Re: [Qemu-devel] [PATCH v4 10/33] tcg-aarch64: Implement mov with tcg_fmt_* functions

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

On 14.09.2013 23:54, Richard Henderson wrote:
> Avoid the magic numbers in the current implementation.
> 
> Signed-off-by: Richard Henderson <rth@twiddle.net>
> ---
>  tcg/aarch64/tcg-target.c | 24 ++++++++++--------------
>  1 file changed, 10 insertions(+), 14 deletions(-)
> 
> diff --git a/tcg/aarch64/tcg-target.c b/tcg/aarch64/tcg-target.c
> index 56625a9..93badfd 100644
> --- a/tcg/aarch64/tcg-target.c
> +++ b/tcg/aarch64/tcg-target.c
> @@ -379,13 +379,18 @@ static inline void tcg_out_ldst_12(TCGContext *s,
>                | op_type << 20 | scaled_uimm << 10 | rn << 5 | rd);
>  }
>  
> +/* Register to register move using ORR (shifted register with no shift). */
>  static inline void tcg_out_movr(TCGContext *s, TCGType ext,
> -                                TCGReg rd, TCGReg src)
> +                                TCGReg rd, TCGReg rm)
>  {
> -    /* register to register move using MOV (shifted register with no shift) */
> -    /* using MOV 0x2a0003e0 | (shift).. */
> -    unsigned int base = ext ? 0xaa0003e0 : 0x2a0003e0;
> -    tcg_out32(s, base | src << 16 | rd);
> +    tcg_fmt_Rdnm(s, INSN_ORR, ext, rd, TCG_REG_XZR, rm);
> +}
> +
> +/* Register to register move using ADDI (move to/from SP).  */
> +static inline void tcg_out_movr_sp(TCGContext *s, TCGType ext,
> +                                   TCGReg rd, TCGReg rn)
> +{
> +    tcg_fmt_Rdn_aimm(s, INSN_ADDI, ext, rd, rn, 0);
>  }
>  
>  static inline void tcg_out_movi_aux(TCGContext *s,
> @@ -460,15 +465,6 @@ static inline void tcg_out_ldst(TCGContext *s, enum aarch64_ldst_op_data data,
>      tcg_out_ldst_r(s, data, type, rd, rn, TCG_REG_TMP);
>  }
>  


I am ok with reusing the existing functions of course, this is an improvement.
See the comments about the tcg_fmt_* functions in previous patches for the related issues.

> -/* mov alias implemented with add immediate, useful to move to/from SP */
> -static inline void tcg_out_movr_sp(TCGContext *s, TCGType ext,
> -                                   TCGReg rd, TCGReg rn)
> -{
> -    /* using ADD 0x11000000 | (ext) | rn << 5 | rd */
> -    unsigned int base = ext ? 0x91000000 : 0x11000000;
> -    tcg_out32(s, base | rn << 5 | rd);
> -}
> -
>  static inline void tcg_out_mov(TCGContext *s,
>                                 TCGType type, TCGReg ret, TCGReg arg)
>  {
>