On 23.04.19 21:21, Richard Henderson wrote:
> On 4/23/19 11:58 AM, David Hildenbrand wrote:
>>> +void tcg_gen_gvec_shls(unsigned vece, uint32_t dofs, uint32_t aofs,
>>> + TCGv_i32 shift, uint32_t oprsz, uint32_t maxsz);
>>> +void tcg_gen_gvec_shrs(unsigned vece, uint32_t dofs, uint32_t aofs,
>>> + TCGv_i32 shift, uint32_t oprsz, uint32_t maxsz);
>>> +void tcg_gen_gvec_sars(unsigned vece, uint32_t dofs, uint32_t aofs,
>>> + TCGv_i32 shift, uint32_t oprsz, uint32_t maxsz);
>>
>> I assume all irrelevant bits of the shift have to be masked off by the
>> caller, right?
>
> Correct, just like for integers.
>
>>
>> On s390x, I would use it for (one variant of) VECTOR ELEMENT SHIFT like
>> this:
>>
>>
>> +static DisasJumpType op_ves(DisasContext *s, DisasOps *o)
>> +{
>> + const uint8_t es = get_field(s->fields, m4);
>> + const uint8_t d2 = get_field(s->fields, d2) &
>> + (NUM_VEC_ELEMENT_BITS(es) - 1);
>> + const uint8_t v1 = get_field(s->fields, v1);
>> + const uint8_t v3 = get_field(s->fields, v3);
>> + TCGv_i32 shift;
>> +
>> + if (es > ES_64) {
>> + gen_program_exception(s, PGM_SPECIFICATION);
>> + return DISAS_NORETURN;
>> + }
>> +
>> + shift = tcg_temp_new_i32();
>> + tcg_gen_extrl_i64_i32(shift, o->addr1);
>> + tcg_gen_andi_i32(shift, shift, NUM_VEC_ELEMENT_BITS(es) - 1);
>> +
>> + switch (s->fields->op2) {
>> + case 0x30:
>> + if (likely(!get_field(s->fields, b2))) {
>> + gen_gvec_fn_2i(shli, es, v1, v3, d2);
>> + } else {
>> + gen_gvec_fn_2s(shls, es, v1, v3, shift);
>> + }
>> + break;
>> + case 0x3a:
>> + if (likely(!get_field(s->fields, b2))) {
>> + gen_gvec_fn_2i(sari, es, v1, v3, d2);
>> + } else {
>> + gen_gvec_fn_2s(sars, es, v1, v3, shift);
>> + }
>> + break;
>> + case 0x38:
>> + if (likely(!get_field(s->fields, b2))) {
>> + gen_gvec_fn_2i(shri, es, v1, v3, d2);
>> + } else {
>> + gen_gvec_fn_2s(shrs, es, v1, v3, shift);
>> + }
>> + break;
>> + default:
>> + g_assert_not_reached();
>> + }
>> + tcg_temp_free_i32(shift);
>> + return DISAS_NEXT;
>> +}
>
> Looks plausible. I might have hoisted the b2 == 0 check,
> and avoid the other tcg arithmetic when unused.
Makes sense, will do. Thanks!
--
Thanks,
David / dhildenb
