On 12.03.2013 10:31, Christian König wrote: > Am 12.03.2013 02:48, schrieb Marek Olšák: >> On Mon, Mar 11, 2013 at 1:44 PM, Christian König >> <deathsim...@vodafone.de> wrote: >>> Hi everybody, >>> >>> this problem has been open for quite some time now, with a bunch of >>> different >>> opinions and sometimes even patches floating on the list. >>> >>> The solutions proposed or implemented so far all more or less >>> incomplete, so >>> this approach was designed in mind with both completeness and >>> compatibility >>> with existing code. >>> >>> Over all it's just an implementation of what Tom Stellard named >>> solution #4 in >>> this eMail thread: >>> http://lists.freedesktop.org/archives/mesa-dev/2013-January/033264.html >> Hi Christian, >> >> this is definitely not the solution #4. According to the TGSI dump >> Christoph posted, it looks more like #3. > > Well, for me the main difference between proposal #3 and #4 is that #3 > tries to identify the declaration to use with the supplied "offset", > while #4 uses a completely distinct identifier for that. > >> The solution #4 completely changes the temporary file such that it >> becomes two-dimensional with the first index being a literal and the >> second index being either a literal or ADDR[literal], and it would >> always be like that regardless of whether drivers support that or not. >> One-dimensional indexing of TEMP is not allowed. For backward >> compatibility, the drivers that do not support it would only get a >> single array declaration TEMP[0][0..n] and TEMP[0][...] would be >> everywhere in the code. > > Ok, then I misunderstood you a bit, but I don't think the difference > is so much. > > What I'm proposing is that we have an optional "ArrayID" attached to > each declaration and refer to this "ArrayID" in the indirect > addressing operand. To sum it up declarations should look something > like this: > > DCL TEMP[0..3] // normal registers > DCL TEMP[1][4..11] // indirectly accessed array > DCL TEMP[2][12..15] // another indirectly accessed array > DCL TEMP[16..17] LOCAL // local registers > > While an indirect operand might look like this: > > MOV TEMP[16], TEMP[1][ADDR[0].x-13] > > On the pro side for this approach is that it is compatible with all > the existing state trackers and driver, and we don't need to generate > different code depending on weather or not the driver supports this. > >> I don't know much about TGSI internals, so I can't review this. I'd >> just like to say that TGSI dumps should make sense (2D indexing should >> be only allowed with 2D declarations) and tgsi_text_translate should >> be able to do the reverse - convert the dumps back to TGSI tokens. > > Completely agree with that, and beside writing documentation testing > this is still one of the todos with this patchset. > > I have to admit that your approach looks a bit cleaner from the high > above view. The problem with it is that it requires this additional 2D > index on every operand, and we just don't have enough bits left for > this. Even with my approach I need to make room for this ArrayID in > the indirect addressing operand token, and this additional token is > only there if the operand uses indirect adressing. > > Do you think we can live with my approach or is there any major > downside I currently don't see? >
I can live with it. I think ... (I hope I don't regret this later; seems like this doesn't contain less information, then it's ok.) If the placement of the hint index offends someone, just write it as "MOV TEMP[16], TEMP(1)[ADDR[0].x-13]" or ... TEMP[ADDR[0].x-13 : 1] or TEMP[ADDR[0].x-13 supposedToBeIn [4,11]] or something ... nicer. Actually ... if TEMP[0] is placed at mem[0] and TEMP[4..1] is placed at, say, mem[0x1000 in bytes] do I have to load $register mem[$addr - 0xd0] (no this can't work) or load $regsiter mem[$addr - 0xd0 + 0x1000] (if you didn't adjust the offset) or load $register mem[$addr - 0xd0 + 0x1000 - 0x40] (if you already added the base TEMP to the immediate offset) This needs to be documented as well. > Thanks for the clarification, > Christian. > _______________________________________________ > mesa-dev mailing list > mesa-dev@lists.freedesktop.org > http://lists.freedesktop.org/mailman/listinfo/mesa-dev > _______________________________________________ mesa-dev mailing list mesa-dev@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/mesa-dev
