diff options
| -rw-r--r-- | source/blender/blenlib/BLI_math_bits.h | 8 | ||||
| -rw-r--r-- | source/blender/blenlib/intern/math_bits_inline.c | 34 |
2 files changed, 42 insertions, 0 deletions
diff --git a/source/blender/blenlib/BLI_math_bits.h b/source/blender/blenlib/BLI_math_bits.h index 40a1d84b0e1..248b615e3f8 100644 --- a/source/blender/blenlib/BLI_math_bits.h +++ b/source/blender/blenlib/BLI_math_bits.h @@ -31,6 +31,14 @@ extern "C" { #include "BLI_math_inline.h" +/* Search the value from LSB to MSB for a set bit. Returns index of this bit. */ +MINLINE int bitscan_forward_i(int a); +MINLINE unsigned int bitscan_forward_uint(unsigned int a); + +/* Search the value from MSB to LSB for a set bit. Returns index of this bit. */ +MINLINE int bitscan_reverse_i(int a); +MINLINE unsigned int bitscan_reverse_uint(unsigned int a); + /* NOTE: Those functions returns 2 to the power of index of highest order bit. */ MINLINE unsigned int highest_order_bit_uint(unsigned int n); MINLINE unsigned short highest_order_bit_s(unsigned short n); diff --git a/source/blender/blenlib/intern/math_bits_inline.c b/source/blender/blenlib/intern/math_bits_inline.c index 9f502d367cb..fdef0f9c9c6 100644 --- a/source/blender/blenlib/intern/math_bits_inline.c +++ b/source/blender/blenlib/intern/math_bits_inline.c @@ -27,6 +27,40 @@ #include "BLI_math_bits.h" +MINLINE int bitscan_forward_i(int a) +{ + BLI_assert(a != 0); +# ifdef _MSC_VER + unsigned long ctz; + _BitScanForward(&ctz, a); + return ctz; +#else + return __builtin_ctz((unsigned int)a); +#endif +} + +MINLINE unsigned int bitscan_forward_uint(unsigned int a) +{ + return (unsigned int)bitscan_forward_i((int)a); +} + +MINLINE int bitscan_reverse_i(int a) +{ + BLI_assert(a != 0); +# ifdef _MSC_VER + unsigned long clz; + _BitScanReverse(&clz, a); + return clz; +#else + return __builtin_clz((unsigned int)a); +#endif +} + +MINLINE unsigned int bitscan_reverse_uint(unsigned int a) +{ + return (unsigned int)bitscan_reverse_i((int)a); +} + MINLINE unsigned int highest_order_bit_uint(unsigned int n) { n |= (n >> 1); |