Mail Archives: djgpp/1997/01/04/23:06:06
Once upon a time (on 4 Jan 97 at 20:42) Nikita Proskourine said:
> Thanks, I already got NASM from one of SimTel mirrors. It seems like
> a really good way to use old .asm code with djgpp, but I got a
> problem: it doesn't seem to recognize "mov byte ptr". What am I
> doing wrong? Oh, another thing, how do I define stack size in my asm
To reference memory in NASM you use the following syntax
mov ax, [your_var] ; Moves ax to the address contained in
;your_var
therefore there's no need for the 'ptr' keyword
NASM usually uses your operand names to determine argument size (in
the above example it will assume 'your_var' to point to a word). NASM
is able to specify other argument size by means of 'word' and 'dword'
keywords:
mov ax, [word es:di]
However these two are the only ones to modify operand size (there are
others as A16, A32, O16, O32 - read about them in section "Writing
Programs with NASM" of the nasm.doc, make sure to read the section
entitled "Unusual Instruction Sizes"). So the conclusion is: don't
bother with the operand sizes - NASM is good enough to deduce it for
you.
> program (I am used to .STACK <size>)
Hmm... the only target that supports stack allocating is Micro$oft
OMF. You declare the stack segment like this:
[SEGMENT STCK STACK] ; or [SECTION STCK STACK]
TIMES 4096 db 0
which defines a 4KB stack. The other formats cannot define stacks.
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