libc/src/math/generic/common_constants.h

   1 //===-- Common constants for math functions ---------------------*- C++ -*-===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8
   9 #ifndef LLVM_LIBC_SRC_MATH_GENERIC_COMMON_CONSTANTS_H
  10 #define LLVM_LIBC_SRC_MATH_GENERIC_COMMON_CONSTANTS_H
  11
  12 namespace __llvm_libc {
  13
  14 // Lookup table for (1/f) where f = 1 + n*2^(-7), n = 0..127.
  15 extern const double ONE_OVER_F[128];
  16
  17 // Lookup table for log(f) = log(1 + n*2^(-7)) where n = 0..127.
  18 extern const double LOG_F[128];
  19
  20 // Lookup table for range reduction constants r for logarithms.
  21 extern const float R[128];
  22
  23 // Lookup table for range reduction constants r for logarithms.
  24 extern const double RD[128];
  25
  26 // Lookup table for -log(r)
  27 extern const double LOG_R[128];
  28
  29 // Lookup table for exp(m) with m = -104, ..., 89.
  30 //   -104 = floor(log(single precision's min denormal))
  31 //     89 = ceil(log(single precision's max normal))
  32 // Table is generated with Sollya as follow:
  33 // > display = hexadecimal;
  34 // > for i from -104 to 89 do { D(exp(i)); };
  35 extern const double EXP_M1[195];
  36
  37 // Lookup table for exp(m * 2^(-7)) with m = 0, ..., 127.
  38 // Table is generated with Sollya as follow:
  39 // > display = hexadecimal;
  40 // > for i from 0 to 127 do { D(exp(i / 128)); };
  41 extern const double EXP_M2[128];
  42
  43 } // namespace __llvm_libc
  44
  45 #endif // LLVM_LIBC_SRC_MATH_GENERIC_COMMON_CONSTANTS_H