sysdeps/ieee754/flt-32/math_config.h

   1 /* Configuration for math routines.
   2    Copyright (C) 2017-2018 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, see
  17    <http://www.gnu.org/licenses/>.  */
  18
  19 #ifndef _MATH_CONFIG_H
  20 #define _MATH_CONFIG_H
  21
  22 #include <math.h>
  23 #include <math_private.h>
  24 #include <nan-high-order-bit.h>
  25 #include <stdint.h>
  26
  27 #ifndef WANT_ROUNDING
  28 /* Correct special case results in non-nearest rounding modes.  */
  29 # define WANT_ROUNDING 1
  30 #endif
  31 #ifndef WANT_ERRNO
  32 /* Set errno according to ISO C with (math_errhandling & MATH_ERRNO) != 0.  */
  33 # define WANT_ERRNO 1
  34 #endif
  35 #ifndef WANT_ERRNO_UFLOW
  36 /* Set errno to ERANGE if result underflows to 0 (in all rounding modes).  */
  37 # define WANT_ERRNO_UFLOW (WANT_ROUNDING && WANT_ERRNO)
  38 #endif
  39
  40 #ifndef TOINT_INTRINSICS
  41 /* When set, the roundtoint and converttoint functions are provided with
  42    the semantics documented below.  */
  43 # define TOINT_INTRINSICS 0
  44 #endif
  45
  46 #if TOINT_INTRINSICS
  47 /* Round x to nearest int in all rounding modes, ties have to be rounded
  48    consistently with converttoint so the results match.  If the result
  49    would be outside of [-2^31, 2^31-1] then the semantics is unspecified.  */
  50 static inline double_t
  51 roundtoint (double_t x);
  52
  53 /* Convert x to nearest int in all rounding modes, ties have to be rounded
  54    consistently with roundtoint.  If the result is not representible in an
  55    int32_t then the semantics is unspecified.  */
  56 static inline int32_t
  57 converttoint (double_t x);
  58 #endif
  59
  60 static inline uint32_t
  61 asuint (float f)
  62 {
  63   union
  64   {
  65     float f;
  66     uint32_t i;
  67   } u = {f};
  68   return u.i;
  69 }
  70
  71 static inline float
  72 asfloat (uint32_t i)
  73 {
  74   union
  75   {
  76     uint32_t i;
  77     float f;
  78   } u = {i};
  79   return u.f;
  80 }
  81
  82 static inline uint64_t
  83 asuint64 (double f)
  84 {
  85   union
  86   {
  87     double f;
  88     uint64_t i;
  89   } u = {f};
  90   return u.i;
  91 }
  92
  93 static inline double
  94 asdouble (uint64_t i)
  95 {
  96   union
  97   {
  98     uint64_t i;
  99     double f;
 100   } u = {i};
 101   return u.f;
 102 }
 103
 104 static inline int
 105 issignalingf_inline (float x)
 106 {
 107   uint32_t ix = asuint (x);
 108   if (HIGH_ORDER_BIT_IS_SET_FOR_SNAN)
 109     return (ix & 0x7fc00000) == 0x7fc00000;
 110   return 2 * (ix ^ 0x00400000) > 2u * 0x7fc00000;
 111 }
 112
 113 #define NOINLINE __attribute__ ((noinline))
 114
 115 attribute_hidden float __math_oflowf (uint32_t);
 116 attribute_hidden float __math_uflowf (uint32_t);
 117 attribute_hidden float __math_may_uflowf (uint32_t);
 118 attribute_hidden float __math_divzerof (uint32_t);
 119 attribute_hidden float __math_invalidf (float);
 120
 121 /* Shared between expf, exp2f and powf.  */
 122 #define EXP2F_TABLE_BITS 5
 123 #define EXP2F_POLY_ORDER 3
 124 extern const struct exp2f_data
 125 {
 126   uint64_t tab[1 << EXP2F_TABLE_BITS];
 127   double shift_scaled;
 128   double poly[EXP2F_POLY_ORDER];
 129   double shift;
 130   double invln2_scaled;
 131   double poly_scaled[EXP2F_POLY_ORDER];
 132 } __exp2f_data attribute_hidden;
 133
 134 #define LOGF_TABLE_BITS 4
 135 #define LOGF_POLY_ORDER 4
 136 extern const struct logf_data
 137 {
 138   struct
 139   {
 140     double invc, logc;
 141   } tab[1 << LOGF_TABLE_BITS];
 142   double ln2;
 143   double poly[LOGF_POLY_ORDER - 1]; /* First order coefficient is 1.  */
 144 } __logf_data attribute_hidden;
 145
 146 #define LOG2F_TABLE_BITS 4
 147 #define LOG2F_POLY_ORDER 4
 148 extern const struct log2f_data
 149 {
 150   struct
 151   {
 152     double invc, logc;
 153   } tab[1 << LOG2F_TABLE_BITS];
 154   double poly[LOG2F_POLY_ORDER];
 155 } __log2f_data attribute_hidden;
 156
 157 #define POWF_LOG2_TABLE_BITS 4
 158 #define POWF_LOG2_POLY_ORDER 5
 159 #if TOINT_INTRINSICS
 160 # define POWF_SCALE_BITS EXP2F_TABLE_BITS
 161 #else
 162 # define POWF_SCALE_BITS 0
 163 #endif
 164 #define POWF_SCALE ((double) (1 << POWF_SCALE_BITS))
 165 extern const struct powf_log2_data
 166 {
 167   struct
 168   {
 169     double invc, logc;
 170   } tab[1 << POWF_LOG2_TABLE_BITS];
 171   double poly[POWF_LOG2_POLY_ORDER];
 172 } __powf_log2_data attribute_hidden;
 173
 174 #endif