registers as pointer q

[HSE]

bt [eax+esi],0
i get errors in assembly

You must indicate to assembler what have to retrieve in memory position:

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bt word ptr [eax+esi],0

bt dword ptr [eax+esi],0
Always is the same in any instruccion when first you have a memory position.

You don't need to make any indication when first there is a known size operand:

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mov al, [eax+esi]

mov ax, [eax+esi]

mov eax, [eax+esi]

[NoCforMe]

Whoa. Stop. Everyone shut up for one minute!

One thing at a time: you said this gave an assembler error:

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bt [eax+esi],0

Of course it did. It's ambiguous: do you want to bit-test a word or a double word? (those are your choices with this instruction)

Try

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bt DWORD PTR [eax+esi],0

(or whatever size you're trying to access here)

[NoCforMe]

i get pointer 'pArray' from globalAlocate
then try to access it like:

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mov esi,index
shl esi,2
mov eax,pArray
bt [eax+esi],0
jc @f


OK, you're very close here. What you're trying to do makes sense.

Seems to me if you just remove the ambiguity of the bt instruction (use DWORD PTR), this should work as written.

One thing bothers me: the Microsoft documentation for GlobalAlloc() states that it returns a handle to the allocated memory*. Not sure if that's the same thing as a pointer which you can use directly. I use HeapAlloc() instead, which definitely returns a pointer. Why don't you try that instead? Any special reason to use GlobalAlloc()?

p.s.: As someone above pointed out, you can eliminate the shl esi, 2 by using

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bt dword ptr [eax + (esi * 4)]

which does that arithmetic for you.

* Of course this could just be an ambiguity in the Micro$oft documentation ...

[dc]

i want to use this on allocated memory that can be any size depending...

[NoCforMe]

You can certainly do that as easily with HeapAlloc() as with GlobalAlloc(). You specify the size of allocation you want.

[daydreamer]

Check alloc macro,in qe macro help file
Returns a pointer to allocated memory or null if it fails allocate

[NoCforMe]

Macro, schmacro.
Just code it:

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CALL GetProcessHeap ;Only need to do this once at program start:
MOV HeapHandle, EAX

INVOKE HeapAlloc, HeapHandle, 0, <how many bytes to allocate>
MOV <pointer to allocated memory>, EAX

Sheesh.

[jj2007]

im gonna have to assume that a pointer and an index are not used together at all in ml... please prove me wrong...
thanx

It's not our job to prove you wrong, it's your job to study the docs, play with code, and show in detail (i.e. with complete code) what's wrong, and what the error messages are.

i want to use this on allocated memory that can be any size depending...

It really, really would help if you sat down, zipped your code and posted it here, instead of asking vague questions. Here is the demo that pointers and indexes can be combined. And guess what, it's complete code. Just copy & paste & build

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include \masm32\include\masm32rt.inc

.data?
ThePointer    dd ?

.code
start:
  mov ThePointer, rv(GlobalAlloc, GPTR, 100)
  mov eax, ThePointer  ; not necessary because eax = ThePointer at this point
  bt word ptr [eax+4*esi], 3
  .if Carry?
    print "bit 3 is set", 13, 10
  .else
    print "bit 3 is clear", 13, 10
  .endif
  mov esi, 25
  mov eax, ThePointer
  mov byte ptr [eax+4*esi], -1
  bt word ptr [eax+4*esi], 3
  .if Carry?
    inkey "bit 3 is set"
  .else
    inkey "bit 3 is clear"
  .endif
  exit

end start
If you start asking what GPTR means, I'll contact your teacher

[NoCforMe]

It really, really would help if you sat down, zipped your code and posted it here, instead of asking vague questions.

Well, in fairness, JJ, I don't think they should be required necessarily to post all of their code, which might be long, complicated and confused. I'd be happy just seeing the relevant parts, a condensed version.

I agree, asking vague questions ain't gonna get anybody nowhere.

OP, please post something from your code so we can get a better idea of what's going on.