Leaked source code of windows server 2003
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142 lines
4.5 KiB

page ,132
title stricmp
;***
;stricmp.asm - contains ASCII only, case-insensitive, string comparision routine
; __ascii_stricmp
;
; Copyright (c) 1985-2001, Microsoft Corporation. All rights reserved.
;
;Purpose:
; contains __ascii_stricmp()
;
;Revision History:
; 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 Minor 386 cleanup
; 10-10-88 JCR Added strcmpi() entry for compatiblity with early revs
; 10-25-88 JCR General cleanup for 386-only code
; 10-27-88 JCR Shuffled regs so no need to save/restore ebx
; 03-23-90 GJF Changed to _stdcall. Also, fixed the copyright.
; 01-18-91 GJF ANSI naming.
; 05-10-91 GJF Back to _cdecl, sigh...
; 10-20-94 GJF Made locale sensitive (i.e., now works for all
; single-byte character locales). Made multi-thread
; safe. Also, deleted obsolete _STDCALL_ code.
; 10-27-94 GJF Adapted above change for Win32S.
; 11-12-94 GJF Must avoid volatile regs or save them across function
; calls. Also, fixed bug in reg operand size.
; 07-03-95 CFW Changed offset of _lc_handle[LC_CTYPE], added sanity check
; to crtlib.c to catch changes to win32s.h that modify offset.
; 10-03-95 GJF New locale locking scheme.
; 11-13-95 GJF Made _strcmpi a proc instead of a label.
; 07-17-96 GJF Added lock prefix to increment and decrement of
; __unguarded_readlc_active
; 07-18-96 GJF Fixed race condition.
; 08-26-98 GJF All locale and multithread support moved up to
; stricmp.c. Renamed this file to _stricmp.asm.
; 06-12-01 PML inc->add 1, dec->sub 1 for Pentium 4 perf (vs7#267015)
;
;*******************************************************************************
.xlist
include cruntime.inc
.list
page
;***
;int __ascii_stricmp(dst, src) - compare strings, ignore case
;
;Purpose:
; _stricmp/_strcmpi perform a case-insensitive string comparision.
; For differences, upper case letters are mapped to lower case.
; Thus, "abc_" < "ABCD" since "_" < "d".
;
; Algorithm:
;
; int _strcmpi (char * dst, char * src)
; {
; int f,l;
;
; do {
; f = tolower(*dst);
; l = tolower(*src);
; dst++;
; src++;
; } while (f && f == l);
;
; return(f - l);
; }
;
;Entry:
; char *dst, *src - strings to compare
;
;Exit:
; AX = -1 if dst < src
; AX = 0 if dst = src
; AX = +1 if dst > src
;
;Uses:
; CX, DX
;
;Exceptions:
;
;*******************************************************************************
CODESEG
public __ascii_stricmp
__ascii_stricmp proc \
uses edi esi ebx, \
dst:ptr, \
src:ptr
; load up args
mov esi,[src] ; esi = src
mov edi,[dst] ; edi = dst
mov al,-1 ; fall into loop
align 4
chk_null:
or al,al
jz short done
mov al,[esi] ; al = next source byte
add esi,1
mov ah,[edi] ; ah = next dest byte
add edi,1
cmp ah,al ; first try case-sensitive comparision
je short chk_null ; match
sub al,'A'
cmp al,'Z'-'A'+1
sbb cl,cl
and cl,'a'-'A'
add al,cl
add al,'A' ; tolower(*dst)
xchg ah,al ; operations on AL are shorter than AH
sub al,'A'
cmp al,'Z'-'A'+1
sbb cl,cl
and cl,'a'-'A'
add al,cl
add al,'A' ; tolower(*src)
cmp al,ah ; inverse of above comparison -- AL & AH are swapped
je short chk_null
; dst < src dst > src
sbb al,al ; AL=-1, CY=1 AL=0, CY=0
sbb al,-1 ; AL=-1 AL=1
done:
movsx eax,al ; extend al to eax
ret
__ascii_stricmp endp
end