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49 lines
1.7 KiB
C
49 lines
1.7 KiB
C
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/* memchr (str, ch, n) -- Return pointer to first occurrence of CH in STR less
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than N.
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For Intel 80x86, x>=3.
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Copyright (C) 1991, 1992, 1993 Free Software Foundation, Inc.
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Contributed by Torbjorn Granlund (tege@sics.se).
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Library General Public License as
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published by the Free Software Foundation; either version 2 of the
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License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Library General Public License for more details.
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You should have received a copy of the GNU Library General Public
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License along with the GNU C Library; see the file COPYING.LIB. If
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not, write to the Free Software Foundation, Inc., 675 Mass Ave,
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Cambridge, MA 02139, USA. */
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#include <ansidecl.h>
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#include <string.h>
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#ifdef __GNUC__
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PTR
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DEFUN(memchr, (str, c, len),
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CONST PTR str AND int c AND size_t len)
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{
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PTR retval;
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asm("cld\n" /* Search forward. */
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"testl %1,%1\n" /* Clear Z flag, to handle LEN == 0. */
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/* Some old versions of gas need `repne' instead of `repnz'. */
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"repnz\n" /* Search for C in al. */
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"scasb\n"
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"movl %2,%0\n" /* Set %0 to 0 (without affecting Z flag). */
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"jnz done\n" /* Jump if we found nothing equal to C. */
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"leal -1(%1),%0\n" /* edi has been incremented. Return edi-1. */
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"done:" :
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"=a" (retval), "=D" (str), "=c" (len) :
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"0" (c), "1" (str), "2" (len));
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return retval;
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}
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#else
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#include <sysdeps/generic/memchr.c>
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#endif
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