target/arm: Handle FPCR.AH in FCMLA by index
The negation step in FCMLA by index mustn't negate a NaN when
FPCR.AH is set. Use the same approach as vector FCMLA of
passing in FPCR.AH and using it to select whether to negate
by XOR or by the muladd negate_product flag.
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-id:
20250129013857.135256-27-richard.henderson@linaro.org
[PMM: Expanded commit message]
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>