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Diffstat (limited to 'sysdeps/generic/memcmp.c')
| -rw-r--r-- | sysdeps/generic/memcmp.c | 381 |
1 files changed, 0 insertions, 381 deletions
diff --git a/sysdeps/generic/memcmp.c b/sysdeps/generic/memcmp.c deleted file mode 100644 index 2f8cf344af..0000000000 --- a/sysdeps/generic/memcmp.c +++ /dev/null @@ -1,381 +0,0 @@ -/* Copyright (C) 1991,1993,1995,1997,1998,2003,2004 - Free Software Foundation, Inc. - This file is part of the GNU C Library. - Contributed by Torbjorn Granlund (tege@sics.se). - - The GNU C Library is free software; you can redistribute it and/or - modify it under the terms of the GNU Lesser General Public - License as published by the Free Software Foundation; either - version 2.1 of the License, or (at your option) any later version. - - The GNU C Library 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 - Lesser General Public License for more details. - - You should have received a copy of the GNU Lesser General Public - License along with the GNU C Library; if not, write to the Free - Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA - 02111-1307 USA. */ - -#ifdef HAVE_CONFIG_H -# include "config.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. */ - -#if defined HAVE_STRING_H || defined _LIBC -# include <string.h> -#endif - -#undef memcmp - -#ifdef _LIBC - -# include <memcopy.h> -# include <endian.h> - -# if __BYTE_ORDER == __BIG_ENDIAN -# define WORDS_BIGENDIAN -# endif - -#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 (op_t, op_t) __THROW; - -# ifdef __GNUC__ -__inline -# endif -static int -memcmp_bytes (a, b) - op_t a, b; -{ - long int srcp1 = (long int) &a; - long int srcp2 = (long int) &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 (long, long, size_t) __THROW; - -/* 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. */ -static int -memcmp_common_alignment (srcp1, srcp2, len) - long int srcp1; - long int 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 (long, long, size_t) __THROW; - -/* 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*. */ -static int -memcmp_not_common_alignment (srcp1, srcp2, len) - long int srcp1; - long int 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 -memcmp (s1, s2, len) - const __ptr_t s1; - const __ptr_t s2; - size_t len; -{ - op_t a0; - op_t b0; - long int srcp1 = (long int) s1; - long int srcp2 = (long int) 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; -} -libc_hidden_builtin_def(memcmp) -#ifdef weak_alias -# undef bcmp -weak_alias (memcmp, bcmp) -#endif |