registers as pointer q

[NoCforMe]

No; you only need to specify the size (WORD, DWORD) if it's not clear otherwise from the context, specifically when you use an immediate constant for the bit number and an ambiguous memory-based first operand (like [EDX], which could be a pointer to anything, byte, word, doubleword, quadword ...):

Code Select Expand

    BT    DWORD PTR [EDX], 5

You don't need the size spec if you use a register for that operand, or a register or a sized variable for the first operand:

Code Select Expand

    BT    [EDX], EAX
    BT    EDX, 5
    BT    dwordSizedVar, 5


[zedd151]

Thank you NoCforMe for the detailed response. I am certain that the OP, dc, will understand better from the examples shown as well.

[NoCforMe]

Just to clarify and summarize, the fact that the ambiguous cases (like BT [reg], imm) are flagged as errors by ML is appropriate. What is dumb, as JJ pointed out, is the exact error message ("invalid instruction operand"). There's nothing "invalid" about it; it's just ambiguous.

[zedd151]

Ambiguous code leads to ambiguous error messages? 
Sounds like an issue to be taken up with Microsoft. 

[NoCforMe]

Sounds like an issue to be taken up with Microsoft. 

Yes, I'm sure Micro$oft is very committed to making improvements to ml.exe:

Copyright (C) Microsoft Corp 1981-1997

We'll have to get Raymond Chen to weigh in on this.

[dc]

oooooo....
preliminarily...this seems to be working!

Code Select Expand

xor dword ptr pbrd[esi],1crap.... got ahead of myself, it doesn't
NEVERMIND!!! IT DOES WORK.... WOOHOO!!!!

[dc]

oooops it doesn't...
that way uses memory after the label... in tester

Code Select Expand

pbrd            dd ?
tester          dd 50 dup (?)


[zedd151]

Hi dc, could you post some more code. Just a line or two isn't really telling us what it is, that you now are trying to do. With a more complete piece of code, we will be able to help you better. Full source preferred, but a more complete snippet may be enough. We don't know what is in pbrd or in esi, or how they got there, or the result that you are expecting. Help us to help you.
Describe at least, what you want to do, with the last code that you posted, preferably with more complete code.

Edit for completeness and clarity.

[dc]

i want to access allocated memory with an index like an array
i don't see why nobody understands my question
is it just not done?
also:
if i just put it in the inc file like:
board  dd 0100000h dup (?)
it works fine but takes a while to assemble

[HSE]

i don't see why nobody understands my question

Where is your code?

[jj2007]

i don't see why nobody understands my question

Where is your code?

HSE, what's wrong with your crystal ball, it's not working?

dc, it's considered bad practice to post snippets, thus assuming that older members love spending their precious time adding headers, includes etc.

If you want help, zip all necessary files, especially the complete *.asm source, and attach it here. Otherwise all your questions will be happily ignored. Please confirm arrival of the message.

[jj2007]

if i just put it in the inc file like:
board  dd 0100000h dup (?)
it works fine but takes a while to assemble

That's a known MASM bug. You can use UAsm instead, it's a perfect MASM clone with less bugs.

[NoCforMe]

oooooo....
preliminarily...this seems to be working!

Code Select Expand

xor dword ptr pbrd[esi],1crap.... got ahead of myself, it doesn't
NEVERMIND!!! IT DOES WORK.... WOOHOO!!!!

oooops it doesn't...
that way uses memory after the label... in tester

Code Select Expand

pbrd            dd ?
tester          dd 50 dup (?)


OK, trying to bring this discussion back down to earth (and Zedd, back off on your net-nanny politeness campaign, please: JJ was just expressing a little irritation back there. Remember: moderation in moderation.)

First thing: if you code

Code Select Expand

pbrd            dd ?

xor dword ptr pbrd[esi],1

you don't need the dword ptr precautionary label, because you've clearly defined that variable as a doubleword, which the assembler, as dumb as it may be, knows about. So just use

Code Select Expand

xor pbrd[esi],1

instead.

[dc]

that's not using allocated memory...
can allocated memory be used as an array?

[Caché GB]

Hi dc

Yes, allocated memory can be used as an array.