Re: [Qemu-devel] [PATCH v4 27/33] tcg-ppc64: Use MFOCRF instead of MFCR

[Aurelien Jarno]

On Thu, Apr 04, 2013 at 05:56:20PM -0500, Richard Henderson wrote:
> It takes half the cycles to read one CR register instead of all 8.
> This is a backward compatible addition to the ISA, so chips prior
> to Power 2.00 spec will simply continue to read the entire CR register.
> 
> Signed-off-by: Richard Henderson <address@hidden>
> ---
>  tcg/ppc64/tcg-target.c | 12 ++++++++----
>  1 file changed, 8 insertions(+), 4 deletions(-)
> 
> diff --git a/tcg/ppc64/tcg-target.c b/tcg/ppc64/tcg-target.c
> index 806f3e2..f0ed698 100644
> --- a/tcg/ppc64/tcg-target.c
> +++ b/tcg/ppc64/tcg-target.c
> @@ -382,6 +382,7 @@ static int tcg_target_const_match (tcg_target_long val,
>  #define SRAWI  XO31(824)
>  #define NEG    XO31(104)
>  #define MFCR   XO31( 19)
> +#define MFOCRF (MFCR | (1u << 20))
>  #define NOR    XO31(124)
>  #define CNTLZW XO31( 26)
>  #define CNTLZD XO31( 58)
> @@ -430,6 +431,7 @@ static int tcg_target_const_match (tcg_target_long val,
>  #define ME(e) ((e)<<1)
>  #define BO(o) ((o)<<21)
>  #define MB64(b) ((b)<<5)
> +#define FXM(b) (1 << (19 - (b)))
>  
>  #define LK    1
>  
> @@ -1226,10 +1228,12 @@ static void tcg_out_setcond (TCGContext *s, TCGType 
> type, TCGCond cond,
>          sh = 31;
>          crop = CRNOR | BT (7, CR_EQ) | BA (7, CR_GT) | BB (7, CR_GT);
>      crtest:
> -        tcg_out_cmp (s, cond, arg1, arg2, const_arg2, 7, type);
> -        if (crop) tcg_out32 (s, crop);
> -        tcg_out32 (s, MFCR | RT (0));
> -        tcg_out_rlw(s, RLWINM, arg0, 0, sh, 31, 31);
> +        tcg_out_cmp(s, cond, arg1, arg2, const_arg2, 7, type);
> +        if (crop) {
> +            tcg_out32(s, crop);
> +        }
> +        tcg_out32(s, MFOCRF | RT(TCG_REG_R0) | FXM(7));
> +        tcg_out_rlw(s, RLWINM, arg0, TCG_REG_R0, sh, 31, 31);
>          break;
>  
>      default:

Reviewed-by: Aurelien Jarno <address@hidden>


-- 
Aurelien Jarno                          GPG: 1024D/F1BCDB73
address@hidden                 http://www.aurel32.net