Re: Phix: #ilasm
- Posted by andreasWagner 2 days ago
- 73 views
No disagreement from me with any of that.
Phix c_func/proc are decidedly hacky and I've long wanted to replace them but no real idea what with,
in fact I've toyed with the idea of forcing the use of asm code snippets just like those you posted.
Ideally perhaps the compiler should be smart enough to generate them itself, but that's not trivial.
I have no intention whatsoever of writing all the calls in assembly language. If anything, I'll only do so in a few places where I think it's necessary.
There is indeed no support as yet for pxor or cvtsi2ss, pilasm.e has been written in an ad hoc fashion,
but is reasonably straightforward to extend, especially if you can find something similar to crib from.
I typically fire up OllyDbg/fdbg/edb, see what binary that assembles summat to and ensure I match that.
There are somewhere between 981 and 3,600 x86 instructions, in fact LLVM says there are 14,600 variants,
and just about the last thing I would ever want to do is add several hundred completely untested ones.
That's more than understandable. That's one of the reasons why I'm spending so much time porting examples from Raylib to Phix. I want to test the functions as thoroughly as possible, not just wrap them.
Mind you, it looks for all the world to me those pxor/cvtsi2ss are completely pointless instructions that
leave eax and ecx exactly as they found them...
My mistake was a false lead: DrawPixel is fed with 2 integers (x, y), but DrawPixelV expects a struct Vector2 - 2 float32s that, according to the MS API, are packed into an integer register. Then it all makes sense again. And color moves from the 3rd parameter R8 to the 2nd parameter RDX. That's why cvti2ss is used (loosely translated: integer to float32). In the case of Phix and a direct call to DrawPixelV, cvtsd2ss would probably be more appropriate. Or just my V2toReg.
If you were having a problem with the direct call, I'm pretty sure they need the ".dll" and it must be
located somewhere in %PATH% for the Windows program loader to find it.
The direct call works without any issues; I just wanted to ensure by brute force that the DLL is referenced only once in the entire program. I currently have several versions of the DLL on my computer.
If you can guarantee the result of V2toReg() is an integer, maybe and_bits(#FFFFFFFF), ditch LoadMint.
There may be an AGI stall on rax, try loading it first see if that helps (or eg call rsi while rax used for "")
If you only need to call DrawPixelV from a few places and can bear to copy that asm there, it should
also make a measurable difference.
V2toReg is definitely anything but a clean integer; it's two float32s in a 64-bit value.
Btw I achieved the biggest speed gain by simply coding some functions from raymath directly as Phix/Euphoria and not calling the DLL at all. Of course, that helps Phix much more than it helps Euphoria.
Thanks for the reply; I'm always happy to learn something new. Unfortunately, I'm making very slow progress at the moment.
