Re: [Qemu-devel] [PATCH v3 21/26] tcg-aarch64: Introduce tcg_out_insn_3507

[Claudio Fontana <claudio.fontana@huawei.com>]

On 03.04.2014 21:56, Richard Henderson wrote:
> Cleaning up the implementation of REV and REV16 at the same time.
> 
> Reviewed-by: Claudio Fontana <claudio.fontana@huawei.com>
> Signed-off-by: Richard Henderson <rth@twiddle.net>
> ---
>  tcg/aarch64/tcg-target.c | 22 ++++++++++++++--------
>  1 file changed, 14 insertions(+), 8 deletions(-)

During testing I found this patch causes a regression for big endian targets (sparc).

Can you take a look?
I think it might be related to the extended form of the REV instruction needing
an additional 0x400. See below.

> 
> diff --git a/tcg/aarch64/tcg-target.c b/tcg/aarch64/tcg-target.c
> index caaf8a2..de7490d 100644
> --- a/tcg/aarch64/tcg-target.c
> +++ b/tcg/aarch64/tcg-target.c
> @@ -327,6 +327,10 @@ typedef enum {
>      I3506_CSEL      = 0x1a800000,
>      I3506_CSINC     = 0x1a800400,
>  
> +    /* Data-processing (1 source) instructions.  */
> +    I3507_REV16     = 0x5ac00400,
> +    I3507_REV       = 0x5ac00800,
> +
>      /* Data-processing (2 source) instructions.  */
>      I3508_LSLV      = 0x1ac02000,
>      I3508_LSRV      = 0x1ac02400,
> @@ -545,6 +549,12 @@ static void tcg_out_insn_3506(TCGContext *s, AArch64Insn insn, TCGType ext,
>                | tcg_cond_to_aarch64[c] << 12);
>  }
>  
> +static void tcg_out_insn_3507(TCGContext *s, AArch64Insn insn, TCGType ext,
> +                              TCGReg rd, TCGReg rn)
> +{
> +    tcg_out32(s, insn | ext << 31 | rn << 5 | rd);
> +}
> +
>  static void tcg_out_insn_3509(TCGContext *s, AArch64Insn insn, TCGType ext,
>                                TCGReg rd, TCGReg rn, TCGReg rm, TCGReg ra)
>  {
> @@ -961,19 +971,15 @@ static void tcg_out_brcond(TCGContext *s, TCGMemOp ext, TCGCond c, TCGArg a,
>  }
>  
>  static inline void tcg_out_rev(TCGContext *s, TCGType ext,
> -                               TCGReg rd, TCGReg rm)
> +                               TCGReg rd, TCGReg rn)
>  {
> -    /* using REV 0x5ac00800 */
> -    unsigned int base = ext ? 0xdac00c00 : 0x5ac00800;

see the extended form 0xdac00c00 <-


> -    tcg_out32(s, base | rm << 5 | rd);
> +    tcg_out_insn(s, 3507, REV, ext, rd, rn);
>  }
>  
>  static inline void tcg_out_rev16(TCGContext *s, TCGType ext,
> -                                 TCGReg rd, TCGReg rm)
> +                                 TCGReg rd, TCGReg rn)
>  {
> -    /* using REV16 0x5ac00400 */
> -    unsigned int base = ext ? 0xdac00400 : 0x5ac00400;
> -    tcg_out32(s, base | rm << 5 | rd);
> +    tcg_out_insn(s, 3507, REV16, ext, rd, rn);

while this does not have it.

>  }
>  
>  static inline void tcg_out_sxt(TCGContext *s, TCGType ext, TCGMemOp s_bits,
> 

Ciao,

Claudio