C++ Problem

**Sornaensis** · 08-13-2008 01:18 AM

I have a problem in this function, on the red line:

Code:

void CreateDivTable()
{
  DivTbl[0] = 0x7fffffff;
  DivTbl[1] = 0x7fffffff;
  DivTbl[2] = 0x7fffffff;
  for( int i = 3; i < 10240; i++ )
     DivTbl[i] = (int) ( float(0x100000000 )/ i);

  for (int y=0; y<32; y++)
   for (int x=0; x<32; x++)
    RandomMap[y][x] = rand()%1024;
}

Here's the declaration of DivTbl:

Code:

_EXTORNOT   int     DivTbl[10240];

The error states that:

"integer constant is too large for 'long' type" on the red line, but changing the variable type (To something larger, like long long) has no effect.

Help plz?

**Sornaensis** · 08-13-2008 01:23 AM

Heh nvm.

Had one too many zeros. (0x100000000)

**kichu** · 08-13-2008 01:25 AM

Yeah, that's what I was going to suggest.

That, or this:

Both are the solution, I'm pretty sure.

**Sornaensis** · 08-13-2008 01:25 AM

New problem:

Code:

void Audio_MixSound(int DestAddr, int SrcAddr, int MixLen, int LVolume, int RVolume)
{
_asm {
       mov      edi, DestAddr
       mov      ecx, MixLen
       mov      esi, SrcAddr
     }

SOUND_CYCLE :

_asm {
       movsx    eax, word ptr [esi]
       imul     LVolume
       sar      eax, 16
       mov      bx, word ptr [edi]

       add      ax, bx
       jo       LEFT_CHECK_OVERFLOW
       mov      word ptr [edi], ax
       jmp      CYCLE_RIGHT
 }
LEFT_CHECK_OVERFLOW :
__asm {
       cmp      bx, 0
       js       LEFT_MAX_NEGATIVE
       mov      ax, 32767
       mov      word ptr [edi], ax
       jmp      CYCLE_RIGHT
}
LEFT_MAX_NEGATIVE :
__asm  mov      word ptr [edi], -32767




CYCLE_RIGHT :
__asm {
       movsx    eax, word ptr [esi]
       imul     dword ptr RVolume
       sar      eax, 16
       mov      bx, word ptr [edi+2]

       add      ax, bx
       jo       RIGHT_CHECK_OVERFLOW
       mov      word ptr [edi+2], ax
       jmp      CYCLE_CONTINUE
}
RIGHT_CHECK_OVERFLOW :
__asm {
       cmp      bx, 0
       js       RIGHT_MAX_NEGATIVE
       mov      word ptr [edi+2], 32767
       jmp      CYCLE_CONTINUE
}
RIGHT_MAX_NEGATIVE :
__asm  mov      word ptr [edi+2], -32767

CYCLE_CONTINUE :
__asm {
       add      edi, 4
       add      esi, 2
       dec      ecx
       jnz      SOUND_CYCLE
}

My compiler (MinGW) doesn't recognize _asm; What linker/ compiler command do I need for this...?

**Ynot** · 08-13-2008 02:02 AM

the GCC (including MinGW & Cygwin on Windows) uses the AT&T (UNIX) assembly format
while MS uses the Intel format

http://www.ibiblio.org/gferg/ldp/GCC...-HOWTO.html#s4

btw,
any particular reason you're using inline assembly?

**Sornaensis** · 08-13-2008 02:04 AM

Oh well shit.

I'm not going to re-write 3000 Assembly functions!

I'll use the compiler the code was originally used with then...

**ninja9578** · 08-13-2008 02:07 AM

I think GNU is the standard. I know that you can do _asm with GNU.

Also, are you doing command line compilation? I think you have to add a whole ton of crap to the make to do inline assembly.

Also, maybe it's different for your compiler, but I always use references for parameters in inline assembly. I don't remember if you need to do that with GNU, I know one of them required you to do that.

