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Make pow() conform to standard definition

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This commit is contained in:
Justine Tunney 2021-03-03 09:05:21 -08:00
parent 754974faaa
commit 8af91bcbe7
15 changed files with 253 additions and 85 deletions
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25
libc/tinymath/truncl.S
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@ -17,18 +17,23 @@
│ PERFORMANCE OF THIS SOFTWARE. │
╚─────────────────────────────────────────────────────────────────────────────*/
#include "libc/macros.internal.h"
.source __FILE__
truncl: .profilable
sub $24,%rsp
fldt 32(%rsp)
fnstcw 14(%rsp)
movzwl 14(%rsp),%eax
// Rounds to integer, toward zero.
//
// @param 𝑥 is long double passed on stack
// @return long double in %st
truncl: pushq %rbp
mov %rsp,%rbp
.profilable
sub $16,%rsp
fnstcw -2(%rbp)
fldt 16(%rbp)
movzwl -2(%rbp),%eax
or $0b1100,%ah # round to zero
mov %ax,12(%rsp)
fldcw 12(%rsp)
mov %ax,-4(%rbp)
fldcw -4(%rbp)
frndint
fldcw 14(%rsp)
add $24,%rsp
fldcw -2(%rbp)
leave
ret
.endfn truncl,globl