2018-02-16 04:36:50 +03:00
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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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/* vim: set ts=8 sts=2 et sw=2 tw=80: */
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/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this file,
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* You can obtain one at http://mozilla.org/MPL/2.0/. */
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2018-02-16 04:36:55 +03:00
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#include "mozilla/Assertions.h"
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2018-02-16 04:36:50 +03:00
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#include "mozilla/WrappingOperations.h"
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#include <stdint.h>
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2018-03-07 06:21:58 +03:00
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using mozilla::WrappingAdd;
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2018-02-16 04:36:55 +03:00
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using mozilla::WrappingMultiply;
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2018-02-16 04:36:50 +03:00
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using mozilla::WrapToSigned;
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2018-03-07 06:22:20 +03:00
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using mozilla::WrappingSubtract;
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2018-02-16 04:36:50 +03:00
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// NOTE: In places below |-FOO_MAX - 1| is used instead of |-FOO_MIN| because
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// in C++ numeric literals are full expressions -- the |-| in a negative
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// number is technically separate. So with most compilers that limit
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// |int| to the signed 32-bit range, something like |-2147483648| is
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// operator-() applied to an *unsigned* expression. And MSVC, at least,
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// warns when you do that. (The operation is well-defined, but it likely
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// doesn't do what was intended.) So we do the usual workaround for this
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// (see your local copy of <stdint.h> for a likely demo of this), writing
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// it out by negating the max value and subtracting 1.
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static_assert(WrapToSigned(uint8_t(17)) == 17,
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"no wraparound should work, 8-bit");
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static_assert(WrapToSigned(uint8_t(128)) == -128,
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"works for 8-bit numbers, wraparound low end");
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static_assert(WrapToSigned(uint8_t(128 + 7)) == -128 + 7,
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"works for 8-bit numbers, wraparound mid");
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static_assert(WrapToSigned(uint8_t(128 + 127)) == -128 + 127,
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"works for 8-bit numbers, wraparound high end");
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static_assert(WrapToSigned(uint16_t(12345)) == 12345,
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"no wraparound should work, 16-bit");
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static_assert(WrapToSigned(uint16_t(32768)) == -32768,
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"works for 16-bit numbers, wraparound low end");
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static_assert(WrapToSigned(uint16_t(32768 + 42)) == -32768 + 42,
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"works for 16-bit numbers, wraparound mid");
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static_assert(WrapToSigned(uint16_t(32768 + 32767)) == -32768 + 32767,
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"works for 16-bit numbers, wraparound high end");
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static_assert(WrapToSigned(uint32_t(8675309)) == 8675309,
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"no wraparound should work, 32-bit");
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static_assert(WrapToSigned(uint32_t(2147483648)) == -2147483647 - 1,
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"works for 32-bit numbers, wraparound low end");
