go/src/math/fma.go

func zero(x uint64) uint64 { … }

func nonzero(x uint64) uint64 { … }

func shl(u1, u2 uint64, n uint) (r1, r2 uint64) { … }

func shr(u1, u2 uint64, n uint) (r1, r2 uint64) { … }

// shrcompress compresses the bottom n+1 bits of the two-word
// value into a single bit. the result is equal to the value
// shifted to the right by n, except the result's 0th bit is
// set to the bitwise OR of the bottom n+1 bits.
func shrcompress(u1, u2 uint64, n uint) (r1, r2 uint64) { … }

func lz(u1, u2 uint64) (l int32) { … }

// split splits b into sign, biased exponent, and mantissa.
// It adds the implicit 1 bit to the mantissa for normal values,
// and normalizes subnormal values.
func split(b uint64) (sign uint32, exp int32, mantissa uint64) { … }

// FMA returns x * y + z, computed with only one rounding.
// (That is, FMA returns the fused multiply-add of x, y, and z.)
func FMA(x, y, z float64) float64 { … }