From a15364ce4d88534ae2295127e5d8e32aefb6b446 Mon Sep 17 00:00:00 2001 From: Abseil Team Date: Wed, 16 Oct 2019 15:51:11 -0700 Subject: Export of internal Abseil changes -- d35c72d705155dcd89a92835103540f14c643d10 by Gennadiy Rozental : helpxml changed to report types of flags with built-in value type. PiperOrigin-RevId: 275131440 -- f3478792943d7dd40a6ef6083a8e5d374f43a65e by Abseil Team : Add space padding tests for hex conversions. PiperOrigin-RevId: 275120155 -- 7c2e4725403e173660f33f94af686a75d3722936 by Andy Soffer : Fix https://github.com/abseil/abseil-cpp/issues/379 by renaming `roundup` to `round_up` PiperOrigin-RevId: 275106110 -- 84cb30d6ee509961ac4359cfdda1360973b9527d by Laramie Leavitt : Move random_internal::wide_multiply into a file by the same name. PiperOrigin-RevId: 275059359 -- 06d691a8c187b5d899e7863784b23bdcfd580cb2 by Abseil Team : Add missing "return" keyword. PiperOrigin-RevId: 275036408 GitOrigin-RevId: d35c72d705155dcd89a92835103540f14c643d10 Change-Id: Id837b4de6c9cfe18f0a088363754bfe389df985b --- absl/random/BUILD.bazel | 1 + absl/random/CMakeLists.txt | 34 ++++++++ absl/random/internal/BUILD.bazel | 27 ++++++ absl/random/internal/distribution_impl.h | 66 --------------- absl/random/internal/distribution_impl_test.cc | 42 ---------- absl/random/internal/wide_multiply.h | 109 +++++++++++++++++++++++++ absl/random/internal/wide_multiply_test.cc | 66 +++++++++++++++ absl/random/uniform_int_distribution.h | 1 + 8 files changed, 238 insertions(+), 108 deletions(-) create mode 100644 absl/random/internal/wide_multiply.h create mode 100644 absl/random/internal/wide_multiply_test.cc (limited to 'absl/random') diff --git a/absl/random/BUILD.bazel b/absl/random/BUILD.bazel index 9211182..828f134 100644 --- a/absl/random/BUILD.bazel +++ b/absl/random/BUILD.bazel @@ -76,6 +76,7 @@ cc_library( "//absl/random/internal:iostream_state_saver", "//absl/random/internal:traits", "//absl/random/internal:uniform_helper", + "//absl/random/internal:wide_multiply", "//absl/strings", "//absl/types:span", ], diff --git a/absl/random/CMakeLists.txt b/absl/random/CMakeLists.txt index 151cefa..19dd2ca 100644 --- a/absl/random/CMakeLists.txt +++ b/absl/random/CMakeLists.txt @@ -65,6 +65,7 @@ absl_cc_library( absl::random_internal_iostream_state_saver absl::random_internal_traits absl::random_internal_uniform_helper + absl::random_internal_wide_multiply absl::strings absl::span absl::type_traits @@ -557,6 +558,22 @@ absl_cc_library( absl::random_internal_traits ) +# Internal-only target, do not depend on directly. +absl_cc_library( + NAME + random_internal_wide_multiply + HDRS + "internal/wide_multiply.h" + COPTS + ${ABSL_DEFAULT_COPTS} + LINKOPTS + ${ABSL_DEFAULT_LINKOPTS} + DEPS + absl::bits + absl::config + absl::int128 +) + # Internal-only target, do not depend on directly. absl_cc_library( NAME @@ -1033,3 +1050,20 @@ absl_cc_test( absl::random_internal_iostream_state_saver gtest_main ) + +# Internal-only target, do not depend on directly. +absl_cc_test( + NAME + random_internal_wide_multiply_test + SRCS + internal/wide_multiply_test.cc + COPTS + ${ABSL_TEST_COPTS} + LINKOPTS + ${ABSL_DEFAULT_LINKOPTS} + DEPS + absl::random_internal_wide_multiply + absl::bits + absl::int128 + gtest_main +) diff --git a/absl/random/internal/BUILD.bazel b/absl/random/internal/BUILD.bazel index cd50982..ec58cec 100644 --- a/absl/random/internal/BUILD.bazel +++ b/absl/random/internal/BUILD.bazel @@ -200,6 +200,19 @@ cc_library( deps = ["//absl/base:bits"], ) +cc_library( + name = "wide_multiply", + hdrs = ["wide_multiply.h"], + copts = ABSL_DEFAULT_COPTS, + linkopts = ABSL_DEFAULT_LINKOPTS, + deps = [ + ":traits", + "//absl/base:bits", + "//absl/base:config", + "//absl/numeric:int128", + ], +) + cc_library( name = "nonsecure_base", hdrs = ["nonsecure_base.h"], @@ -598,6 +611,20 @@ cc_test( ], ) +cc_test( + name = "wide_multiply_test", + size = "small", + srcs = ["wide_multiply_test.cc"], + copts = ABSL_TEST_COPTS, + linkopts = ABSL_DEFAULT_LINKOPTS, + deps = [ + ":wide_multiply", + "//absl/base:bits", + "//absl/numeric:int128", + "@com_google_googletest//:gtest_main", + ], +) + cc_library( name = "nanobenchmark", srcs = ["nanobenchmark.cc"], diff --git a/absl/random/internal/distribution_impl.h b/absl/random/internal/distribution_impl.h index 9b6ffb0..49b3e1a 100644 --- a/absl/random/internal/distribution_impl.h +++ b/absl/random/internal/distribution_impl.h @@ -188,72 +188,6 @@ struct RandU64ToReal { } }; -inline uint128 MultiplyU64ToU128(uint64_t a, uint64_t b) { -#if defined(ABSL_HAVE_INTRINSIC_INT128) - return uint128(static_cast<__uint128_t>(a) * b); -#elif defined(ABSL_INTERNAL_USE_UMUL128) - // uint64_t * uint64_t => uint128 multiply using imul intrinsic on MSVC. - uint64_t high = 0; - const uint64_t low = _umul128(a, b, &high); - return absl::MakeUint128(high, low); -#else - // uint128(a) * uint128(b) in emulated mode computes a full 128-bit x 128-bit - // multiply. However there are many cases where that is not necessary, and it - // is only necessary to support a 64-bit x 64-bit = 128-bit multiply. This is - // for those cases. - const uint64_t a00 = static_cast(a); - const uint64_t a32 = a >> 32; - const uint64_t b00 = static_cast(b); - const uint64_t b32 = b >> 32; - - const uint64_t c00 = a00 * b00; - const uint64_t c32a = a00 * b32; - const uint64_t c32b = a32 * b00; - const uint64_t c64 = a32 * b32; - - const uint32_t carry = - static_cast(((c00 >> 32) + static_cast(c32a) + - static_cast(c32b)) >> - 32); - - return absl::MakeUint128(c64 + (c32a >> 32) + (c32b >> 32) + carry, - c00 + (c32a << 32) + (c32b << 32)); -#endif -} - -// wide_multiply multiplies two N-bit values to a 2N-bit result. -template -struct wide_multiply { - static constexpr size_t kN = std::numeric_limits::digits; - using input_type = UIntType; - using result_type = typename random_internal::unsigned_bits::type; - - static result_type multiply(input_type a, input_type b) { - return static_cast(a) * b; - } - - static input_type hi(result_type r) { return r >> kN; } - static input_type lo(result_type r) { return r; } - - static_assert(std::is_unsigned::value, - "Class-template wide_multiply<> argument must be unsigned."); -}; - -#ifndef ABSL_HAVE_INTRINSIC_INT128 -template <> -struct wide_multiply { - using input_type = uint64_t; - using result_type = uint128; - - static result_type multiply(uint64_t a, uint64_t b) { - return MultiplyU64ToU128(a, b); - } - - static uint64_t hi(result_type r) { return Uint128High64(r); } - static uint64_t lo(result_type r) { return Uint128Low64(r); } -}; -#endif - } // namespace random_internal } // namespace absl diff --git a/absl/random/internal/distribution_impl_test.cc b/absl/random/internal/distribution_impl_test.cc index 09e7a31..fcc1690 100644 --- a/absl/random/internal/distribution_impl_test.cc +++ b/absl/random/internal/distribution_impl_test.cc @@ -461,46 +461,4 @@ TEST(DistributionImplTest, ExhaustiveFloat) { } } -TEST(DistributionImplTest, MultiplyU64ToU128Test) { - using absl::random_internal::MultiplyU64ToU128; - constexpr uint64_t k1 = 1; - constexpr uint64_t kMax = ~static_cast(0); - - EXPECT_EQ(absl::uint128(0), MultiplyU64ToU128(0, 0)); - - // Max uint64 - EXPECT_EQ(MultiplyU64ToU128(kMax, kMax), - absl::MakeUint128(0xfffffffffffffffe, 