rooty/dxvk
1
0
Fork 0
mirror of https://github.com/doitsujin/dxvk.git synced 2024-12-02 19:24:12 +01:00
Code Issues Projects Releases Wiki Activity

[util] Optimize popcnt operation

Browse Source
This commit is contained in:
Philip Rebohle 2019-05-09 16:37:45 +02:00
parent a1feaa6748
commit dcd75a4f09
No known key found for this signature in database
GPG Key ID: C8CC613427A31C99
1 changed files with 11 additions and 5 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

16
src/util/util_bit.h
View File

@ -15,11 +15,17 @@ namespace dxvk::bit {
return (value >> fst) & ~(~T(0) << (lst - fst + 1)); return (value >> fst) & ~(~T(0) << (lst - fst + 1));
} }
template<typename T> inline uint32_t popcntStep(uint32_t n, uint32_t mask, uint32_t shift) {
T popcnt(T value) { return (n & mask) + ((n & ~mask) >> shift);
return value != 0 }
? (value & 1) + popcnt(value >> 1)
: 0; inline uint32_t popcnt(uint32_t n) {
n = popcntStep(n, 0x55555555, 1);
n = popcntStep(n, 0x33333333, 2);
n = popcntStep(n, 0x0F0F0F0F, 4);
n = popcntStep(n, 0x00FF00FF, 8);
n = popcntStep(n, 0x0000FFFF, 16);
return n;
} }
inline uint32_t tzcnt(uint32_t n) { inline uint32_t tzcnt(uint32_t n) {