Re: [PATCH v3 7/9] target/riscv: add support for Zcmt extension

[Richard Henderson]

On 11/17/22 17:46, weiwei wrote:
> However, to some extent, JVT and FCSR in statenen CSR are  used to 
> enable/disable
> Zfinx and Zcmt extensions.  When they are disabled, It seems reasonable to look 
> for
> another insn, just like the processor doesn't support them at all.
>
> From the other aspect, is it possible that we support many overlapping extensions(such 
> as Zcmt and Zcd or CD) in one processor  and only one work once (just disable anothers
> if we need another to work)?

I don't think any processor will support overlapping, mutual exclusive extensions.  The 
decode within the processor would be wildly complicated by that.

While you might be able to get away with returning false in this particular case right 
now, it's incorrect usage of the tool and might just come back to cause bugs in the future.


r~