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static_assert(WrapToSigned(uint32_t(2147483648 + 42)) == -2147483647 - 1 + 42,
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"works for 32-bit numbers, wraparound mid");
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static_assert(WrapToSigned(uint32_t(2147483648 + 2147483647)) ==
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-2147483647 - 1 + 2147483647,
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"works for 32-bit numbers, wraparound high end");
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static_assert(WrapToSigned(uint64_t(4152739164)) == 4152739164,
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"no wraparound should work, 64-bit");
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static_assert(WrapToSigned(uint64_t(9223372036854775808ULL)) == -9223372036854775807LL - 1,
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"works for 64-bit numbers, wraparound low end");
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static_assert(WrapToSigned(uint64_t(9223372036854775808ULL + 8005552368LL)) ==
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-9223372036854775807LL - 1 + 8005552368LL,
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"works for 64-bit numbers, wraparound mid");
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static_assert(WrapToSigned(uint64_t(9223372036854775808ULL + 9223372036854775807ULL)) ==
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-9223372036854775807LL - 1 + 9223372036854775807LL,
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"works for 64-bit numbers, wraparound high end");
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2018-02-16 04:36:55 +03:00
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template<typename T>
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inline constexpr bool
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TestEqual(T aX, T aY)
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{
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return aX == aY;
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}
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2018-03-07 06:21:58 +03:00
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static void
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TestWrappingAdd8()
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{
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MOZ_RELEASE_ASSERT(TestEqual(WrappingAdd(uint8_t(0), uint8_t(128)),
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uint8_t(128)),
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"zero plus anything is anything");
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MOZ_RELEASE_ASSERT(TestEqual(WrappingAdd(uint8_t(17), uint8_t(42)),
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uint8_t(59)),
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"17 + 42 == 59");
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MOZ_RELEASE_ASSERT(TestEqual(WrappingAdd(uint8_t(255), uint8_t(1)),
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uint8_t(0)),
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"all bits plus one overflows to zero");
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MOZ_RELEASE_ASSERT(TestEqual(WrappingAdd(uint8_t(128), uint8_t(127)),
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uint8_t(255)),
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"high bit plus all lower bits is all bits");
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MOZ_RELEASE_ASSERT(TestEqual(WrappingAdd(uint8_t(128), uint8_t(193)),
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uint8_t(65)),
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"128 + 193 is 256 + 65");
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MOZ_RELEASE_ASSERT(TestEqual(WrappingAdd(int8_t(0), int8_t(-128)),
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int8_t(-128)),
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"zero plus anything is anything");
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MOZ_RELEASE_ASSERT(TestEqual(WrappingAdd(int8_t(123), int8_t(8)),
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int8_t(-125)),
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"overflow to negative");
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MOZ_RELEASE_ASSERT(TestEqual(WrappingAdd(int8_t(5), int8_t(-123)),
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int8_t(-118)),
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"5 - 123 is -118");
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MOZ_RELEASE_ASSERT(TestEqual(WrappingAdd(int8_t(-85), int8_t(-73)),
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int8_t(98)),
