kolibrios/programs/develop/open watcom/trunk/clib/string/fstrncmp.c

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/****************************************************************************
*
* Open Watcom Project
*
* Portions Copyright (c) 1983-2002 Sybase, Inc. All Rights Reserved.
*
* ========================================================================
*
* This file contains Original Code and/or Modifications of Original
* Code as defined in and that are subject to the Sybase Open Watcom
* Public License version 1.0 (the 'License'). You may not use this file
* except in compliance with the License. BY USING THIS FILE YOU AGREE TO
* ALL TERMS AND CONDITIONS OF THE LICENSE. A copy of the License is
* provided with the Original Code and Modifications, and is also
* available at www.sybase.com/developer/opensource.
*
* The Original Code and all software distributed under the License are
* distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
* EXPRESS OR IMPLIED, AND SYBASE AND ALL CONTRIBUTORS HEREBY DISCLAIM
* ALL SUCH WARRANTIES, INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR
* NON-INFRINGEMENT. Please see the License for the specific language
* governing rights and limitations under the License.
*
* ========================================================================
*
* Description: WHEN YOU FIGURE OUT WHAT THIS FILE DOES, PLEASE
* DESCRIBE IT HERE!
*
****************************************************************************/
#include "variety.h"
#include <string.h>
#ifdef M_I86
extern int _fast_strncmp( const char _WCFAR *, const char _WCFAR *, size_t );
#pragma aux _fast_strncmp = \
0x1e /* push ds */ \
0x96 /* xchg si,ax */\
0x8e 0xd8 /* mov ds,ax */\
0x89 0xfa /* mov dx,di */ \
0x30 0xc0 /* xor al,al */ \
0xf2 0xae /* repne scasb */ \
0x89 0xf9 /* mov cx,di */ \
0x89 0xd7 /* mov di,dx */ \
0x29 0xf9 /* sub cx,di */ \
0xf3 0xa6 /* repe cmpsb */ \
0x74 0x05 /* je L1 */ \
0x19 0xc9 /* sbb cx,cx */ \
0x83 0xd9 0xff /* sbb cx,ffffh */ \
/* L1: */ \
0x1f /* pop ds */\
parm caller [si ax] [es di] [cx] \
value [cx] \
modify exact [dx ax di cx si];
#endif
/* return <0 if s<t, 0 if s==t, >0 if s>t */
_WCRTLINK int _fstrncmp( const char _WCFAR *s, const char _WCFAR *t, size_t n )
{
#if defined(M_I86)
if( n ) {
return( _fast_strncmp( s, t, n ) );
}
return( 0 );
#else
for(;;) {
if( n == 0 ) return( 0 ); /* equal */
if( *s != *t ) return( *s - *t ); /* less than or greater than */
if( *s == '\0' ) return( 0 ); /* equal */
++s;
++t;
--n;
}
#endif
}