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page ,132 title memicmp - compare blocks of memory, ignore case;***;memicmp.asm - compare memory, ignore case;; Copyright (c) 1985-2001, Microsoft Corporation. All rights reserved.;;Purpose:; defines __ascii_memicmp() - compare two blocks of memory for lexical; order. Case is ignored in the comparison.;;Revision History:; 05-16-83 RN initial version; 05-17-88 SJM Add model-independent (large model) ifdef; 08-04-88 SJM convert to cruntime/ add 32-bit support; 08-23-88 JCR Cleanup...; 10-25-88 JCR General cleanup for 386-only code; 03-23-90 GJF Changed to _stdcall. Also, fixed the copyright.; 01-17-91 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.; 07-17-96 GJF Added lock prefix to increment and decrement of ; __unguarded_readlc_active.; 07-18-96 GJF Fixed race condition.; 09-08-98 GJF All locale and multithread support moved up to; memicmp.c. Renamed this file to _memicmp.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_memicmp(first, last, count) - compare two blocks of memory, ignore case;;Purpose:; Compares count bytes of the two blocks of memory stored at first; and last. The characters are converted to lowercase before; comparing (not permanently), so case is ignored in the search.;; Algorithm:; int; _memicmp (first, last, count); char *first, *last;; unsigned count;; {; if (!count); return(0);; while (--count && tolower(*first) == tolower(*last)); {; first++;; last++;; }; return(tolower(*first) - tolower(*last));; };;Entry:; char *first, *last - memory buffers to compare; unsigned count - maximum length to compare;;Exit:; returns <0 if first < last; returns 0 if first == last; returns >0 if first > last;;Uses:;;Exceptions:;;*******************************************************************************
CODESEG
public __ascii_memicmp__ascii_memicmp proc \ uses edi esi ebx, \ first:ptr byte, \ last:ptr byte, \ count:IWORD
mov ecx,[count] ; cx = count or ecx,ecx jz short toend ; if count=0, nothing to do
mov esi,[first] ; si = first mov edi,[last] ; di = last
; C locale
mov bh,'A' mov bl,'Z' mov dh,'a'-'A' ; add to cap to make lower
align 4
lupe: mov ah,[esi] ; ah = *first add esi,1 ; first++ mov al,[edi] ; al = *last add edi,1 ; last++
cmp ah,al ; test for equality BEFORE converting case je short dolupe
cmp ah,bh ; ah < 'A' ?? jb short skip1
cmp ah,bl ; ah > 'Z' ?? ja short skip1
add ah,dh ; make lower case
skip1: cmp al,bh ; al < 'A' ?? jb short skip2
cmp al,bl ; al > 'Z' ?? ja short skip2
add al,dh ; make lower case
skip2: cmp ah,al ; *first == *last ?? jne short differ ; nope, found mismatched chars
dolupe: sub ecx,1 jnz short lupe
jmp short toend ; cx = 0, return 0
differ: mov ecx,-1 ; assume last is bigger ; *** can't use "or ecx,-1" due to flags *** jb short toend ; last is, in fact, bigger (return -1) neg ecx ; first is bigger (return 1)
toend: mov eax,ecx ; move return value to ax
ret ; _cdecl return
__ascii_memicmp endp end
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