;; simple task switcher

.symbol
	stop 	0
	cnt  	20
	stack 	2000
	sp   	29

.code 0
:main
	mv r1 #tswitch
	st r1 1000   ;; set up int vector
	mv sp #stack ;; set stack
	mv r1 #0
	st r1 cnt    ;; cnt = 0
	jmp process1

:process1
:loop			;; count to 10
	ld r1 cnt
	add r1 r1 #1
	st r1 cnt
	eq r2 r1 #10
	jf r2 loop
	trap stop

;;  an ISR
:tswitch	    ;; use r3 for ret-ads
	savt r3     ;; save current process PC to r3
	savr sp
;;	mv sp #next  ;; pointer to data of next process
	resr sp
	rest r3     ;; restore next process PC to return-address
	reti
.end