Re: [Qemu-devel] [PATCH 5/5] tcg-i386: Implement setcond.

[Aurelien Jarno]

On Sat, Dec 19, 2009 at 10:46:38AM -0800, Richard Henderson wrote:
> Signed-off-by: Richard Henderson <address@hidden>

This looks ok, though I would appreciate someone else to review it in
details.

> ---
>  tcg/i386/tcg-target.c |   73 
> +++++++++++++++++++++++++++++++++++++++++++++++--
>  1 files changed, 70 insertions(+), 3 deletions(-)
> 
> diff --git a/tcg/i386/tcg-target.c b/tcg/i386/tcg-target.c
> index 4c42caf..43e0155 100644
> --- a/tcg/i386/tcg-target.c
> +++ b/tcg/i386/tcg-target.c
> @@ -360,9 +360,8 @@ static void tcg_out_jxx(TCGContext *s, int opc, int 
> label_index, int small)
>      }
>  }
>  
> -static void tcg_out_brcond(TCGContext *s, int cond, 
> -                           TCGArg arg1, TCGArg arg2, int const_arg2,
> -                           int label_index, int small)
> +static void tcg_out_cmp(TCGContext *s, TCGArg arg1, TCGArg arg2,
> +                        int const_arg2)
>  {
>      if (const_arg2) {
>          if (arg2 == 0) {
> @@ -374,6 +373,13 @@ static void tcg_out_brcond(TCGContext *s, int cond,
>      } else {
>          tcg_out_modrm(s, 0x01 | (ARITH_CMP << 3), arg2, arg1);
>      }
> +}
> +
> +static void tcg_out_brcond(TCGContext *s, int cond,
> +                           TCGArg arg1, TCGArg arg2, int const_arg2,
> +                           int label_index, int small)
> +{
> +    tcg_out_cmp(s, arg1, arg2, const_arg2);
>      tcg_out_jxx(s, tcg_cond_to_jcc[cond], label_index, small);
>  }
>  
> @@ -459,6 +465,57 @@ static void tcg_out_brcond2(TCGContext *s, const TCGArg 
> *args,
>      tcg_out_label(s, label_next, (tcg_target_long)s->code_ptr);
>  }
>  
> +static void tcg_out_setcond(TCGContext *s, int cond, TCGArg dest,
> +                            TCGArg arg1, TCGArg arg2, int const_arg2)
> +{
> +    tcg_out_cmp(s, arg1, arg2, const_arg2);
> +    /* setcc */
> +    tcg_out_modrm(s, 0x90 | tcg_cond_to_jcc[cond] | P_EXT, 0, dest);
> +    tgen_arithi(s, ARITH_AND, dest, 0xff, 0);
> +}
> +
> +static void tcg_out_setcond2(TCGContext *s, const TCGArg *args,
> +                             const int *const_args)
> +{
> +    TCGArg new_args[6];
> +    int label_true, label_over;
> +
> +    memcpy(new_args, args+1, 5*sizeof(TCGArg));
> +
> +    if (args[0] == args[1] || args[0] == args[2]
> +        || (!const_args[3] && args[0] == args[3])
> +        || (!const_args[4] && args[0] == args[4])) {
> +        /* When the destination overlaps with one of the argument
> +           registers, don't do anything tricky.  */
> +        label_true = gen_new_label();
> +        label_over = gen_new_label();
> +
> +        new_args[5] = label_true;
> +        tcg_out_brcond2(s, new_args, const_args+1, 1);
> +
> +        tcg_out_movi(s, TCG_TYPE_I32, args[0], 0);
> +        tcg_out_jxx(s, JCC_JMP, label_over, 1);
> +        tcg_out_label(s, label_true, (tcg_target_long)s->code_ptr);
> +
> +        tcg_out_movi(s, TCG_TYPE_I32, args[0], 1);
> +        tcg_out_label(s, label_over, (tcg_target_long)s->code_ptr);
> +    } else {
> +        /* When the destination does not overlap one of the arguments,
> +           clear the destination first, jump if cond false, and emit an
> +           increment in the true case.  This results in smaller code.  */
> +
> +        tcg_out_movi(s, TCG_TYPE_I32, args[0], 0);
> +
> +        label_over = gen_new_label();
> +        new_args[4] = tcg_invert_cond(new_args[4]);
> +        new_args[5] = label_over;
> +        tcg_out_brcond2(s, new_args, const_args+1, 1);
> +
> +        tgen_arithi(s, ARITH_ADD, args[0], 1, 0);
> +        tcg_out_label(s, label_over, (tcg_target_long)s->code_ptr);
> +    }
> +}
> +
>  #if defined(CONFIG_SOFTMMU)
>  
>  #include "../../softmmu_defs.h"
> @@ -1120,6 +1177,13 @@ static inline void tcg_out_op(TCGContext *s, int opc,
>          tcg_out_modrm(s, 0xb7 | P_EXT, args[0], args[1]);
>          break;
>  
> +    case INDEX_op_setcond_i32:
> +        tcg_out_setcond(s, args[3], args[0], args[1], args[2], 
> const_args[2]);
> +        break;
> +    case INDEX_op_setcond2_i32:
> +        tcg_out_setcond2(s, args, const_args);
> +        break;
> +
>      case INDEX_op_qemu_ld8u:
>          tcg_out_qemu_ld(s, args, 0);
>          break;
> @@ -1208,6 +1272,9 @@ static const TCGTargetOpDef x86_op_defs[] = {
>      { INDEX_op_ext8u_i32, { "r", "q"} },
>      { INDEX_op_ext16u_i32, { "r", "r"} },
>  
> +    { INDEX_op_setcond_i32, { "q", "r", "ri" } },
> +    { INDEX_op_setcond2_i32, { "r", "r", "r", "ri", "ri" } },
> +
>  #if TARGET_LONG_BITS == 32
>      { INDEX_op_qemu_ld8u, { "r", "L" } },
>      { INDEX_op_qemu_ld8s, { "r", "L" } },
> -- 
> 1.6.5.2
> 
> 
> 
> 

-- 
Aurelien Jarno                          GPG: 1024D/F1BCDB73
address@hidden                 http://www.aurel32.net