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"underflow to positive");
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MOZ_RELEASE_ASSERT(TestEqual(WrappingAdd(int8_t(-128), int8_t(127)),
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int8_t(-1)),
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"high bit plus all lower bits is -1");
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}
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static void
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TestWrappingAdd16()
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{
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MOZ_RELEASE_ASSERT(TestEqual(WrappingAdd(uint16_t(0), uint16_t(32768)),
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uint16_t(32768)),
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"zero plus anything is anything");
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MOZ_RELEASE_ASSERT(TestEqual(WrappingAdd(uint16_t(24389), uint16_t(2682)),
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uint16_t(27071)),
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"24389 + 2682 == 27071");
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MOZ_RELEASE_ASSERT(TestEqual(WrappingAdd(uint16_t(65535), uint16_t(1)),
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uint16_t(0)),
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"all bits plus one overflows to zero");
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MOZ_RELEASE_ASSERT(TestEqual(WrappingAdd(uint16_t(32768), uint16_t(32767)),
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uint16_t(65535)),
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"high bit plus all lower bits is all bits");
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MOZ_RELEASE_ASSERT(TestEqual(WrappingAdd(uint16_t(32768), uint16_t(47582)),
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uint16_t(14814)),
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"32768 + 47582 is 65536 + 14814");
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MOZ_RELEASE_ASSERT(TestEqual(WrappingAdd(int16_t(0), int16_t(-32768)),
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int16_t(-32768)),
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"zero plus anything is anything");
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MOZ_RELEASE_ASSERT(TestEqual(WrappingAdd(int16_t(32765), int16_t(8)),
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int16_t(-32763)),
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"overflow to negative");
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MOZ_RELEASE_ASSERT(TestEqual(WrappingAdd(int16_t(5), int16_t(-28933)),
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int16_t(-28928)),
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"5 - 28933 is -28928");
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MOZ_RELEASE_ASSERT(TestEqual(WrappingAdd(int16_t(-23892), int16_t(-12893)),
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int16_t(28751)),
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"underflow to positive");
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MOZ_RELEASE_ASSERT(TestEqual(WrappingAdd(int16_t(-32768), int16_t(32767)),
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int16_t(-1)),
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"high bit plus all lower bits is -1");
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}
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static void
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TestWrappingAdd32()
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{
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MOZ_RELEASE_ASSERT(TestEqual(WrappingAdd(uint32_t(0), uint32_t(2147483648)),
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uint32_t(2147483648)),
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"zero plus anything is anything");
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MOZ_RELEASE_ASSERT(TestEqual(WrappingAdd(uint32_t(1398742328), uint32_t(714192829)),
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uint32_t(2112935157)),
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"1398742328 + 714192829 == 2112935157");
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MOZ_RELEASE_ASSERT(TestEqual(WrappingAdd(uint32_t(4294967295), uint32_t(1)),
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uint32_t(0)),
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"all bits plus one overflows to zero");
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MOZ_RELEASE_ASSERT(TestEqual(WrappingAdd(uint32_t(2147483648), uint32_t(2147483647)),
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uint32_t(4294967295)),
