diff options
Diffstat (limited to 'src/mesa/main/imports.h')
| -rw-r--r-- | src/mesa/main/imports.h | 48 |
1 files changed, 48 insertions, 0 deletions
diff --git a/src/mesa/main/imports.h b/src/mesa/main/imports.h index b01fe5b0ab..3843f50036 100644 --- a/src/mesa/main/imports.h +++ b/src/mesa/main/imports.h @@ -405,6 +405,54 @@ _mesa_is_pow_two(int x) return !(x & (x - 1)); } +/** + * Round given integer to next higer power of two + * If X is zero result is undefined. + * + * Source for the fallback implementation is + * Sean Eron Anderson's webpage "Bit Twiddling Hacks" + * http://graphics.stanford.edu/~seander/bithacks.html + */ +static INLINE int32_t +_mesa_next_pow_two_32(uint32_t x) +{ +#ifdef __GNUC__ + x--; + return 1 << ((__builtin_clz(x) ^ 31) + 1); +#else + x--; + x |= x >> 1; + x |= x >> 2; + x |= x >> 4; + x |= x >> 8; + x |= x >> 16; + x++; + return x; +#endif +} + +static INLINE int64_t +_mesa_next_pow_two_64(uint64_t x) +{ +#ifdef __GNUC__ + x--; + if (sizeof(x) == sizeof(long)) + return 1 << ((__builtin_clzl(x) ^ 63) + 1); + else + return 1 << ((__builtin_clzll(x) ^ 63) + 1); +#else + x--; + x |= x >> 1; + x |= x >> 2; + x |= x >> 4; + x |= x >> 8; + x |= x >> 16; + x |= x >> 32; + x++; + return x; +#endif +} + /*** *** UNCLAMPED_FLOAT_TO_UBYTE: clamp float to [0,1] and map to ubyte in [0,255] |