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| author | Yang Liu <liuyang22@iscas.ac.cn> | 2023-03-16 14:43:53 +0800 |
|---|---|---|
| committer | GitHub <noreply@github.com> | 2023-03-16 07:43:53 +0100 |
| commit | e579450af61a2b953b6309c5a3aad4a3d94a8393 (patch) | |
| tree | 061d1c76e4113ac1ba7d58ee1bc31953addb8e64 /src/tools/bitutils.c | |
| parent | 50e463917ca388d1fd7285ce0b12476963e97c0f (diff) | |
| download | box64-e579450af61a2b953b6309c5a3aad4a3d94a8393.tar.gz box64-e579450af61a2b953b6309c5a3aad4a3d94a8393.zip | |
[RV64_DYNAREC] Optimize MOV64 emitter (#572)
Diffstat (limited to 'src/tools/bitutils.c')
| -rw-r--r-- | src/tools/bitutils.c | 17 |
1 files changed, 17 insertions, 0 deletions
diff --git a/src/tools/bitutils.c b/src/tools/bitutils.c new file mode 100644 index 00000000..518085c2 --- /dev/null +++ b/src/tools/bitutils.c @@ -0,0 +1,17 @@ +#include <stdint.h> + +const uint64_t deBruijn64 = 0x03f79d71b4ca8b09; +const uint8_t deBruijn64tab[64] = { + 0, 1, 56, 2, 57, 49, 28, 3, 61, 58, 42, 50, 38, 29, 17, 4, + 62, 47, 59, 36, 45, 43, 51, 22, 53, 39, 33, 30, 24, 18, 12, 5, + 63, 55, 48, 27, 60, 41, 37, 16, 46, 35, 44, 21, 52, 32, 23, 11, + 54, 26, 40, 15, 34, 20, 31, 10, 25, 14, 19, 9, 13, 8, 7, 6, +}; + +int TrailingZeros64(uint64_t x) { + if (x == 0) { + return 64; + } + + return (int)deBruijn64tab[(x&-x)*deBruijn64>>(64-6)]; +} |