From d556327b382760f32a6cb81b213bc653bdad5d38 Mon Sep 17 00:00:00 2001 From: Ben Pfaff Date: Wed, 18 Jan 2012 11:29:57 -0800 Subject: [PATCH] hash: Convert macros to inline functions. I always assumed that macros would generate better code. I was wrong. The generated code was identical with inline functions, with GCC version 4.4.5. Signed-off-by: Ben Pfaff --- lib/hash.c | 12 ++++++------ lib/hash.h | 50 ++++++++++++++++++++++++++++---------------------- 2 files changed, 34 insertions(+), 28 deletions(-) diff --git a/lib/hash.c b/lib/hash.c index 61e17b27..b3d91563 100644 --- a/lib/hash.c +++ b/lib/hash.c @@ -1,5 +1,5 @@ /* - * Copyright (c) 2008, 2009, 2010 Nicira Networks. + * Copyright (c) 2008, 2009, 2010, 2012 Nicira Networks. * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. @@ -30,7 +30,7 @@ hash_words(const uint32_t *p, size_t n, uint32_t basis) a += p[0]; b += p[1]; c += p[2]; - HASH_MIX(a, b, c); + hash_mix(&a, &b, &c); n -= 3; p += 3; } @@ -44,7 +44,7 @@ hash_words(const uint32_t *p, size_t n, uint32_t basis) /* fall through */ case 1: a += p[0]; - HASH_FINAL(a, b, c); + hash_final(&a, &b, &c); /* fall through */ case 0: break; @@ -59,7 +59,7 @@ hash_3words(uint32_t a, uint32_t b, uint32_t c) a += 0xdeadbeef; b += 0xdeadbeef; c += 0xdeadbeef; - HASH_FINAL(a, b, c); + hash_final(&a, &b, &c); return c; } @@ -85,7 +85,7 @@ hash_bytes(const void *p_, size_t n, uint32_t basis) a += tmp[0]; b += tmp[1]; c += tmp[2]; - HASH_MIX(a, b, c); + hash_mix(&a, &b, &c); n -= sizeof tmp; p += sizeof tmp; } @@ -96,7 +96,7 @@ hash_bytes(const void *p_, size_t n, uint32_t basis) a += tmp[0]; b += tmp[1]; c += tmp[2]; - HASH_FINAL(a, b, c); + hash_final(&a, &b, &c); } return c; diff --git a/lib/hash.h b/lib/hash.h index 026eedaf..05799b2e 100644 --- a/lib/hash.h +++ b/lib/hash.h @@ -1,5 +1,5 @@ /* - * Copyright (c) 2008, 2009, 2010 Nicira Networks. + * Copyright (c) 2008, 2009, 2010, 2012 Nicira Networks. * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. @@ -29,28 +29,34 @@ extern "C" { /* This is the public domain lookup3 hash by Bob Jenkins from * http://burtleburtle.net/bob/c/lookup3.c, modified for style. */ -#define HASH_ROT(x, k) (((x) << (k)) | ((x) >> (32 - (k)))) +static inline uint32_t +hash_rot(uint32_t x, int k) +{ + return (x << k) | (x >> (32 - k)); +} -#define HASH_MIX(a, b, c) \ - do { \ - a -= c; a ^= HASH_ROT(c, 4); c += b; \ - b -= a; b ^= HASH_ROT(a, 6); a += c; \ - c -= b; c ^= HASH_ROT(b, 8); b += a; \ - a -= c; a ^= HASH_ROT(c, 16); c += b; \ - b -= a; b ^= HASH_ROT(a, 19); a += c; \ - c -= b; c ^= HASH_ROT(b, 4); b += a; \ - } while (0) +static inline void +hash_mix(uint32_t *a, uint32_t *b, uint32_t *c) +{ + *a -= *c; *a ^= hash_rot(*c, 4); *c += *b; + *b -= *a; *b ^= hash_rot(*a, 6); *a += *c; + *c -= *b; *c ^= hash_rot(*b, 8); *b += *a; + *a -= *c; *a ^= hash_rot(*c, 16); *c += *b; + *b -= *a; *b ^= hash_rot(*a, 19); *a += *c; + *c -= *b; *c ^= hash_rot(*b, 4); *b += *a; +} -#define HASH_FINAL(a, b, c) \ - do { \ - c ^= b; c -= HASH_ROT(b, 14); \ - a ^= c; a -= HASH_ROT(c, 11); \ - b ^= a; b -= HASH_ROT(a, 25); \ - c ^= b; c -= HASH_ROT(b, 16); \ - a ^= c; a -= HASH_ROT(c, 4); \ - b ^= a; b -= HASH_ROT(a, 14); \ - c ^= b; c -= HASH_ROT(b, 24); \ - } while (0) +static inline void +hash_final(uint32_t *a, uint32_t *b, uint32_t *c) +{ + *c ^= *b; *c -= hash_rot(*b, 14); + *a ^= *c; *a -= hash_rot(*c, 11); + *b ^= *a; *b -= hash_rot(*a, 25); + *c ^= *b; *c -= hash_rot(*b, 16); + *a ^= *c; *a -= hash_rot(*c, 4); + *b ^= *a; *b -= hash_rot(*a, 14); + *c ^= *b; *c -= hash_rot(*b, 24); +} uint32_t hash_words(const uint32_t *, size_t n_word, uint32_t basis); uint32_t hash_2words(uint32_t, uint32_t); @@ -87,7 +93,7 @@ static inline uint32_t hash_boolean(bool x, uint32_t basis) { const uint32_t P0 = 0xc2b73583; /* This is hash_int(1, 0). */ const uint32_t P1 = 0xe90f1258; /* This is hash_int(2, 0). */ - return (x ? P0 : P1) ^ HASH_ROT(basis, 1); + return (x ? P0 : P1) ^ hash_rot(basis, 1); } static inline uint32_t hash_double(double x, uint32_t basis) -- 2.30.2