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Add ANSI version of bsr/bsf

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Justine Tunney 2023-08-13 08:19:00 -07:00
parent b40d41085d
commit 5d5b4ce691
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GPG key ID: BE714B4575D6E328
2 changed files with 51 additions and 29 deletions
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25
libc/intrin/bsf.c
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@ -32,11 +32,20 @@
* 0x08000000 27 27 28 27 4
* 0xffffffff 0 0 1 31 0
*
* @param x is a 32-bit integer
* @return number in range 0..31 or undefined if 𝑥 is 0
* @param 𝑥 is a 64-bit integer
* @return number in range 0..63 or undefined if 𝑥 is 0
*/
int(_bsf)(int x) {
return _bsf(x);
int(_bsfl)(long x) {
unsigned l, r;
x &= -x;
l = x | x >> 32;
r = !!(x >> 32), r <<= 1;
r += !!((l & 0xffff0000)), r <<= 1;
r += !!((l & 0xff00ff00)), r <<= 1;
r += !!((l & 0xf0f0f0f0)), r <<= 1;
r += !!((l & 0xcccccccc)), r <<= 1;
r += !!((l & 0xaaaaaaaa));
return r;
}
/**
@ -53,11 +62,11 @@ int(_bsf)(int x) {
* 0x08000000 27 27 28 27 4
* 0xffffffff 0 0 1 31 0
*
* @param 𝑥 is a 64-bit integer
* @return number in range 0..63 or undefined if 𝑥 is 0
* @param x is a 32-bit integer
* @return number in range 0..31 or undefined if 𝑥 is 0
*/
int(_bsfl)(long x) {
return _bsfl(x);
int(_bsf)(int x) {
return _bsf((unsigned)x);
}
__weak_reference(_bsfl, _bsfll);