Re: [Qemu-devel] [PATCH v4 41/64] tcg/aarch64: Handle ctz and clz opcodes

["Alex Bennée" <alex.bennee@linaro.org>]

Richard Henderson <rth@twiddle.net> writes:

> Signed-off-by: Richard Henderson <rth@twiddle.net>
> ---
>  tcg/aarch64/tcg-target.h     |  8 ++++----
>  tcg/aarch64/tcg-target.inc.c | 47 ++++++++++++++++++++++++++++++++++++++++++++
>  2 files changed, 51 insertions(+), 4 deletions(-)
>
> diff --git a/tcg/aarch64/tcg-target.h b/tcg/aarch64/tcg-target.h
> index 976f493..9d6b00f 100644
> --- a/tcg/aarch64/tcg-target.h
> +++ b/tcg/aarch64/tcg-target.h
> @@ -62,8 +62,8 @@ typedef enum {
>  #define TCG_TARGET_HAS_eqv_i32          1
>  #define TCG_TARGET_HAS_nand_i32         0
>  #define TCG_TARGET_HAS_nor_i32          0
> -#define TCG_TARGET_HAS_clz_i32          0
> -#define TCG_TARGET_HAS_ctz_i32          0
> +#define TCG_TARGET_HAS_clz_i32          1
> +#define TCG_TARGET_HAS_ctz_i32          1
>  #define TCG_TARGET_HAS_deposit_i32      1
>  #define TCG_TARGET_HAS_extract_i32      1
>  #define TCG_TARGET_HAS_sextract_i32     1
> @@ -96,8 +96,8 @@ typedef enum {
>  #define TCG_TARGET_HAS_eqv_i64          1
>  #define TCG_TARGET_HAS_nand_i64         0
>  #define TCG_TARGET_HAS_nor_i64          0
> -#define TCG_TARGET_HAS_clz_i64          0
> -#define TCG_TARGET_HAS_ctz_i64          0
> +#define TCG_TARGET_HAS_clz_i64          1
> +#define TCG_TARGET_HAS_ctz_i64          1
>  #define TCG_TARGET_HAS_deposit_i64      1
>  #define TCG_TARGET_HAS_extract_i64      1
>  #define TCG_TARGET_HAS_sextract_i64     1
> diff --git a/tcg/aarch64/tcg-target.inc.c b/tcg/aarch64/tcg-target.inc.c
> index 17c0b20..91345fc 100644
> --- a/tcg/aarch64/tcg-target.inc.c
> +++ b/tcg/aarch64/tcg-target.inc.c
> @@ -201,6 +201,9 @@ static int tcg_target_const_match(tcg_target_long val, TCGType type,
>      if ((ct & TCG_CT_CONST_MONE) && val == -1) {
>          return 1;
>      }
> +    if ((ct & TCG_CT_CONST_WSZ) && val == (type ? 64 : 32)) {
> +        return 1;
> +    }
>

Did this sneak in again? This break the aarch64 build due to the missing
constant.

>      return 0;
>  }
> @@ -339,8 +342,12 @@ typedef enum {
>      /* Conditional select instructions.  */
>      I3506_CSEL      = 0x1a800000,
>      I3506_CSINC     = 0x1a800400,
> +    I3506_CSINV     = 0x5a800000,
> +    I3506_CSNEG     = 0x5a800400,
>
>      /* Data-processing (1 source) instructions.  */
> +    I3507_CLZ       = 0x5ac01000,
> +    I3507_RBIT      = 0x5ac00000,
>      I3507_REV16     = 0x5ac00400,
>      I3507_REV32     = 0x5ac00800,
>      I3507_REV64     = 0x5ac00c00,
> @@ -993,6 +1000,32 @@ static inline void tcg_out_mb(TCGContext *s, TCGArg a0)
>      tcg_out32(s, sync[a0 & TCG_MO_ALL]);
>  }
>
> +static void tcg_out_clz(TCGContext *s, TCGType ext, TCGReg d,
> +                        TCGReg a, TCGArg b, bool const_b)
> +{
> +    if (const_b && b == (ext ? 64 : 32)) {
> +        tcg_out_insn(s, 3507, CLZ, ext, d, a);
> +    } else {
> +        AArch64Insn sel = I3506_CSEL;
> +
> +        tcg_out_cmp(s, ext, a, 0, 1);
> +        tcg_out_insn(s, 3507, CLZ, ext, TCG_REG_TMP, a);
> +
> +        if (const_b) {
> +            if (b == -1) {
> +                b = TCG_REG_XZR;
> +                sel = I3506_CSINV;
> +            } else if (b == 0) {
> +                b = TCG_REG_XZR;
> +            } else {
> +                tcg_out_movi(s, ext, d, b);
> +                b = d;
> +            }
> +        }
> +        tcg_out_insn_3506(s, sel, ext, d, TCG_REG_TMP, b, TCG_COND_NE);
> +    }
> +}
> +
>  #ifdef CONFIG_SOFTMMU
>  /* helper signature: helper_ret_ld_mmu(CPUState *env, target_ulong addr,
>   *                                     TCGMemOpIdx oi, uintptr_t ra)
> @@ -1559,6 +1592,16 @@ static void tcg_out_op(TCGContext *s, TCGOpcode opc,
>          }
>          break;
>
> +    case INDEX_op_clz_i64:
> +    case INDEX_op_clz_i32:
> +        tcg_out_clz(s, ext, a0, a1, a2, c2);
> +        break;
> +    case INDEX_op_ctz_i64:
> +    case INDEX_op_ctz_i32:
> +        tcg_out_insn(s, 3507, RBIT, ext, TCG_REG_TMP, a1);
> +        tcg_out_clz(s, ext, a0, TCG_REG_TMP, a2, c2);
> +        break;
> +
>      case INDEX_op_brcond_i32:
>          a1 = (int32_t)a1;
>          /* FALLTHRU */
> @@ -1750,11 +1793,15 @@ static const TCGTargetOpDef aarch64_op_defs[] = {
>      { INDEX_op_sar_i32, { "r", "r", "ri" } },
>      { INDEX_op_rotl_i32, { "r", "r", "ri" } },
>      { INDEX_op_rotr_i32, { "r", "r", "ri" } },
> +    { INDEX_op_clz_i32, { "r", "r", "rAL" } },
> +    { INDEX_op_ctz_i32, { "r", "r", "rAL" } },
>      { INDEX_op_shl_i64, { "r", "r", "ri" } },
>      { INDEX_op_shr_i64, { "r", "r", "ri" } },
>      { INDEX_op_sar_i64, { "r", "r", "ri" } },
>      { INDEX_op_rotl_i64, { "r", "r", "ri" } },
>      { INDEX_op_rotr_i64, { "r", "r", "ri" } },
> +    { INDEX_op_clz_i64, { "r", "r", "rAL" } },
> +    { INDEX_op_ctz_i64, { "r", "r", "rAL" } },
>
>      { INDEX_op_brcond_i32, { "r", "rA" } },
>      { INDEX_op_brcond_i64, { "r", "rA" } },


--
Alex Bennée