diff options
Diffstat (limited to 'libc/utils/FPUtil/LongDoubleBitsX86.h')
| -rw-r--r-- | libc/utils/FPUtil/LongDoubleBitsX86.h | 16 |
1 files changed, 12 insertions, 4 deletions
diff --git a/libc/utils/FPUtil/LongDoubleBitsX86.h b/libc/utils/FPUtil/LongDoubleBitsX86.h index 5438e0b..4d64490 100644 --- a/libc/utils/FPUtil/LongDoubleBitsX86.h +++ b/libc/utils/FPUtil/LongDoubleBitsX86.h @@ -23,10 +23,10 @@ template <> struct MantissaWidth<long double> { template <unsigned Width> struct Padding; // i386 padding. -template <> struct Padding<4> { static constexpr unsigned Value = 16; }; +template <> struct Padding<4> { static constexpr unsigned value = 16; }; // x86_64 padding. -template <> struct Padding<8> { static constexpr unsigned Value = 48; }; +template <> struct Padding<8> { static constexpr unsigned value = 48; }; template <> struct __attribute__((packed)) FPBits<long double> { using UIntType = __uint128_t; @@ -38,7 +38,7 @@ template <> struct __attribute__((packed)) FPBits<long double> { uint8_t implicitBit : 1; uint16_t exponent : ExponentWidth<long double>::value; uint8_t sign : 1; - uint64_t padding : Padding<sizeof(uintptr_t)>::Value; + uint64_t padding : Padding<sizeof(uintptr_t)>::value; template <typename XType, cpp::EnableIfType<cpp::IsSame<long double, XType>::Value, int> = 0> @@ -91,7 +91,15 @@ template <> struct __attribute__((packed)) FPBits<long double> { // zero in case i386. UIntType result = UIntType(0); *reinterpret_cast<FPBits<long double> *>(&result) = *this; - return result; + + // Even though we zero out |result| before copying the long double value, + // there can be garbage bits in the padding. So, we zero the padding bits + // in |result|. + static constexpr UIntType mask = + (UIntType(1) << (sizeof(long double) - + Padding<sizeof(uintptr_t)>::value / 8)) - + 1; + return result & mask; } static FPBits<long double> zero() { return FPBits<long double>(0.0l); } |