Re: [PATCH v2 05/28] target/arm: Use gen_jmp for ISB and SB

[Richard Henderson]

On 7/8/21 9:11 AM, Peter Maydell wrote:
> > > Why isn't it enough here just to set is_jmp to DISAS_NEXT ?
> >
> > You mean DISAS_TOO_MANY?  That would work, yes.
> > At the time I was just thinking of replacing one jump with another.
>
> You've implicitly answered my question, which is that the main
> translator loop code treats DISAS_NEXT as "keep adding insns to
> the TB" :-)
>
> It feels slightly like misuse to use DISAS_TOO_MANY, unless we
> renamed it to something like DISAS_END_TB (which is what it's
> actually doing).

Yeah, better naming would have been a good.  In this instance I think I chose an odd 
colour for the bike shed.

The problem with just DISAS_END_TB is that there are many ways to end a tb, with at least: 
(1) goto_tb next, (2) goto_ptr next, (3) exit_tb.  We wind up replicating these three 
across many of the targets, so it would be a really nice cleanup to standardize, and with 
good names.


r~