OpenEuphoria

1. Nokia n900 and Euphoria

• Posted by Jerome May 13, 2011
• 5872 views

Hunting through the forums I found some posts about porting euphoria to arm processors: http://openeuphoria.org/forum/112156.wc#112156, http://openeuphoria.org/forum/110757.wc#110757. I recently got a nokia n900 cell phone that runs the Linux Maemo operating system with an ARM Cortex processor. So following the suggestions in the posts and making some tweaks I was able to get the EU 4.0.2 interpreter working on my phone! But now I've run into the following issue which I don't know anything about. Any code that requires the call_back() function in std/dll.e fails with the following error:

Internal error: CallBack routine id patch failed: missing magic 

This error is related to be_machine.c at line 2372 in the source code, but that's as much as I know. Some googling shows info about magic numbers, but I'm not sure how to proceed. Any thoughts or suggestions?

Thanks in advance!
- Ira

P.S. I've done this with Scratchbox, EU 4.0.2, and the Nokia n900 SDK on Arch Linux

3. Re: Nokia n900 and Euphoria

• Posted by mattlewis (admin) May 13, 2011
• 5851 views

Internal error: CallBack routine id patch failed: missing magic 

Very nice! It might be a little more complicated than just what Shawn said about changing the size of the callback code, since ARM machine code looks different than x86. I had to do some investigating to figure out how to make x86_64 callbacks work (and OSX callbacks weren't much fun, either).

The first step is to get the output from something like objdump. Then we need to figure out how to change the euphoria backend.

You'll need to run it on the be_runtime.o file, and look for the output for cdecl_call_back. If you need help, please put the output into a Pastey.

Also, it would be great to get this into the official code!

Matt

5. Re: Nokia n900 and Euphoria

• Posted by mattlewis (admin) May 16, 2011
• 5711 views

Sorry, forgot to mention the flags. Use the -d flag to get the disassembly.

Matt

7. Re: Nokia n900 and Euphoria

• Posted by mattlewis (admin) May 16, 2011
• 5708 views

Hmmm....didn't get any symbols. Also, from your previous pastey, I see:

0000cd10 g     F .text	0000007c cdecl_call_back 

Unfortunately, I think the output may have been too big for the pastey, since the objdump output ends at 1960. So, third try...look for the block that starts at 0000cd10 (which should be cdecl_call_back) and paste that in. It might also be good to try building in debug mode, which might give us the symbols, to make it easier to spot.

Matt

9. Re: Nokia n900 and Euphoria

• Posted by mattlewis (admin) May 17, 2011
• 5644 views

Heh...well, we got some callbacks in pastey 70. Based on that, 124 looks like the right answer, and it seems to be finding it. I think that the blx instruction is relative, not absolute, however. I don't know much about ARM assembly, but this looks like the relevant part:

    d500:	e59f0020 	ldr	r0, [pc, #32]	; d528 <call_back9+0x7c>  
    d504:	e51b1008 	ldr	r1, [fp, #-8]  
    d508:	e51b200c 	ldr	r2, [fp, #-12]  
    d50c:	e51b3010 	ldr	r3, [fp, #-16]  
    d510:	e12fff3c 	blx	ip  
    d514:	e1a03000 	mov	r3, r0  
    d518:	e1a00003 	mov	r0, r3  
    d51c:	e24bd004 	sub	sp, fp, #4	; 0x4  
    d520:	e8bd8800 	pop	{fp, pc}  
    d524:	00000000 	.word	0x00000000  
    d528:	12345678 	.word	0x12345678 

Matt

11. Re: Nokia n900 and Euphoria

• Posted by Jerome May 21, 2011
• 5627 views

Ok, so it looks like I made a few mistakes early on by making too many changes at once... So I retraced my steps, double checked my changes to the eu source code (there are only a few), and cross-compiled the interpreter again. Now, most things seem to be working well, including call_back functions (I tested a simple case). So pushing forward, I cross-compiled wxWidgets according to this post: http://maemogeek.blogspot.com/2007/12/wxgtk-working-on-maemo.html. Finally, I cross-compiled wxEuphoria 0.15 and was able to run some of the demos! Here is a screenshot of the about.exw demo running on my phone: http://dl.dropbox.com/u/5805068/About.png.

There seem to be a few issues with wxEu, for example mouse events work but a call to mouse_event_position() crashes. In any case, it looks like I can write GUI programs with wxEu on my phone, which was my goal.

Thanks for your help and patience!
- Ira

13. Re: Nokia n900 and Euphoria

• Posted by Jerome May 21, 2011
• 5408 views

Sorry, I did not mean to apply I was done and wouldn't share code! What is the best way to share changes to the source code? I made changes in be_call.c, be_machine.c, and some of the std includes. Also, I'm sure of my changes are not the most appropriate, but they seem to work on my ARM system.

Thanks,
Ira

15. Re: Nokia n900 and Euphoria

• Posted by mattlewis (admin) May 22, 2011
• 5372 views

I think you were also working with 4.0. For a change like this, we'll probably want to add the port into 4.1 (but I guess that's open for discussion).

