PPC binutils opcodes

[Peter Bergner]

On 5/11/22 6:38 PM, Alan Modra via Binutils wrote:
> On Wed, May 11, 2022 at 08:46:16PM +0100, Luke Kenneth Casson Leighton wrote:
>> btw what's the best advice for submitting Draft work? we're attempting
>> to keep to the Sandbox EXT022 but at some point we're going to run
>> out of space there.  is there a "--draft" or "--experimental" flag
>> that can be set?
>> or is it something that is fine under a new CPU name (e.g. -mlibresoc)?
> 
> I don't see any reason why you shouldn't use -mlibresoc or whatever
> you choose.  

+1

There is also no problem if your cpu uses a particular set of major and/or
minor opcode bits that another cpu already uses or a new cpu might use in
the future.  We already have multiple cases of this in the opcode table.
You just have to ensure that your cpu's bitmask (ie, the combination of
powerpc_opcode flags that describe what your cpu implements) doesn't enable
your new instruction(s) as well as any instruction(s) that have conflicting
opcode bits.

As Alan said, as long as you don't break other cpus, I think you're fine.

Peter