Re: [Qemu-devel] [PATCH 06/14] ppc: introduce helpers for mfocrf/mtocrf

[Richard Henderson <rth@twiddle.net>]

On 09/15/2014 08:03 AM, Paolo Bonzini wrote:
> @@ -4173,24 +4173,7 @@ static void gen_mfcr(DisasContext *ctx)
>                              cpu_gpr[rD(ctx->opcode)], crn * 4);
>          }
>      } else {
> -        TCGv_i32 t0 = tcg_temp_new_i32();
> -        tcg_gen_mov_i32(t0, cpu_crf[0]);
> -        tcg_gen_shli_i32(t0, t0, 4);
> -        tcg_gen_or_i32(t0, t0, cpu_crf[1]);
> -        tcg_gen_shli_i32(t0, t0, 4);
> -        tcg_gen_or_i32(t0, t0, cpu_crf[2]);
> -        tcg_gen_shli_i32(t0, t0, 4);
> -        tcg_gen_or_i32(t0, t0, cpu_crf[3]);
> -        tcg_gen_shli_i32(t0, t0, 4);
> -        tcg_gen_or_i32(t0, t0, cpu_crf[4]);
> -        tcg_gen_shli_i32(t0, t0, 4);
> -        tcg_gen_or_i32(t0, t0, cpu_crf[5]);
> -        tcg_gen_shli_i32(t0, t0, 4);
> -        tcg_gen_or_i32(t0, t0, cpu_crf[6]);
> -        tcg_gen_shli_i32(t0, t0, 4);
> -        tcg_gen_or_i32(t0, t0, cpu_crf[7]);
> -        tcg_gen_extu_i32_tl(cpu_gpr[rD(ctx->opcode)], t0);
> -        tcg_temp_free_i32(t0);
> +        gen_helper_mfocrf(cpu_gpr[rD(ctx->opcode)], cpu_env);

I don't like this helper name, because it isn't mfocrf.  We handled the "one"
case above.  This is the old-style "mfcr", i.e. move from all cr.

> @@ -4285,15 +4268,9 @@ static void gen_mtcrf(DisasContext *ctx)
>              tcg_temp_free_i32(temp);
>          }
>      } else {
> -        TCGv_i32 temp = tcg_temp_new_i32();
> -        tcg_gen_trunc_tl_i32(temp, cpu_gpr[rS(ctx->opcode)]);
> -        for (crn = 0 ; crn < 8 ; crn++) {
> -            if (crm & (1 << crn)) {
> -                    tcg_gen_shri_i32(cpu_crf[7 - crn], temp, crn * 4);
> -                    tcg_gen_andi_i32(cpu_crf[7 - crn], cpu_crf[7 - crn], 0xf);
> -            }
> -        }
> -        tcg_temp_free_i32(temp);
> +        TCGv_i32 t0 = tcg_const_i32(crm);
> +        gen_helper_mtocrf(cpu_env, cpu_gpr[rS(ctx->opcode)], t0);
> +        tcg_temp_free_i32(t0);

Similarly.


r~