v8/tools/generate-trig-table.py

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#!/usr/bin/env python
#
# Copyright 2013 the V8 project authors. All rights reserved.
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions are
# met:
#
# * Redistributions of source code must retain the above copyright
# notice, this list of conditions and the following disclaimer.
# * Redistributions in binary form must reproduce the above
# copyright notice, this list of conditions and the following
# disclaimer in the documentation and/or other materials provided
# with the distribution.
# * Neither the name of Google Inc. nor the names of its
# contributors may be used to endorse or promote products derived
# from this software without specific prior written permission.
#
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
# This is a utility for populating the lookup table for the
# approximation of trigonometric functions.
import sys, math
SAMPLES = 1800
TEMPLATE = """\
// Copyright 2013 Google Inc. All Rights Reserved.
// This file was generated from a python script.
#include "v8.h"
#include "trig-table.h"
namespace v8 {
namespace internal {
const double TrigonometricLookupTable::kSinTable[] =
{ %(sine_table)s };
const double TrigonometricLookupTable::kCosXIntervalTable[] =
{ %(cosine_table)s };
const int TrigonometricLookupTable::kSamples = %(samples)i;
const int TrigonometricLookupTable::kTableSize = %(table_size)i;
const double TrigonometricLookupTable::kSamplesOverPiHalf =
%(samples_over_pi_half)s;
} } // v8::internal
"""
def main():
pi_half = math.pi / 2
interval = pi_half / SAMPLES
sin = []
cos_times_interval = []
table_size = SAMPLES + 2
for i in range(0, table_size):
sample = i * interval
sin.append(repr(math.sin(sample)))
cos_times_interval.append(repr(math.cos(sample) * interval))
output_file = sys.argv[1]
output = open(str(output_file), "w")
output.write(TEMPLATE % {
'sine_table': ','.join(sin),
'cosine_table': ','.join(cos_times_interval),
'samples': SAMPLES,
'table_size': table_size,
'samples_over_pi_half': repr(SAMPLES / pi_half)
})
if __name__ == "__main__":
main()