Windows NT 4.0 source code leak
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page ,132
title memicmp - compare blocks of memory, ignore case
;***
;memicmp.asm - compare memory, ignore case
;
; Copyright (c) 1985-1991, Microsoft Corporation. All rights reserved.
;
;Purpose:
; defines _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...
;
;*******************************************************************************
.xlist
include cruntime.inc
.list
page
;***
;int _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 _memicmp
_memicmp proc \
uses edi esi ebx, \
first:ptr byte, \
last:ptr byte, \
count:IWORD
mov esi,[first] ; si = first
mov edi,[last] ; di = last
mov ecx,[count] ; cx = count
jecxz short toend ; if count=0, nothing to do
mov bh,'A'
mov bl,'Z'
mov dh,'a'-'A' ; add to cap to make lower
lupe:
mov ah,[esi] ; ah = *first
mov al,[edi] ; al = *last
inc esi ; first++
inc edi ; last++
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
loop 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
ifdef _STDCALL_
ret 2*DPSIZE + ISIZE ; _stdcall return
else
ret ; _cdecl return
endif
_memicmp endp
end