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Bug 913282: Add mfbt Float32 asserts and constants; r=Waldo

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This commit is contained in:
Benjamin Bouvier 2013-09-20 12:08:49 -07:00
parent da2b672b39
commit adb7f75b72
1 changed files with 24 additions and 0 deletions
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24
mfbt/FloatingPoint.h
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@ -58,6 +58,30 @@ static_assert((DoubleSignBit | DoubleExponentBits | DoubleSignificandBits) ==
~uint64_t(0),
"all bits accounted for");
/*
* Ditto for |float| that must be a 32-bit double format number type, compatible
* with the IEEE-754 standard.
*/
static_assert(sizeof(float) == sizeof(uint32_t), "float must be 32bits");
const unsigned FloatExponentBias = 127;
const unsigned FloatExponentShift = 23;
const uint32_t FloatSignBit = 0x80000000UL;
const uint32_t FloatExponentBits = 0x7F800000UL;
const uint32_t FloatSignificandBits = 0x007FFFFFUL;
static_assert((FloatSignBit & FloatExponentBits) == 0,
"sign bit doesn't overlap exponent bits");
static_assert((FloatSignBit & FloatSignificandBits) == 0,
"sign bit doesn't overlap significand bits");
static_assert((FloatExponentBits & FloatSignificandBits) == 0,
"exponent bits don't overlap significand bits");
static_assert((FloatSignBit | FloatExponentBits | FloatSignificandBits) ==
~uint32_t(0),
"all bits accounted for");
/** Determines whether a double is NaN. */
static MOZ_ALWAYS_INLINE bool
IsNaN(double d)