Re: [PATCH 3/4] gdb/aarch64: Display fp8 formats in registers

[Ezra Sitorus <ezra.sitorus@arm.com>]

On Sat, Oct 11, 2025 at 02:10:11PM +0100, Luis wrote:
> Hi Ezra,
> 
> Given Pedro's input about the representation of fp8's, I'm not sure this is
> the right path. Enabling these types for the registers would also make the
> types visible to the rest of GDB. And users can operate on them via
> arithmetic operators etc.
> 
> Being integers, the ending result wouldn�t be correct.
> 
> It might be viable to explore the python extension option to print the types
> accordingly. We already make vector fields (neon or sve) available as 8, 16,
> 32, 64 and 128 integers. Converting from that would therefore be easy.
> 

Fair! I think a python pretty printer is a good idea. However, would a pretty
belong in the gdb project or the gcc project? The only examples in gdb are from
testcases. The gdb docs references gdb.libstdcxx.v6, but this exists in gcc. In
either scenario, I'm not too sure where the actual files would go to.

> Also, I'm not too keen on expanding even further these neon/sve union types.
> They are very hard to parse due to the multitude of representations. Ideally
> we�d put together some pseudo-registers to do the job. That would also help
> with remote debugging stub target description compatibility, as those
> wouldn�t need to expose these internal details of gdb.

Your previous comment seems to suggest adding a pretty printer for the registers
too but this one seems to suggest adding pseudo-registers instead. For pseudo-regs,
would the approach be something like putting the new float formats in aarch64-tdep.c,
and assigning the new pseudo regs' types to be the fp8 float formats? 

Thanks!

Ezra