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| author | Marek Olšák <marek.olsak@amd.com> | 2015-08-28 20:53:08 +0200 |
|---|---|---|
| committer | Marek Olšák <marek.olsak@amd.com> | 2015-09-01 21:51:13 +0200 |
| commit | fc292b5821ca2d21cf5ebc83994138b87085d878 (patch) | |
| tree | 025a83ee541f601109361ffd816f56d14b2ac6cc /src/gallium/auxiliary | |
| parent | d38a5601068ae1d923efece8f28757777f4474e4 (diff) | |
| download | external_mesa3d-fc292b5821ca2d21cf5ebc83994138b87085d878.zip external_mesa3d-fc292b5821ca2d21cf5ebc83994138b87085d878.tar.gz external_mesa3d-fc292b5821ca2d21cf5ebc83994138b87085d878.tar.bz2 | |
gallium/util: add u_bit_scan_consecutive_range
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Acked-by: Christian König <christian.koenig@amd.com>
Diffstat (limited to 'src/gallium/auxiliary')
| -rw-r--r-- | src/gallium/auxiliary/util/u_math.h | 20 |
1 files changed, 20 insertions, 0 deletions
diff --git a/src/gallium/auxiliary/util/u_math.h b/src/gallium/auxiliary/util/u_math.h index 56bd185..7175d1d 100644 --- a/src/gallium/auxiliary/util/u_math.h +++ b/src/gallium/auxiliary/util/u_math.h @@ -483,6 +483,26 @@ u_bit_scan64(uint64_t *mask) } #endif +/* For looping over a bitmask when you want to loop over consecutive bits + * manually, for example: + * + * while (mask) { + * int start, count, i; + * + * u_bit_scan_consecutive_range(&mask, &start, &count); + * + * for (i = 0; i < count; i++) + * ... process element (start+i) + * } + */ +static inline void +u_bit_scan_consecutive_range(unsigned *mask, int *start, int *count) +{ + *start = ffs(*mask) - 1; + *count = ffs(~(*mask >> *start)) - 1; + *mask &= ~(((1 << *count) - 1) << *start); +} + /** * Return float bits. */ |