[r300] Fragment program ops + questions

[Rune P. <ru...@me...>]

I've been having some fun with fragment shader and found allot of ops 
missing. someone might be interested in some more ops.

Fragment ops added:
- ABS
- CMP
- DP4
- DPH
- DST
- EX2
- FLR
- FRC
- LG2
- MAX
- MIN
- RCP
- SGE
- SLT
- XPD

Fragment ops still missing:
- COS
- KIL
- LIT
- SCS
- SIN

They all pass the basic test in Mesa/progs/fp though Humus demos 
(www.humus.ca) still are far from looking proper.

Now the Questions:

- Missing Commit from r300.sf.net:
When trying to Implement the KIL ops I found a commit by Ben Skeggs on 
r300.sf.net that was lost in the Mesa tree:

http://sourceforge.net/mailarchive/forum.php?thread_id=7728162&forum_id=42268

At the very least the changes for r300_reg.h should be included in Mesa.

- whats with the DP3 op?

	if (fpi->DstReg.WriteMask & WRITEMASK_W) {
		/* I assume these need to share the same alu slot */
		sync_streams(rp);
		emit_arith(rp, PFS_OP_DP4, dest, WRITEMASK_W,
			pfs_zero, pfs_zero, pfs_zero,
			flags);
	}
	emit_arith(rp, PFS_OP_DP3, t_dst(rp, fpi->DstReg),
		fpi->DstReg.WriteMask & WRITEMASK_XYZ,
		t_src(rp, fpi->SrcReg[0]),
		t_src(rp, fpi->SrcReg[1]),
		pfs_zero, flags);

Why is DP4 called for W and why does DP3 excluding W?
I don't see how it can conform to the specs:

       tmp0 = VectorLoad(op0);
       tmp1 = VectorLoad(op1);
       dot = (tmp0.x * tmp1.x) + (tmp0.y * tmp1.y) + (tmp0.z * tmp1.z);
       result.x = dot;
       result.y = dot;
       result.z = dot;
       result.w = dot;