mantissa <<= shift
		exp = 1 - int32(shift)
	} else {
		// Add implicit 1 bit
		mantissa |= 1 << 52
	}
	return
}

// 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 {
	bx, by, bz := Float64bits(x), Float64bits(y), Float64bits(z)

	// Inf or NaN or zero involved. At most one rounding will occur.

David Chase <******@****.***> 1667836928 -0500

	}

	testenv.MustHaveGoBuild(t)
	gocmd := testenv.GoToolPath(t)
	tmpdir := t.TempDir()
	source := filepath.Join("testdata", "fma.go")
	output := filepath.Join(tmpdir, "fma.exe")
	cmd := testenv.Command(t, gocmd, "build", "-o", output, source)
	// The hash-dependence on file path name is dodged by specifying "all hashes ending in 1" plus "all hashes ending in 0"

	sink64[3] = math.Copysign(-1, c)
}

func fma(x, y, z float64) float64 {
	// amd64/v3:-".*x86HasFMA"
	// amd64:"VFMADD231SD"
	// arm/6:"FMULAD"
	// arm64:"FMADDD"
	// s390x:"FMADD"
	// ppc64x:"FMADD"
	// riscv64:"FMADDD"
	return math.FMA(x, y, z)
}

func fms(x, y, z float64) float64 {
	// riscv64:"FMSUBD"
	return math.FMA(x, y, -z)
}

func fnms(x, y, z float64) float64 {

			option{Name: "avx", Feature: &X86.HasAVX},
			option{Name: "avx2", Feature: &X86.HasAVX2},
			option{Name: "bmi1", Feature: &X86.HasBMI1},
			option{Name: "bmi2", Feature: &X86.HasBMI2},
			option{Name: "fma", Feature: &X86.HasFMA})
	}
	if level < 4 {
		// These options are required at level 4. At lower levels
		// they can be turned off.
		options = append(options,
			option{Name: "avx512f", Feature: &X86.HasAVX512F},

		{Name: "amxbf16", Feature: &X86.HasAMXBF16},
		{Name: "bmi1", Feature: &X86.HasBMI1},
		{Name: "bmi2", Feature: &X86.HasBMI2},
		{Name: "cx16", Feature: &X86.HasCX16},
		{Name: "erms", Feature: &X86.HasERMS},
		{Name: "fma", Feature: &X86.HasFMA},
		{Name: "osxsave", Feature: &X86.HasOSXSAVE},
		{Name: "pclmulqdq", Feature: &X86.HasPCLMULQDQ},
		{Name: "popcnt", Feature: &X86.HasPOPCNT},
		{Name: "rdrand", Feature: &X86.HasRDRAND},