[Mesa-dev] [PATCH] tgsi: document and fixup IF and BREAKC instrunctions

[Zack Rusin]

----- Original Message -----
> Ah.. This indeed rings a bell. I don't recall the details but I'm pretty sure
> I was against dual semantics. And the fact that this problem is again
> showing its ugly head is the proof of it.
> 
> We really should have two IF opcodes. And the state tracker should choose
> which one it wants.

What would be the difference between those two opcodes though? The current IF does a bitwise comparison, so would we add another opcode that does exactly the same thing and say that the first one can be emulated with float comparisons? I'm not sure if that helps. I guess we could change the first one and make that one compare floats, then introduce another one that does what IF currently is doing, but that seems weird as well. Why not just say that if your hardware can't do bitwise comparisons, just keep emulating them with floats? That seems easier and it preserves the current behavior for everyone.