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

[Laurent Desnogues <laurent.desnogues@gmail.com>]

On Sun, Dec 20, 2009 at 12:11 AM, Aurelien Jarno <aurelien@aurel32.net> wrote:
> On Sat, Dec 19, 2009 at 10:46:38AM -0800, Richard Henderson wrote:
>> Signed-off-by: Richard Henderson <rth@twiddle.net>
>
> This looks ok, though I would appreciate someone else to review it in
> details.

It looks good to me too (though I didn't test it explicitly).


Laurent

>> ---
>>  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
> aurelien@aurel32.net                 http://www.aurel32.net
>
>
>