1/**
 2 * This file has no copyright assigned and is placed in the Public Domain.
 3 * This file is part of the mingw-w64 runtime package.
 4 * No warranty is given; refer to the file DISCLAIMER.PD within this package.
 5 */
 6/*
 7 * Written by J.T. Conklin <jtc@netbsd.org>.
 8 * Public domain.
 9 */
10
11#include <math.h>
12
13float
14acosf (float x)
15{
16  float res = 0.0F;
17
18  /* acosl = atanl (sqrtl(1 - x^2) / x) */
19  asm volatile (
20	"fld	%%st\n\t"
21	"fmul	%%st(0)\n\t"		/* x^2 */
22	"fld1\n\t"
23	"fsubp\n\t"			/* 1 - x^2 */
24	"fsqrt\n\t"			/* sqrtl (1 - x^2) */
25	"fxch	%%st(1)\n\t"
26	"fpatan"
27	: "=t" (res) : "0" (x) : "st(1)");
28  return res;
29}