sysdeps/ieee754/flt-32/math_config.h

   1 /* Configuration for math routines.
   2    Copyright (C) 2017-2021 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    <https://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 #define NOINLINE __attribute__ ((noinline))
 105
 106 attribute_hidden float __math_oflowf (uint32_t);
 107 attribute_hidden float __math_uflowf (uint32_t);
 108 attribute_hidden float __math_may_uflowf (uint32_t);
 109 attribute_hidden float __math_divzerof (uint32_t);
 110 attribute_hidden float __math_invalidf (float);
 111
 112 /* Shared between expf, exp2f, exp10f, and powf.  */
 113 #define EXP2F_TABLE_BITS 5
 114 #define EXP2F_POLY_ORDER 3
 115 extern const struct exp2f_data
 116 {
 117   uint64_t tab[1 << EXP2F_TABLE_BITS];
 118   double shift_scaled;
 119   double poly[EXP2F_POLY_ORDER];
 120   double shift;
 121   double invln2_scaled;
 122   double poly_scaled[EXP2F_POLY_ORDER];
 123 } __exp2f_data attribute_hidden;
 124
 125 #define LOGF_TABLE_BITS 4
 126 #define LOGF_POLY_ORDER 4
 127 extern const struct logf_data
 128 {
 129   struct
 130   {
 131     double invc, logc;
 132   } tab[1 << LOGF_TABLE_BITS];
 133   double ln2;
 134   double poly[LOGF_POLY_ORDER - 1]; /* First order coefficient is 1.  */
 135 } __logf_data attribute_hidden;
 136
 137 #define LOG2F_TABLE_BITS 4
 138 #define LOG2F_POLY_ORDER 4
 139 extern const struct log2f_data
 140 {
 141   struct
 142   {
 143     double invc, logc;
 144   } tab[1 << LOG2F_TABLE_BITS];
 145   double poly[LOG2F_POLY_ORDER];
 146 } __log2f_data attribute_hidden;
 147
 148 #define POWF_LOG2_TABLE_BITS 4
 149 #define POWF_LOG2_POLY_ORDER 5
 150 #if TOINT_INTRINSICS
 151 # define POWF_SCALE_BITS EXP2F_TABLE_BITS
 152 #else
 153 # define POWF_SCALE_BITS 0
 154 #endif
 155 #define POWF_SCALE ((double) (1 << POWF_SCALE_BITS))
 156 extern const struct powf_log2_data
 157 {
 158   struct
 159   {
 160     double invc, logc;
 161   } tab[1 << POWF_LOG2_TABLE_BITS];
 162   double poly[POWF_LOG2_POLY_ORDER];
 163 } __powf_log2_data attribute_hidden;
 164
 165 #endif