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authorGravatar Abseil Team <absl-team@google.com>2019-10-16 15:51:11 -0700
committerGravatar Andy Soffer <asoffer@google.com>2019-10-17 14:43:24 -0400
commita15364ce4d88534ae2295127e5d8e32aefb6b446 (patch)
treec01afa5f859f563b7bfd8cfdafa6b6fd1fed3aa6 /absl/random/internal/distribution_impl.h
parentab3552a18964e7063c8324f45b3896a6a20b08a8 (diff)
Export of internal Abseil changes
-- d35c72d705155dcd89a92835103540f14c643d10 by Gennadiy Rozental <rogeeff@google.com>: helpxml changed to report types of flags with built-in value type. PiperOrigin-RevId: 275131440 -- f3478792943d7dd40a6ef6083a8e5d374f43a65e by Abseil Team <absl-team@google.com>: Add space padding tests for hex conversions. PiperOrigin-RevId: 275120155 -- 7c2e4725403e173660f33f94af686a75d3722936 by Andy Soffer <asoffer@google.com>: Fix https://github.com/abseil/abseil-cpp/issues/379 by renaming `roundup` to `round_up` PiperOrigin-RevId: 275106110 -- 84cb30d6ee509961ac4359cfdda1360973b9527d by Laramie Leavitt <lar@google.com>: Move random_internal::wide_multiply into a file by the same name. PiperOrigin-RevId: 275059359 -- 06d691a8c187b5d899e7863784b23bdcfd580cb2 by Abseil Team <absl-team@google.com>: Add missing "return" keyword. PiperOrigin-RevId: 275036408 GitOrigin-RevId: d35c72d705155dcd89a92835103540f14c643d10 Change-Id: Id837b4de6c9cfe18f0a088363754bfe389df985b
Diffstat (limited to 'absl/random/internal/distribution_impl.h')
-rw-r--r--absl/random/internal/distribution_impl.h66
1 files changed, 0 insertions, 66 deletions
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