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Diffstat (limited to 'private/crt32/string/i386/strrchr.asm')
| -rw-r--r-- | private/crt32/string/i386/strrchr.asm | 105 |
1 files changed, 105 insertions, 0 deletions
diff --git a/private/crt32/string/i386/strrchr.asm b/private/crt32/string/i386/strrchr.asm new file mode 100644 index 000000000..3808b7b8b --- /dev/null +++ b/private/crt32/string/i386/strrchr.asm @@ -0,0 +1,105 @@ + page ,132 + title strrchr - find last occurence of character in string +;*** +;strrchr.asm - find last occurrence of character in string +; +; Copyright (c) 1985-1991, Microsoft Corporation. All rights reserved. +; +;Purpose: +; defines strrchr() - find the last occurrence of a given character +; in a string. +; +;Revision History: +; 10-27-83 RN initial version +; 05-18-88 SJM Add model-independent (large model) ifdef +; 08-04-88 SJM convert to cruntime/ add 32-bit support +; 08-23-88 JCR 386 cleanup +; 10-26-88 JCR General cleanup for 386-only code +; 03-26-90 GJF Changed to _stdcall. Also, fixed the copyright. +; 05-10-91 GJF Back to _cdecl, sigh... +; +;******************************************************************************* + + .xlist + include cruntime.inc + .list + +page +;*** +;char *strrchr(string, ch) - find last occurrence of ch in string +; +;Purpose: +; Finds the last occurrence of ch in string. The terminating +; null character is used as part of the search. +; +; Algorithm: +; char * +; strrchr (string, ch) +; char *string, ch; +; { +; char *start = string; +; +; while (*string++) +; ; +; while (--string != start && *string != ch) +; ; +; if (*string == ch) +; return(string); +; return(NULL); +; } +; +;Entry: +; char *string - string to search in +; char ch - character to search for +; +;Exit: +; returns a pointer to the last occurrence of ch in the given +; string +; returns NULL if ch does not occurr in the string +; +;Uses: +; +;Exceptions: +; +;******************************************************************************* + + CODESEG + + public strrchr +strrchr proc \ + uses edi, \ + string:ptr byte, \ + chr:byte + + mov edi,[string] ; di = string + xor eax,eax ; al=null byte + or ecx,-1 ; cx = -1 +repne scasb ; find the null & count bytes + inc ecx ; cx=-byte count (with null) + neg ecx ; cx=+byte count (with null) + dec edi ; di points to terminal null + mov al,chr ; al=search byte + std ; count 'down' on string this time +repne scasb ; find that byte + inc edi ; di points to byte which stopped scan + + cmp [edi],al ; see if we have a hit + je short returndi ; yes, point to byte + + xor eax,eax ; no, return NULL + jmp short toend ; do return sequence + +returndi: + mov eax,edi ; ax=pointer to byte + +toend: + cld + +ifdef _STDCALL_ + ret DPSIZE + ISIZE ; _stdcall return +else + ret ; _cdecl return +endif + +strrchr endp + end |