Re: [Qemu-devel] [PATCH v2 2/2] target-arm: Implement abs_i32 inline rather than as a helper

[Aurelien Jarno]

On Fri, Oct 19, 2012 at 02:06:59PM +0100, Peter Maydell wrote:
> Implement abs_i32 inline (with movcond) rather than using a helper
> function.
> 
> Signed-off-by: Peter Maydell <address@hidden>
> ---
>  target-arm/helper.c    |    5 -----
>  target-arm/helper.h    |    1 -
>  target-arm/translate.c |   11 +++++++++--
>  3 files changed, 9 insertions(+), 8 deletions(-)
> 
> diff --git a/target-arm/helper.c b/target-arm/helper.c
> index 58340bd..0601760 100644
> --- a/target-arm/helper.c
> +++ b/target-arm/helper.c
> @@ -1562,11 +1562,6 @@ uint32_t HELPER(rbit)(uint32_t x)
>      return x;
>  }
>  
> -uint32_t HELPER(abs)(uint32_t x)
> -{
> -    return ((int32_t)x < 0) ? -x : x;
> -}
> -
>  #if defined(CONFIG_USER_ONLY)
>  
>  void do_interrupt (CPUARMState *env)
> diff --git a/target-arm/helper.h b/target-arm/helper.h
> index fa3472f..60812de 100644
> --- a/target-arm/helper.h
> +++ b/target-arm/helper.h
> @@ -13,7 +13,6 @@ DEF_HELPER_2(double_saturate, i32, env, s32)
>  DEF_HELPER_FLAGS_2(sdiv, TCG_CALL_CONST | TCG_CALL_PURE, s32, s32, s32)
>  DEF_HELPER_FLAGS_2(udiv, TCG_CALL_CONST | TCG_CALL_PURE, i32, i32, i32)
>  DEF_HELPER_FLAGS_1(rbit, TCG_CALL_CONST | TCG_CALL_PURE, i32, i32)
> -DEF_HELPER_FLAGS_1(abs, TCG_CALL_CONST | TCG_CALL_PURE, i32, i32)
>  
>  #define PAS_OP(pfx)  \
>      DEF_HELPER_3(pfx ## add8, i32, i32, i32, ptr) \
> diff --git a/target-arm/translate.c b/target-arm/translate.c
> index d33f94c..25433da 100644
> --- a/target-arm/translate.c
> +++ b/target-arm/translate.c
> @@ -462,8 +462,15 @@ static void gen_sar(TCGv dest, TCGv t0, TCGv t1)
>      tcg_temp_free_i32(tmp1);
>  }
>  
> -/* FIXME:  Implement this natively.  */
> -#define tcg_gen_abs_i32(t0, t1) gen_helper_abs(t0, t1)
> +static void tcg_gen_abs_i32(TCGv dest, TCGv src)
> +{
> +    TCGv c0 = tcg_const_i32(0);
> +    TCGv tmp = tcg_temp_new_i32();
> +    tcg_gen_neg_i32(tmp, src);
> +    tcg_gen_movcond_i32(TCG_COND_GT, dest, src, c0, src, tmp);
> +    tcg_temp_free_i32(c0);
> +    tcg_temp_free_i32(tmp);
> +}
>  
>  static void shifter_out_im(TCGv var, int shift)
>  {


Reviewed-by: Aurelien Jarno <address@hidden>

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