Re: [PATCH v7 1/4] LoongArch: Simulate branch and PC instructions

[Tiezhu Yang]

On 12/07/2022 11:06 AM, Huacai Chen wrote:
> Hi, Tiezhu,
>
> On Fri, Dec 2, 2022 at 9:08 PM Tiezhu Yang <yangtiezhu@xxxxxxxxxxx> wrote:
> > According to LoongArch Reference Manual, simulate branch and
> > PC instructions, this is preparation for later patch.

...

> > +static inline unsigned long sign_extended(unsigned long val, unsigned int idx)
> > +{
> > +       if (val & (1UL << idx))
> > +               return ~((1UL << (idx + 1)) - 1) | val;
> > +       else
> > +               return ((1UL << (idx + 1)) - 1) & val;
> > +}
> You can use existing __SIGNEX and its friends rather than reinvent them.

Thanks for your reminder.

In my opinion, this static inline function sign_extended()
is much more clear and readable than the macro __SIGNEX()
defined in alternative.c, the helper function bs_dest_*()
seems redundant too, use "pc + sign_extended()" is a more
straightforward way to simulate instruction according to
the ISA Manual, so here I prefer to keep it as is.

Additionally, we can use sign_extended() instead of __SIGNEX()
in alternative.c, the __SIGNEX() related code can be removed
in a seperate patch in some day.

Thanks,
Tiezhu