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      1 /* s_cosf.c -- float version of s_cos.c.
      2  * Conversion to float by Ian Lance Taylor, Cygnus Support, ian (at) cygnus.com.
      3  * Optimized by Bruce D. Evans.
      4  */
      5 
      6 /*
      7  * ====================================================
      8  * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
      9  *
     10  * Developed at SunPro, a Sun Microsystems, Inc. business.
     11  * Permission to use, copy, modify, and distribute this
     12  * software is freely granted, provided that this notice
     13  * is preserved.
     14  * ====================================================
     15  */
     16 
     17 #include <sys/cdefs.h>
     18 __FBSDID("$FreeBSD$");
     19 
     20 #include <float.h>
     21 
     22 #include "math.h"
     23 #define	INLINE_KERNEL_COSDF
     24 #define	INLINE_KERNEL_SINDF
     25 #define INLINE_REM_PIO2F
     26 #include "math_private.h"
     27 #include "e_rem_pio2f.c"
     28 #include "k_cosf.c"
     29 #include "k_sinf.c"
     30 
     31 /* Small multiples of pi/2 rounded to double precision. */
     32 static const double
     33 c1pio2 = 1*M_PI_2,			/* 0x3FF921FB, 0x54442D18 */
     34 c2pio2 = 2*M_PI_2,			/* 0x400921FB, 0x54442D18 */
     35 c3pio2 = 3*M_PI_2,			/* 0x4012D97C, 0x7F3321D2 */
     36 c4pio2 = 4*M_PI_2;			/* 0x401921FB, 0x54442D18 */
     37 
     38 float
     39 cosf(float x)
     40 {
     41 	double y;
     42 	int32_t n, hx, ix;
     43 
     44 	GET_FLOAT_WORD(hx,x);
     45 	ix = hx & 0x7fffffff;
     46 
     47 	if(ix <= 0x3f490fda) {		/* |x| ~<= pi/4 */
     48 	    if(ix<0x39800000)		/* |x| < 2**-12 */
     49 		if(((int)x)==0) return 1.0;	/* 1 with inexact if x != 0 */
     50 	    return __kernel_cosdf(x);
     51 	}
     52 	if(ix<=0x407b53d1) {		/* |x| ~<= 5*pi/4 */
     53 	    if(ix>0x4016cbe3)		/* |x|  ~> 3*pi/4 */
     54 		return -__kernel_cosdf(x + (hx > 0 ? -c2pio2 : c2pio2));
     55 	    else {
     56 		if(hx>0)
     57 		    return __kernel_sindf(c1pio2 - x);
     58 		else
     59 		    return __kernel_sindf(x + c1pio2);
     60 	    }
     61 	}
     62 	if(ix<=0x40e231d5) {		/* |x| ~<= 9*pi/4 */
     63 	    if(ix>0x40afeddf)		/* |x|  ~> 7*pi/4 */
     64 		return __kernel_cosdf(x + (hx > 0 ? -c4pio2 : c4pio2));
     65 	    else {
     66 		if(hx>0)
     67 		    return __kernel_sindf(x - c3pio2);
     68 		else
     69 		    return __kernel_sindf(-c3pio2 - x);
     70 	    }
     71 	}
     72 
     73     /* cos(Inf or NaN) is NaN */
     74 	else if (ix>=0x7f800000) return x-x;
     75 
     76     /* general argument reduction needed */
     77 	else {
     78 	    n = __ieee754_rem_pio2f(x,&y);
     79 	    switch(n&3) {
     80 		case 0: return  __kernel_cosdf(y);
     81 		case 1: return  __kernel_sindf(-y);
     82 		case 2: return -__kernel_cosdf(y);
     83 		default:
     84 		        return  __kernel_sindf(y);
     85 	    }
     86 	}
     87 }
     88