LibC: add math.h with floorl

This commit is contained in:
Bananymous 2023-05-10 22:35:20 +03:00
parent 0d9422ead8
commit 5f89f083a2
3 changed files with 37 additions and 1 deletions

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@ -1,6 +1,6 @@
cmake_minimum_required(VERSION 3.26)
project(libc CXX)
project(libc CXX ASM)
set(LIBC_SOURCES
ctype.cpp
@ -10,6 +10,7 @@ set(LIBC_SOURCES
stdlib.cpp
string.cpp
unistd.cpp
math.S
)
add_custom_target(libc-headers

9
libc/include/math.h Normal file
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@ -0,0 +1,9 @@
#pragma once
#include <sys/cdefs.h>
__BEGIN_DECLS
long double floorl(long double);
__END_DECLS

26
libc/math.S Normal file
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@ -0,0 +1,26 @@
.global floorl;
floorl:
fldt 8(%rsp)
fnstenv -28(%rsp) /* store fpu environment */
/* We use here %edx although only the low 1 bits are defined.
But none of the operations should care and they are faster
than the 16 bit operations. */
movl $0x400,%edx /* round towards -oo */
orl -28(%rsp),%edx
andl $0xf7ff,%edx
movl %edx,-32(%rsp)
fldcw -32(%rsp) /* load modified control word */
frndint /* round */
/* Preserve "invalid" exceptions from sNaN input. */
fnstsw
andl $0x1, %eax
orl %eax, -24(%rsp)
fldenv -28(%rsp) /* restore original environment */
ret