Unified · Split
| @@ -3,6 +3,7 @@ · 2 unmodified lines | |||
| 3 | Random snippets of code that are in public domain. | 3 | Random snippets of code that are in public domain. |
| 4 | Just copy and use for whatever you want. | 4 | Just copy and use for whatever you want. |
| 5 | 5 | ||
| 6 | * `c_builtins*` a few __builtin_* for Plan 9, useful for porting other software | ||
| 6 | * `lrint.c` lrint* implementation | 7 | * `lrint.c` lrint* implementation |
| 7 | * `msr.c` MSR reading tool | 8 | * `msr.c` MSR reading tool |
| 8 | * `nanosec.c` nanosec(), a replacement for (way more expensive) nsec() | 9 | * `nanosec.c` nanosec(), a replacement for (way more expensive) nsec() |
| @@ -0,0 +1,29 @@ | |||
| 1 | int | ||
| 2 | __builtin_ctz(unsigned int x) | ||
| 3 | { | ||
| 4 | unsigned int r; | ||
| 5 | if(x == 0) | ||
| 6 | return 32; | ||
| 7 | for(r = 0; (x & 1) == 0; x >>= 1, r++); | ||
| 8 | return r; | ||
| 9 | } | ||
| 10 | |||
| 11 | int | ||
| 12 | __builtin_clz(unsigned int x) | ||
| 13 | { | ||
| 14 | unsigned int r; | ||
| 15 | if(x == 0) | ||
| 16 | return 32; | ||
| 17 | for(r = 0; (x & (1UL<<31)) == 0; x <<= 1, r++); | ||
| 18 | return r; | ||
| 19 | } | ||
| 20 | |||
| 21 | int | ||
| 22 | __builtin_clzll(unsigned long long x) | ||
| 23 | { | ||
| 24 | unsigned long long r; | ||
| 25 | if(x == 0) | ||
| 26 | return 64; | ||
| 27 | for(r = 0; (x & (1ULL<<63)) == 0; x <<= 1, r++); | ||
| 28 | return r; | ||
| 29 | } | ||
| @@ -0,0 +1,13 @@ | |||
| 1 | TEXT __builtin_ctz(SB),1,$0 | ||
| 2 | BYTE $0x0F; BYTE $0xBC; BYTE $0xC5 /* BSFL RARG, AX */ | ||
| 3 | RET | ||
| 4 | |||
| 5 | TEXT __builtin_clz(SB),1,$0 | ||
| 6 | BYTE $0x0F; BYTE $0xBD; BYTE $0xC5 /* BSRL RARG, AX */ | ||
| 7 | XORL $31, AX | ||
| 8 | RET | ||
| 9 | |||
| 10 | TEXT __builtin_clzll(SB),1,$0 | ||
| 11 | BYTE $0x48; BYTE $0x0F; BYTE $0xBD; BYTE $0xC5 /* BSRQ RARG, AX */ | ||
| 12 | XORL $63, AX | ||
| 13 | RET | ||