[ASM] Invalid istruction

[tossam]

Hi, I'm italian so I don't speak English very well....
I wrote an simple program in assembly that would hyde keyboard, modify the PIC (programmable interrupt controller)...
With:

IN al, 21h ; move in al semiregister bits stored in register for abiliting interrupt request
OR al, 00000010b; should disability Keyboard (set to 1 the second bit)
OUT 21h,al

I compiled this program with CC (using at school for intel 8086), but on my pc (i never been run this program at school), pc showed this message: "C:\windows system32\cmd.exe - keyboard
CPU NTVDM ha inontrato un'istruzione non valida.
CS:0700 IP:01b6 OP:FF 7F 00 00 00 Scegliere "chiudi" per terminare l'applicazione"

The same in English:
"c:\eindows.. keyboard
CPU have meet an invalid istruction.
Cs:....... swicth "close" for closing the application"

can u help me?
thanks...

 

[mjohnson44]

Windows does not allow I/O instructions to the PIC (or APIC) in user mode. It was allowed under DOS, however.

The above can be done from a ring 0 Process (driver, etc.), however.

Sorry!

 

[tossam]

Thanks... I didn't kow this....