Re: [PATCH 6/8] target/arm: Prepare bfdotadd() callers for FEAT_EBF support

[Richard Henderson <richard.henderson@linaro.org>]

On 7/31/24 02:03, Peter Maydell wrote:
> We use bfdotadd() in four callsites for various helper functions. Currently
> this all assumes that we have the FPCR.EBF=0 semantics. For FPCR.EBF=1
> we will need to:
>   * call a different routine to bfdotadd() because we need to do a
>     fused multiply-add rather than separate multiply and add steps
>   * use a different float_status that honours the FPCR rounding mode
>     and denormal-flushing fields
>   * pass in an extra float_status that has been set up to perform
>     round-to-odd rounding
> 
> To prepare for this, refactor all the callsites so that instead of
>     for (...) {
>         x = bfdotadd(...);
>     }
> 
> they are:
>     float_status fpst, fpst_odd;
>     if (is_ebf(env, &fpst, &fpst_odd)) {
>         for (...) {
>             x = bfdotadd_ebf(..., &fpst, &fpst_odd);
>         }
>     } else {
>         for (...) {
>             x = bfdotadd(..., &fpst);
>         }
>     }
> 
> For the moment the is_ebf() function always returns false, sets up
> fpst for EBF=0 semantics and never sets up fpst_odd; bfdotadd_ebf()
> will assert if called. We'll fill in the handling for EBF=1 in the
> next commit.
> 
> This change should be a zero-behaviour-change refactor.
> 
> Signed-off-by: Peter Maydell<peter.maydell@linaro.org>
> ---
>   target/arm/tcg/vec_internal.h |  37 ++++++++-
>   target/arm/tcg/sme_helper.c   |  74 ++++++++++++------
>   target/arm/tcg/vec_helper.c   | 141 +++++++++++++++++++++++++---------
>   3 files changed, 192 insertions(+), 60 deletions(-)

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>

r~