fstrchr.c

来自「开放源码的编译器open watcom 1.6.0版的源代码」· C语言 代码 · 共 92 行

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*                            Open Watcom Project
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*    This file contains Original Code and/or Modifications of Original
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#include "variety.h"
#include <string.h>

#ifdef  M_I86

extern  char _WCFAR * _scan1( char _WCFAR *s, int c );

/* use scan1 to find the char we are looking for */

#pragma aux    _scan1 = 0x1e            /* push ds   */\
                        0x8e 0xda       /* mov ds,dx */\
                        0xad            /* L1:lodsw  */\
                        0x38 0xd8       /* cmp al,bl */\
                        0x74 0x22       /* je L3     */\
                        0x84 0xc0       /* test al,al*/\
                        0x74 0x19       /* je L2     */\
                        0x38 0xdc       /* cmp ah,bl */\
                        0x74 0x1b       /* je L4     */\
                        0x84 0xe4       /* test ah,ah*/\
                        0x74 0x11       /* je L2     */\
                        0xad            /* lodsw     */\
                        0x38 0xd8       /* cmp al,bl */\
                        0x74 0x11       /* je L3     */\
                        0x84 0xc0       /* test al,al*/\
                        0x74 0x08       /* je L2     */\
                        0x38 0xdc       /* cmp ah,bl */\
                        0x74 0x0a       /* je L4     */\
                        0x84 0xe4       /* test ah,ah*/\
                        0x75 0xde       /* jne L1    */\
                        0x31 0xf6       /* L2:xor si,si*/\
                        0x89 0xf2       /* mov dx,si */\
                        0xa9            /* test ax,... */\
                        0x4e            /* L3:dec si */\
                        0x4e            /* L4:dec si */\
                        0x1f            /* pop ds    */\
                        parm caller [dx si] [bl]\
                        value [dx si]\
                        modify [ax dx si];
#endif


/* locate the first occurrence of c in the initial n characters of the
   string pointed to by s. The terminating null character is considered
   to be part of the string.
   If the character c is not found, NULL is returned.
*/
#undef  _fstrchr

_WCRTLINK char _WCFAR *_fstrchr( const char _WCFAR *s, int c )
    {
//#if defined(M_I86)
        //return( _scan1( (char _WCFAR *)s, c ) );
//#else
        do {
            if( *s == c ) return( (char _WCFAR *)s );
        } while( *s++ != '\0' );
        return( NULL );
//#endif
    }