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[/] [openrisc/] [trunk/] [gnu-stable/] [newlib-1.18.0/] [newlib/] [libc/] [machine/] [microblaze/] [strcmp.c] - Blame information for rev 207

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1 207 jeremybenn
/* Copyright (c) 2009 Xilinx, Inc.  All rights reserved.
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   Redistribution and use in source and binary forms, with or without
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   modification, are permitted provided that the following conditions are
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   met:
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   1.  Redistributions source code must retain the above copyright notice,
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   this list of conditions and the following disclaimer.
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   2.  Redistributions in binary form must reproduce the above copyright
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   notice, this list of conditions and the following disclaimer in the
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   documentation and/or other materials provided with the distribution.
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   3.  Neither the name of Xilinx nor the names of its contributors may be
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   used to endorse or promote products derived from this software without
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   specific prior written permission.
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   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER AND CONTRIBUTORS "AS
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   IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
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   TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
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   PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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   HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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   SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
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   TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
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   PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
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   LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
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   NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
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   SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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FUNCTION
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        <<strcmp>>---character string compare
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INDEX
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        strcmp
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ANSI_SYNOPSIS
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        #include <string.h>
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        int strcmp(const char *<[a]>, const char *<[b]>);
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TRAD_SYNOPSIS
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        #include <string.h>
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        int strcmp(<[a]>, <[b]>)
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        char *<[a]>;
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        char *<[b]>;
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DESCRIPTION
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        <<strcmp>> compares the string at <[a]> to
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        the string at <[b]>.
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RETURNS
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        If <<*<[a]>>> sorts lexicographically after <<*<[b]>>>,
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        <<strcmp>> returns a number greater than zero.  If the two
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        strings match, <<strcmp>> returns zero.  If <<*<[a]>>>
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        sorts lexicographically before <<*<[b]>>>, <<strcmp>> returns a
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        number less than zero.
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PORTABILITY
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<<strcmp>> is ANSI C.
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<<strcmp>> requires no supporting OS subroutines.
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QUICKREF
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        strcmp ansi pure
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*/
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#include <string.h>
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#include <limits.h>
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/* Nonzero if either X or Y is not aligned on a "long" boundary.  */
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#define UNALIGNED(X, Y) \
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  (((long)X & (sizeof (long) - 1)) | ((long)Y & (sizeof (long) - 1)))
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/* DETECTNULL returns nonzero if (long)X contains a NULL byte. */
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#if LONG_MAX == 2147483647L
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#define DETECTNULL(X) (((X) - 0x01010101) & ~(X) & 0x80808080)
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#else
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#if LONG_MAX == 9223372036854775807L
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#define DETECTNULL(X) (((X) - 0x0101010101010101) & ~(X) & 0x8080808080808080)
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#else
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#error long int is not a 32bit or 64bit type.
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#endif
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#endif
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#ifndef DETECTNULL
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#error long int is not a 32bit or 64bit byte
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#endif
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int
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_DEFUN (strcmp, (s1, s2),
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        _CONST char *s1 _AND
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        _CONST char *s2)
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{
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#ifndef HAVE_HW_PCMP
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#if defined(PREFER_SIZE_OVER_SPEED) || defined(__OPTIMIZE_SIZE__)
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  while (*s1 != '\0' && *s1 == *s2)
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    {
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      s1++;
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      s2++;
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    }
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  return (*(unsigned char *) s1) - (*(unsigned char *) s2);
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#else
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  unsigned long *a1;
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  unsigned long *a2;
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  /* If s1 or s2 are unaligned, then compare bytes. */
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  if (!UNALIGNED (s1, s2))
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    {
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      /* If s1 and s2 are word-aligned, compare them a word at a time. */
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      a1 = (unsigned long*)s1;
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      a2 = (unsigned long*)s2;
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      while (*a1 == *a2)
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        {
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          /* To get here, *a1 == *a2, thus if we find a null in *a1,
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             then the strings must be equal, so return zero.  */
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          if (DETECTNULL (*a1))
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            return 0;
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          a1++;
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          a2++;
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        }
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      /* A difference was detected in last few bytes of s1, so search bytewise */
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      s1 = (char*)a1;
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      s2 = (char*)a2;
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    }
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  while (*s1 != '\0' && *s1 == *s2)
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    {
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      s1++;
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      s2++;
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    }
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  return (*(unsigned char *) s1) - (*(unsigned char *) s2);
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#endif /* not PREFER_SIZE_OVER_SPEED */
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#else
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    asm volatile ("                                          \n\
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       or      r9, r0, r0               /* Index register */ \n\
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check_alignment:                                             \n\
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        andi    r3, r5, 3                                    \n\
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        andi    r4, r6, 3                                    \n\
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        bnei    r3, try_align_args                           \n\
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        bnei    r4, regular_strcmp     /* At this point we don't have a choice */ \n\
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cmp_loop:                                                                       \n\
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        lw      r3, r5, r9                                                      \n\
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        lw      r4, r6, r9                                                      \n\
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        pcmpbf  r7, r3, r0              /* See if there is Null byte */                         \n\
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        bnei    r7, end_cmp_loop        /* IF yes (r7 > 0) use byte compares in end_cmp_loop */ \n\
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        cmpu    r7, r4, r3              /* ELSE compare whole word */                   \n\
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        bnei    r7, end_cmp                                                             \n\
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        brid    cmp_loop                                                                \n\
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        addik   r9, r9, 4               /* delay slot */                                \n\
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end_cmp_loop:                                                                           \n\
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        lbu     r3, r5, r9              /* byte compare loop */                         \n\
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        lbu     r4, r6, r9                                                              \n\
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        cmpu    r7, r4, r3              /* Compare bytes */                             \n\
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        bnei    r7, end_cmp_early                                                       \n\
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        bneid   r3, end_cmp_loop        /* If reached null on one string, terminate */  \n\
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        addik   r9, r9, 1               /* delay slot */                        \n\
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end_cmp_early:                                                                  \n\
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        rtsd    r15, 8                                                          \n\
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        or      r3, r0, r7                                                      \n\
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try_align_args:                                                                 \n\
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        xor     r7, r4, r3                                                      \n\
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        bnei    r7, regular_strcmp      /* cannot align args */                 \n\
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        rsubik  r10, r3, 4              /* Number of initial bytes to align */  \n\
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align_loop:                                                                     \n\
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        lbu     r3, r5, r9                                                      \n\
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        lbu     r4, r6, r9                                                      \n\
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        cmpu    r7, r4, r3                                                      \n\
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        bnei    r7, end_cmp                                                     \n\
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        beqi    r3, end_cmp                                                     \n\
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        addik   r10, r10, -1                                                    \n\
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        beqid   r10, cmp_loop                                                   \n\
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        addik   r9, r9, 1                                                       \n\
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        bri     align_loop                                                      \n\
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regular_strcmp:                                                                 \n\
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        lbu     r3, r5, r9                                                      \n\
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        lbu     r4, r6, r9                                                      \n\
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        cmpu    r7, r4, r3                                                      \n\
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        bnei    r7, end_cmp                                                     \n\
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        beqi    r3, end_cmp                                                     \n\
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        brid    regular_strcmp                                                  \n\
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        addik   r9, r9, 1                                                       \n\
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end_cmp:                                                                        \n\
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        rtsd    r15, 8                                                          \n\
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        or      r3, r0, r7              /* Return strcmp result */");
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#endif /* ! HAVE_HW_PCMP */
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}
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