Re: [Qemu-arm] [PATCH 01/23] scripts: Add decodetree.py

[Peter Maydell]

On 18 December 2017 at 17:45, Richard Henderson
<address@hidden> wrote:
> To be used to decode ARM SVE, but could be used for any 32-bit RISC.
> It would need additional work to extend to insn sizes other than 32-bit.

I guess we could make that extension without requiring all
existing pattern files to be updated, right?

> Signed-off-by: Richard Henderson <address@hidden>
> ---
>  scripts/decodetree.py | 984 
> ++++++++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 984 insertions(+)
>  create mode 100755 scripts/decodetree.py

This is rather large for a single patch...

> +# Pattern examples:
> +#
> +#   addl_r   010000 ..... ..... .... 0000000 ..... @opr
> +#   addl_i   010000 ..... ..... .... 0000000 ..... @opi
> +#

I think we should insist that a pattern defines all the
bits (either as constant values or as fields that get
passed to the decode function). That will help prevent
accidental under-decoding.

thanks
-- PMM