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"high bit plus all lower bits is all bits");
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MOZ_RELEASE_ASSERT(TestEqual(WrappingAdd(uint32_t(2147483648), uint32_t(3146492712)),
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uint32_t(999009064)),
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"2147483648 + 3146492712 is 4294967296 + 999009064");
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MOZ_RELEASE_ASSERT(TestEqual(WrappingAdd(int32_t(0), int32_t(-2147483647 - 1)),
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int32_t(-2147483647 - 1)),
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"zero plus anything is anything");
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MOZ_RELEASE_ASSERT(TestEqual(WrappingAdd(int32_t(2147483645), int32_t(8)),
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int32_t(-2147483643)),
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"overflow to negative");
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MOZ_RELEASE_ASSERT(TestEqual(WrappingAdd(int32_t(257), int32_t(-23947248)),
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int32_t(-23946991)),
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"257 - 23947248 is -23946991");
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MOZ_RELEASE_ASSERT(TestEqual(WrappingAdd(int32_t(-2147483220), int32_t(-12893)),
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int32_t(2147471183)),
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"underflow to positive");
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MOZ_RELEASE_ASSERT(TestEqual(WrappingAdd(int32_t(-32768), int32_t(32767)),
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int32_t(-1)),
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"high bit plus all lower bits is -1");
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}
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static void
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TestWrappingAdd64()
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{
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MOZ_RELEASE_ASSERT(TestEqual(WrappingAdd(uint64_t(0), uint64_t(9223372036854775808ULL)),
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uint64_t(9223372036854775808ULL)),
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"zero plus anything is anything");
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MOZ_RELEASE_ASSERT(TestEqual(WrappingAdd(uint64_t(70368744177664), uint64_t(3740873592)),
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uint64_t(70372485051256)),
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"70368744177664 + 3740873592 == 70372485051256");
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MOZ_RELEASE_ASSERT(TestEqual(WrappingAdd(uint64_t(18446744073709551615ULL), uint64_t(1)),
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uint64_t(0)),
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"all bits plus one overflows to zero");
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MOZ_RELEASE_ASSERT(TestEqual(WrappingAdd(uint64_t(9223372036854775808ULL),
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uint64_t(9223372036854775807ULL)),
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uint64_t(18446744073709551615ULL)),
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"high bit plus all lower bits is all bits");
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MOZ_RELEASE_ASSERT(TestEqual(WrappingAdd(uint64_t(14552598638644786479ULL), uint64_t(3894174382537247221ULL)),
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uint64_t(28947472482084)),
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"9223372036854775808 + 3146492712 is 18446744073709551616 + 28947472482084");
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MOZ_RELEASE_ASSERT(TestEqual(WrappingAdd(int64_t(0), int64_t(-9223372036854775807LL - 1)),
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int64_t(-9223372036854775807LL - 1)),
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"zero plus anything is anything");
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MOZ_RELEASE_ASSERT(TestEqual(WrappingAdd(int64_t(9223372036854775802LL), int64_t(8)),
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int64_t(-9223372036854775806LL)),
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"overflow to negative");
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MOZ_RELEASE_ASSERT(TestEqual(WrappingAdd(int64_t(37482739294298742LL), int64_t(-437843573929483498LL)),
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int64_t(-400360834635184756LL)),
