[Mesa-dev] [PATCH 2/3] r600g: replace trans/vector-only instruction lists with ranges

[Christian König]

On 22.01.2012 17:24, Dave Airlie wrote:
> 2012/1/22 Christian König<deathsimple at vodafone.de>:
>> On 22.01.2012 16:46, Dave Airlie wrote:
>>> 2012/1/22 Christian König<deathsimple at vodafone.de>:
>>>> Sorry, but that looks really ugly and pretty much unmaintainable, cause
>>>> you
>>>> constantly need to lookup the meaning of the values.
>>>>
>>>> Also I haven't looked into the docs (but going to do so tomorrow), but
>>>> I'm
>>>> pretty sure that those ranges aren't 100% correct.
>>> It was the docs that the ranges came from, and we keep forgetting to
>>> add things to these lookup functions.
>>
>> Really? Where? I asked around when I coded this in the first place if it
>> could be simplified by using ranges, but never got an clear answer on this
>> topic.
>>
>> When I now look into the AMD docs they mostly seems to use tables for opcode
>> attributes, so I assumed that they are spread around in the opcode range.
>>
>> If this isn't the case then this indeed seems to be an good idea.
> Its in the Evergreen ISA docs (it might only be evergreen they managed this).
>
> ALU_WORD1_OP2
> ALU_INST
> [17:7]
> enum(11)
> Instruction. The top three bits of this field must be zero. Gaps in
> opcode values
> are not marked in the list below. See Chapter 7 for descriptions of each
> instruction. Opcodes 0..95 can be used in either the Vector or Trans unit.
> Opcodes 128..159 are Trans only. Opcodes 160..255 are vector only.
Those ranges are even better than the table based documentation! The 
tables contained an quite ugly bug which lead to this comment in the 
original code:

/* Note that FLT_TO_INT_* instructions are vector-only instructions
  * on Evergreen, despite what the documentation says. FLT_TO_INT
  * can do both vector and scalar. */

Very interesting, but I couldn't such ranges for R6xx and R7xx. Alex do 
you remember where you got that original documentation from?

Anyway I would still suggest to not use magic numbers, let's define the 
beginning and end of ranges in r600_opcode.h instead, and then use those 
defines inside the code.

Christian.