lib/msun/src/s_sincosf.c

   1 /*-
   2  * ====================================================
   3  * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
   4  *
   5  * Developed at SunPro, a Sun Microsystems, Inc. business.
   6  * Permission to use, copy, modify, and distribute this
   7  * software is freely granted, provided that this notice
   8  * is preserved.
   9  * ====================================================
  10  */
  11
  12 /* s_sincosf.c -- float version of s_sincos.c.
  13  * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com.
  14  * Optimized by Bruce D. Evans.
  15  * Merged s_sinf.c and s_cosf.c by Steven G. Kargl.
  16  */
  17
  18 #include <sys/cdefs.h>
  19 #include <float.h>
  20
  21 #include "math.h"
  22 #define INLINE_REM_PIO2F
  23 #include "math_private.h"
  24 #include "e_rem_pio2f.c"
  25 #include "k_sincosf.h"
  26
  27 /* Small multiples of pi/2 rounded to double precision. */
  28 static const double
  29 p1pio2 = 1*M_PI_2,                      /* 0x3FF921FB, 0x54442D18 */
  30 p2pio2 = 2*M_PI_2,                      /* 0x400921FB, 0x54442D18 */
  31 p3pio2 = 3*M_PI_2,                      /* 0x4012D97C, 0x7F3321D2 */
  32 p4pio2 = 4*M_PI_2;                      /* 0x401921FB, 0x54442D18 */
  33
  34 void
  35 sincosf(float x, float *sn, float *cs)
  36 {
  37         float c, s;
  38         double y;
  39         int32_t n, hx, ix;
  40
  41         GET_FLOAT_WORD(hx, x);
  42         ix = hx & 0x7fffffff;
  43
  44         if (ix <= 0x3f490fda) {         /* |x| ~<= pi/4 */
  45                 if (ix < 0x39800000) {  /* |x| < 2**-12 */
  46                         if ((int)x == 0) {
  47                                 *sn = x;        /* x with inexact if x != 0 */
  48                                 *cs = 1;
  49                                 return;
  50                         }
  51                 }
  52                 __kernel_sincosdf(x, sn, cs);
  53                 return;
  54         }
  55
  56         if (ix <= 0x407b53d1) {         /* |x| ~<= 5*pi/4 */
  57                 if (ix <= 0x4016cbe3) { /* |x| ~<= 3pi/4 */
  58                         if (hx > 0) {
  59                                 __kernel_sincosdf(x - p1pio2, cs, sn);
  60                                 *cs = -*cs;
  61                         } else {
  62                                 __kernel_sincosdf(x + p1pio2, cs, sn);
  63                                 *sn = -*sn;
  64                         }
  65                 } else {
  66                         if (hx > 0)
  67                                 __kernel_sincosdf(x - p2pio2, sn, cs);
  68                         else
  69                                 __kernel_sincosdf(x + p2pio2, sn, cs);
  70                         *sn = -*sn;
  71                         *cs = -*cs;
  72                 }
  73                 return;
  74         }
  75
  76         if (ix <= 0x40e231d5) {         /* |x| ~<= 9*pi/4 */
  77                 if (ix <= 0x40afeddf) { /* |x| ~<= 7*pi/4 */
  78                         if (hx > 0) {
  79                                 __kernel_sincosdf(x - p3pio2, cs, sn);
  80                                 *sn = -*sn;
  81                         } else {
  82                                 __kernel_sincosdf(x + p3pio2, cs, sn);
  83                                 *cs = -*cs;
  84                         }
  85                 } else {
  86                         if (hx > 0)
  87                                 __kernel_sincosdf(x - p4pio2, sn, cs);
  88                         else
  89                                 __kernel_sincosdf(x + p4pio2, sn, cs);
  90                 }
  91                 return;
  92         }
  93
  94         /* If x = Inf or NaN, then sin(x) = NaN and cos(x) = NaN. */
  95         if (ix >= 0x7f800000) {
  96                 *sn = x - x;
  97                 *cs = x - x;
  98                 return;
  99         }
 100
 101         /* Argument reduction. */
 102         n = __ieee754_rem_pio2f(x, &y);
 103         __kernel_sincosdf(y, &s, &c);
 104
 105         switch(n & 3) {
 106         case 0:
 107                 *sn = s;
 108                 *cs = c;
 109                 break;
 110         case 1:
 111                 *sn = c;
 112                 *cs = -s;
 113                 break;
 114         case 2:
 115                 *sn = -s;
 116                 *cs = -c;
 117                 break;
 118         default:
 119                 *sn = -c;
 120                 *cs = s;
 121         }
 122 }
 123
 124