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"37482739294298742 - 437843573929483498 is -400360834635184756");
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MOZ_RELEASE_ASSERT(TestEqual(WrappingAdd(int64_t(-9127837934058953374LL), int64_t(-4173572032144775807LL)),
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int64_t(5145334107505822435L)),
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"underflow to positive");
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MOZ_RELEASE_ASSERT(TestEqual(WrappingAdd(int64_t(-9223372036854775807LL - 1), int64_t(9223372036854775807LL)),
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int64_t(-1)),
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"high bit plus all lower bits is -1");
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}
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static void
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TestWrappingAdd()
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{
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TestWrappingAdd8();
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TestWrappingAdd16();
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TestWrappingAdd32();
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TestWrappingAdd64();
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}
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2018-03-07 06:22:20 +03:00
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static void
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TestWrappingSubtract8()
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{
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MOZ_RELEASE_ASSERT(TestEqual(WrappingSubtract(uint8_t(0), uint8_t(128)),
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uint8_t(128)),
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"zero minus half is half");
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MOZ_RELEASE_ASSERT(TestEqual(WrappingSubtract(uint8_t(17), uint8_t(42)),
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uint8_t(231)),
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"17 - 42 == -25 added to 256 is 231");
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MOZ_RELEASE_ASSERT(TestEqual(WrappingSubtract(uint8_t(0), uint8_t(1)),
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uint8_t(255)),
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"zero underflows to all bits");
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MOZ_RELEASE_ASSERT(TestEqual(WrappingSubtract(uint8_t(128), uint8_t(127)),
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uint8_t(1)),
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"128 - 127 == 1");
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MOZ_RELEASE_ASSERT(TestEqual(WrappingSubtract(uint8_t(128), uint8_t(193)),
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uint8_t(191)),
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"128 - 193 is -65 so -65 + 256 == 191");
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MOZ_RELEASE_ASSERT(TestEqual(WrappingSubtract(int8_t(0), int8_t(-128)),
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int8_t(-128)),
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"zero minus high bit wraps to high bit");
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MOZ_RELEASE_ASSERT(TestEqual(WrappingSubtract(int8_t(-126), int8_t(4)),
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int8_t(126)),
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"underflow to positive");
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MOZ_RELEASE_ASSERT(TestEqual(WrappingSubtract(int8_t(5), int8_t(-123)),
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int8_t(-128)),
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"overflow to negative");
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MOZ_RELEASE_ASSERT(TestEqual(WrappingSubtract(int8_t(-85), int8_t(-73)),
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int8_t(-12)),
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|
"negative minus smaller negative");
|
|
|
|
|
MOZ_RELEASE_ASSERT(TestEqual(WrappingSubtract(int8_t(-128), int8_t(127)),
|
|
|
|
|
int8_t(1)),
|
|
|
|
|
"underflow to 1");
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
static void
|
|
|
|
|
TestWrappingSubtract16()
|
|
|
|
|
{
|
|
|
|
|
MOZ_RELEASE_ASSERT(TestEqual(WrappingSubtract(uint16_t(0), uint16_t(32768)),
|
|
|
|
|
uint16_t(32768)),
|
|
|
|
|
"zero minus half is half");
|
|
|
|
|
MOZ_RELEASE_ASSERT(TestEqual(WrappingSubtract(uint16_t(24389), uint16_t(2682)),
|
|
|
|
|
uint16_t(21707)),
|
|
|
|
|
"24389 - 2682 == 21707");
|
|
|
|
|
MOZ_RELEASE_ASSERT(TestEqual(WrappingSubtract(uint16_t(0), uint16_t(1)),
|
|
|
|
|
uint16_t(65535)),
|
|
|
|
|
"zero underflows to all bits");
