X-Git-Url: http://erislabs.net/gitweb/?a=blobdiff_plain;f=lib%2Fmemcmp.c;h=ecba1288df947111e23b80a3a162674749404689;hb=43593319b31e6b0175b8eec4433bac744959822d;hp=01810715b0e926daaa1068f2fbb23a7b181ba823;hpb=978619651b0d1562882641de860f8adfb3cc25d6;p=gnulib.git diff --git a/lib/memcmp.c b/lib/memcmp.c index 01810715b..ecba1288d 100644 --- a/lib/memcmp.c +++ b/lib/memcmp.c @@ -1,5 +1,5 @@ -/* Copyright (C) 1991, 1993, 1995, 1997, 1998, 2003, 2006, 2009 Free Software - Foundation, Inc. +/* Copyright (C) 1991, 1993, 1995, 1997-1998, 2003, 2006, 2009-2013 Free + Software Foundation, Inc. Contributed by Torbjorn Granlund (tege@sics.se). @@ -38,18 +38,18 @@ # define WORDS_BIGENDIAN # endif -#else /* Not in the GNU C library. */ +#else /* Not in the GNU C library. */ # include /* 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)) +# 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 +# define OP_T_THRES 16 /* Type to use for unaligned operations. */ typedef unsigned char byte; @@ -60,12 +60,12 @@ typedef unsigned char byte; # define MERGE(w0, sh_1, w1, sh_2) (((w0) << (sh_1)) | ((w1) >> (sh_2))) # endif -#endif /* In the GNU C library. */ +#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)) +# define CMP_LT_OR_GT(a, b) memcmp_bytes (a, b) #endif /* BE VERY CAREFUL IF YOU CHANGE THIS CODE! */ @@ -108,10 +108,10 @@ memcmp_bytes (op_t a, op_t b) } #endif -/* memcmp_common_alignment -- Compare blocks at SRCP1 and SRCP2 with LEN `op_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__ + memory operations on 'op_t's. */ +#ifdef __GNUC__ __inline #endif static int @@ -139,7 +139,7 @@ memcmp_common_alignment (uintptr_t srcp1, uintptr_t srcp2, size_t len) goto do2; case 0: if (OP_T_THRES <= 3 * OPSIZ && len == 0) - return 0; + return 0; a0 = ((op_t *) srcp1)[0]; b0 = ((op_t *) srcp2)[0]; goto do3; @@ -150,7 +150,7 @@ memcmp_common_alignment (uintptr_t srcp1, uintptr_t srcp2, size_t len) srcp2 += OPSIZ; len -= 1; if (OP_T_THRES <= 3 * OPSIZ && len == 0) - goto do0; + goto do0; /* Fall through. */ } @@ -159,25 +159,25 @@ memcmp_common_alignment (uintptr_t srcp1, uintptr_t srcp2, size_t len) a0 = ((op_t *) srcp1)[0]; b0 = ((op_t *) srcp2)[0]; if (a1 != b1) - return CMP_LT_OR_GT (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); + 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); + 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); + return CMP_LT_OR_GT (a0, b0); srcp1 += 4 * OPSIZ; srcp2 += 4 * OPSIZ; @@ -194,9 +194,9 @@ memcmp_common_alignment (uintptr_t srcp1, uintptr_t srcp2, size_t len) } /* 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__ + '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 @@ -213,7 +213,7 @@ memcmp_not_common_alignment (uintptr_t srcp1, uintptr_t srcp2, size_t len) shl = 8 * (srcp1 % OPSIZ); shr = 8 * OPSIZ - shl; - /* Make SRCP1 aligned by rounding it down to the beginning of the `op_t' + /* Make SRCP1 aligned by rounding it down to the beginning of the 'op_t' it points in the middle of. */ srcp1 &= -OPSIZ; @@ -237,7 +237,7 @@ memcmp_not_common_alignment (uintptr_t srcp1, uintptr_t srcp2, size_t len) goto do2; case 0: if (OP_T_THRES <= 3 * OPSIZ && len == 0) - return 0; + return 0; a3 = ((op_t *) srcp1)[0]; a0 = ((op_t *) srcp1)[1]; b0 = ((op_t *) srcp2)[0]; @@ -251,7 +251,7 @@ memcmp_not_common_alignment (uintptr_t srcp1, uintptr_t srcp2, size_t len) srcp2 += 1 * OPSIZ; len -= 1; if (OP_T_THRES <= 3 * OPSIZ && len == 0) - goto do0; + goto do0; /* Fall through. */ } @@ -259,30 +259,30 @@ memcmp_not_common_alignment (uintptr_t srcp1, uintptr_t srcp2, size_t len) { a0 = ((op_t *) srcp1)[0]; b0 = ((op_t *) srcp2)[0]; - x = MERGE(a2, shl, a3, shr); + x = MERGE (a2, shl, a3, shr); if (x != b3) - return CMP_LT_OR_GT (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); + x = MERGE (a3, shl, a0, shr); if (x != b0) - return CMP_LT_OR_GT (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); + x = MERGE (a0, shl, a1, shr); if (x != b1) - return CMP_LT_OR_GT (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); + x = MERGE (a1, shl, a2, shr); if (x != b2) - return CMP_LT_OR_GT (x, b2); + return CMP_LT_OR_GT (x, b2); srcp1 += 4 * OPSIZ; srcp2 += 4 * OPSIZ; @@ -293,7 +293,7 @@ memcmp_not_common_alignment (uintptr_t srcp1, uintptr_t srcp2, size_t len) /* This is the right position for do0. Please don't move it into the loop. */ do0: - x = MERGE(a2, shl, a3, shr); + x = MERGE (a2, shl, a3, shr); if (x != b3) return CMP_LT_OR_GT (x, b3); return 0; @@ -311,29 +311,29 @@ rpl_memcmp (const void *s1, const void *s2, size_t len) if (len >= OP_T_THRES) { /* There are at least some bytes to compare. No need to test - for LEN == 0 in this alignment loop. */ + 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. */ + { + 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); + res = memcmp_common_alignment (srcp1, srcp2, len / OPSIZ); else - res = memcmp_not_common_alignment (srcp1, srcp2, len / OPSIZ); + res = memcmp_not_common_alignment (srcp1, srcp2, len / OPSIZ); if (res != 0) - return res; + return res; /* Number of bytes remaining in the interval [0..OPSIZ-1]. */ srcp1 += len & -OPSIZ; @@ -350,7 +350,7 @@ rpl_memcmp (const void *s1, const void *s2, size_t len) srcp2 += 1; res = a0 - b0; if (res != 0) - return res; + return res; len -= 1; }