asm AND operator

**DavidP** · 05-06-2002

I have a question about the AND operator in assembler. What is its limit on how much you can AND at one time?

A normal statement would be like:

Code:

asm {
    and dx, bx 
}

if you were ANDing registers, or:

Code:

asm {
    and myInt, dx
}

if you were ANDing an int with a register, etc...

But lets say I have two arrays and want to AND them together:

Code:

int array[10];
int arrayB[10];

...code to fill arrays goes here....

asm {
    and array, arrayB
}

Am I allowed to do what I just did?

Or what if I made them pointers:

Code:

int *array = new int[10];
int *arrayB = new int[10];

...code...

asm {
    and array, arrayB
}

Is that legal?

**InFeStEd-ArCh0n** · 05-06-2002

No, those last two are not legal. You can only logically AND two variables and no more. If you want to do anything else you'll have to use a loop. Also, the variable on the right cannot be bigger than the variable on the left. It is illegal to AND mem, mem. It is only:

and mem, reg
and reg, mem
and reg, const

I do believe

**Fordy** · 05-06-2002

The registers are mostly 32bit - much less than the arrays you have declared......and so 32Bit what modern CPUs likes to play with per "and" instruction.......Not too difficult to iterate through these 2 arrays and do it that way......

**InFeStEd-ArCh0n** · 05-06-2002

They are only 32 bit if you use the extended version (I.E.: edx, ecx, ebx, eax)

**Xei** · 05-06-2002

You can do ASM in VC++?

**InFeStEd-ArCh0n** · 05-06-2002

Yes you can use assembly in VC++, like this:

Code:

__asm
{
(ASM code here)
}

**Xei** · 05-06-2002

OMG! Yay! Yay! ASM! So sweet!

**DavidP** · 05-07-2002

Ha....I figured it out, you can AND two arrays together...you just have to pass the memory addresses instead:

so you do this:

asm {
and [array], [arrayB]
}

instead of this:

asm {
and array, arrayB
}

mwaha...

**InFeStEd-ArCh0n** · 05-07-2002

Wow that really works? The [] around it would make sense, but how is it possible? How does it know where to end and whatnot? Where is the logic behind it?

**NANO** · 05-07-2002

See how great is C++...$$$$

but make sure it is les than 32 bit as what one of the BOSSES said before....

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asm AND operator

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