|
|
|
|
|
MOZ_RELEASE_ASSERT(TestEqual(WrappingSubtract(uint16_t(32768), uint16_t(32767)),
|
|
|
|
|
uint16_t(1)),
|
|
|
|
|
"high bit minus all lower bits is one");
|
|
|
|
|
MOZ_RELEASE_ASSERT(TestEqual(WrappingSubtract(uint16_t(32768), uint16_t(47582)),
|
|
|
|
|
uint16_t(50722)),
|
|
|
|
|
"32768 - 47582 + 65536 is 50722");
|
|
|
|
|
|
|
|
|
|
MOZ_RELEASE_ASSERT(TestEqual(WrappingSubtract(int16_t(0), int16_t(-32768)),
|
|
|
|
|
int16_t(-32768)),
|
|
|
|
|
"zero minus high bit wraps to high bit");
|
|
|
|
|
MOZ_RELEASE_ASSERT(TestEqual(WrappingSubtract(int16_t(-32766), int16_t(4)),
|
|
|
|
|
int16_t(32766)),
|
|
|
|
|
"underflow to positive");
|
|
|
|
|
MOZ_RELEASE_ASSERT(TestEqual(WrappingSubtract(int16_t(5), int16_t(-28933)),
|
|
|
|
|
int16_t(28938)),
|
|
|
|
|
"5 - -28933 is 28938");
|
|
|
|
|
MOZ_RELEASE_ASSERT(TestEqual(WrappingSubtract(int16_t(-23892), int16_t(-12893)),
|
|
|
|
|
int16_t(-10999)),
|
|
|
|
|
"negative minus smaller negative");
|
|
|
|
|
MOZ_RELEASE_ASSERT(TestEqual(WrappingSubtract(int16_t(-32768), int16_t(32767)),
|
|
|
|
|
int16_t(1)),
|
|
|
|
|
"underflow to 1");
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
static void
|
|
|
|
|
TestWrappingSubtract32()
|
|
|
|
|
{
|
|
|
|
|
MOZ_RELEASE_ASSERT(TestEqual(WrappingSubtract(uint32_t(0), uint32_t(2147483648)),
|
|
|
|
|
uint32_t(2147483648)),
|
|
|
|
|
"zero minus half is half");
|
|
|
|
|
MOZ_RELEASE_ASSERT(TestEqual(WrappingSubtract(uint32_t(1398742328), uint32_t(714192829)),
|
|
|
|
|
uint32_t(684549499)),
|
|
|
|
|
"1398742328 - 714192829 == 684549499");
|
|
|
|
|
MOZ_RELEASE_ASSERT(TestEqual(WrappingSubtract(uint32_t(0), uint32_t(1)),
|
|
|
|
|
uint32_t(4294967295)),
|
|
|
|
|
"zero underflows to all bits");
|
|
|
|
|
MOZ_RELEASE_ASSERT(TestEqual(WrappingSubtract(uint32_t(2147483648), uint32_t(2147483647)),
|
|
|
|
|
uint32_t(1)),
|
|
|
|
|
"high bit minus all lower bits is one");
|
|
|
|
|
MOZ_RELEASE_ASSERT(TestEqual(WrappingSubtract(uint32_t(2147483648), uint32_t(3146492712)),
|
|
|
|
|
uint32_t(3295958232)),
|
|
|
|
|
"2147483648 - 3146492712 + 4294967296 is 3295958232");
|
|
|
|
|
|
|
|
|
|
MOZ_RELEASE_ASSERT(TestEqual(WrappingSubtract(int32_t(0), int32_t(-2147483647 - 1)),
|
|
|
|
|
int32_t(-2147483647 - 1)),
|
|
|
|
|
"zero minus high bit wraps to high bit");
|
|
|
|
|
MOZ_RELEASE_ASSERT(TestEqual(WrappingSubtract(int32_t(-2147483646), int32_t(4)),
|
|
|
|
|
int32_t(2147483646)),
|
|
|
|
|
"underflow to positive");
|
|
|
|
|
MOZ_RELEASE_ASSERT(TestEqual(WrappingSubtract(int32_t(257), int32_t(-23947248)),
|
|
|
|
|
int32_t(23947505)),
|
|
|
|
|
"257 - -23947248 is 23947505");
|
|
|
|
|
MOZ_RELEASE_ASSERT(TestEqual(WrappingSubtract(int32_t(-2147483220), int32_t(-12893)),
|
|
|
|
|
int32_t(-2147470327)),
|
|
|
|
|
"negative minus smaller negative");
|
|
|
|
|
MOZ_RELEASE_ASSERT(TestEqual(WrappingSubtract(int32_t(-2147483647 - 1), int32_t(2147483647)),
|
|
|
|
|
int32_t(1)),
|
|
|
|
|
"underflow to 1");
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
static void
|
|
|
|
|
TestWrappingSubtract64()
|
|
|
|
|
{
|
|
|
|
|
MOZ_RELEASE_ASSERT(TestEqual(WrappingSubtract(uint64_t(0), uint64_t(9223372036854775808ULL)),
|
|
|
|
|
uint64_t(9223372036854775808ULL)),
|
|
|
|
|
"zero minus half is half");
|
|
|
|
|
MOZ_RELEASE_ASSERT(TestEqual(WrappingSubtract(uint64_t(70368744177664), uint64_t(3740873592)),
|
|
|
|
|
uint64_t(70365003304072)),
|
|
|
|
|
"70368744177664 - 3740873592 == 70365003304072");
|
|
|
|
|
MOZ_RELEASE_ASSERT(TestEqual(WrappingSubtract(uint64_t(0), uint64_t(1)),
|
|
|
|
|
uint64_t(18446744073709551615ULL)),
|
|
|
|
|
"zero underflows to all bits");
|
|
|
|
|
MOZ_RELEASE_ASSERT(TestEqual(WrappingSubtract(uint64_t(9223372036854775808ULL),
|
|
|
|
|
uint64_t(9223372036854775807ULL)),
|
|
|
|
|
uint64_t(1)),
|
|
|
|
|
"high bit minus all lower bits is one");
|
|
|
|
|
MOZ_RELEASE_ASSERT(TestEqual(WrappingSubtract(uint64_t(14552598638644786479ULL), uint64_t(3894174382537247221ULL)),
|
|
|
|
|
uint64_t(10658424256107539258ULL)),
|
|
|
|
|
"14552598638644786479 - 39763621533397112216 is 10658424256107539258L");
|
|
|
|
|
|
|
|
|
|
MOZ_RELEASE_ASSERT(TestEqual(WrappingSubtract(int64_t(0), int64_t(-9223372036854775807LL - 1)),
|
|
|
|
|
int64_t(-9223372036854775807LL - 1)),
|
|
|
|
|
"zero minus high bit wraps to high bit");
|
|
|
|
|
MOZ_RELEASE_ASSERT(TestEqual(WrappingSubtract(int64_t(-9223372036854775802LL), int64_t(8)),
|
|
|
|
|
int64_t(9223372036854775806LL)),
|
|
|
|
|
"overflow to negative");
|
|
|
|
|
MOZ_RELEASE_ASSERT(TestEqual(WrappingSubtract(int64_t(37482739294298742LL), int64_t(-437843573929483498LL)),
|
|
|
|
|
int64_t(475326313223782240)),
|
|
|
|
|
"37482739294298742 - -437843573929483498 is 475326313223782240");
|
|
|
|
|
