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

[Richard Henderson]

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.

> +/*
> + * 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The comment is out-of-date vs -fwrapv, which we use.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.


r~