diff options
Diffstat (limited to 'third_party/abseil-cpp/absl/numeric/int128.cc')
-rw-r--r-- | third_party/abseil-cpp/absl/numeric/int128.cc | 53 |
1 files changed, 16 insertions, 37 deletions
diff --git a/third_party/abseil-cpp/absl/numeric/int128.cc b/third_party/abseil-cpp/absl/numeric/int128.cc index b605a87042..17d88744ae 100644 --- a/third_party/abseil-cpp/absl/numeric/int128.cc +++ b/third_party/abseil-cpp/absl/numeric/int128.cc @@ -15,6 +15,7 @@ #include "absl/numeric/int128.h" #include <stddef.h> + #include <cassert> #include <iomanip> #include <ostream> // NOLINT(readability/streams) @@ -22,6 +23,9 @@ #include <string> #include <type_traits> +#include "absl/base/optimization.h" +#include "absl/numeric/bits.h" + namespace absl { ABSL_NAMESPACE_BEGIN @@ -31,44 +35,26 @@ ABSL_DLL const uint128 kuint128max = MakeUint128( namespace { // Returns the 0-based position of the last set bit (i.e., most significant bit) -// in the given uint64_t. The argument may not be 0. +// in the given uint128. The argument is not 0. // // For example: // Given: 5 (decimal) == 101 (binary) // Returns: 2 -#define STEP(T, n, pos, sh) \ - do { \ - if ((n) >= (static_cast<T>(1) << (sh))) { \ - (n) = (n) >> (sh); \ - (pos) |= (sh); \ - } \ - } while (0) -static inline int Fls64(uint64_t n) { - assert(n != 0); - int pos = 0; - STEP(uint64_t, n, pos, 0x20); - uint32_t n32 = static_cast<uint32_t>(n); - STEP(uint32_t, n32, pos, 0x10); - STEP(uint32_t, n32, pos, 0x08); - STEP(uint32_t, n32, pos, 0x04); - return pos + ((uint64_t{0x3333333322221100} >> (n32 << 2)) & 0x3); -} -#undef STEP - -// Like Fls64() above, but returns the 0-based position of the last set bit -// (i.e., most significant bit) in the given uint128. The argument may not be 0. -static inline int Fls128(uint128 n) { +inline ABSL_ATTRIBUTE_ALWAYS_INLINE int Fls128(uint128 n) { if (uint64_t hi = Uint128High64(n)) { - return Fls64(hi) + 64; + ABSL_INTERNAL_ASSUME(hi != 0); + return 127 - countl_zero(hi); } - return Fls64(Uint128Low64(n)); + const uint64_t low = Uint128Low64(n); + ABSL_INTERNAL_ASSUME(low != 0); + return 63 - countl_zero(low); } // Long division/modulo for uint128 implemented using the shift-subtract // division algorithm adapted from: // https://stackoverflow.com/questions/5386377/division-without-using -void DivModImpl(uint128 dividend, uint128 divisor, uint128* quotient_ret, - uint128* remainder_ret) { +inline void DivModImpl(uint128 dividend, uint128 divisor, uint128* quotient_ret, + uint128* remainder_ret) { assert(divisor != 0); if (divisor > dividend) { @@ -152,28 +138,21 @@ uint128::uint128(float v) : uint128(MakeUint128FromFloat(v)) {} uint128::uint128(double v) : uint128(MakeUint128FromFloat(v)) {} uint128::uint128(long double v) : uint128(MakeUint128FromFloat(v)) {} +#if !defined(ABSL_HAVE_INTRINSIC_INT128) uint128 operator/(uint128 lhs, uint128 rhs) { -#if defined(ABSL_HAVE_INTRINSIC_INT128) - return static_cast<unsigned __int128>(lhs) / - static_cast<unsigned __int128>(rhs); -#else // ABSL_HAVE_INTRINSIC_INT128 uint128 quotient = 0; uint128 remainder = 0; DivModImpl(lhs, rhs, "ient, &remainder); return quotient; -#endif // ABSL_HAVE_INTRINSIC_INT128 } + uint128 operator%(uint128 lhs, uint128 rhs) { -#if defined(ABSL_HAVE_INTRINSIC_INT128) - return static_cast<unsigned __int128>(lhs) % - static_cast<unsigned __int128>(rhs); -#else // ABSL_HAVE_INTRINSIC_INT128 uint128 quotient = 0; uint128 remainder = 0; DivModImpl(lhs, rhs, "ient, &remainder); return remainder; -#endif // ABSL_HAVE_INTRINSIC_INT128 } +#endif // !defined(ABSL_HAVE_INTRINSIC_INT128) namespace { |