cli + hlt

[nyarmi]

I downloaded the art of asm and read that hlt instruction stops the cpu until new int comes in. so what happens if i do this:
cli
hlt

???

 

[Pavlo]

Greetinx!

The Win95 can be cycled by executing some instructions:
cli
m1:
jmp m1

Later version Win98 or Nt cant be cycled by this. So, i think what processor will continue work after the non-masked interrupt has come. Happy programming!))

 

[AmkG]

I presume that Win98 and WinNT have FINALLY used a feature which has been present since the PC AT, the one with a 286. The NMI is connected to the second timer chip. In fact the only one channel of PIT#2 is used, and that is the one connected to the NMI, through a gate (which I don't know how to enable, can anyone inform me on this?). The NMI handling routine can check if the timer has timed-out to differentiate it from a memory system failuer.

This feature was intended for operating systems to detect crashed programs. "Information has a tendency to be free. Which means someone will always tell you something you don't want to know."

 

[AmkG]

BTB, I think cli hlt is a durned good way of hanging a computer... although in most cases a l1: jmp l1 is good enough. "Information has a tendency to be free. Which means someone will always tell you something you don't want to know."