s_cosf.c revision 152540 
12116Sjkh/* s_cosf.c -- float version of s_cos.c.
22116Sjkh * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com.
32116Sjkh */
42116Sjkh
52116Sjkh/*
62116Sjkh * ====================================================
72116Sjkh * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
82116Sjkh *
92116Sjkh * Developed at SunPro, a Sun Microsystems, Inc. business.
102116Sjkh * Permission to use, copy, modify, and distribute this
118870Srgrimes * software is freely granted, provided that this notice
122116Sjkh * is preserved.
132116Sjkh * ====================================================
142116Sjkh */
152116Sjkh
162116Sjkh#ifndef lint
1750476Speterstatic char rcsid[] = "$FreeBSD: head/lib/msun/src/s_cosf.c 152540 2005-11-17 03:53:22Z bde $";
182116Sjkh#endif
192116Sjkh
202116Sjkh#include "math.h"
212116Sjkh#include "math_private.h"
222116Sjkh
2397413Salfredfloat
2497413Salfredcosf(float x)
252116Sjkh{
26152540Sbde	float y[2];
272116Sjkh	int32_t n,ix;
282116Sjkh
292116Sjkh	GET_FLOAT_WORD(ix,x);
30152540Sbde	ix &= 0x7fffffff;
312116Sjkh
32152540Sbde	if(ix <= 0x3f490fda) {		/* |x| ~<= pi/4 */
33152540Sbde	    if(ix<0x39800000)		/* |x| < 2**-12 */
34152540Sbde		if(((int)x)==0) return 1.0;	/* 1 with inexact if x != 0 */
35152540Sbde	    return __kernel_cosf(x,0.0);
36151620Sbde	}
372116Sjkh
382116Sjkh    /* cos(Inf or NaN) is NaN */
392116Sjkh	else if (ix>=0x7f800000) return x-x;
402116Sjkh
412116Sjkh    /* argument reduction needed */
422116Sjkh	else {
432116Sjkh	    n = __ieee754_rem_pio2f(x,y);
442116Sjkh	    switch(n&3) {
452116Sjkh		case 0: return  __kernel_cosf(y[0],y[1]);
462116Sjkh		case 1: return -__kernel_sinf(y[0],y[1],1);
472116Sjkh		case 2: return -__kernel_cosf(y[0],y[1]);
482116Sjkh		default:
492116Sjkh		        return  __kernel_sinf(y[0],y[1],1);
502116Sjkh	    }
512116Sjkh	}
522116Sjkh}
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