Re: [Qemu-devel] [PATCH 02/13] target-arm: A64: add support for logical (shifted register)

[Richard Henderson <rth@twiddle.net>]

On 12/06/2013 10:51 AM, Peter Maydell wrote:
> +    if (invert) {
> +        tcg_gen_not_i64(tcg_rm, tcg_rm);
> +    }
> +
> +    tcg_rd = cpu_reg(s, rd);
> +    tcg_rn = cpu_reg(s, rn);
> +
> +    switch (opc) {
> +    case 0: /* AND, BIC */
> +    case 3: /* ANDS, BICS */
> +        tcg_gen_and_i64(tcg_rd, tcg_rn, tcg_rm);
> +        break;
> +    case 1: /* ORR, ORN */
> +        tcg_gen_or_i64(tcg_rd, tcg_rn, tcg_rm);
> +        break;
> +    case 2: /* EOR, EON */
> +        tcg_gen_xor_i64(tcg_rd, tcg_rn, tcg_rm);
> +        break;
> +    default:
> +        assert(FALSE);
> +        break;
> +    }

While correct, surely better to work with tcg and select on opc:invert to
generate andc/orc/eqv?

Also, isn't MOV (register) canonical for ORR (rn=31 && shift_amount=0), and MVN
(register) canonical for ORN (rn=31 && shift_amount=0), and both therefore also
worth a special case?


r~