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| author | Nathan Moinvaziri <nathan@nathanm.com> | 2020-05-22 20:06:21 -0700 |
|---|---|---|
| committer | Hans Kristian Rosbach <hk-github@circlestorm.org> | 2020-05-24 13:53:25 +0200 |
| commit | 71fd2dcc40ed12bca3787b30a1ff867b6d2fe4ee (patch) | |
| tree | 4df5e1e1bea34e97a623147209fb90dde4f5db79 /compare258.c | |
| parent | de7cfabb48c88bdba6120448f080b8f6dd941f65 (diff) | |
Unroll more in compare258_c for performance improvement.
Unify length count variable across all compare256 variants.
Early return without break for possible performance improvements.
Diffstat (limited to 'compare258.c')
| -rw-r--r-- | compare258.c | 62 |
1 files changed, 36 insertions, 26 deletions
diff --git a/compare258.c b/compare258.c index 7763bb6..76d0627 100644 --- a/compare258.c +++ b/compare258.c @@ -10,25 +10,36 @@ /* ALIGNED, byte comparison */ static inline int32_t compare256_c_static(const unsigned char *src0, const unsigned char *src1) { - const unsigned char *src0start = src0; - const unsigned char *src0end = src0 + 256; + int32_t len = 0; do { if (*src0 != *src1) - break; - src0 += 1, src1 += 1; + return len + (*src0 == *src1); + src0 += 1, src1 += 1, len += 1; + if (*src0 != *src1) + return len + (*src0 == *src1); + src0 += 1, src1 += 1, len += 1; + if (*src0 != *src1) + return len + (*src0 == *src1); + src0 += 1, src1 += 1, len += 1; + if (*src0 != *src1) + return len + (*src0 == *src1); + src0 += 1, src1 += 1, len += 1; if (*src0 != *src1) - break; - src0 += 1, src1 += 1; + return len + (*src0 == *src1); + src0 += 1, src1 += 1, len += 1; if (*src0 != *src1) - break; - src0 += 1, src1 += 1; + return len + (*src0 == *src1); + src0 += 1, src1 += 1, len += 1; if (*src0 != *src1) - break; - src0 += 1, src1 += 1; - } while (src0 < src0end); + return len + (*src0 == *src1); + src0 += 1, src1 += 1, len += 1; + if (*src0 != *src1) + return len + (*src0 == *src1); + src0 += 1, src1 += 1, len += 1; + } while (len < 256); - return (int32_t)(src0 - src0start); + return 256; } static inline int32_t compare258_c_static(const unsigned char *src0, const unsigned char *src1) { @@ -55,25 +66,24 @@ int32_t compare258_c(const unsigned char *src0, const unsigned char *src1) { #ifdef UNALIGNED_OK /* UNALIGNED_OK, 16-bit integer comparison */ static inline int32_t compare256_unaligned_16_static(const unsigned char *src0, const unsigned char *src1) { - const unsigned char *src0start = src0; - const unsigned char *src0end = src0 + 256; + int32_t len = 0; do { if (*(uint16_t *)src0 != *(uint16_t *)src1) - break; - src0 += 2, src1 += 2; + return len + (*src0 == *src1); + src0 += 2, src1 += 2, len += 2; if (*(uint16_t *)src0 != *(uint16_t *)src1) - break; - src0 += 2, src1 += 2; + return len + (*src0 == *src1); + src0 += 2, src1 += 2, len += 2; if (*(uint16_t *)src0 != *(uint16_t *)src1) - break; - src0 += 2, src1 += 2; + return len + (*src0 == *src1); + src0 += 2, src1 += 2, len += 2; if (*(uint16_t *)src0 != *(uint16_t *)src1) - break; - src0 += 2, src1 += 2; - } while (src0 < src0end); + return len + (*src0 == *src1); + src0 += 2, src1 += 2, len += 2; + } while (len < 256); - return (int32_t)(src0 - src0start) + (src0 < src0end && *src0 == *src1); + return 256; } static inline int32_t compare258_unaligned_16_static(const unsigned char *src0, const unsigned char *src1) { @@ -111,7 +121,7 @@ static inline int32_t compare256_unaligned_32_static(const unsigned char *src0, src0 += 4, src1 += 4, len += 4; } while (len < 256); - return len; + return 256; } static inline int32_t compare258_unaligned_32_static(const unsigned char *src0, const unsigned char *src1) { @@ -151,7 +161,7 @@ static inline int32_t compare256_unaligned_64_static(const unsigned char *src0, src0 += 8, src1 += 8, len += 8; } while (len < 256); - return len; + return 256; } static inline int32_t compare258_unaligned_64_static(const unsigned char *src0, const unsigned char *src1) { |