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5.
Set the mask bit in the Interrupt Mask register for any interrupts that you wish to disable.
Example 8-1 shows sample code to initialize the Interrupt Control Unit.
$mod186
name
example_80C186_ICU_initialization
;
;This routine configures the interrupt controller to provide two cascaded
;interrupt inputs (through an external 8259A connected to INT0 and INTA0#)
;and two direct interrupt inputs connected to INT1 and INT3. The default
;priorities are used.
;
;The example assumes that the register addresses have been properly defined.
;
code
segment
assume cs:code
set_int_
proc near
push dx
push ax
mov
mov
out
mov
mov
out
pop
pop
ret
set_int_
endp
code
ends
end
Example 8-1. Initializing the Interrupt Control Unit for Master Mode
ax,0110111B
dx,I0CON
dx,ax
ax,01001101B
dx,IMASK
dx,ax
ax
dx
INTERRUPT CONTROL UNIT
;cascade mode, priority seven
;INT0 control register
;unmask INT1 and INT3
8-31
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