Re: [Qemu-devel] defining VIXL_DEBUG?

[Peter Maydell]

On 18 January 2016 at 10:57, Paolo Bonzini <address@hidden> wrote:
> One issue I have found after posting is that I'm not sure whether bad
> instructions (aka reserved encodings) are handled properly by libvixl.
> See for example this:
>
>     case 'A': {  // IAddSub.
>       VIXL_ASSERT(instr->ShiftAddSub() <= 1);
>       int64_t imm = instr->ImmAddSub() << (12 * instr->ShiftAddSub());
>       AppendToOutput("#0x%" PRIx64 " (%" PRId64 ")", imm, imm);
>       return 7;
>     }
>
> where the '1x' encodings of bits 22:23 (marked as reserved in the ARMv8
> ARM) would cause an abort as far as I can see.

Isn't this handled by  Decoder::DecodeAddSubImmediate(), which checks
bit 23?

In any case if we're worried it would be easy to set up a trivial
test loop that just feeds all 2^32 integers to the disassembler.

thanks
-- PMM