[Mesa-dev] [PATCH 28/53] st/nine: Match REP implementation to LOOP

[Axel Davy]

Le 07/01/2015 21:13, Ilia Mirkin a écrit :
> On Wed, Jan 7, 2015 at 11:36 AM, Axel Davy <axel.davy at ens.fr> wrote:
>> Previous implementation was fine,
>> just instead of having increasing counter,
>> have a decreasing counter.
>>
>> Signed-off-by: Axel Davy <axel.davy at ens.fr>
>> ---
>>   src/gallium/state_trackers/nine/nine_shader.c | 41 +++++++++++++++------------
>>   1 file changed, 23 insertions(+), 18 deletions(-)
>>
>> diff --git a/src/gallium/state_trackers/nine/nine_shader.c b/src/gallium/state_trackers/nine/nine_shader.c
>> index 21b06ce..88d4c07 100644
>> --- a/src/gallium/state_trackers/nine/nine_shader.c
>> +++ b/src/gallium/state_trackers/nine/nine_shader.c
>> @@ -1562,9 +1562,7 @@ DECL_SPECIAL(REP)
>>       unsigned *label;
>>       struct ureg_src rep = tx_src_param(tx, &tx->insn.src[0]);
>>       struct ureg_dst ctr;
>> -    struct ureg_dst tmp = tx_scratch_scalar(tx);
>> -    struct ureg_src imm =
>> -        tx->native_integers ? ureg_imm1u(ureg, 0) : ureg_imm1f(ureg, 0.0f);
>> +    struct ureg_dst tmp;
>>
>>       label = tx_bgnloop(tx);
>>       ctr = tx_get_loopctr(tx, FALSE);
>> @@ -1572,33 +1570,40 @@ DECL_SPECIAL(REP)
>>       /* NOTE: rep must be constant, so we don't have to save the count */
>>       assert(rep.File == TGSI_FILE_CONSTANT || rep.File == TGSI_FILE_IMMEDIATE);
>>
>> -    ureg_MOV(ureg, ctr, imm);
>> +    ureg_MOV(ureg, ureg_writemask(ctr, NINED3DSP_WRITEMASK_0), rep);
>> +    /* in the case ctr is float, remove 0.5 to avoid precision issues for comparisons */
>> +    if (!tx->native_integers)
>> +        ureg_ADD(ureg, ureg_writemask(ctr, NINED3DSP_WRITEMASK_0), ureg_src(ctr), ureg_imm1f(ureg, -0.5f));
>> +
>>       ureg_BGNLOOP(ureg, label);
>> -    if (tx->native_integers)
>> -    {
>> -        ureg_USGE(ureg, tmp, tx_src_scalar(ctr), rep);
>> -        ureg_UIF(ureg, tx_src_scalar(tmp), tx_cond(tx));
>> -    }
>> -    else
>> -    {
>> -        ureg_SGE(ureg, tmp, tx_src_scalar(ctr), rep);
>> +    tmp = tx_scratch_scalar(tx);
>> +
>> +    /* stop when crt.x <= 0 */
> ctr.x
>
>> +    if (!tx->native_integers) {
>> +        ureg_SLE(ureg, tmp, ureg_scalar(ureg_src(ctr), TGSI_SWIZZLE_X), ureg_imm1f(ureg, 0.0f));
> It would be less confusing if this were the same as below, i.e. switch
> it to SGT. Or switch the other one to ISLT. Having one be greater and
> one less-than is weird.
>
>>           ureg_IF(ureg, tx_src_scalar(tmp), tx_cond(tx));
>> +    } else {
>> +        ureg_ISGE(ureg, tmp, ureg_imm1i(ureg, 0), ureg_scalar(ureg_src(ctr), TGSI_SWIZZLE_X));
>> +        ureg_UIF(ureg, tx_src_scalar(tmp), tx_cond(tx));
>>       }
>>       ureg_BRK(ureg);
>>       tx_endcond(tx);
>>       ureg_ENDIF(ureg);
>>
>> -    if (tx->native_integers) {
>> -        ureg_UADD(ureg, ctr, tx_src_scalar(ctr), ureg_imm1u(ureg, 1));
>> -    } else {
>> -        ureg_ADD(ureg, ctr, tx_src_scalar(ctr), ureg_imm1f(ureg, 1.0f));
>> -    }
>> -
>>       return D3D_OK;
>>   }
>>
>>   DECL_SPECIAL(ENDREP)
>>   {
>> +    struct ureg_program *ureg = tx->ureg;
>> +    struct ureg_dst ctr = tx_get_loopctr(tx, FALSE);
>> +
>> +    if (!tx->native_integers) {
>> +        ureg_ADD(ureg, ureg_writemask(ctr, NINED3DSP_WRITEMASK_0), ureg_src(ctr), ureg_imm1f(ureg, -1.0f));
>> +    } else {
>> +        ureg_UADD(ureg, ureg_writemask(ctr, NINED3DSP_WRITEMASK_0), ureg_src(ctr), ureg_imm1i(ureg, -1.0));
> -1 -- presumably this is an integer...
Yep, should be -1. Strange compiler didn't warn.
>
> But at what point does ctr get converted to an integer? At the
> beginning, when you subtract 0.5, it appears to still be a float... I
> think that ADD is wrong and needs to be a UADD? (But then obviously
> -0.5 doesn't make sense).
ctr is either an integer from the start, or not.

When the card doesn't support integers, ctr is a float. To avoid 
precision issues when doing comparison to 0, I choosed to substract 0.5 
to ctr.

I realise now it makes more sense to compare ctr to 0.5 and not 
substract anything at the start.
>
>> +    }
>> +
>>       ureg_ENDLOOP(tx->ureg, tx_endloop(tx));
>>       return D3D_OK;
>>   }
>> --
>> 2.1.3
>>
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