You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
106 lines
2.5 KiB
106 lines
2.5 KiB
page ,132
|
|
title strrchr - find last occurence of character in string
|
|
;***
|
|
;strrchr.asm - find last occurrence of character in string
|
|
;
|
|
; Copyright (c) 1985-2001, 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...
|
|
; 06-12-01 PML inc->add 1, dec->sub 1 for Pentium 4 perf (vs7#267015)
|
|
;
|
|
;*******************************************************************************
|
|
|
|
.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
|
|
add ecx,1 ; cx=-byte count (with null)
|
|
neg ecx ; cx=+byte count (with null)
|
|
sub edi,1 ; di points to terminal null
|
|
mov al,chr ; al=search byte
|
|
std ; count 'down' on string this time
|
|
repne scasb ; find that byte
|
|
add edi,1 ; 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
|