Re: [PATCH 1/2] target/arm: Disable VFPv4-D32 when NEON is not available

[Richard Henderson]

On 9/28/22 09:47, Cédric Le Goater wrote:
> As the Cortex A7 MPCore Technical reference says :
>
>    "When FPU option is selected without NEON, the FPU is VFPv4-D16 and
>    uses 16 double-precision registers. When the FPU is implemented with
>    NEON, the FPU is VFPv4-D32 and uses 32 double-precision registers.
>    This register bank is shared with NEON."
>
> Modify the mvfr0 register value of the cortex A7 to advertise only 16
> registers when NEON is not available, and not 32 registers.

Looks like A5 has the same language, while A15 says that NEON cannot be enabled without 
VFP (which is the same as all aarch64 cores).  I guess this is a decent compromise.

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>


r~