Re: [PATCH 2/2] target/arm: Fail on invalid size for VMUL (float)

[Peter Maydell]

On Wed, 8 Apr 2020 at 16:29, Fredrik Strupe <address@hidden> wrote:
>
> Bit 1 of VMUL (float)'s size field encodes the opcode and must be 0,
> with 1 making it undefined. Thus, make VMUL (float) instructions
> with size=0b10 or size=0b11 (size >= 2) undefined.
>
> (U is 1 for VMUL, while it is 0 for VMLA/VMLS.)
>
> Signed-off-by: Fredrik Strupe <address@hidden>
> ---
>  target/arm/translate.c | 5 +++++
>  1 file changed, 5 insertions(+)

Thanks for this patch. I'm actually in the middle of a
refactoring of this code to use decodetree, but I'll make
sure I check that the refactoring fixes this decode bug.

Also undef-checks like this in the old neon decode structure
should be in the switch (op) outside the loop-for-each-element:
compare NEON_3R_FLOAT_CMP; but it's a bit moot with the
refactoring as all that code will be deleted.

thanks
-- PMM