Re: [PATCH] target/arm: Move minor arithmetic helpers out of helper.c

[Peter Maydell]

On Tue, 17 Dec 2024 at 18:17, Richard Henderson
<richard.henderson@linaro.org> wrote:
>
> On 12/17/24 11:44, Peter Maydell wrote:
> > helper.c includes some small TCG helper functions used for mostly
> > arithmetic instructions.  These are TCG only and there's no need for
> > them to be in the large and unwieldy helper.c.  Move them out to
> > their own source file in the tcg/ subdirectory, together with the
> > op_addsub.h multiply-included template header that they use.
> >
> > (Ironically, this means that helper.c no longer contains
> > any TCG helper function definitions at all.)
> >
> > Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
> > ---
> > One last tiny cleanup for the end of the year...this is a pure
> > code movement, with no changes.
>
> Because of pure code movement,
> Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
>
> Ideally op_addsub.h would become tcg/op_addsub.h.inc too.

Yeah, I did think about that but decided to be lazy :-)

> > +/*
> > + * Note that signed overflow is undefined in C.  The following routines are
> > + * careful to use unsigned types where modulo arithmetic is required.
> > + * Failure to do so _will_ break on newer gcc.
> > + */
>
> The comment is out-of-date vs -fwrapv, which we use.
>
> There are a bunch of other saturation related macros/functions hanging about. 
>  We should
> probably unify them.

Mmmm; this is all rather elderly code from the A32 decoder,
though. I'm not sure it hugely merits much effort. My
aim here was really just to do another little bit
towards slimming down helper.c.

-- PMM