On 12/20/2013 05:18 AM, Peter Maydell wrote:
> On 19 December 2013 19:29, Richard Henderson <rth@xxxxxxxxxxx> wrote:
>> On 12/17/2013 07:12 AM, Peter Maydell wrote:
>>> + tcg_gen_mul_i64(tcg_tmp, tcg_op1, tcg_op2);
>>> + if (is_sub) {
>>> + tcg_gen_sub_i64(cpu_reg(s, rd), cpu_reg(s, ra), tcg_tmp);
>>> + } else {
>>> + tcg_gen_add_i64(cpu_reg(s, rd), cpu_reg(s, ra), tcg_tmp);
>>> + }
>>
>> Perhaps worth noticing the RA=XZR special case for the MUL alias?
>
> Yeah, makes sense: have adjusted to:
> + if (ra == 31) {
> + /* We special-case rA == XZR as it is the standard MUL alias */
> + tcg_gen_mul_i64(cpu_reg(s, rd), tcg_op1, tcg_op2);
> + } else {
You need to handle (or dismiss) is_sub.
Either (ra == 31 && !is_sub) or
if (is_sub) {
tcg_gen_neg_i64(tcg_rd, tcg_rd);
}
with tcg_rd pre-loaded along with tcg_op1 and tcg_op2.
That said, unlike MUL I don't expect MNEG to be common at all.
> + tcg_gen_mul_i64(tcg_tmp, tcg_op1, tcg_op2);
> + if (is_sub) {
> + tcg_gen_sub_i64(cpu_reg(s, rd), cpu_reg(s, ra), tcg_tmp);
> + } else {
> + tcg_gen_add_i64(cpu_reg(s, rd), cpu_reg(s, ra), tcg_tmp);
> + }
> + }
r~
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