lib/msun/ld80/invtrig.h

   1 /*-
   2  * Copyright (c) 2008 David Schultz <das@FreeBSD.ORG>
   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, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  *
  14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  24  * SUCH DAMAGE.
  25  *
  26  * $FreeBSD$
  27  */
  28
  29 #include <float.h>
  30
  31 #include "fpmath.h"
  32
  33 #define BIAS            (LDBL_MAX_EXP - 1)
  34 #define MANH_SIZE       LDBL_MANH_SIZE
  35
  36 /* Approximation thresholds. */
  37 #define ASIN_LINEAR     (BIAS - 32)     /* 2**-32 */
  38 #define ACOS_CONST      (BIAS - 65)     /* 2**-65 */
  39 #define ATAN_CONST      (BIAS + 65)     /* 2**65 */
  40 #define ATAN_LINEAR     (BIAS - 32)     /* 2**-32 */
  41
  42 /* 0.95 */
  43 #define THRESH  ((0xe666666666666666ULL>>(64-(MANH_SIZE-1)))|LDBL_NBIT)
  44
  45 /* Constants shared by the long double inverse trig functions. */
  46 #define pS0     _ItL_pS0
  47 #define pS1     _ItL_pS1
  48 #define pS2     _ItL_pS2
  49 #define pS3     _ItL_pS3
  50 #define pS4     _ItL_pS4
  51 #define pS5     _ItL_pS5
  52 #define pS6     _ItL_pS6
  53 #define qS1     _ItL_qS1
  54 #define qS2     _ItL_qS2
  55 #define qS3     _ItL_qS3
  56 #define qS4     _ItL_qS4
  57 #define qS5     _ItL_qS5
  58 #define atanhi  _ItL_atanhi
  59 #define atanlo  _ItL_atanlo
  60 #define aT      _ItL_aT
  61 #define pi_lo   _ItL_pi_lo
  62
  63 #define pio2_hi atanhi[3]
  64 #define pio2_lo atanlo[3]
  65 #define pio4_hi atanhi[1]
  66
  67 #ifdef STRUCT_DECLS
  68 typedef struct longdouble {
  69         uint64_t mant;
  70         uint16_t expsign;
  71 } LONGDOUBLE;
  72 #else
  73 typedef long double LONGDOUBLE;
  74 #endif
  75
  76 extern const LONGDOUBLE pS0, pS1, pS2, pS3, pS4, pS5, pS6;
  77 extern const LONGDOUBLE qS1, qS2, qS3, qS4, qS5;
  78 extern const LONGDOUBLE atanhi[], atanlo[], aT[];
  79 extern const LONGDOUBLE pi_lo;
  80
  81 #ifndef STRUCT_DECLS
  82
  83 static inline long double
  84 P(long double x)
  85 {
  86
  87         return (x * (pS0 + x * (pS1 + x * (pS2 + x * (pS3 + x * \
  88                 (pS4 + x * (pS5 + x * pS6)))))));
  89 }
  90
  91 static inline long double
  92 Q(long double x)
  93 {
  94
  95         return (1.0 + x * (qS1 + x * (qS2 + x * (qS3 + x * (qS4 + x * qS5)))));
  96 }
  97
  98 static inline long double
  99 T_even(long double x)
 100 {
 101
 102         return (aT[0] + x * (aT[2] + x * (aT[4] + x * (aT[6] + x * \
 103                 (aT[8] + x * (aT[10] + x * aT[12]))))));
 104 }
 105
 106 static inline long double
 107 T_odd(long double x)
 108 {
 109
 110         return (aT[1] + x * (aT[3] + x * (aT[5] + x * (aT[7] + x * \
 111                 (aT[9] + x * aT[11])))));
 112 }
 113
 114 #endif