s_sinf.c revision 152647
1/* s_sinf.c -- float version of s_sin.c. 2 * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com. 3 */ 4 5/* 6 * ==================================================== 7 * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved. 8 * 9 * Developed at SunPro, a Sun Microsystems, Inc. business. 10 * Permission to use, copy, modify, and distribute this 11 * software is freely granted, provided that this notice 12 * is preserved. 13 * ==================================================== 14 */ 15 16#ifndef lint 17static char rcsid[] = "$FreeBSD: head/lib/msun/src/s_sinf.c 152647 2005-11-21 04:57:12Z bde $"; 18#endif 19 20#include "math.h" 21#define INLINE_KERNEL_COSF 22#define INLINE_KERNEL_SINF 23#include "math_private.h" 24#include "k_cosf.c" 25#include "k_sinf.c" 26 27/* Small multiples of pi/2 rounded to double precision. */ 28static const double 29s1pio2 = 1*M_PI_2, /* 0x3FF921FB, 0x54442D18 */ 30s2pio2 = 2*M_PI_2, /* 0x400921FB, 0x54442D18 */ 31s3pio2 = 3*M_PI_2, /* 0x4012D97C, 0x7F3321D2 */ 32s4pio2 = 4*M_PI_2; /* 0x401921FB, 0x54442D18 */ 33 34static inline float 35__kernel_cosdf(double x) 36{ 37 return __kernel_cosf((float)x, x - (float)x); 38} 39 40static inline float 41__kernel_sindf(double x) 42{ 43 return __kernel_sinf((float)x, x - (float)x, 1); 44} 45 46float 47sinf(float x) 48{ 49 float y[2]; 50 int32_t n, hx, ix; 51 52 GET_FLOAT_WORD(hx,x); 53 ix = hx & 0x7fffffff; 54 55 if(ix <= 0x3f490fda) { /* |x| ~<= pi/4 */ 56 if(ix<0x39800000) /* |x| < 2**-12 */ 57 if(((int)x)==0) return x; /* x with inexact if x != 0 */ 58 return __kernel_sinf(x,0.0,0); 59 } 60 if(ix<=0x407b53d1) { /* |x| <= ~5*pi/4 */ 61 if(ix<=0x4016cbe3) { /* |x| <= ~3pi/4 */ 62 if(hx>0) 63 return __kernel_cosdf(x - s1pio2); 64 else 65 return -__kernel_cosdf(x + s1pio2); 66 } else 67 return -__kernel_sindf(x + (hx > 0 ? -s2pio2 : s2pio2)); 68 } 69 if(ix<=0x40e231d5) { /* |x| <= ~9*pi/4 */ 70 if(ix<=0x40afeddf) { /* |x| <= ~7*pi/4 */ 71 if(hx>0) 72 return -__kernel_cosdf(x - s3pio2); 73 else 74 return __kernel_cosdf(x + s3pio2); 75 } else 76 return __kernel_sindf(x + (hx > 0 ? -s4pio2 : s4pio2)); 77 } 78 79 /* sin(Inf or NaN) is NaN */ 80 else if (ix>=0x7f800000) return x-x; 81 82 /* general argument reduction needed */ 83 else { 84 n = __ieee754_rem_pio2f(x,y); 85 switch(n&3) { 86 case 0: return __kernel_sinf(y[0],y[1],1); 87 case 1: return __kernel_cosf(y[0],y[1]); 88 case 2: return -__kernel_sinf(y[0],y[1],1); 89 default: 90 return -__kernel_cosf(y[0],y[1]); 91 } 92 } 93} 94