iposva@google.com
624273f372
- Makes it much easier to intrinsify the operation. Review URL: https://codereview.chromium.org//11339027 git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge/dart@14235 260f80e4-7a28-3924-810f-c04153c831b5
99 lines
2.9 KiB
Dart
99 lines
2.9 KiB
Dart
// Copyright (c) 2012, the Dart project authors. Please see the AUTHORS file
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// for details. All rights reserved. Use of this source code is governed by a
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// BSD-style license that can be found in the LICENSE file.
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// A VM patch of the dart:math library.
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patch num pow(num x, num exponent) => MathNatives.pow(x, exponent);
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patch double atan2(num a, num b) => MathNatives.atan2(a, b);
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patch double sin(num x) => MathNatives.sin(x);
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patch double cos(num x) => MathNatives.cos(x);
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patch double tan(num x) => MathNatives.tan(x);
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patch double acos(num x) => MathNatives.acos(x);
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patch double asin(num x) => MathNatives.asin(x);
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patch double atan(num x) => MathNatives.atan(x);
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patch double sqrt(num x) => MathNatives.sqrt(x);
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patch double exp(num x) => MathNatives.exp(x);
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patch double log(num x) => MathNatives.log(x);
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// TODO(iposva): Handle patch methods within a patch class correctly.
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patch class Random {
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/*patch*/ factory Random([int seed]) {
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if (seed == null) {
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seed = _Random._nextSeed();
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}
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do {
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seed = (seed + 0x5A17) & _Random._MASK_64;
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} while (seed == 0);
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return new _Random._internal(seed);
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}
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}
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class _Random implements Random {
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// Internal state of the random number generator.
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var _state_lo;
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var _state_hi;
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_Random._internal(state)
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: _state_lo = (state & _MASK_32), _state_hi = (state >> 32);
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// The algorithm used here is Multiply with Carry (MWC) with a Base b = 2^32.
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// http://en.wikipedia.org/wiki/Multiply-with-carry
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// The constant A is selected from "Numerical Recipes 3rd Edition" p.348 B1.
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int _nextInt32() {
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var state = ((_A * (_state_lo)) + _state_hi) & _MASK_64;
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_state_lo = state & _MASK_32;
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_state_hi = state >> 32;
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return _state_lo;
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}
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int nextInt(int max) {
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if (max <= 0 || max > _POW2_32) {
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throw new ArgumentError("max must be positive and < 2^32:"
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" $max");
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}
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if ((max & -max) == max) {
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// Fast case for powers of two.
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return _nextInt32() & (max - 1);
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}
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var rnd32;
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var result;
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do {
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rnd32 = _nextInt32();
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result = rnd32 % max;
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} while ((rnd32 - result + max) >= _POW2_32);
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return result;
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}
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double nextDouble() {
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return ((nextInt(1 << 26) << 27) + nextInt(1 << 27)) / _POW2_53_D;
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}
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bool nextBool() {
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return nextInt(2) == 0;
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}
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// Constants used by the algorithm or masking.
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static const _MASK_32 = (1 << 32) - 1;
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static const _MASK_64 = (1 << 64) - 1;
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static const _POW2_32 = 1 << 32;
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static const _POW2_53_D = 1.0 * (1 << 53);
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static const _A = 0xffffda61;
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// Use a singleton Random object to get a new seed if no seed was passed.
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static var _prng = null;
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static int _nextSeed() {
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if (_prng == null) {
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// TODO(iposva): Use system to get a random seed.
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_prng = new Random(new Date.now().millisecondsSinceEpoch);
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}
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// Trigger the PRNG once to change the internal state.
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return _prng._nextInt32();
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}
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}
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