Le 20/10/2021 à 19:47, Richard Henderson a écrit :
> On 10/19/21 2:48 AM, Frédéric Pétrot wrote:
>> The 128-bit bitwise instructions do not need any function prototype change
>> as the functions can be applied independently on the lower and upper part of
>> the registers.
>>
>> Signed-off-by: Frédéric Pétrot <frederic.pet...@univ-grenoble-alpes.fr>
>> Co-authored-by: Fabien Portas <fabien.por...@grenoble-inp.org>
>> ---
>> target/riscv/translate.c | 22 ++++++++++++++++++++++
>> 1 file changed, 22 insertions(+)
>>
>> diff --git a/target/riscv/translate.c b/target/riscv/translate.c
>> index e8f08f921e..71982f6284 100644
>> --- a/target/riscv/translate.c
>> +++ b/target/riscv/translate.c
>> @@ -429,6 +429,17 @@ static bool gen_logic_imm_fn(DisasContext *ctx, arg_i
>> *a,
>> DisasExtend ext,
>> gen_set_gpr(ctx, a->rd, dest);
>> + if (get_xl_max(ctx) == MXL_RV128) {
>> + if (get_ol(ctx) == MXL_RV128) {
>> + uint64_t immh = -(a->imm < 0);
>> + src1 = get_gprh(ctx, a->rs1);
>> + dest = dest_gprh(ctx, a->rd);
>> +
>> + func(dest, src1, immh);
>> + }
>> + gen_set_gprh(ctx, a->rd, dest);
>> + }
>
> If ol < RV128, you're storing the low dest into the gprh, which is wrong. It
> should be the sign-extension of the low part. But that should happen for all
> writes.
Thanks for your feedback (on the other parts too) that I'll apply.
On this specific case, in gen_set_gprh I check that the operation is not on
128 bit in which case I propagate the sign of the low part instead of using
dest (the spec says that the sign should propagate to misa_xl_max, irrelevant
of xl).
This implicitly forces the order in which the functions must be called as you
noticed, and introducing a higher level function as you suggest would indeed
make things more readable, and this can probably be applied in most places.
Frédéric
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