcpy(target,"first part"),"Second part");
+ 
+        One of the ways the C code appears is:
+        char *strecpy(char *target,const char *src)
+        {
+           return target+strlen(strcpy(target,src));
+        }
+        Another way is to do your own looping:
+ 
+        char *strecpy(char *target,const char *src)
+        {
+          char *cpt,*cps;        /* many compilers optimise better
+                                  * when local pointers are declared
+                                  * (locals can be assigned registers)
+                                  */
+          cpt=target-1;
+          cps=src-1;
+          do
+          {
+            *++cpt = *++src;     /* copy first, ask questions later */
+          } while(*cpt!='\0');
+          return cpt;
+        }
+
+        $
+ 
+;  Requires MASM 5.1 or later or equivalent
+;
+;  Assemble with:       MASM /Mx /z ...
+;                       TASM /jMASM /mx /z ...
+
+%       .MODEL  memodel,C               ;Add model support via command
+                                        ;line macros, e.g.
+                                        ;MASM /Dmemodel=LARGE,
+                                        ;MASM /Dmemodel=SMALL, etc.
+        PUBLIC STRECPY
+ 
+        .DATA
+        .CODE
+if    @DataSize
+strecpy  proc uses si di ds,target:FAR ptr byte,src:FAR ptr byte
+        les     di,src          ; load es:di with src
+        mov     si,di           ; put copy to bx:si
+        mov     bx,es
+else
+strecpy  proc uses si di,target:NEAR ptr byte,src:NEAR ptr byte
+        mov     di,ds           ; make es same as ds
+        mov     es,di
+        mov     di,src
+        mov     si,di           ; put copy to es:si
+endif
+        xor     ax,ax           ; scan for the nul at end of string
+        mov     cx,-1
+        repne   scasb
+        not     cx              ; cx =    strlen(src)+1 ;
+if    @Datasize
+        les     di,target       ; this is where copy is to begin
+        mov     dx,es           ; dx has segment, di has offset to target
+        mov     ds,bx           ; ds:si have pointer to src
+else
+        mov     di,target       ; this is where copy is to begin
+endif
+        test    di,1            ; if we are on odd address, do one byte move
+        jz      on_even
+        movsb                   ; now, prepare to move words at a
+        dec     cx              ;time to target
+on_even:
+        shr     cx,1            ; carry flag has remainder after divide by 2
+        rep     movsw           ; move this many words
+        jnc     fini            ; if no carry, we are finished
+        movsb
+fini:
+        xchg    di,ax           ; set up return value, dx has seg value
+        dec     ax              ; backup to the nul character
+        ret
+strecpy endp
+        end
-- 
cgit v1.2.3-54-g00ecf