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Win32 ctz and clz

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This commit is contained in:
Matthew Barr 2016-04-07 13:17:55 +10:00
parent 5234639736
commit b5be8ef6aa
1 changed files with 23 additions and 6 deletions
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29
src/util/bitutils.h
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@ -1,5 +1,5 @@
/* /*
* Copyright (c) 2015, Intel Corporation * Copyright (c) 2015-2016, Intel Corporation
* *
* Redistribution and use in source and binary forms, with or without * Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met: * modification, are permitted provided that the following conditions are met:
@ -86,10 +86,20 @@ u32 clz32(u32 x) {
static really_inline static really_inline
u32 clz64(u64a x) { u32 clz64(u64a x) {
assert(x); // behaviour not defined for x == 0 assert(x); // behaviour not defined for x == 0
#if defined(_WIN32) #if defined(_WIN64)
unsigned long r; unsigned long r;
_BitScanReverse64(&r, x); _BitScanReverse64(&r, x);
return 63 - r; return 63 - r;
#elif defined(_WIN32)
unsigned long x1 = (u32)x;
unsigned long x2 = (u32)(x >> 32);
unsigned long r;
if (x2) {
_BitScanReverse(&r, x2);
return (u32)(31 - r);
}
_BitScanReverse(&r, (u32)x1);
return (u32)(63 - r);
#else #else
return (u32)__builtin_clzll(x); return (u32)__builtin_clzll(x);
#endif #endif
@ -111,10 +121,17 @@ u32 ctz32(u32 x) {
static really_inline static really_inline
u32 ctz64(u64a x) { u32 ctz64(u64a x) {
assert(x); // behaviour not defined for x == 0 assert(x); // behaviour not defined for x == 0
#if defined(_WIN32) #if defined(_WIN64)
unsigned long r; unsigned long r;
_BitScanForward64(&r, x); _BitScanForward64(&r, x);
return r; return r;
#elif defined(_WIN32)
unsigned long r;
if (_BitScanForward(&r, (u32)x)) {
return (u32)r;
}
_BitScanForward(&r, x >> 32);
return (u32)(r + 32);
#else #else
return (u32)__builtin_ctzll(x); return (u32)__builtin_ctzll(x);
#endif #endif
@ -177,8 +194,8 @@ u32 findAndClearLSB_64(u64a *v) {
#else #else
// fall back to doing things with two 32-bit cases, since gcc-4.1 doesn't // fall back to doing things with two 32-bit cases, since gcc-4.1 doesn't
// inline calls to __builtin_ctzll // inline calls to __builtin_ctzll
u32 v1 = *v; u32 v1 = (u32)*v;
u32 v2 = (*v >> 32); u32 v2 = (u32)(*v >> 32);
u32 offset; u32 offset;
if (v1) { if (v1) {
offset = findAndClearLSB_32(&v1); offset = findAndClearLSB_32(&v1);
@ -233,7 +250,7 @@ u32 findAndClearMSB_64(u64a *v) {
#else #else
// fall back to doing things with two 32-bit cases, since gcc-4.1 doesn't // fall back to doing things with two 32-bit cases, since gcc-4.1 doesn't
// inline calls to __builtin_ctzll // inline calls to __builtin_ctzll
u32 v1 = *v; u32 v1 = (u32)*v;
u32 v2 = (*v >> 32); u32 v2 = (*v >> 32);
u32 offset; u32 offset;
if (v2) { if (v2) {