[Nouveau] [PATCH 1/3] nv50/ir: Add support for MAD short+IMM notation

[Ilia Mirkin]

On Sat, Jan 10, 2015 at 7:45 PM, Roy Spliet <seven at nimrod-online.com> wrote:
> Op 11-01-15 om 01:34 schreef Ilia Mirkin:
>>
>> And you're allowing saturate/neg emission on the short form.
>
> Yes
>>
>> Is this already in envytools?
>
> Tesla floating point instructions are poorly documented in the RST
> documents; fmad is no exception. I'll make sure to check envydis.

Sorry, I meant envydis

>>
>> Also, what's the shortForm thing?
>
> Documented in envytools; see
> http://envytools.readthedocs.org/en/latest/hw/graph/tesla/cuda/isa.html#instruction-format
> . In short, opcodes are either 4 bytes (short) or 8 bytes (long).

Yes, I'm aware of that bit :)

>>
>> This change is
>> probably fine, but the changelog needs work.
>
> If you insist I could elaborate a little further. However, documenting what
> a short opcode is seems a bit superfluous.

I meant what was the reason for the change to the shortForm array in
target_nv50? I don't remember offhand what it is, and you were doing a
bunch of things in here and I wasn't sure which of them it was related
to.

>
>>
>> On Sat, Jan 10, 2015 at 7:22 PM, Roy Spliet <rspliet at eclipso.eu> wrote:
>>>
>>> MAD IMM has a very specific SDST == SSRC2 requirement, so don't emit
>>>
>>> Signed-off-by: Roy Spliet <rspliet at eclipso.eu>
>>> ---
>>>   .../drivers/nouveau/codegen/nv50_ir_emit_nv50.cpp      | 18
>>> ++++++++++++------
>>>   .../drivers/nouveau/codegen/nv50_ir_target_nv50.cpp    |  2 +-
>>>   2 files changed, 13 insertions(+), 7 deletions(-)
>>>
>>> diff --git a/src/gallium/drivers/nouveau/codegen/nv50_ir_emit_nv50.cpp
>>> b/src/gallium/drivers/nouveau/codegen/nv50_ir_emit_nv50.cpp
>>> index 2077388..b1e7409 100644
>>> --- a/src/gallium/drivers/nouveau/codegen/nv50_ir_emit_nv50.cpp
>>> +++ b/src/gallium/drivers/nouveau/codegen/nv50_ir_emit_nv50.cpp
>>> @@ -939,9 +939,20 @@ CodeEmitterNV50::emitFMAD(const Instruction *i)
>>>
>>>      code[0] = 0xe0000000;
>>>
>>> +   if (i->src(1).getFile() == FILE_IMMEDIATE) {
>>> +      code[1] = 0;
>>> +      emitForm_IMM(i);
>>> +      code[0] |= neg_mul << 15;
>>> +      code[0] |= neg_add << 22;
>>> +      if (i->saturate)
>>> +         code[0] |= 1 << 8;
>>> +   } else
>>>      if (i->encSize == 4) {
>>>         emitForm_MUL(i);
>>> -      assert(!neg_mul && !neg_add);
>>> +      code[0] |= neg_mul << 15;
>>> +      code[0] |= neg_add << 22;
>>> +      if (i->saturate)
>>> +         code[0] |= 1 << 8;
>>>      } else {
>>>         code[1]  = neg_mul << 26;
>>>         code[1] |= neg_add << 27;
>>> @@ -1931,11 +1942,6 @@ CodeEmitterNV50::getMinEncodingSize(const
>>> Instruction *i) const
>>>
>>>      // check constraints on short MAD
>>>      if (info.srcNr >= 2 && i->srcExists(2)) {
>>> -      if (i->saturate || i->src(2).mod)
>>> -         return 8;
>>> -      if ((i->src(0).mod ^ i->src(1).mod) ||
>>> -          (i->src(0).mod | i->src(1).mod).abs())
>>> -         return 8;
>>>         if (!i->defExists(0) ||
>>>             i->def(0).rep()->reg.data.id != i->src(2).rep()->reg.data.id)
>>>            return 8;
>>> diff --git a/src/gallium/drivers/nouveau/codegen/nv50_ir_target_nv50.cpp
>>> b/src/gallium/drivers/nouveau/codegen/nv50_ir_target_nv50.cpp
>>> index 48f996b..f4dedd7 100644
>>> --- a/src/gallium/drivers/nouveau/codegen/nv50_ir_target_nv50.cpp
>>> +++ b/src/gallium/drivers/nouveau/codegen/nv50_ir_target_nv50.cpp
>>> @@ -118,7 +118,7 @@ void TargetNV50::initOpInfo()
>>>      static const uint32_t shortForm[(OP_LAST + 31) / 32] =
>>>      {
>>>         // MOV,ADD,SUB,MUL,SAD,L/PINTERP,RCP,TEX,TXF
>>> -      0x00010e40, 0x00000040, 0x00000498, 0x00000000
>>> +      0x00014e40, 0x00000040, 0x00000498, 0x00000000
>>>      };
>>>      static const operation noDestList[] =
>>>      {
>>> --
>>> 2.1.0
>>>
>>>
>>>
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>>
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