LC3Tools/Documentation/keyboard_interrupt.lc3 at master · dinomight/LC3Tools · GitHub

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;***************************************************
;Sample program to install our own keyboard handler.
;Simulate the program, and while the code is
;spinning on the Halt, you can enter characters
;and strings into the Console I/O Window and
;the handler will get invoked once for each
;character entered.
;***************************************************

INCLUDE "../AshOS/AshOS_LC3.ah"
ORIGIN
SEGMENT

Code: SEGMENT
	;Load the address of the IVT into R2
	lea r6, Data
	ldr r6, r6, IVT
	;Store the address of our handler function
	;into the Keyboard vector of the IVT
	lea r5, KeyboardHandler
	str r5, r6, Keyboard
Halt:
	br Halt

Data: SEGMENT
IVT: DATA2 InterruptVectorTable
;byte-strings for PUTSP must end in full word of "0"
KBmessage: DATA2[] "Keyboard received: \0\0\0"
ALIGN 2
KBEnd: DATA2[] "\n\0"

;*************************************************
;Keyboard interrupt handler
;Simply gets the character from the keyboard
;and outputs a message to show what it got.
;***************************************************
Handlers: SEGMENT
KeyboardHandler:
	lea r0, KBmessage
	trap PUTS
	trap GETC
	trap OUT
	lea r0, KBEnd
	trap PUTS
	rti