nsz Git - musl/blob - src/math/sincosf.c

   1 /* origin: FreeBSD /usr/src/lib/msun/src/s_sinf.c */
   2 /*
   3  * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com.
   4  * Optimized by Bruce D. Evans.
   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 "libm.h"
  18
  19 /* Small multiples of pi/2 rounded to double precision. */
  20 static const double
  21 s1pio2 = 1*M_PI_2, /* 0x3FF921FB, 0x54442D18 */
  22 s2pio2 = 2*M_PI_2, /* 0x400921FB, 0x54442D18 */
  23 s3pio2 = 3*M_PI_2, /* 0x4012D97C, 0x7F3321D2 */
  24 s4pio2 = 4*M_PI_2; /* 0x401921FB, 0x54442D18 */
  25
  26 void sincosf(float x, float *sin, float *cos)
  27 {
  28         double y, s, c;
  29         uint32_t n, hx, ix;
  30
  31         GET_FLOAT_WORD(hx, x);
  32         ix = hx & 0x7fffffff;
  33
  34         /* |x| ~<= pi/4 */
  35         if (ix <= 0x3f490fda) {
  36                 /* |x| < 2**-12 */
  37                 if (ix < 0x39800000) {
  38                         /* raise inexact if x != 0 */
  39                         if((int)x == 0) {
  40                                 *sin = x;
  41                                 *cos = 1.0f;
  42                         }
  43                         return;
  44                 }
  45                 *sin = __sindf(x);
  46                 *cos = __cosdf(x);
  47                 return;
  48         }
  49
  50         /* |x| ~<= 5*pi/4 */
  51         if (ix <= 0x407b53d1) {
  52                 if (ix <= 0x4016cbe3) {  /* |x| ~<= 3pi/4 */
  53                         if (hx < 0x80000000) {
  54                                 *sin = __cosdf(x - s1pio2);
  55                                 *cos = __sindf(s1pio2 - x);
  56                         } else {
  57                                 *sin = -__cosdf(x + s1pio2);
  58                                 *cos = __sindf(x + s1pio2);
  59                         }
  60                         return;
  61                 }
  62                 *sin = __sindf(hx < 0x80000000 ? s2pio2 - x : -s2pio2 - x);
  63                 *cos = -__cosdf(hx < 0x80000000 ? x - s2pio2 : x + s2pio2);
  64                 return;
  65         }
  66
  67         /* |x| ~<= 9*pi/4 */
  68         if (ix <= 0x40e231d5) {
  69                 if (ix <= 0x40afeddf) {  /* |x| ~<= 7*pi/4 */
  70                         if (hx < 0x80000000) {
  71                                 *sin = -__cosdf(x - s3pio2);
  72                                 *cos = __sindf(x - s3pio2);
  73                         } else {
  74                                 *sin = __cosdf(x + s3pio2);
  75                                 *cos = __sindf(-s3pio2 - x);
  76                         }
  77                         return;
  78                 }
  79                 *sin = __sindf(hx < 0x80000000 ? x - s4pio2 : x + s4pio2);
  80                 *cos = __cosdf(hx < 0x80000000 ? x - s4pio2 : x + s4pio2);
  81                 return;
  82         }
  83
  84         /* sin(Inf or NaN) is NaN */
  85         if (ix >= 0x7f800000) {
  86                 *sin = *cos = x - x;
  87                 return;
  88         }
  89
  90         /* general argument reduction needed */
  91         n = __rem_pio2f(x, &y);
  92         s = __sindf(y);
  93         c = __cosdf(y);
  94         switch (n&3) {
  95         case 0:
  96                 *sin = s;
  97                 *cos = c;
  98                 break;
  99         case 1:
 100                 *sin = c;
 101                 *cos = -s;
 102                 break;
 103         case 2:
 104                 *sin = -s;
 105                 *cos = -c;
 106                 break;
 107         case 3:
 108         default:
 109                 *sin = -c;
 110                 *cos = s;
 111                 break;
 112         }
 113 }