Question

I use inline assembly massively in a project where I need to call functions with an unknown number of arguments at compile time and while I manage myself to get it to work, sometimes, in linux (in windows I don’t recall having that problem) strange things like this happen:

If I have something like

for(int i = 1; i >= 0; i--)
   asm("push %0"::"m"(someArray[i]));

It works.

If I have

for(int i = this->someVar; i >= 0; i--)
   asm("push %0"::"m"(someArray[i]));

and I guarantee with my life that someVar is holding the value 1 it throws segmentation fault.

Also if I have

int x = 1;
for(int i = x; i >= 0; i--)
   asm("push %0"::"m"(someArray[i]));

it works but

int x = this->someVar;
for(int i = x; i >= 0; i--)
    asm("push %0"::"m"(someArray[i]));

does not.

Also, and also strangely, I can say that while in some functions I don’t have problems doing that in others I have, all in the same object.

If someone can point me to some information that can clear up what’s the problem there, I would appreciate.

Beware that I really have to push the arguments in a for loop so avoiding it is not an option.

I also tried using the inline assembly word “volatile” but nothing changed.

Answer 1

I can’t understand what’s the problem but try to write code using clear asm code same as

asm{
   loop1:
     mov ax, this->var
     ...
     dec ax
     cmp ax, 0
     je exit
     jmp loop1
}

…

exit:

Also try to make “var” value as static may it help too.