ea79fa426d
Bug: v8:9213 Change-Id: Iee04bfe25e37cfe639964f8ab31e6702d3750bfb Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1645319 Commit-Queue: Nico Hartmann <nicohartmann@google.com> Reviewed-by: Georg Neis <neis@chromium.org> Reviewed-by: Sigurd Schneider <sigurds@chromium.org> Reviewed-by: Jakob Kummerow <jkummerow@chromium.org> Cr-Commit-Position: refs/heads/master@{#62016}
66 lines
1.6 KiB
JavaScript
66 lines
1.6 KiB
JavaScript
// Copyright 2019 the V8 project authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file.
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"use strict";
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function RandomHexDigit(allow_zero) {
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const chars = allow_zero ? '0123456789ABCDEF' : '123456789ABCDEF';
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return chars.charAt(Math.floor(Math.random() * chars.length));
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}
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// Some benchmarks shall compute sums but the result must not grow in terms
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// of digits. These can use "small" BigInts, which are BigInts where the most
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// significant bits of a digit are 0, so it does not overflow.
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function SmallRandomBigIntWithBits(bits) {
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console.assert(bits % 4 === 0);
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if (bits <= 0) {
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return 0n;
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}
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// Make sure it does not start with four 0-bits.
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let s = "0x" + RandomHexDigit(false);
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bits -= 4;
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// Digits are at least 32 bits long, so we round down to the next smaller
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// multiple of 32 to keep the most significant digit small.
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bits = Math.floor(bits / 32) * 32;
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for (; bits > 0; bits -= 4) {
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s += RandomHexDigit(true);
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}
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return BigInt(s);
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}
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function MaxBigIntWithBits(bits) {
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console.assert(bits % 4 === 0);
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if (bits <= 0) {
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return 0n;
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}
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let s = "0x";
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for (; bits > 0; bits -= 4) {
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s += "F";
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}
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return BigInt(s);
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}
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// Generates a random BigInt between 2^(bits-4) and 2^bits-1 (for bits > 0).
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function RandomBigIntWithBits(bits) {
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console.assert(bits % 4 === 0);
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if (bits <= 0) {
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return 0n;
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}
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// Make sure it does not start with four 0-bits.
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let s = "0x" + RandomHexDigit(false);
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bits -= 4;
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// Randomly generate remaining bits.
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for (; bits > 0; bits -= 4) {
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s += RandomHexDigit(true);
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}
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return BigInt(s);
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}
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