/*      $OpenBSD: e_acos.S,v 1.4 2016/09/12 19:47:02 guenther Exp $ */
/*
 * Written by J.T. Conklin <jtc@netbsd.org>.
 * Public domain.
 */

#include <machine/asm.h>

/* acos = atan (sqrt(1 - x^2) / x) */
ENTRY(acos)
        fldl    4(%esp)                 /* x */
        fst     %st(1)
        fmul    %st(0)                  /* x^2 */
        fld1                            
        fsubp                           /* 1 - x^2 */
        fsqrt                           /* sqrt (1 - x^2) */
        fxch    %st(1)
        fpatan
        ret
END(acos)