MOZ_RELEASE_ASSERT(TestEqual(WrappingSubtract(int64_t(-9127837934058953374LL), int64_t(-4173572032144775807LL)),
|
|
|
|
|
int64_t(-4954265901914177567LL)),
|
|
|
|
|
"negative minus smaller negative");
|
|
|
|
|
MOZ_RELEASE_ASSERT(TestEqual(WrappingSubtract(int64_t(-9223372036854775807LL - 1), int64_t(9223372036854775807LL)),
|
|
|
|
|
int64_t(1)),
|
|
|
|
|
"underflow to 1");
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
static void
|
|
|
|
|
TestWrappingSubtract()
|
|
|
|
|
{
|
|
|
|
|
TestWrappingSubtract8();
|
|
|
|
|
TestWrappingSubtract16();
|
|
|
|
|
TestWrappingSubtract32();
|
|
|
|
|
TestWrappingSubtract64();
|
|
|
|
|
}
|
|
|
|
|
|
2018-02-16 04:36:55 +03:00
|
|
|
static void
|
|
|
|
|
TestWrappingMultiply8()
|
|
|
|
|
{
|
|
|
|
|
MOZ_RELEASE_ASSERT(TestEqual(WrappingMultiply(uint8_t(0), uint8_t(128)),
|
|
|
|
|
uint8_t(0)),
|
|
|
|
|
"zero times anything is zero");
|
|
|
|
|
MOZ_RELEASE_ASSERT(TestEqual(WrappingMultiply(uint8_t(128), uint8_t(1)),
|
|
|
|
|
uint8_t(128)),
|
|
|
|
|
"1 times anything is anything");
|
|
|
|
|
MOZ_RELEASE_ASSERT(TestEqual(WrappingMultiply(uint8_t(2), uint8_t(128)),
|
|
|
|
|
uint8_t(0)),
|
|
|
|
|
"2 times high bit overflows, produces zero");
|
|
|
|
|
MOZ_RELEASE_ASSERT(TestEqual(WrappingMultiply(uint8_t(8), uint8_t(16)),
|
|
|
|
|
uint8_t(128)),
|
|
|
|
|
"multiply that populates the high bit produces that value");
|
|
|
|
|
MOZ_RELEASE_ASSERT(TestEqual(WrappingMultiply(uint8_t(127), uint8_t(127)),
|
|
|
|
|
uint8_t(1)),
|
|
|
|
|
"multiplying signed maxvals overflows all the way to 1");
|
|
|
|
|
|
|
|
|
|
MOZ_RELEASE_ASSERT(TestEqual(WrappingMultiply(int8_t(0), int8_t(-128)),
|
|
|
|
|
int8_t(0)),
|
|
|
|
|
"zero times anything is zero");
|
|
|
|
|
MOZ_RELEASE_ASSERT(TestEqual(WrappingMultiply(int8_t(-128), int8_t(1)),
|
|
|
|
|
int8_t(-128)),
|
|
|
|
|
"1 times anything is anything");
|
|
|
|
|
MOZ_RELEASE_ASSERT(TestEqual(WrappingMultiply(int8_t(2), int8_t(-128)),
|
|
|
|
|
int8_t(0)),
|
|
|
|
|
"2 times min overflows, produces zero");
|
|
|
|
|
MOZ_RELEASE_ASSERT(TestEqual(WrappingMultiply(int8_t(16), int8_t(24)),
|
|
|
|
|
int8_t(-128)),
|
|
|
|
|
"multiply that populates the sign bit produces minval");
|
|
|
|
|
MOZ_RELEASE_ASSERT(TestEqual(WrappingMultiply(int8_t(8), int8_t(16)),
|
|
|
|
|
int8_t(-128)),
|
|
|
|
|
"multiply that populates the sign bit produces minval");
|
|
|
|
|
MOZ_RELEASE_ASSERT(TestEqual(WrappingMultiply(int8_t(127), int8_t(127)),
|
|
|
|
|
int8_t(1)),
|
|
|
|
|
"multiplying maxvals overflows all the way to 1");
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
static void
|
|
|
|
|
TestWrappingMultiply16()
|
|
|
|
|
{
|
|
|
|
|
MOZ_RELEASE_ASSERT(TestEqual(WrappingMultiply(uint16_t(0), uint16_t(32768)),
|
|
|
|
|
uint16_t(0)),
|
|
|
|
|
"zero times anything is zero");
|
|
|
|
|
MOZ_RELEASE_ASSERT(TestEqual(WrappingMultiply(uint16_t(32768), uint16_t(1)),
|
|
|
|
|
uint16_t(32768)),
|
|
|
|
|
"1 times anything is anything");
|
|
|
|
|
MOZ_RELEASE_ASSERT(TestEqual(WrappingMultiply(uint16_t(2), uint16_t(32768)),
|
|
|
|
|
uint16_t(0)),
|
|
|
|
|
"2 times high bit overflows, produces zero");
|
|
|
|
|
MOZ_RELEASE_ASSERT(TestEqual(WrappingMultiply(uint16_t(3), uint16_t(32768)),
|
|
|
|
|
uint16_t(-32768)),
|
|
|
|
|
"3 * 32768 - 65536 is 32768");
|
|
|
|
|
MOZ_RELEASE_ASSERT(TestEqual(WrappingMultiply(uint16_t(64), uint16_t(512)),
|
|
|
|
|
uint16_t(32768)),
|
|
|
|
|
"multiply that populates the high bit produces that value");
|
|
|
|
|
MOZ_RELEASE_ASSERT(TestEqual(WrappingMultiply(uint16_t(32767), uint16_t(32767)),
|
|
|
|
|
uint16_t(1)),
|
|
|
|
|
"multiplying signed maxvals overflows all the way to 1");
|
|
|
|
|
|
|
|
|
|
MOZ_RELEASE_ASSERT(TestEqual(WrappingMultiply(int16_t(0), int16_t(-32768)),
|
|
|
|
|
int16_t(0)),
|
|
|
|
|
"zero times anything is zero");
|
|
|
|
|
MOZ_RELEASE_ASSERT(TestEqual(WrappingMultiply(int16_t(-32768), int16_t(1)),
|
|
|
|
|
int16_t(-32768)),
|
|
|
|
|
"1 times anything is anything");
|
|
|
|
|
MOZ_RELEASE_ASSERT(TestEqual(WrappingMultiply(int16_t(-456), int16_t(123)),
|
|
|
|
|
int16_t(9448)),
|
|
|
|
|
"multiply opposite signs, then add 2**16 for the result");
|
|
|
|
|
MOZ_RELEASE_ASSERT(TestEqual(WrappingMultiply(int16_t(2), int16_t(-32768)),
|
|
|
|
|
int16_t(0)),
|
|
|
|
|
"2 times min overflows, produces zero");
|
|
|
|
|
MOZ_RELEASE_ASSERT(TestEqual(WrappingMultiply(int16_t(64), int16_t(512)),
|
|
|
|
|
int16_t(-32768)),
|
|
|
|
|
"multiply that populates the sign bit produces minval");
|
|
|
|
|
MOZ_RELEASE_ASSERT(TestEqual(WrappingMultiply(int16_t(32767), int16_t(32767)),
|
|
|
|
|
int16_t(1)),
|
|
|
|
|
"multiplying maxvals overflows all the way to 1");
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
static void
|
|
|
|
|
TestWrappingMultiply32()
|
|
|
|
|
{
|
|
|
|
|
MOZ_RELEASE_ASSERT(TestEqual(WrappingMultiply(uint32_t(0), uint32_t(2147483648)),
