Re: [Qemu-devel] [PATCH] Fix qemu_ld64 on arm

[Laurent Desnogues <laurent.desnogues@gmail.com>]

On Tue, Feb 24, 2009 at 9:03 AM, Pablo Virolainen
<Pablo.Virolainen@nomovok.com> wrote:
>
> Emulating fldl on arm doesn't seem to work too well. It's the way qemu_ld64
> is translated to arm instructions.
>
>        tcg_out_ld32_12(s, COND_AL, data_reg, addr_reg, 0);
>        tcg_out_ld32_12(s, COND_AL, data_reg2, addr_reg, 4);

It seems you are using an old version of qemu.  Taking a quick
look at current svn, I think your patch is not needed anymore.


Laurent

>
>
> Consider case where data_reg==0, data_reg2==1, and addr_reg==0. First load
> overwrited addr_reg. So let's put an if (data_ref==addr_reg).
>
> Index: tcg-target.c
> ===================================================================
> --- tcg-target.c        (revision 6642)
> +++ tcg-target.c        (working copy)
> @@ -1011,8 +1011,14 @@
>     case 3:
>         /* TODO: use block load -
>          * check that data_reg2 > data_reg or the other way */
> -        tcg_out_ld32_12(s, COND_AL, data_reg, addr_reg, 0);
> -        tcg_out_ld32_12(s, COND_AL, data_reg2, addr_reg, 4);
> +
> +        if (data_reg==addr_reg) {
> +            tcg_out_ld32_12(s, COND_AL, data_reg2, addr_reg, 4);
> +            tcg_out_ld32_12(s, COND_AL, data_reg, addr_reg, 0);
> +        } else {
> +            tcg_out_ld32_12(s, COND_AL, data_reg, addr_reg, 0);
> +            tcg_out_ld32_12(s, COND_AL, data_reg2, addr_reg, 4);
> +        }
>         break;
>     }
>  #endif
>
>
>