OpenEuphoria

1. Phix: #ilasm

• Posted by andreasWagner 6 days ago
• 163 views

Hallo,

This isn't meant to be a criticism or a complaint. It's just something I've noticed.

Phix is leisurely and slow when it comes to c_func/c_proc. That's not a problem for most applications.

But sometimes it becomes a bottleneck. That's why I followed your recommendations and came up with this solution it's certainly still far from ideal, but it's already significantly faster. But still slower than Euphoria c_func/c_proc.

constant DrawPixel_=GetProcAddress(ray,"DrawPixel") 
global procedure _DrawPixel(integer x,integer y,sequence color) 
integer col=bytes_to_int(color) 
--/**/#ilASM{  
--/**/  [64] 
--/**/      mov rcx,[x] 
--/**/      mov rdx,[y] 
--/**/      mov r8,[col] 
--/**/      sub rsp, 40                 -- Shadow Space (32) + Alignment (8) 
--/**/      mov rax,[DrawPixel_] 
--/**/      call rax 
--/**/  --  call "libraylib","DrawPixel"         -- Direkter Sprung 
--/**/      add rsp, 40 
--/**/  } 
--/* 
    c_proc(xDrawPixel,{x,y,col}) 
--*/ 
end procedure 

constant DrawPixelV_=GetProcAddress(ray,"DrawPixelV") 
global procedure _DrawPixelV(sequence pos,sequence color) 
atom reg=V2toReg(pos) 
integer col=bytes_to_int(color) 
--/**/#ilASM{  
--/**/  [64] 
--/**/      mov rax,[reg] 
--/**/      call :%pLoadMint     
--/**/      mov rcx,rax   
--/**/      mov rdx,[col] 
--/**/      sub rsp, 40                 -- Shadow Space (32) + Alignment (8) 
--/**/      mov rax,[DrawPixelV_] 
--/**/      call rax 
--/**/  --  call "libraylib","DrawPixelV"        -- Direkter Sprung 
--/**/      add rsp, 40 
--/**/  } 
--/* 
    c_proc(xDrawPixelV,{reg,col}) 
--*/ 
end procedure 

That's why I wanted to know how a C compiler does it. I was lucky DrawPixel in raylib simply calls DrawPixelV, and it looks like this:

00000001d64790ea <DrawPixel>: 
   1d64790ea:	48 83 ec 28          	sub    rsp,0x28 
   1d64790ee:	89 d0                	mov    eax,edx 
   1d64790f0:	44 89 c2             	mov    edx,r8d 
   1d64790f3:	66 0f ef c0          	pxor   xmm0,xmm0 
   1d64790f7:	f3 0f 2a c1          	cvtsi2ss xmm0,ecx 
   1d64790fb:	66 0f ef c9          	pxor   xmm1,xmm1 
   1d64790ff:	f3 0f 2a c8          	cvtsi2ss xmm1,eax 
   1d6479103:	66 0f 7e c8          	movd   eax,xmm1 
   1d6479107:	48 c1 e0 20          	shl    rax,0x20 
   1d647910b:	66 0f 7e c1          	movd   ecx,xmm0 
   1d647910f:	48 09 c1             	or     rcx,rax 
   1d6479112:	e8 c2 fd ff ff       	call   1d6478ed9 <DrawPixelV> 
   1d6479117:	90                   	nop 
   1d6479118:	48 83 c4 28          	add    rsp,0x28 
   1d647911c:	c3                   	ret     

I think there are a few assembly instructions missing in ilasm to reproduce that. Or maybe I just couldn't find them.

3. Re: Phix: #ilasm

• Posted by andreasWagner 2 days ago
• 70 views

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.

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.

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.

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.

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.