0x0000000000000001)); - EXPECT_EQ(absl::MakeUint128(0, kMax), MultiplyU64ToU128(kMax, 1)); - EXPECT_EQ(absl::MakeUint128(0, kMax), MultiplyU64ToU128(1, kMax)); - for (int i = 0; i < 64; ++i) { - EXPECT_EQ(absl::MakeUint128(0, kMax) << i, - MultiplyU64ToU128(kMax, k1 << i)); - EXPECT_EQ(absl::MakeUint128(0, kMax) << i, - MultiplyU64ToU128(k1 << i, kMax)); - } - - // 1-bit x 1-bit. - for (int i = 0; i < 64; ++i) { - for (int j = 0; j < 64; ++j) { - EXPECT_EQ(absl::MakeUint128(0, 1) << (i + j), - MultiplyU64ToU128(k1 << i, k1 << j)); - EXPECT_EQ(absl::MakeUint128(0, 1) << (i + j), - MultiplyU64ToU128(k1 << i, k1 << j)); - } - } - - // Verified multiplies - EXPECT_EQ(MultiplyU64ToU128(0xffffeeeeddddcccc, 0xbbbbaaaa99998888), - absl::MakeUint128(0xbbbb9e2692c5dddc, 0xc28f7531048d2c60)); - EXPECT_EQ(MultiplyU64ToU128(0x0123456789abcdef, 0xfedcba9876543210), - absl::MakeUint128(0x0121fa00ad77d742, 0x2236d88fe5618cf0)); - EXPECT_EQ(MultiplyU64ToU128(0x0123456789abcdef, 0xfdb97531eca86420), - absl::MakeUint128(0x0120ae99d26725fc, 0xce197f0ecac319e0)); - EXPECT_EQ(MultiplyU64ToU128(0x97a87f4f261ba3f2, 0xfedcba9876543210), - absl::MakeUint128(0x96fbf1a8ae78d0ba, 0x5a6dd4b71f278320)); - EXPECT_EQ(MultiplyU64ToU128(0xfedcba9876543210, 0xfdb97531eca86420), - absl::MakeUint128(0xfc98c6981a413e22, 0x342d0bbf48948200)); -} - } // namespace diff --git a/absl/random/internal/wide_multiply.h b/absl/random/internal/wide_multiply.h new file mode 100644 index 0000000..ebbfa1f --- /dev/null +++ b/absl/random/internal/wide_multiply.h @@ -0,0 +1,109 @@ +// Copyright 2017 The Abseil Authors. +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// https://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +#ifndef ABSL_RANDOM_INTERNAL_WIDE_MULTIPLY_H_ +#define ABSL_RANDOM_INTERNAL_WIDE_MULTIPLY_H_ + +#include +#include +#include + +#if (defined(_WIN32) || defined(_WIN64)) && defined(_M_IA64) +#include // NOLINT(build/include_order) +#pragma intrinsic(_umul128) +#define ABSL_INTERNAL_USE_UMUL128 1 +#endif + +#include "absl/base/config.h" +#include "absl/base/internal/bits.h" +#include "absl/numeric/int128.h" +#include "absl/random/internal/traits.h" + +namespace absl { +namespace random_internal { + +// Helper object to multiply two 64-bit values to a 128-bit value. +// MultiplyU64ToU128 multiplies two 64-bit values to a 128-bit value. +// If an intrinsic is available, it is used, otherwise use native 32-bit +// multiplies to construct the result. +inline uint128 MultiplyU64ToU128(uint64_t a, uint64_t b) { +#if defined(ABSL_HAVE_INTRINSIC_INT128) + return uint128(static_cast<__uint128_t>(a) * b); +#elif defined(ABSL_INTERNAL_USE_UMUL128) + // uint64_t * uint64_t => uint128 multiply using imul intrinsic on MSVC. + uint64_t high = 0; + const uint64_t low = _umul128(a, b, &high); + return absl::MakeUint128(high, low); +#else + // uint128(a) * uint128(b) in emulated mode computes a full 128-bit x 128-bit + // multiply. However there are many cases where that is not necessary, and it + // is only necessary to support a 64-bit x 64-bit = 128-bit multiply. This is + // for those cases. + const uint64_t a00 = static_cast(a); + const uint64_t a32 = a >> 32; + const uint64_t b00 = static_cast(b); + const uint64_t b32 = b >> 32; + + const uint64_t c00 = a00 * b00; + const uint64_t c32a = a00 * b32; + const uint64_t c32b = a32 * b00; + const uint64_t c64 = a32 * b32; + + const uint32_t carry = + static_cast(((c00 >> 32) + static_cast(c32a) + + static_cast(c32b)) >> + 32); + + return absl::MakeUint128(c64 + (c32a >> 32) + (c32b >> 32) + carry, + c00 + (c32a << 32) + (c32b << 32)); +#endif +} + +// wide_multiply multiplies two N-bit values to a 2N-bit result. +template +struct