gentrigtables.py

   1 #!/usr/bin/python
   2 # Script to generate trigonometric function tables.
   3 #
   4 #  GRUB  --  GRand Unified Bootloader
   5 #  Copyright (C) 2008  Free Software Foundation, Inc.
   6 #
   7 #  GRUB is free software: you can redistribute it and/or modify
   8 #  it under the terms of the GNU General Public License as published by
   9 #  the Free Software Foundation, either version 3 of the License, or
  10 #  (at your option) any later version.
  11 #
  12 #  GRUB is distributed in the hope that it will be useful,
  13 #  but WITHOUT ANY WARRANTY; without even the implied warranty of
  14 #  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15 #  GNU General Public License for more details.
  16 #
  17 #  You should have received a copy of the GNU General Public License
  18 #  along with GRUB.  If not, see <http://www.gnu.org/licenses/>.
  19
  20 from math import *
  21 from sys import stdout
  22
  23 def write(x):
  24     stdout.write(x)
  25
  26 def writeTable(arr, name):
  27     indent = ' ' * 4
  28     write("short ")
  29     write(name)
  30     write("[] =\n{\n")
  31     write(indent)
  32     for i in range(len(arr)):
  33         if i != 0:
  34             write(",")
  35             if i % 10 == 0:
  36                 write("\n")
  37                 write(indent)
  38         write("%d" % arr[i])
  39     write("\n};\n")
  40
  41 def main():
  42     sintab = []
  43     costab = []
  44     for i in range(256):
  45         # Convert to an angle in 1/256 of a circle.
  46         x = i * 2 * pi / 256
  47         sintab.append(int(round(sin(x) * 16384)))
  48         costab.append(int(round(cos(x) * 16384)))
  49
  50     write("#define TRIG_ANGLE_MAX 256\n")
  51     write("#define TRIG_FRACTION_SCALE 16384\n")
  52     writeTable(sintab, "sintab")
  53     writeTable(costab, "costab")
  54
  55 if __name__ == "__main__":
  56     main()
  57
  58 # vim:ai et sw=4 ts=4