diff options
Diffstat (limited to 'private/crt32/string/i386/strcat.asm')
| -rw-r--r-- | private/crt32/string/i386/strcat.asm | 155 |
1 files changed, 155 insertions, 0 deletions
diff --git a/private/crt32/string/i386/strcat.asm b/private/crt32/string/i386/strcat.asm new file mode 100644 index 000000000..9781440c1 --- /dev/null +++ b/private/crt32/string/i386/strcat.asm @@ -0,0 +1,155 @@ + page ,132 + title strcat - concatenate (append) one string to another +;*** +;strcat.asm - contains strcat() and strcpy() routines +; +; Copyright (c) 1985-1991, Microsoft Corporation. All rights reserved. +; +;Purpose: +; STRCAT concatenates (appends) a copy of the source string to the +; end of the destination string, returning the destination string. +; +;Revision History: +; 04-21-87 SKS Rewritten to be fast and small, added file header +; 05-17-88 SJM Add model-independent (large model) ifdef +; 07-27-88 SJM Rewritten to be 386-specific and to include strcpy +; 08-29-88 JCR 386 cleanup... +; 10-07-88 JCR Correct off-by-1 strcat bug; optimize ecx=-1 +; 10-25-88 JCR General cleanup for 386-only code +; 03-23-90 GJF Changed to _stdcall. Also, fixed the copyright. +; 05-10-91 GJF Back to _cdecl, sigh... +; +;******************************************************************************* + + .xlist + include cruntime.inc + .list + + +page +;*** +;char *strcat(dst, src) - concatenate (append) one string to another +; +;Purpose: +; Concatenates src onto the end of dest. Assumes enough +; space in dest. +; +; Algorithm: +; char * strcat (char * dst, char * src) +; { +; char * cp = dst; +; +; while( *cp ) +; ++cp; /* Find end of dst */ +; while( *cp++ = *src++ ) +; ; /* Copy src to end of dst */ +; return( dst ); +; } +; +;Entry: +; char *dst - string to which "src" is to be appended +; const char *src - string to be appended to the end of "dst" +; +;Exit: +; The address of "dst" in AX/DX:AX +; +;Uses: +; BX, CX, DX +; +;Exceptions: +; +;******************************************************************************* + +page +;*** +;char *strcpy(dst, src) - copy one string over another +; +;Purpose: +; Copies the string src into the spot specified by +; dest; assumes enough room. +; +; Algorithm: +; char * strcpy (char * dst, char * src) +; { +; char * cp = dst; +; +; while( *cp++ = *src++ ) +; ; /* Copy src over dst */ +; return( dst ); +; } +; +;Entry: +; char * dst - string over which "src" is to be copied +; const char * src - string to be copied over "dst" +; +;Exit: +; The address of "dst" in AX/DX:AX +; +;Uses: +; BX, CX, DX +; +;Exceptions: +;******************************************************************************* + + + CODESEG + +% public strcat, strcpy ; make both functions available + +strcat label proc ;--- strcat --- + + clc ; carry clear = append + jmp short _docat + + align @wordsize ; want to come in on a nice boundary... +strcpy label proc ;--- strcpy --- + + stc ; carry set = don't append to end of string + ;fall thru + + +; --- Common code --- + +_docat proc private \ + uses esi edi, \ + dst:ptr byte, \ + src:ptr byte + + mov edi, dst ; di = dest pointer + jc short @F ; jump if not appending + + ; now skip to end of destination string + + xor eax, eax ; search for the null terminator + or ecx,-1 ; ecx = -1 +repne scasb + dec edi ; edi points to null terminator + + ; copy source string + +@@: mov esi, src + xchg esi, edi ; now ds:esi->dst and es:edi->src + xor eax, eax ; search for null + or ecx,-1 ; ecx = -1 + +repne scasb ; find the length of the src string + not ecx + sub edi, ecx + xchg esi, edi ; now es:edi->dst and ds:esi->src + + mov eax, ecx + shr ecx, ISHIFT ; get the double-word count +rep movsd + and eax, (ISIZE-1) ; get the byte cound + xchg ecx, eax +rep movsb ; move remaining bytes, if any + mov eax, dst ; returned address + +ifdef _STDCALL_ + ret 2*DPSIZE ; _stdcall return +else + ret ; _cdecl return +endif + +_docat endp + end |