Code:

mov      edi, [DestAddr]
       mov      ecx, [MixLen]
       mov      esi, [SrcAddr]

**ninja9578** · 08-13-2008 02:09 AM

Why are you using your own sound routines? It might be easier to use OpenAL

**Sornaensis** · 08-13-2008 02:10 AM

So I can or I can't keep the functions as-is?

I didn't write the Assembly code-- This is apart of a game enginge I'm editing and adding to.

**ninja9578** · 08-13-2008 02:16 AM

I would use OpenAL for a game, that way you are guaranteed that it will work.

3000 audio commands in asm? What is the name of this engine that you're working on, it sounds really big.

**Ynot** · 08-13-2008 02:19 AM

Originally Posted by Seismosaur

So I can or I can't keep the functions as-is?

you cannot use Intel style assembly with GCC

I believe there are some pre-processor macros around to convert between the two syntaxes, but I have near zero experience with assembly inside C++

**ninja9578** · 08-13-2008 02:26 AM

Yes you can

I forget how though, some type of compiler flags. Try

Code:

-xchip=pentium5

I' think that's actually something else, but there is a similar flag for the asm. I don't do command line, my IDE takes care of that.

**Ynot** · 08-13-2008 02:30 AM

Originally Posted by ninja9578

Yes you can

you're right,
I just googled it

Code:

gcc -o my_program -masm=intel my_program.c

**ninja9578** · 08-13-2008 02:33 AM

I find intel asm soooo much easier than the unix style one. How do people read that junk?

You can do misp asm inline too if you are on a PPC computer like me

**Ynot** · 08-13-2008 02:54 AM

I like to think I'm a fairly competent programmer
but I draw the line at assembly

now, I've never done anything game orientated
I'm primarily database and web server middleware

but seriously,
does DIY assembly *really* make that much of a difference?
(with all it's portability & bug pitfalls and show-stoppers)

maybe it's cause I change my mind too often
A minor re-jig to C code vs. scraping and re-writing pages of assembly

anyway....

**Sornaensis** · 08-13-2008 02:55 AM

Ausome, now I don't have to phuck around with other compilers!

**ninja9578** · 08-13-2008 02:58 AM

Originally Posted by Ynot

does DIY assembly *really* make that much of a difference?

Assembly code is INSANELY fast. It also has a better memory footprint. I've never had a compiler make better asm than me (for small routines obviously.) Compilers are very liberal with the stack (liveliness analysis isn't very good), when I do something in asm I try to use the stack as little as possible, that usually means moving parts of the code around, which compilers have a hard time doing.

I do graphics and when doing extensions for OpenGL or shaders, you have to use assembly because C just isn't fast enough, even with the 3 pass optimizer turned on.

**Sornaensis** · 08-13-2008 03:00 AM

Okay, it worked, but it's taking forever to compile

**Sornaensis** · 08-13-2008 03:05 AM

Actually, it didn't work.

It just took forever and gave me 5x the errors...

**ninja9578** · 08-13-2008 03:06 AM

Must be your C++ code, asm should be really fast to compiler. What other flags did you set, are you doing multiple passes?

As for your errors: see post above about referencing with asm.

**Sornaensis** · 08-13-2008 03:07 AM

None and no.

I just put gcc -o my_program -masm=intel my_program.c twice for the two (huge) files that use inline assembly.

It still doesn't recognize __asm { }

**ninja9578** · 08-13-2008 03:15 AM

I see some errors in the programmer, are you sure this program worked once?

Code:

mov bx, word ptr [edi]

Pointers are 64-bit, bx is 16-bit

**ninja9578** · 08-13-2008 03:15 AM

Originally Posted by Seismosaur

It still doesn't recognize __asm { }

GCC accepts either asm or _asm_. You need either no underscores or two.

**Sornaensis** · 08-13-2008 03:16 AM

Oh okay.

Well I sure hope it did as it's a game engine for a video game that was once produced

A few other people have managed to get it working, but I have limited contact with them.

**ninja9578** · 08-13-2008 03:19 AM

I think most games are written in .NET which means a M$ compiler. I'm not sure if you can get that for free.

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