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kolibrios/programs/develop/open watcom/trunk/clib/string/fstrncpy.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 char _WCFAR *fast_strncpy( char _WCFAR *, const char _WCFAR *, size_t );
#pragma aux fast_strncpy = \
0x1e /* push ds */\
0x96 /* xchg si,ax */\
0x8e 0xd8 /* mov ds,ax */\
0x57 /* push di */\
0xac /* L1: lodsb */\
0xaa /* stosb */\
0x84 0xc0 /* test al,al */\
0xe0 0xfa /* loopne L1 */\
0x31 0xc0 /* xor ax,ax */\
0xd1 0xe9 /* shr cx,1 */\
0xf3 0xab /* rep stosw */\
0x11 0xc9 /* adc cx,cx */\
0xf3 0xaa /* rep stosb */\
0x58 /* pop ax */\
0x1f /* pop ds */\
parm caller [es di] [si ax] [cx]\
value [es ax] \
modify exact [ax cx si di];
#endif
_WCRTLINK char _WCFAR *_fstrncpy( char _WCFAR *dst, const char _WCFAR *src, size_t len )
{
#ifdef M_I86
if( len ) {
return( fast_strncpy( dst, src, len ) );
}
return( dst );
#else
char _WCFAR *ret;
ret = dst;
for(;len; --len ) {
if( *src == '\0' ) break;
*dst++ = *src++;
}
while( len != 0 ) {
*dst++ = '\0'; /* pad destination string with null chars */
--len;
}
return( ret );
#endif
}