|
|
|
|
|
uint32_t(0)),
|
|
|
|
|
"zero times anything is zero");
|
|
|
|
|
MOZ_RELEASE_ASSERT(TestEqual(WrappingMultiply(uint32_t(42), uint32_t(17)),
|
|
|
|
|
uint32_t(714)),
|
|
|
|
|
"42 * 17 is 714 without wraparound");
|
|
|
|
|
MOZ_RELEASE_ASSERT(TestEqual(WrappingMultiply(uint32_t(2147483648), uint32_t(1)),
|
|
|
|
|
uint32_t(2147483648)),
|
|
|
|
|
"1 times anything is anything");
|
|
|
|
|
MOZ_RELEASE_ASSERT(TestEqual(WrappingMultiply(uint32_t(2), uint32_t(2147483648)),
|
|
|
|
|
uint32_t(0)),
|
|
|
|
|
"2 times high bit overflows, produces zero");
|
|
|
|
|
MOZ_RELEASE_ASSERT(TestEqual(WrappingMultiply(uint32_t(8192), uint32_t(262144)),
|
|
|
|
|
uint32_t(2147483648)),
|
|
|
|
|
"multiply that populates the high bit produces that value");
|
|
|
|
|
MOZ_RELEASE_ASSERT(TestEqual(WrappingMultiply(uint32_t(2147483647),
|
|
|
|
|
uint32_t(2147483647)),
|
|
|
|
|
uint32_t(1)),
|
|
|
|
|
"multiplying signed maxvals overflows all the way to 1");
|
|
|
|
|
|
|
|
|
|
MOZ_RELEASE_ASSERT(TestEqual(WrappingMultiply(int32_t(0), int32_t(-2147483647 - 1)),
|
|
|
|
|
int32_t(0)),
|
|
|
|
|
"zero times anything is zero");
|
|
|
|
|
MOZ_RELEASE_ASSERT(TestEqual(WrappingMultiply(int32_t(-2147483647 - 1), int32_t(1)),
|
|
|
|
|
int32_t(-2147483647 - 1)),
|
|
|
|
|
"1 times anything is anything");
|
|
|
|
|
MOZ_RELEASE_ASSERT(TestEqual(WrappingMultiply(int32_t(2), int32_t(-2147483647 - 1)),
|
|
|
|
|
int32_t(0)),
|
|
|
|
|
"2 times min overflows, produces zero");
|
|
|
|
|
MOZ_RELEASE_ASSERT(TestEqual(WrappingMultiply(int32_t(-7), int32_t(-9)),
|
|
|
|
|
int32_t(63)),
|
|
|
|
|
"-7 * -9 is 63, no wraparound needed");
|
|
|
|
|
MOZ_RELEASE_ASSERT(TestEqual(WrappingMultiply(int32_t(8192), int32_t(262144)),
|
|
|
|
|
int32_t(-2147483647 - 1)),
|
|
|
|
|
"multiply that populates the sign bit produces minval");
|
|
|
|
|
MOZ_RELEASE_ASSERT(TestEqual(WrappingMultiply(int32_t(2147483647), int32_t(2147483647)),
|
|
|
|
|
int32_t(1)),
|
|
|
|
|
"multiplying maxvals overflows all the way to 1");
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
static void
|
|
|
|
|
TestWrappingMultiply64()
|
|
|
|
|
{
|
|
|
|
|
MOZ_RELEASE_ASSERT(TestEqual(WrappingMultiply(uint64_t(0),
|
|
|
|
|
uint64_t(9223372036854775808ULL)),
|
|
|
|
|
uint64_t(0)),
|
|
|
|
|
"zero times anything is zero");
|
|
|
|
|
MOZ_RELEASE_ASSERT(TestEqual(WrappingMultiply(uint64_t(9223372036854775808ULL),
|
|
|
|
|
uint64_t(1)),
|
|
|
|
|
uint64_t(9223372036854775808ULL)),
|
|
|
|
|
"1 times anything is anything");
|
|
|
|
|
MOZ_RELEASE_ASSERT(TestEqual(WrappingMultiply(uint64_t(2),
|
|
|
|
|
uint64_t(9223372036854775808ULL)),
|
|
|
|
|
uint64_t(0)),
|
|
|
|
|
"2 times high bit overflows, produces zero");
|
|
|
|
|
MOZ_RELEASE_ASSERT(TestEqual(WrappingMultiply(uint64_t(131072),
|
|
|
|
|
uint64_t(70368744177664)),
|
|
|
|
|
uint64_t(9223372036854775808ULL)),
|
|
|
|
|
"multiply that populates the high bit produces that value");
|
|
|
|
|
MOZ_RELEASE_ASSERT(TestEqual(WrappingMultiply(uint64_t(9223372036854775807),
|
|
|
|
|
uint64_t(9223372036854775807)),
|
|
|
|
|
uint64_t(1)),
|
|
|
|
|
"multiplying signed maxvals overflows all the way to 1");
|
|
|
|
|
|
|
|
|
|
MOZ_RELEASE_ASSERT(TestEqual(WrappingMultiply(int64_t(0), int64_t(-9223372036854775807 - 1)),
|
|
|
|
|
int64_t(0)),
|
|
|
|
|
"zero times anything is zero");
|
|
|
|
|
MOZ_RELEASE_ASSERT(TestEqual(WrappingMultiply(int64_t(-9223372036854775807 - 1),
|
|
|
|
|
int64_t(1)),
|
|
|
|
|
int64_t(-9223372036854775807 - 1)),
|
|
|
|
|
"1 times anything is anything");
|
|
|
|
|
MOZ_RELEASE_ASSERT(TestEqual(WrappingMultiply(int64_t(2),
|
|
|
|
|
int64_t(-9223372036854775807 - 1)),
|
|
|
|
|
int64_t(0)),
|
|
|
|
|
"2 times min overflows, produces zero");
|
|
|
|
|
MOZ_RELEASE_ASSERT(TestEqual(WrappingMultiply(int64_t(131072),
|
|
|
|
|
int64_t(70368744177664)),
|
|
|
|
|
int64_t(-9223372036854775807 - 1)),
|
|
|
|
|
"multiply that populates the sign bit produces minval");
|
|
|
|
|
MOZ_RELEASE_ASSERT(TestEqual(WrappingMultiply(int64_t(9223372036854775807),
|
|
|
|
|
int64_t(9223372036854775807)),
|
|
|
|
|
int64_t(1)),
|
|
|
|
|
"multiplying maxvals overflows all the way to 1");
|
|
|
|
|
}
|
|
|
|
|
|
2018-03-07 06:21:58 +03:00
|
|
|
static void
|
|
|
|
|
TestWrappingMultiply()
|
2018-02-16 04:36:50 +03:00
|
|
|
{
|
2018-02-16 04:36:55 +03:00
|
|
|
TestWrappingMultiply8();
|
|
|
|
|
TestWrappingMultiply16();
|
|
|
|
|
TestWrappingMultiply32();
|
|
|
|
|
TestWrappingMultiply64();
|
2018-03-07 06:21:58 +03:00
|
|
|
}
|
|
|
|
|
|
|
|
|
|
int
|
|
|
|
|
main()
|
|
|
|
|
{
|
|
|
|
|
TestWrappingAdd();
|
2018-03-07 06:22:20 +03:00
|
|
|
TestWrappingSubtract();
|
2018-03-07 06:21:58 +03:00
|
|
|
TestWrappingMultiply();
|
2018-02-16 04:36:50 +03:00
|
|
|
return 0;
|
|
|
|
|
}
|
