Re: [Qemu-devel] [PATCH v4 06/33] tcg-aarch64: Merge enum aarch64_srr_opc with AArch64Insn

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

On 14.09.2013 23:54, Richard Henderson wrote:
> And since we're no longer talking about opcodes, merge the 0x1ac02000
> data2 primary opcode with the shift subcode to create the full insn.
> 
> Signed-off-by: Richard Henderson <rth@twiddle.net>
> ---
>  tcg/aarch64/tcg-target.c | 49 ++++++++++++++++++++++++------------------------
>  1 file changed, 24 insertions(+), 25 deletions(-)
> 
> diff --git a/tcg/aarch64/tcg-target.c b/tcg/aarch64/tcg-target.c
> index 99d9884..be6d05a 100644
> --- a/tcg/aarch64/tcg-target.c
> +++ b/tcg/aarch64/tcg-target.c
> @@ -216,14 +216,13 @@ typedef enum {
>      INSN_ADDS   = 0x2b000000,
>      INSN_SUB    = 0x4b000000,
>      INSN_SUBS   = 0x6b000000,
> -} AArch64Insn;
>  
> -enum aarch64_srr_opc {
> -    SRR_SHL = 0x0,
> -    SRR_SHR = 0x4,
> -    SRR_SAR = 0x8,
> -    SRR_ROR = 0xc
> -};
> +    /* Data-processing (2 source) instructions */
> +    INSN_LSLV  = 0x1ac02000,
> +    INSN_LSRV  = 0x1ac02400,
> +    INSN_ASRV  = 0x1ac02800,
> +    INSN_RORV  = 0x1ac02c00,
> +} AArch64Insn;
>  
>  static inline enum aarch64_ldst_op_data
>  aarch64_ldst_get_data(TCGOpcode tcg_op)
> @@ -472,12 +471,12 @@ static inline void tcg_out_mul(TCGContext *s, TCGType ext,
>  }
>  
>  static inline void tcg_out_shiftrot_reg(TCGContext *s,
> -                                        enum aarch64_srr_opc opc, TCGType ext,
> +                                        AArch64Insn insn, TCGType ext,
>                                          TCGReg rd, TCGReg rn, TCGReg rm)
>  {
>      /* using 2-source data processing instructions 0x1ac02000 */
> -    unsigned int base = ext ? 0x9ac02000 : 0x1ac02000;
> -    tcg_out32(s, base | rm << 16 | opc << 8 | rn << 5 | rd);
> +    unsigned int base = insn | (ext ? 0x80000000 : 0);
> +    tcg_out32(s, base | rm << 16 | rn << 5 | rd);
>  }
>  
>  static inline void tcg_out_ubfm(TCGContext *s, TCGType ext, TCGReg rd,
> @@ -1214,47 +1213,47 @@ static void tcg_out_op(TCGContext *s, TCGOpcode opc,
>  
>      case INDEX_op_shl_i64:
>      case INDEX_op_shl_i32:
> -        if (c2) {    /* LSL / UBFM Wd, Wn, (32 - m) */
> +        if (c2) {
>              tcg_out_shl(s, ext, a0, a1, a2);
> -        } else {                /* LSL / LSLV */
> -            tcg_out_shiftrot_reg(s, SRR_SHL, ext, a0, a1, a2);
> +        } else {
> +            tcg_out_shiftrot_reg(s, INSN_LSLV, ext, a0, a1, a2);
>          }
>          break;

Any reason you strip all comments out?
They are supposed to hint the reader about how the tcg operation is implemented.

>      case INDEX_op_shr_i64:
>      case INDEX_op_shr_i32:
> -        if (c2) {    /* LSR / UBFM Wd, Wn, m, 31 */
> +        if (c2) {
>              tcg_out_shr(s, ext, a0, a1, a2);
> -        } else {                /* LSR / LSRV */
> -            tcg_out_shiftrot_reg(s, SRR_SHR, ext, a0, a1, a2);
> +        } else {
> +            tcg_out_shiftrot_reg(s, INSN_LSRV, ext, a0, a1, a2);
>          }
>          break;
>  
>      case INDEX_op_sar_i64:
>      case INDEX_op_sar_i32:
> -        if (c2) {    /* ASR / SBFM Wd, Wn, m, 31 */
> +        if (c2) {
>              tcg_out_sar(s, ext, a0, a1, a2);
> -        } else {                /* ASR / ASRV */
> -            tcg_out_shiftrot_reg(s, SRR_SAR, ext, a0, a1, a2);
> +        } else {
> +            tcg_out_shiftrot_reg(s, INSN_ASRV, ext, a0, a1, a2);
>          }
>          break;
>  
>      case INDEX_op_rotr_i64:
>      case INDEX_op_rotr_i32:
> -        if (c2) {    /* ROR / EXTR Wd, Wm, Wm, m */
> +        if (c2) {
>              tcg_out_rotr(s, ext, a0, a1, a2);
> -        } else {                /* ROR / RORV */
> -            tcg_out_shiftrot_reg(s, SRR_ROR, ext, a0, a1, a2);
> +        } else {
> +            tcg_out_shiftrot_reg(s, INSN_RORV, ext, a0, a1, a2);
>          }
>          break;
>  
>      case INDEX_op_rotl_i64:
> -    case INDEX_op_rotl_i32:     /* same as rotate right by (32 - m) */
> -        if (c2) {    /* ROR / EXTR Wd, Wm, Wm, 32 - m */
> +    case INDEX_op_rotl_i32:
> +        if (c2) {
>              tcg_out_rotl(s, ext, a0, a1, a2);
>          } else {
>              tcg_out_arith(s, INSN_SUB, 0, TCG_REG_TMP, TCG_REG_XZR, a2, 0);
> -            tcg_out_shiftrot_reg(s, SRR_ROR, ext, a0, a1, TCG_REG_TMP);
> +            tcg_out_shiftrot_reg(s, INSN_RORV, ext, a0, a1, TCG_REG_TMP);
>          }
>          break;
>  
>