[Mesa-dev] GL_MAX_PROGRAM_NATIVE_INSTRUCTIONS_ARB on r300g

[Tom Stellard]

On Mon, Apr 25, 2011 at 07:01:49PM +0200, Sven Arvidsson wrote:
> On Fri, 2011-04-22 at 22:02 -0700, Tom Stellard wrote:
> > R500 cards do support 1024 fragment shader instructions (512 ALU + 512 TEX), so I
> > think the value of GL_MAX_PROGRAM_NATIVE_INSTRUCTIONS_ARB should be 1024.

I was wrong about this.  Only r400 can do 512 ALU + 512 TEX.  R500 is
limited to 512 total instructions.
> 
> I noticed that some OEMs marketed the card as having "1024 shader
> instructions", but perhaps that's just confusion from the fact that it
> does have 1024 VS instructions. 
> 

I'm just guessing, but since each instruction is capable of doing one
vec3 and one scalar operation maybe they are counting 512 vec3 + 512
scalar = 1024 total instructions.  The R500 Acceleration Document[1] counts
instructions this way.

-Tom

[1] http://www.x.org/docs/AMD/R5xx_Acceleration_v1.5.pdf pg. 7