
The ARMv8 instruction set includes a fused floating point reciprocal square root step instruction which demands an "(x * y + z) / 2" fused operation. Support this by adding a flag to the softfloat muladd operations which requests that the result is halved before rounding. Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Richard Henderson <rth@twiddle.net>