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-rw-r--r--absl/random/internal/BUILD.bazel27
-rw-r--r--absl/random/internal/distribution_impl.h66
-rw-r--r--absl/random/internal/distribution_impl_test.cc42
-rw-r--r--absl/random/internal/wide_multiply.h109
-rw-r--r--absl/random/internal/wide_multiply_test.cc66
5 files changed, 202 insertions, 108 deletions
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
@@ -201,6 +201,19 @@ cc_library(
)
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"],
copts = ABSL_DEFAULT_COPTS,
@@ -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<float> {
}
};
-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<uint32_t>(a);
- const uint64_t a32 = a >> 32;
- const uint64_t b00 = static_cast<uint32_t>(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<uint32_t>(((c00 >> 32) + static_cast<uint32_t>(c32a) +
- static_cast<uint32_t>(c32b)) >>
- 32);
-
- return absl::MakeUint128(c64 + (c32a >> 32) + (c32b >> 32) + carry,
- c00 + (c32a << 32) + (c32b << 32));
-#endif
-}
-
-// wide_multiply<T> multiplies two N-bit values to a 2N-bit result.
-template <typename UIntType>
-struct wide_multiply {
- static constexpr size_t kN = std::numeric_limits<UIntType>::digits;
- using input_type = UIntType;
- using result_type = typename random_internal::unsigned_bits<kN * 2>::type;
-
- static result_type multiply(input_type a, input_type b) {
- return static_cast<result_type>(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<UIntType>::value,
- "Class-template wide_multiply<> argument must be unsigned.");
-};
-
-#ifndef ABSL_HAVE_INTRINSIC_INT128
-template <>
-struct wide_multiply<uint64_t> {
- 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<uint64_t>(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 <cstdint>
+#include <limits>
+#include <type_traits>
+
+#if (defined(_WIN32) || defined(_WIN64)) && defined(_M_IA64)
+#include <intrin.h> // 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<uint32_t>(a);
+ const uint64_t a32 = a >> 32;
+ const uint64_t b00 = static_cast<uint32_t>(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<uint32_t>(((c00 >> 32) + static_cast<uint32_t>(c32a) +
+ static_cast<uint32_t>(c32b)) >>
+ 32);
+
+ return absl::MakeUint128(c64 + (c32a >> 32) + (c32b >> 32) + carry,
+ c00 + (c32a << 32) + (c32b << 32));
+#endif
+}
+
+// wide_multiply<T> multiplies two N-bit values to a 2N-bit result.
+template <typename UIntType>
+struct wide_multiply {
+ static constexpr size_t kN = std::numeric_limits<UIntType>::digits;
+ using input_type = UIntType;
+ using result_type = typename random_internal::unsigned_bits<kN * 2>::type;
+
+ static result_type multiply(input_type a, input_type b) {
+ return static_cast<result_type>(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<UIntType>::value,
+ "Class-template wide_multiply<> argument must be unsigned.");
+};
+
+#ifndef ABSL_HAVE_INTRINSIC_INT128
+template <>
+struct wide_multiply<uint64_t> {
+ 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<uint64_t>(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
generated by cgit v1.2.3 (git 2.39.1) at 2024-06-01 08:10:35 +0000