zig/lib/libc/mingw/math/x86/acosf.c
Andrew Kelley 49d1a4c562 move lib dirs to lib subdir
also start prefering NtDll API. so far:
 * NtQueryInformationFile
 * NtClose

adds a performance workaround for windows unicode conversion. but that
should probably be removed before merging
2019-07-15 17:54:50 -04:00

30 lines
618 B
C

/**
* This file has no copyright assigned and is placed in the Public Domain.
* This file is part of the mingw-w64 runtime package.
* No warranty is given; refer to the file DISCLAIMER.PD within this package.
*/
/*
* Written by J.T. Conklin <jtc@netbsd.org>.
* Public domain.
*/
#include <math.h>
float
acosf (float x)
{
float res = 0.0F;
/* acosl = atanl (sqrtl(1 - x^2) / x) */
asm volatile (
"fld %%st\n\t"
"fmul %%st(0)\n\t" /* x^2 */
"fld1\n\t"
"fsubp\n\t" /* 1 - x^2 */
"fsqrt\n\t" /* sqrtl (1 - x^2) */
"fxch %%st(1)\n\t"
"fpatan"
: "=t" (res) : "0" (x) : "st(1)");
return res;
}