volatile not working ( i think )[FIXED]

[GLneo]

hi all, ok, i have this:

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volatile int irq6_state = 0;
void wait_irq6()
{
    while(irq6_state == 0)
        yield(); // give up prossesor
    irq6_state = 0;
}

and when i run it on bochs it just locks up, so i started tracing and found this:

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mov eax, [ds:0xc000afcc] ; which is where irq6_state is
test eax, eax ; weird ???
jnz 0xc00023cd ; most likely out of the loop
call 0xc000442c ; yield();

i'm not sure what is going on, any help welcome

i'm using DJGPP

thx!

[nick8325]

Code: Select all

mov eax, [ds:0xc000afcc] ; which is where irq6_state is
test eax, eax ; weird ???
jnz 0xc00023cd ; most likely out of the loop
call 0xc000442c ; yield();

That's "if (irq6_state == 0) yield();". Which should be right, assuming there's a jump back to the top of the loop after the call to yield().

[GLneo]

but testing eax with eax will never be false!

[B.E]

but testing eax with eax will never be false!

Yes, but it's jumping if the zero flag is set. (ie when eax = 0, (eax & eax) sets the zeor flag)

[GLneo]

O, ok!