Detecting CPU Speed: Difference between revisions

* it's assumed that the command CPUID is supported.

 

;__get_speed__:

;first do a cpuid command, with eax=1

; ax contains measured speed in MHz

mov ~[mhz], ax

 

See the intel manual (see links) for more information.

I'd be tempted to say 'yes', though I haven't gave it a test nor heard of it elsewhere so far. Here is the trick:

 

disable() // disable interrupts (if still not done)

outb(0x43,0x34); // set PIT channel 0 to single-shot mode

byte lo=inb(0x40);

byte hi=inb(0x40);

 

Now, we know that