Mercurial can generate patches for you with the "export" command (i.e., "hg export"). Locally, you can just use the sequential rev number (those numbers don't necessarily mean anything outside of your repo), so something like:

$ hg export -o arm_patches 1234:1240 

Try "hg help export" for more details on using the export command.

Matt

17. Re: Nokia n900 and Euphoria

• Posted by mattlewis (admin) May 24, 2011
• 5302 views

Program received signal SIGILL, Illegal Instruction.  
0x002ff9b4 in decompress (c=251) at be_decompress.c:75 
75        d = (double)*(float *)string_ptr; 
 

Yeah, that seems like it should work. Try adding a float variable to the function:

    float f; 
    .... 
    f = *(float*)string_ptr; 
    d = (double) f; 

Also, does this operation always fail? Try something like the following (stand alone):

// bug.c 
// gcc bug.c -o bug 
#include <stdio.h> 
 
int main(){ 
	char string_ptr[10]; 
	float f; 
	double d; 
	 
	// 3.5 in 32-bit floating point: 
	string_ptr[0] = 0; 
	string_ptr[1] = 0; 
	string_ptr[2] = 96; 
	string_ptr[3] = 64; 
	 
	f = *(float*)string_ptr; 
	d = (double) f; 
	d = (double)*(float*)string_ptr; 
	printf("float: %g  double: %g\n", f, d ); 
	 
	return 0; 
} 

Matt

19. Re: Nokia n900 and Euphoria

• Posted by mattlewis (admin) May 25, 2011
• 5206 views

Ah, yes, I'd forgotten about the alignment issue. That makes sense.

Matt

21. Re: Nokia n900 and Euphoria

• Posted by SDPringle May 25, 2011
• 5175 views

From Jerome's code listing

* on my Scratchbox_x86 target (This way it can use a pre-built eui binary), \\ 
       ./configure ##--##plat ARM \\ 
        make source  \\ 
* switch to my Scratchbox_ARMEL target, \\  
        make 

Here, I am a little surprised Jerome could supply ARM to '--plat' when that was only for the OS. If this goes to the translator, you should get an error. Whether you use Windows or Linux, the translator should answer the same way the following command line:

 
D:\Documents and Settings\Pringle>euc -con -plat ARM hello.ex 
Unknown platform: ARM.  Supported platforms are: WIN, LINUX, FREEBSD, OSX, OPENB 
SD, NETBSD 
 

It seems you changed the functionality of --plat argument in 'configure' to set the ARCH variable in Makefile.eu. Instead of testing for--plat ARM, you should make configure test an argument like --arch ARM for that purpose.

23. Re: Nokia n900 and Euphoria

• Posted by mattlewis (admin) May 25, 2011
• 5203 views

The arch configurability is still pretty new. But I'd agree that the ARM belongs there. The platform is still Linux. I don't know enough about ARM to know if one ARM is basically the same as any other. It's possible we'll need to get more specific at some point. Currently, the arch option is used to distinguish between x86 and x86-64.

Matt

25. Re: Nokia n900 and Euphoria

• Posted by Jerome May 25, 2011
• 5195 views

#if ARCH == ARM  
// ARM code 
#endif 
 
#if ARCH == ix86 
// Intel x86 code 
#endif 

I might be off base, but I think c preprocessor comparasions can only work with integers. Take the following the example:

#include <stdio.h> 
int main() { 
 
#if ARCH == ARM 
  printf("Arch is ARM \n"); 
#else 
  printf("Arch is something else \n") 
#endif 
return 0; 
} 

Compiling and running with:
1) gcc -DARCH=x86 test.c -o test outputs "Arch is ARM"
2) gcc -DARCH=ARM test.c -o test outputs "Arch is ARM"

The code works as expected with the following:

#include <stdio.h> 
int main() { 
 
#if ARCH == 1 
  printf("Arch is ARM \n"); 
#else 
  printf("Arch is something else \n") 
#endif 
return 0; 
} 

1) gcc -DARCH=1 test.c -o test outputs "Arch is ARM"
2) gcc -DARCH=0 test.c -o test outputs "Arch is something else"

Thanks,
Ira

27. Re: Nokia n900 and Euphoria

• Posted by SDPringle May 25, 2011
• 5161 views

We just need a couple of #define lines.

 
#include <stdio.h> 
#define ARM 0xA 
#define ix86 86 
  
int main() {  
  
#if ARCH == 1  
  printf("Arch is ARM \n");  
#else  
  printf("Arch is something else \n")  
#endif  
return 0;  
}  

wcc386 -DARCH=ARM arch.c 
wlink name arch.exe file arch.obj 
.\arch 
 
Arch is ARM 
 
wcc386 ARCH=ix86 arch.c 
wlink name arch.exe file arch.obj 
.\arch 
 
Arch is not ARM 
 

So we just need to add these lines to execute.h in source:

#define ARM 0xA 
#define ix86 86