+++ /dev/null
-/* Copyright (C) 1991, 1993, 1995, 1997, 1998 Free Software Foundation, Inc.
- Contributed by Torbjorn Granlund (tege@sics.se).
-
- NOTE: The canonical source of this file is maintained with the GNU C Library.
- Bugs can be reported to bug-glibc@prep.ai.mit.edu.
-
- This program is free software; you can redistribute it and/or modify it
- under the terms of the GNU General Public License as published by the
- Free Software Foundation; either version 2, or (at your option) any
- later version.
-
- This program is distributed in the hope that it will be useful,
- but WITHOUT ANY WARRANTY; without even the implied warranty of
- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- GNU General Public License for more details.
-
- You should have received a copy of the GNU General Public License along
- with this program; if not, write to the Free Software Foundation, Inc.,
- 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
-*/
-
-#ifdef HAVE_CONFIG_H
-# include "config.h"
-#endif
-
-#ifdef HAVE_INTTYPES_H
-#include <inttypes.h>
-#endif
-
-#undef __ptr_t
-#if defined __cplusplus || (defined __STDC__ && __STDC__)
-# define __ptr_t void *
-#else /* Not C++ or ANSI C. */
-# undef const
-# define const
-# define __ptr_t char *
-#endif /* C++ or ANSI C. */
-
-#ifndef __P
-# if defined __GNUC__ || (defined __STDC__ && __STDC__)
-# define __P(args) args
-# else
-# define __P(args) ()
-# endif /* GCC. */
-#endif /* Not __P. */
-
-#if defined HAVE_STRING_H || defined _LIBC
-# include <string.h>
-#endif
-
-#undef memcmp
-
-#ifdef _LIBC
-
-# include <memcopy.h>
-
-#else /* Not in the GNU C library. */
-
-# include <sys/types.h>
-
-/* Type to use for aligned memory operations.
- This should normally be the biggest type supported by a single load
- and store. Must be an unsigned type. */
-# define op_t unsigned long int
-# define OPSIZ (sizeof(op_t))
-
-/* Threshold value for when to enter the unrolled loops. */
-# define OP_T_THRES 16
-
-/* Type to use for unaligned operations. */
-typedef unsigned char byte;
-
-# ifndef WORDS_BIGENDIAN
-# define MERGE(w0, sh_1, w1, sh_2) (((w0) >> (sh_1)) | ((w1) << (sh_2)))
-# else
-# define MERGE(w0, sh_1, w1, sh_2) (((w0) << (sh_1)) | ((w1) >> (sh_2)))
-# endif
-
-#endif /* In the GNU C library. */
-
-#ifdef WORDS_BIGENDIAN
-# define CMP_LT_OR_GT(a, b) ((a) > (b) ? 1 : -1)
-#else
-# define CMP_LT_OR_GT(a, b) memcmp_bytes ((a), (b))
-#endif
-
-/* BE VERY CAREFUL IF YOU CHANGE THIS CODE! */
-
-/* The strategy of this memcmp is:
-
- 1. Compare bytes until one of the block pointers is aligned.
-
- 2. Compare using memcmp_common_alignment or
- memcmp_not_common_alignment, regarding the alignment of the other
- block after the initial byte operations. The maximum number of
- full words (of type op_t) are compared in this way.
-
- 3. Compare the few remaining bytes. */
-
-#ifndef WORDS_BIGENDIAN
-/* memcmp_bytes -- Compare A and B bytewise in the byte order of the machine.
- A and B are known to be different.