wide_multiply { + static constexpr size_t kN = std::numeric_limits::digits; + using input_type = UIntType; + using result_type = typename random_internal::unsigned_bits::type; + + static result_type multiply(input_type a, input_type b) { + return static_cast(a) * b; + } + + static input_type hi(result_type r) { return r >> kN; } + static input_type lo(result_type r) { return r; } + + static_assert(std::is_unsigned::value, + "Class-template wide_multiply<> argument must be unsigned."); +}; + +#ifndef ABSL_HAVE_INTRINSIC_INT128 +template <> +struct wide_multiply { + using input_type = uint64_t; + using result_type = uint128; + + static result_type multiply(uint64_t a, uint64_t b) { + return MultiplyU64ToU128(a, b); + } + + static uint64_t hi(result_type r) { return Uint128High64(r); } + static uint64_t lo(result_type r) { return Uint128Low64(r); } +}; +#endif + +} // namespace random_internal +} // namespace absl + +#endif // ABSL_RANDOM_INTERNAL_WIDE_MULTIPLY_H_ diff --git a/absl/random/internal/wide_multiply_test.cc b/absl/random/internal/wide_multiply_test.cc new file mode 100644 index 0000000..922603f --- /dev/null +++ b/absl/random/internal/wide_multiply_test.cc @@ -0,0 +1,66 @@ +// Copyright 2017 The Abseil Authors. +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// https://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +#include "absl/random/internal/wide_multiply.h" + +#include "gtest/gtest.h" +#include "absl/base/internal/bits.h" +#include "absl/numeric/int128.h" + +using absl::random_internal::MultiplyU64ToU128; + +namespace { + +TEST(WideMultiplyTest, MultiplyU64ToU128Test) { + constexpr uint64_t k1 = 1; + constexpr uint64_t kMax = ~static_cast(0); + + EXPECT_EQ(absl::uint128(0), MultiplyU64ToU128(0, 0)); + + // Max uint64 + EXPECT_EQ(MultiplyU64ToU128(kMax, kMax), + absl::MakeUint128(0xfffffffffffffffe, 0x0000000000000001)); + EXPECT_EQ(absl::MakeUint128(0, kMax), MultiplyU64ToU128(kMax, 1)); + EXPECT_EQ(absl::MakeUint128(0, kMax), MultiplyU64ToU128(1, kMax)); + for (int i = 0; i < 64; ++i) { + EXPECT_EQ(absl::MakeUint128(0, kMax) << i, + MultiplyU64ToU128(kMax, k1 << i)); + EXPECT_EQ(absl::MakeUint128(0, kMax) << i, + MultiplyU64ToU128(k1 << i, kMax)); + } + + // 1-bit x 1-bit. + for (int i = 0; i < 64; ++i) { + for (int j = 0; j < 64; ++j) { + EXPECT_EQ(absl::MakeUint128(0, 1) << (i + j), + MultiplyU64ToU128(k1 << i, k1 << j)); + EXPECT_EQ(absl::MakeUint128(0, 1) << (i + j), + MultiplyU64ToU128(k1 << i, k1 << j)); + } + } + + // Verified multiplies + EXPECT_EQ(MultiplyU64ToU128(0xffffeeeeddddcccc, 0xbbbbaaaa99998888), + absl::MakeUint128(0xbbbb9e2692c5dddc, 0xc28f7531048d2c60)); + EXPECT_EQ(MultiplyU64ToU128(0x0123456789abcdef, 0xfedcba9876543210), + absl::MakeUint128(0x0121fa00ad77d742, 0x2236d88fe5618cf0)); + EXPECT_EQ(MultiplyU64ToU128(0x0123456789abcdef, 0xfdb97531eca86420), + absl::MakeUint128(0x0120ae99d26725fc, 0xce197f0ecac319e0)); + EXPECT_EQ(MultiplyU64ToU128(0x97a87f4f261ba3f2, 0xfedcba9876543210), + absl::MakeUint128(0x96fbf1a8ae78d0ba, 0x5a6dd4b71f278320)); + EXPECT_EQ(MultiplyU64ToU128(0xfedcba9876543210, 0xfdb97531eca86420), + absl::MakeUint128(0xfc98c6981a413e22, 0x342d0bbf48948200)); +} + +} // namespace diff --git a/absl/random/uniform_int_distribution.h b/absl/random/uniform_int_distribution.h index 4970486..02aa376 100644 --- a/absl/random/uniform_int_distribution.h +++ b/absl/random/uniform_int_distribution.h @@ -38,6 +38,7 @@ #include "absl/random/internal/fast_uniform_bits.h" #include "absl/random/internal/iostream_state_saver.h" #include "absl/random/internal/traits.h" +#include "absl/random/internal/wide_multiply.h" namespace absl { -- cgit v1.2.3