Re: [Qemu-devel] [PATCH v3 14/29] tcg-aarch64: Support movcond

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

On 02.09.2013 19:54, Richard Henderson wrote:
> Also tidy the implementation of setcond in order to share code.
> 
> Signed-off-by: Richard Henderson <rth@twiddle.net>
> ---
>  tcg/aarch64/tcg-target.c | 33 +++++++++++++++++++++++++--------
>  tcg/aarch64/tcg-target.h |  4 ++--
>  2 files changed, 27 insertions(+), 10 deletions(-)
> 
> diff --git a/tcg/aarch64/tcg-target.c b/tcg/aarch64/tcg-target.c
> index ea1db85..322660d 100644
> --- a/tcg/aarch64/tcg-target.c
> +++ b/tcg/aarch64/tcg-target.c
> @@ -284,6 +284,10 @@ typedef enum {
>      INSN_LSRV  = 0x1ac02400,
>      INSN_ASRV  = 0x1ac02800,
>      INSN_RORV  = 0x1ac02c00,
> +
> +    /* Conditional select instructions */
> +    INSN_CSEL  = 0x1a800000,
> +    INSN_CSINC = 0x1a800400,
>  } AArch64Insn;
>  
>  static inline enum aarch64_ldst_op_data
> @@ -435,6 +439,14 @@ static void tcg_fmt_Rdn_limm(TCGContext *s, AArch64Insn insn, bool ext,
>      tcg_fmt_Rdn_r_s(s, insn, ext, rd, rn, r, c);
>  }
>  
> +static inline void tcg_fmt_Rdnm_cond(TCGContext *s, AArch64Insn insn,
> +                                     bool ext, TCGReg rd, TCGReg rn,
> +                                     TCGReg rm, TCGCond c)
> +{
> +    tcg_out32(s, insn | ext << 31 | rm << 16 | rn << 5 | rd
> +              | tcg_cond_to_aarch64[c] << 12);
> +}
> +
>  static inline void tcg_out_ldst_9(TCGContext *s,
>                                    enum aarch64_ldst_op_data op_data,
>                                    enum aarch64_ldst_op_type op_type,
> @@ -661,13 +673,6 @@ static void tcg_out_cmp(TCGContext *s, bool ext, TCGReg a,
>      }
>  }
>  
> -static inline void tcg_out_cset(TCGContext *s, bool ext, TCGReg rd, TCGCond c)
> -{
> -    /* Using CSET alias of CSINC 0x1a800400 Xd, XZR, XZR, invert(cond) */
> -    unsigned int base = ext ? 0x9a9f07e0 : 0x1a9f07e0;
> -    tcg_out32(s, base | tcg_cond_to_aarch64[tcg_invert_cond(c)] << 12 | rd);
> -}
> -
>  static inline void tcg_out_goto(TCGContext *s, tcg_target_long target)
>  {
>      tcg_target_long offset;
> @@ -1394,7 +1399,17 @@ static void tcg_out_op(TCGContext *s, TCGOpcode opc,
>          /* FALLTHRU */
>      case INDEX_op_setcond_i64:
>          tcg_out_cmp(s, ext, a1, a2, c2);
> -        tcg_out_cset(s, 0, a0, args[3]);
> +        /* Using CSET alias of CSINC Xd, XZR, XZR, invert(cond) */
> +        tcg_fmt_Rdnm_cond(s, INSN_CSINC, 0, a0, TCG_REG_XZR,
> +                          TCG_REG_XZR, tcg_invert_cond(args[3]));
> +        break;
> +
> +    case INDEX_op_movcond_i32:
> +        a2 = (int32_t)a2;
> +        /* FALLTHRU */
> +    case INDEX_op_movcond_i64:
> +        tcg_out_cmp(s, ext, a1, a2, c2);
> +        tcg_fmt_Rdnm_cond(s, INSN_CSEL, ext, a0, REG0(3), REG0(4), args[5]);
>          break;
>  
>      case INDEX_op_qemu_ld8u:
> @@ -1553,6 +1568,8 @@ static const TCGTargetOpDef aarch64_op_defs[] = {
>      { INDEX_op_brcond_i64, { "r", "rA" } },
>      { INDEX_op_setcond_i32, { "r", "r", "rwA" } },
>      { INDEX_op_setcond_i64, { "r", "r", "rA" } },
> +    { INDEX_op_movcond_i32, { "r", "r", "rwA", "rZ", "rZ" } },
> +    { INDEX_op_movcond_i64, { "r", "r", "rwA", "rZ", "rZ" } },
>  
>      { INDEX_op_qemu_ld8u, { "r", "l" } },
>      { INDEX_op_qemu_ld8s, { "r", "l" } },
> diff --git a/tcg/aarch64/tcg-target.h b/tcg/aarch64/tcg-target.h
> index 6242136..ff073ca 100644
> --- a/tcg/aarch64/tcg-target.h
> +++ b/tcg/aarch64/tcg-target.h
> @@ -56,7 +56,7 @@ typedef enum {
>  #define TCG_TARGET_HAS_nand_i32         0
>  #define TCG_TARGET_HAS_nor_i32          0
>  #define TCG_TARGET_HAS_deposit_i32      0
> -#define TCG_TARGET_HAS_movcond_i32      0
> +#define TCG_TARGET_HAS_movcond_i32      1
>  #define TCG_TARGET_HAS_add2_i32         0
>  #define TCG_TARGET_HAS_sub2_i32         0
>  #define TCG_TARGET_HAS_mulu2_i32        0
> @@ -84,7 +84,7 @@ typedef enum {
>  #define TCG_TARGET_HAS_nand_i64         0
>  #define TCG_TARGET_HAS_nor_i64          0
>  #define TCG_TARGET_HAS_deposit_i64      0
> -#define TCG_TARGET_HAS_movcond_i64      0
> +#define TCG_TARGET_HAS_movcond_i64      1
>  #define TCG_TARGET_HAS_add2_i64         0
>  #define TCG_TARGET_HAS_sub2_i64         0
>  #define TCG_TARGET_HAS_mulu2_i64        0
> 

This breaks the x86-64 target.
Had you separated the additional operation from the cset change we would know which part is at fault.