Re: [Qemu-devel] [PATCH 16/28] target/riscv: Convert quadrant 1 of RVXC insns to decodetree

[Bastian Koppelmann]

On 10/13/18 8:53 PM, Richard Henderson wrote:
> On 10/12/18 10:30 AM, Bastian Koppelmann wrote:
> > +static bool trans_c_addi(DisasContext *ctx, arg_c_addi *a, uint16_t insn)
> > +{
> > +    if (a->imm == 0) {
> > +        return true;
> > +    }
> return false, I think.


Those are HINTS, which means the instruction in valid, but does not 
affect state, so true is correct. If I do return false, then Linux does 
not boot anymore :)


> > +    arg_jal arg = { .rd = 1, .imm = a->imm };
> > +    return trans_jal(ctx, &arg, insn);
> > +#else
> > +    /* C.ADDIW */
> > +    arg_addiw arg = { .rd = a->rd, .rs1 = a->rd, .imm = a->imm };
> > +    return trans_addiw(ctx, &arg, insn);
> > +#endif
> > +}
> > +
> > +static bool trans_c_li(DisasContext *ctx, arg_c_li *a, uint16_t insn)
> > +{
> > +    if (a->rd == 0) {
> > +        return true;
> > +    }
> return false.


Likewise.


> > +static bool trans_c_addi16sp_lui(DisasContext *ctx, arg_c_addi16sp_lui *a,
> > +        uint16_t insn)
> > +{
> > +    if (a->rd == 2) {
> > +        /* C.ADDI16SP */
> > +        arg_addi arg = { .rd = 2, .rs1 = 2, .imm = a->imm_addi16sp };
> > +        return trans_addi(ctx, &arg, insn);
> > +    } else if (a->imm_lui != 0) {
> > +        if (a->rd == 0) {
> > +            return true;
> > +        }
> I think it should be
>
>    } else if (a->imm_lui != 0 && a->rd != 0) {

Likewise.


Cheers,

Bastian