ref: b9ff09189979b272200d32668b4e42f292512dcd
dir: /posix/s_tanf.c/
/* s_tanf.c -- float version of s_tan.c.
* Conversion to float by Ian Lance Taylor, Cygnus Support, [email protected].
*/
/*
* ====================================================
* Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
*
* Developed at SunPro, a Sun Microsystems, Inc. business.
* Permission to use, copy, modify, and distribute this
* software is freely granted, provided that this notice
* is preserved.
* ====================================================
*/
#include "math.h"
#include "math_private.h"
float
tanf(float x)
{
float y[2],z=0.0;
int32_t n, ix;
GET_FLOAT_WORD(ix,x);
/* |x| ~< pi/4 */
ix &= 0x7fffffff;
if(ix <= 0x3f490fda) return __kernel_tanf(x,z,1);
/* tan(Inf or NaN) is NaN */
else if (ix>=0x7f800000) return x-x; /* NaN */
/* argument reduction needed */
else {
n = __ieee754_rem_pio2f(x,y);
return __kernel_tanf(y[0],y[1],1-((n&1)<<1)); /* 1 -- n even
-1 -- n odd */
}
}