Re: [Nasm-users] Working with pointers

[<p1...@ja...>]

On 12/17/2010 4:37 AM, Jakob Bohm wrote:
> On 17-12-2010 07:27, Littlefield, Tyler wrote:
>> hello all,
>> I have a quick question.
>> I have the following:
>> section .data
>> ptr dd 0
>> array times 100 db 0
>>
>> Now, when I want to assign array to p, I can't mov it--how can I assign
>> the pointer to point there? Last, is there a way to get the type of
>> processor?
>> (32-64), as that will make a difference on the code in some places?
>>
> ; For 32 bits, I think this should assemble just fine:
>
>       ptr dd 0
>       array times 100 db 0
>
>       mov [ptr], array
>
> ; For 64 bits, The code should become
>
>       ptr dq 0
>       array times 100 db 0
>
>       lea rax,[array] ; Add some notation here to make this rip relative!
>       mov [ptr], rax
>
> I don't know how to test if nasm is compiling for 16, 32 or 64 bits with
> assembler directives,
> sorry I don't do that much nasm coding these days.
>

Here is one way:

%ifidn __BITS__,64
     ptr dq 0
%else
     ptr dd 0
%endif