New to ASM

[Nigh™a®e]

Hi,

i'm new to ASM code.

Before i start learning ASM code, i need to know if its a good sollution for my new project.

For while i'm working on a game engine, last week started building a script engine using c++ styled scripts.

I know how to lex and parse the c++ scripts. For the execution i was thinking of calling asm code from my c++ project.

For now the script engine only can register and manupilate variables (can be a standard data type of structure or class)
It's not using ASM code yet.

I have done some more reading about c++ compilers and noticed before making an exe of it, the make some kind of ASM code of it (opcode), as i understanded, using asm code the script engine is more powerfull.


The big idee behind the script engine, is making an independe script engine (not linked to any existing game or game engine) where users can register functions they wanna use in theyre game scripts or implement headers in the game scripts so the application defined functions can be read from header.

Greetz Nightmare

[Darkwraith]

Assembler is used more as optimization than to implement large sections of code.

You may want to write the thing in C++ and then refactor piceces of it into assembler. Its safer, cleaner, and more reliable than going straight assembler.

[Nigh™a®e]

You may want to write the thing in C++ and then refactor piceces of it into assembler. Its safer, cleaner, and more reliable than going straight assembler.

i'm testing a little with asm now,
for example, when i want the source

int nTest = 10 + 20;

i can execute by doing

int Add( int nVal1, int nVal2 )
{
	return nVal1+nVal2;
}

or

int ASM_Add( int op1, int op2 )
{
	__asm
	{
		mov eax, op1
		sub eax, op2
		mov op1, eax
	}
	return op1;
}

i guess the ASM_Add has better performace than the normal Add function.

now i'm looking if its possible to register variables from script right now.
my variable are stored in a vector class, so i have to loop trough the vector to find the requested variable.

for example

int nTest = 0;

this will first register a int variable on the vector.
to set the value of the nTest is will need to look up the variable first.

[Darkwraith]

mov eax, op1
sub eax, op2
mov op1, eax

I don't think that's what you want. (did you mean substract?) Try this implementation. It's a little more underhanded than yours but I save a few instructions.

 
int add(op1, op2)
{
_asm
{
	mov eax, op1
	add eax, op2
}
}

[Nigh™a®e]

I don't think that's what you want. (did you mean substract?) Try this implementation. It's a little more underhanded than yours but I save a few instructions.

c&p wrong code, this was substract code in a add function

had to be this

	_asm
	{
		mov eax, op1
		add eax, op2
		mov op1, eax
	}
	return op1;

will add eax, op1 auto return the value of op1?

[Darkwraith]

I know on MSVC++6 compilers, if you return an int value, whatever was in eax will be returned. Like I said, its underhanded but it saves instructions (esp. on something that small)

[Maven]

Just so you know, your probably not going to see any speed difference between the asm version and the C++ version in that example.

Just because you handcoded asm doesn't automatically mean that the code will be faster.