MASM, JWASM and the strange beast DPMI

[Antariy]

But in that case can't we just do a switch to real mode and then pushf/call far int*4 ?

I guess that won't work. A few interrupt handlers enable interrupts with STI as soon as possible to allow higher interrupts to be handled. At least I found such code in some keyboard interrupt handlers.

Using of 21h port is not gives anything?
I.e., before sinsi's suggestion:

Code Select Expand


mov al,0FFh
out 21h,al




Alex

[japheth]

Using of 21h port is not gives anything?
I.e., before sinsi's suggestion:

Code Select Expand


mov al,0FFh
out 21h,al


That's also a bit hackish. Some code inside interrupt handlers does not only enable interrupts, but does wait for further interrupts to occur. IIRC the DOS keyboard interrupt handler may enter such a wait loop if it has to modify the keyboard LEDs. Your hack wouldn't work then.

The best and most robust strategy is not to reprogram the PICs.

[sinsi]

The first instruction in my BIOS's timer interrupt is STI  :lol
The keyboard ISR enables interrupts and sends EOI because it waits for an ACK from the keyboard.