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s_sinf.cpp (2220B)


      1 /* s_sinf.c -- float version of s_sin.c.
      2 * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@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 #define	INLINE_KERNEL_COSDF
     23 #define	INLINE_KERNEL_SINDF
     24 #define INLINE_REM_PIO2F
     25 #include "math_private.h"
     26 #include "e_rem_pio2f.cpp"
     27 #include "k_cosf.cpp"
     28 #include "k_sinf.cpp"
     29 
     30 /* Small multiples of pi/2 rounded to double precision. */
     31 static const double
     32 s1pio2 = 1*M_PI_2,			/* 0x3FF921FB, 0x54442D18 */
     33 s2pio2 = 2*M_PI_2,			/* 0x400921FB, 0x54442D18 */
     34 s3pio2 = 3*M_PI_2,			/* 0x4012D97C, 0x7F3321D2 */
     35 s4pio2 = 4*M_PI_2;			/* 0x401921FB, 0x54442D18 */
     36 
     37 float
     38 sinf(float x)
     39 {
     40 double y;
     41 int32_t n, hx, ix;
     42 
     43 GET_FLOAT_WORD(hx,x);
     44 ix = hx & 0x7fffffff;
     45 
     46 if(ix <= 0x3f490fda) {		/* |x| ~<= pi/4 */
     47     if(ix<0x39800000)		/* |x| < 2**-12 */
     48 	if(((int)x)==0) return x;	/* x with inexact if x != 0 */
     49     return __kernel_sindf(x);
     50 }
     51 if(ix<=0x407b53d1) {		/* |x| ~<= 5*pi/4 */
     52     if(ix<=0x4016cbe3) {	/* |x| ~<= 3pi/4 */
     53 	if(hx>0)
     54 	    return __kernel_cosdf(x - s1pio2);
     55 	else
     56 	    return -__kernel_cosdf(x + s1pio2);
     57     } else
     58 	return __kernel_sindf((hx > 0 ? s2pio2 : -s2pio2) - x);
     59 }
     60 if(ix<=0x40e231d5) {		/* |x| ~<= 9*pi/4 */
     61     if(ix<=0x40afeddf) {	/* |x| ~<= 7*pi/4 */
     62 	if(hx>0)
     63 	    return -__kernel_cosdf(x - s3pio2);
     64 	else
     65 	    return __kernel_cosdf(x + s3pio2);
     66     } else
     67 	return __kernel_sindf(x + (hx > 0 ? -s4pio2 : s4pio2));
     68 }
     69 
     70    /* sin(Inf or NaN) is NaN */
     71 else if (ix>=0x7f800000) return x-x;
     72 
     73    /* general argument reduction needed */
     74 else {
     75     n = __ieee754_rem_pio2f(x,&y);
     76     switch(n&3) {
     77 	case 0: return  __kernel_sindf(y);
     78 	case 1: return  __kernel_cosdf(y);
     79 	case 2: return  __kernel_sindf(-y);
     80 	default:
     81 		return -__kernel_cosdf(y);
     82     }
     83 }
     84 }