- This is needed only on little-endian machines. */
-
-static int memcmp_bytes __P((op_t, op_t));
-
-# ifdef __GNUC__
-__inline
-# endif
-static int
-memcmp_bytes (a, b)
- op_t a, b;
-{
- intptr_t srcp1 = (intptr_t) &a;
- intptr_t srcp2 = (intptr_t) &b;
- op_t a0, b0;
-
- do
- {
- a0 = ((byte *) srcp1)[0];
- b0 = ((byte *) srcp2)[0];
- srcp1 += 1;
- srcp2 += 1;
- }
- while (a0 == b0);
- return a0 - b0;
-}
-#endif
-
-static int memcmp_common_alignment __P((intptr_t, intptr_t, size_t));
-
-/* memcmp_common_alignment -- Compare blocks at SRCP1 and SRCP2 with LEN `op_t'
- objects (not LEN bytes!). Both SRCP1 and SRCP2 should be aligned for
- memory operations on `op_t's. */
-#ifdef __GNUC__
-__inline
-#endif
-static int
-memcmp_common_alignment (srcp1, srcp2, len)
- intptr_t srcp1;
- intptr_t srcp2;
- size_t len;
-{
- op_t a0, a1;
- op_t b0, b1;
-
- switch (len % 4)
- {
- default: /* Avoid warning about uninitialized local variables. */
- case 2:
- a0 = ((op_t *) srcp1)[0];
- b0 = ((op_t *) srcp2)[0];
- srcp1 -= 2 * OPSIZ;
- srcp2 -= 2 * OPSIZ;
- len += 2;
- goto do1;
- case 3:
- a1 = ((op_t *) srcp1)[0];
- b1 = ((op_t *) srcp2)[0];
- srcp1 -= OPSIZ;
- srcp2 -= OPSIZ;
- len += 1;
- goto do2;
- case 0:
- if (OP_T_THRES <= 3 * OPSIZ && len == 0)
- return 0;
- a0 = ((op_t *) srcp1)[0];
- b0 = ((op_t *) srcp2)[0];
- goto do3;
- case 1:
- a1 = ((op_t *) srcp1)[0];
- b1 = ((op_t *) srcp2)[0];
- srcp1 += OPSIZ;
- srcp2 += OPSIZ;
- len -= 1;
- if (OP_T_THRES <= 3 * OPSIZ && len == 0)
- goto do0;
- /* Fall through. */
- }
-
- do
- {
- a0 = ((op_t *) srcp1)[0];
- b0 = ((op_t *) srcp2)[0];
- if (a1 != b1)
- return CMP_LT_OR_GT (a1, b1);
-
- do3:
- a1 = ((op_t *) srcp1)[1];
- b1 = ((op_t *) srcp2)[1];
- if (a0 != b0)
- return CMP_LT_OR_GT (a0, b0);
-
- do2:
- a0 = ((op_t *) srcp1)[2];
- b0 = ((op_t *) srcp2)[2];
- if (a1 != b1)
- return CMP_LT_OR_GT (a1, b1);
-
- do1:
- a1 = ((op_t *) srcp1)[3];
- b1 = ((op_t *) srcp2)[3];
- if (a0 != b0)
- return CMP_LT_OR_GT (a0, b0);
-
- srcp1 += 4 * OPSIZ;
- srcp2 += 4 * OPSIZ;
- len -= 4;
- }
- while (len != 0);
-
- /* This is the right position for do0. Please don't move
- it into the loop. */
- do0:
- if (a1 != b1)
- return CMP_LT_OR_GT (a1, b1);
- return 0;
-}
-
-static int memcmp_not_common_alignment __P((intptr_t, intptr_t, size_t));
-
-/* memcmp_not_common_alignment -- Compare blocks at SRCP1 and SRCP2 with LEN
- `op_t' objects (not LEN bytes!). SRCP2 should be aligned for memory
- operations on `op_t', but SRCP1 *should be unaligned*. */
-#ifdef __GNUC__
-__inline
-#endif
-static int
-memcmp_not_common_alignment (srcp1, srcp2, len)
- intptr_t srcp1;
- intptr_t srcp2;
- size_t len;
-{
- op_t a0, a1, a2, a3;
- op_t b0, b1, b2, b3;
- op_t x;
- int shl, shr;
-
- /* Calculate how to shift a word read at the memory operation
- aligned srcp1 to make it aligned for comparison. */
-
- shl = 8 * (srcp1 % OPSIZ);
- shr = 8 * OPSIZ - shl;
-
- /* Make SRCP1 aligned by rounding it down to the beginning of the `op_t'
- it points in the middle of. */
- srcp1 &= -OPSIZ;
