Re: [Qemu-devel] [PATCH v5 10/28] target/arm: convert conversion helpers to fpst/ahp_flag

[Peter Maydell]

On 14 May 2018 at 23:12, Richard Henderson <address@hidden> wrote:
> From: Alex Bennée <address@hidden>
>
> Instead of passing env and leaving it up to the helper to get the
> right fpstatus we pass it explicitly. There was already a get_fpstatus
> helper for neon for the 32 bit code. We also add an get_ahp_flag() for
> passing the state of the alternative FP16 format flag. This leaves
> scope for later tracking the AHP state in translation flags.
>
> Signed-off-by: Alex Bennée <address@hidden>
> Signed-off-by: Richard Henderson <address@hidden>
>
> ---
> v4
>   - remove neon_fcvt_*; they are now identical to vfp_fcvt_*.
>   - add flags to vfp_fcvt_* helper decls.
>   - add some missing tcg_temp_free_*.
> v5
>   - always use get_fpstatus_ptr(false) for FZ, since FZ16 is
>     supposed to be supressed.
> ---

> @@ -9053,12 +9066,17 @@ static void handle_2misc_narrow(DisasContext *s, bool 
> scalar,
>              } else {
>                  TCGv_i32 tcg_lo = tcg_temp_new_i32();
>                  TCGv_i32 tcg_hi = tcg_temp_new_i32();
> +                TCGv_ptr fpst = get_fpstatus_ptr(true);

Still the wrong fpstatus here...

> +                TCGv_i32 ahp = get_ahp_flag();
> +
>                  tcg_gen_extr_i64_i32(tcg_lo, tcg_hi, tcg_op);
> -                gen_helper_vfp_fcvt_f32_to_f16(tcg_lo, tcg_lo, cpu_env);
> -                gen_helper_vfp_fcvt_f32_to_f16(tcg_hi, tcg_hi, cpu_env);
> +                gen_helper_vfp_fcvt_f32_to_f16(tcg_lo, tcg_lo, fpst, ahp);
> +                gen_helper_vfp_fcvt_f32_to_f16(tcg_hi, tcg_hi, fpst, ahp);
>                  tcg_gen_deposit_i32(tcg_res[pass], tcg_lo, tcg_hi, 16, 16);
>                  tcg_temp_free_i32(tcg_lo);
>                  tcg_temp_free_i32(tcg_hi);
> +                tcg_temp_free_ptr(fpst);
> +                tcg_temp_free_i32(ahp);
>              }
>              break;
>          case 0x56:  /* FCVTXN, FCVTXN2 */

> @@ -11532,18 +11550,24 @@ static void handle_2misc_widening(DisasContext *s, 
> int opcode, bool is_q,
>          /* 16 -> 32 bit fp conversion */
>          int srcelt = is_q ? 4 : 0;
>          TCGv_i32 tcg_res[4];
> +        TCGv_ptr fpst = get_fpstatus_ptr(true);

...and here.

> +        TCGv_i32 ahp = get_ahp_flag();
> +
>
>          for (pass = 0; pass < 4; pass++) {
>              tcg_res[pass] = tcg_temp_new_i32();
>
>              read_vec_element_i32(s, tcg_res[pass], rn, srcelt + pass, MO_16);
>              gen_helper_vfp_fcvt_f16_to_f32(tcg_res[pass], tcg_res[pass],
> -                                           cpu_env);
> +                                           fpst, ahp);
>          }
>          for (pass = 0; pass < 4; pass++) {
>              write_vec_element_i32(s, tcg_res[pass], rd, pass, MO_32);
>              tcg_temp_free_i32(tcg_res[pass]);
>          }
> +
> +        tcg_temp_free_ptr(fpst);
> +        tcg_temp_free_i32(ahp);
>      }
>  }

thanks
-- PMM