On Tue, 23 Mar 1999, Stacy D. Coil wrote:
> uint32 v;
> uint32 m;
> #asm
> mov v, eax
> mov m, ebx
> #endasm
>
> But this returns and no symbol for v and m. Could someone be kind enough
> to show me how to pass varibles from c to assembly and back?
You can't just say "mov v, eax", because that's not being passed through
the compiler. There's 2 ways you can try it.. prefix the 'v' with an
underscore:
mov _v,eax
Alternatively, you simply find out where abouts in memory that variable
is, and write there. For example:
int c,d;
c=0x123;
d=0x456;
Compiles into:
push bp
mov bp,sp
push di
push si
add sp,*-4
mov ax,#$123
mov -6[bp],ax
mov ax,#$456
mov -8[bp],ax
So, you use "mov -n[bp],ax", where n is the offset into the stack of the
variable you want (plus 6 (sizeof(bp)+sizeof(di)+sizeof(si)), in bcc's
case). So if you've got 3 int's, and 4 char's, and you want the offset of
the 4th char, you say 6+(3*sizeof(int))+(4*sizeof(char)), which works out
to 16.
At least that's how I understand it to work. Anyone got anything to
add/correct?
Davey
