1 /*- 2 * Copyright (c) 2017 Steven G. Kargl 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice unmodified, this list of conditions, and the following 10 * disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 16 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 17 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 18 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 19 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 20 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 21 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 22 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 24 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 25 */ 26 27 /* 28 * See ../src/s_cospi.c for implementation details. 29 */ 30 #define INLINE_KERNEL_SINDF 31 #define INLINE_KERNEL_COSDF 32 33 #include "math.h" 34 #include "math_private.h" 35 #include "k_cosf.c" 36 #include "k_sinf.c" 37 38 #define __kernel_cospif(x) (__kernel_cosdf(M_PI * (x))) 39 #define __kernel_sinpif(x) (__kernel_sindf(M_PI * (x))) 40 41 volatile static const float vzero = 0; 42 43 float 44 cospif(float x) 45 { 46 float ax, c; 47 uint32_t ix, j0; 48 49 GET_FLOAT_WORD(ix, x); 50 ix = ix & 0x7fffffff; 51 SET_FLOAT_WORD(ax, ix); 52 53 if (ix < 0x3f800000) { /* |x| < 1 */ 54 if (ix < 0x3e800000) { /* |x| < 0.25 */ 55 if (ix < 0x38800000) { /* |x| < 0x1p-14 */ 56 /* Raise inexact iff != 0. */ 57 if ((int)ax == 0) 58 return (1); 59 } 60 return (__kernel_cospif(ax)); 61 } 62 63 if (ix < 0x3f000000) /* |x| < 0.5 */ 64 c = __kernel_sinpif(0.5F - ax); 65 else if (ix < 0x3f400000) { /* |x| < 0.75 */ 66 if (ix == 0x3f000000) 67 return (0); 68 c = -__kernel_sinpif(ax - 0.5F); 69 } else 70 c = -__kernel_cospif(1 - ax); 71 return (c); 72 } 73 74 if (ix < 0x4b000000) { /* 1 <= |x| < 0x1p23 */ 75 /* Determine integer part of ax. */ 76 j0 = ((ix >> 23) & 0xff) - 0x7f; 77 ix &= ~(0x007fffff >> j0); 78 SET_FLOAT_WORD(x, ix); 79 80 ax -= x; 81 GET_FLOAT_WORD(ix, ax); 82 83 if (ix < 0x3f000000) { /* |x| < 0.5 */ 84 if (ix < 0x3e800000) /* |x| < 0.25 */ 85 c = ix == 0 ? 1 : __kernel_cospif(ax); 86 else 87 c = __kernel_sinpif(0.5F - ax); 88 } else { 89 if (ix < 0x3f400000) { /* |x| < 0.75 */ 90 if (ix == 0x3f000000) 91 return (0); 92 c = -__kernel_sinpif(ax - 0.5F); 93 } else 94 c = -__kernel_cospif(1 - ax); 95 } 96 97 j0 = (uint32_t)x; 98 return (j0 & 1 ? -c : c); 99 } 100 101 /* x = +-inf or nan. */ 102 if (ix >= 0x7f800000) 103 return (vzero / vzero); 104 105 /* 106 * |x| >= 0x1p23 is always an even integer, so return 1. 107 */ 108 return (1); 109 } 110