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_tanpi.c for implementation details. 29 */ 30 31 #define INLINE_KERNEL_TANDF 32 33 #include "math.h" 34 #include "math_private.h" 35 #include "k_tanf.c" 36 37 static const float 38 pi_hi = 3.14160156e+00F, /* 0x40491000 */ 39 pi_lo = -8.90890988e-06F; /* 0xb715777a */ 40 41 static inline float 42 __kernel_tanpif(float x) 43 { 44 float t; 45 46 if (x < 0.25F) 47 t = __kernel_tandf(M_PI * x, 1); 48 else if (x > 0.25F) 49 t = -__kernel_tandf(M_PI * (0.5 - x), -1); 50 else 51 t = 1; 52 53 return (t); 54 } 55 56 volatile static const float vzero = 0; 57 58 float 59 tanpif(float x) 60 { 61 float ax, hi, lo, t; 62 uint32_t hx, ix, j0; 63 64 GET_FLOAT_WORD(hx, x); 65 ix = hx & 0x7fffffff; 66 SET_FLOAT_WORD(ax, ix); 67 68 if (ix < 0x3f800000) { /* |x| < 1 */ 69 if (ix < 0x3f000000) { /* |x| < 0.5 */ 70 if (ix < 0x38800000) { /* |x| < 0x1p-14 */ 71 if (ix == 0) 72 return (x); 73 SET_FLOAT_WORD(hi, hx & 0xffff0000); 74 hi *= 0x1p23F; 75 lo = x * 0x1p23F - hi; 76 t = (pi_lo + pi_hi) * lo + pi_lo * hi + 77 pi_hi * hi; 78 return (t * 0x1p-23F); 79 } 80 t = __kernel_tanpif(ax); 81 } else if (ix == 0x3f000000) 82 return ((ax - ax) / (ax - ax)); 83 else 84 t = - __kernel_tanpif(1 - ax); 85 return ((hx & 0x80000000) ? -t : t); 86 } 87 88 if (ix < 0x4b000000) { /* 1 <= |x| < 0x1p23 */ 89 /* Determine integer part of ax. */ 90 j0 = ((ix >> 23) & 0xff) - 0x7f; 91 ix &= ~(0x007fffff >> j0); 92 SET_FLOAT_WORD(x, ix); 93 94 ax -= x; 95 GET_FLOAT_WORD(ix, ax); 96 97 if (ix < 0x3f000000) /* |x| < 0.5 */ 98 t = ix == 0 ? 0 : __kernel_tanpif(ax); 99 else if (ix == 0x3f000000) 100 return ((ax - ax) / (ax - ax)); 101 else 102 t = - __kernel_tanpif(1 - ax); 103 return ((hx & 0x80000000) ? -t : t); 104 } 105 106 /* x = +-inf or nan. */ 107 if (ix >= 0x7f800000) 108 return (vzero / vzero); 109 110 /* 111 * |x| >= 0x1p23 is always an integer, so return +-0. 112 */ 113 return (copysignf(0, x)); 114 } 115