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 # define TOINT_INTRINSICS 0
  42 #endif
  43 #ifndef TOINT_RINT
  44 # define TOINT_RINT 0
  45 #endif
  46 #ifndef TOINT_SHIFT
  47 # define TOINT_SHIFT 1
  48 #endif
  49
  50 static inline uint32_t
  51 asuint (float f)
  52 {
  53   union
  54   {
  55     float f;
  56     uint32_t i;
  57   } u = {f};
  58   return u.i;
  59 }
  60
  61 static inline float
  62 asfloat (uint32_t i)
  63 {
  64   union
  65   {
  66     uint32_t i;
  67     float f;
  68   } u = {i};
  69   return u.f;
  70 }
  71
  72 static inline uint64_t
  73 asuint64 (double f)
  74 {
  75   union
  76   {
  77     double f;
  78     uint64_t i;
  79   } u = {f};
  80   return u.i;
  81 }
  82
  83 static inline double
  84 asdouble (uint64_t i)
  85 {
  86   union
  87   {
  88     uint64_t i;
  89     double f;
  90   } u = {i};
  91   return u.f;
  92 }
  93
  94 static inline int
  95 issignalingf_inline (float x)
  96 {
  97   uint32_t ix = asuint (x);
  98   if (HIGH_ORDER_BIT_IS_SET_FOR_SNAN)
  99     return (ix & 0x7fc00000) == 0x7fc00000;
 100   return 2 * (ix ^ 0x00400000) > 2u * 0x7fc00000;
 101 }
 102
 103 #define NOINLINE __attribute__ ((noinline))
 104
 105 attribute_hidden float __math_oflowf (unsigned long);
 106 attribute_hidden float __math_uflowf (unsigned long);
 107 attribute_hidden float __math_may_uflowf (unsigned long);
 108 attribute_hidden float __math_divzerof (unsigned long);
 109 attribute_hidden float __math_invalidf (float);
 110
 111 /* Shared between expf, exp2f and powf.  */
 112 #define EXP2F_TABLE_BITS 5
 113 #define EXP2F_POLY_ORDER 3
 114 extern const struct exp2f_data
 115 {
 116   uint64_t tab[1 << EXP2F_TABLE_BITS];
 117   double shift_scaled;
 118   double poly[EXP2F_POLY_ORDER];
 119   double shift;
 120   double invln2_scaled;
 121   double poly_scaled[EXP2F_POLY_ORDER];
 122 } __exp2f_data attribute_hidden;
 123
 124 #define LOGF_TABLE_BITS 4
 125 #define LOGF_POLY_ORDER 4
 126 extern const struct logf_data
 127 {
 128   struct
 129   {
 130     double invc, logc;
 131   } tab[1 << LOGF_TABLE_BITS];
 132   double ln2;
 133   double poly[LOGF_POLY_ORDER - 1]; /* First order coefficient is 1.  */
 134 } __logf_data attribute_hidden;
 135
 136 #define LOG2F_TABLE_BITS 4
 137 #define LOG2F_POLY_ORDER 4
 138 extern const struct log2f_data
 139 {
 140   struct
 141   {
 142     double invc, logc;
 143   } tab[1 << LOG2F_TABLE_BITS];
 144   double poly[LOG2F_POLY_ORDER];
 145 } __log2f_data attribute_hidden;
 146
 147 #define POWF_LOG2_TABLE_BITS 4
 148 #define POWF_LOG2_POLY_ORDER 5
 149 #if TOINT_INTRINSICS
 150 # define POWF_SCALE_BITS EXP2F_TABLE_BITS
 151 #else
 152 # define POWF_SCALE_BITS 0
 153 #endif
 154 #define POWF_SCALE ((double) (1 << POWF_SCALE_BITS))
 155 extern const struct powf_log2_data
 156 {
 157   struct
 158   {
 159     double invc, logc;
 160   } tab[1 << POWF_LOG2_TABLE_BITS];
 161   double poly[POWF_LOG2_POLY_ORDER];
 162 } __powf_log2_data attribute_hidden;
 163
 164 #endif