-
- switch (len % 4)
- {
- default: /* Avoid warning about uninitialized local variables. */
- case 2:
- a1 = ((op_t *) srcp1)[0];
- a2 = ((op_t *) srcp1)[1];
- b2 = ((op_t *) srcp2)[0];
- srcp1 -= 1 * OPSIZ;
- srcp2 -= 2 * OPSIZ;
- len += 2;
- goto do1;
- case 3:
- a0 = ((op_t *) srcp1)[0];
- a1 = ((op_t *) srcp1)[1];
- b1 = ((op_t *) srcp2)[0];
- srcp2 -= 1 * OPSIZ;
- len += 1;
- goto do2;
- case 0:
- if (OP_T_THRES <= 3 * OPSIZ && len == 0)
- return 0;
- a3 = ((op_t *) srcp1)[0];
- a0 = ((op_t *) srcp1)[1];
- b0 = ((op_t *) srcp2)[0];
- srcp1 += 1 * OPSIZ;
- goto do3;
- case 1:
- a2 = ((op_t *) srcp1)[0];
- a3 = ((op_t *) srcp1)[1];
- b3 = ((op_t *) srcp2)[0];
- srcp1 += 2 * OPSIZ;
- srcp2 += 1 * OPSIZ;
- len -= 1;
- if (OP_T_THRES <= 3 * OPSIZ && len == 0)
- goto do0;
- /* Fall through. */
- }
-
- do
- {
- a0 = ((op_t *) srcp1)[0];
- b0 = ((op_t *) srcp2)[0];
- x = MERGE(a2, shl, a3, shr);
- if (x != b3)
- return CMP_LT_OR_GT (x, b3);
-
- do3:
- a1 = ((op_t *) srcp1)[1];
- b1 = ((op_t *) srcp2)[1];
- x = MERGE(a3, shl, a0, shr);
- if (x != b0)
- return CMP_LT_OR_GT (x, b0);
-
- do2:
- a2 = ((op_t *) srcp1)[2];
- b2 = ((op_t *) srcp2)[2];
- x = MERGE(a0, shl, a1, shr);
- if (x != b1)
- return CMP_LT_OR_GT (x, b1);
-
- do1:
- a3 = ((op_t *) srcp1)[3];
- b3 = ((op_t *) srcp2)[3];
- x = MERGE(a1, shl, a2, shr);
- if (x != b2)
- return CMP_LT_OR_GT (x, b2);
-
- srcp1 += 4 * OPSIZ;
- srcp2 += 4 * OPSIZ;
- len -= 4;
- }
- while (len != 0);
-
- /* This is the right position for do0. Please don't move
- it into the loop. */
- do0:
- x = MERGE(a2, shl, a3, shr);
- if (x != b3)
- return CMP_LT_OR_GT (x, b3);
- return 0;
-}
-
-int
-rpl_memcmp (s1, s2, len)
- const __ptr_t s1;
- const __ptr_t s2;
- size_t len;
-{
- op_t a0;
- op_t b0;
- intptr_t srcp1 = (intptr_t) s1;
- intptr_t srcp2 = (intptr_t) s2;
- op_t res;
-
- if (len >= OP_T_THRES)
- {
- /* There are at least some bytes to compare. No need to test
- for LEN == 0 in this alignment loop. */
- while (srcp2 % OPSIZ != 0)
- {
- a0 = ((byte *) srcp1)[0];
- b0 = ((byte *) srcp2)[0];
- srcp1 += 1;
- srcp2 += 1;
- res = a0 - b0;
- if (res != 0)
- return res;
- len -= 1;
- }
-
- /* SRCP2 is now aligned for memory operations on `op_t'.
- SRCP1 alignment determines if we can do a simple,
- aligned compare or need to shuffle bits. */
-
- if (srcp1 % OPSIZ == 0)
- res = memcmp_common_alignment (srcp1, srcp2, len / OPSIZ);
- else
- res = memcmp_not_common_alignment (srcp1, srcp2, len / OPSIZ);
- if (res != 0)
- return res;
-
- /* Number of bytes remaining in the interval [0..OPSIZ-1]. */
- srcp1 += len & -OPSIZ;
- srcp2 += len & -OPSIZ;
- len %= OPSIZ;
- }
-
- /* There are just a few bytes to compare. Use byte memory operations. */
- while (len != 0)
- {
- a0 = ((byte *) srcp1)[0];
- b0 = ((byte *) srcp2)[0];
- srcp1 += 1;
- srcp2 += 1;
- res = a0 - b0;
- if (res != 0)
- return res;
- len -= 1;
- }
-
- return 0;
-}
-
-#ifdef weak_alias
-# undef bcmp
-weak_alias (memcmp, bcmp)
-#endif
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