.data
.org 0x10
inputdata:
;4 8 * 8
.fill 1, 0x34382A38
;8 * X 1
.fill 1, 0x382A5831
;- X D +
.fill 1, 0x2D58442B
;D J \xF8 P
.fill 1, 0x444AF850
;6 8 * +
.fill 1, 0x36382A2B
;D I \020 \000
.fill 1, 0x44492000
;\000 \000 < ~
.fill 1, 0x00003C7E
;J \005 P 8
.fill 1, 0x4A055038
;8 *
.fill 1, 0x382A

stack:
.fill 256, 0
jumptable:
;0
.fill 0, vm_eof
.fill 40, vm_default
;42
.fill 1, vm_mul
;43
.fill 1, vm_add
;44
.fill 1, vm_default
;45
.fill 1, vm_sub
;46-47
.fill 2, vm_default
;48-57
.fill 10, vm_consts
;58-59
.fill 2, vm_default
;60
.fill 1, vm_lessthan
;61-67
.fill 7, vm_default
;68
.fill 1, vm_dup
;69-72
.fill 4, vm_default
;73
.fill 1, vm_imm
;74
.fill 1, vm_jmp
;75-79
.fill 5, vm_default
;80
.fill 1, vm_pop
;81-87
.fill 7, vm_default
;88
.fill 1, vm_xch
;88-125
.fill 40, vm_default
;126
.fill 1, vm_not
;127-255
.fill 129, vm_default

.text
main:
	ldi r1, inputdata
	call+ vm
	br+ main

vm:
	;r1 ... addr to input
	;r2 ... pc
	;r3 ... effective stack address
	;r4 ... effective input addr
	;r5 ... input

	;set pc to -4
	ldis r2, 0xFFFF
	;load base address of stack
	ldi r3, stack

vm_default:	
vm_loop:
	;increment pc
	addi r2, r2, 1
	;generate effective input addr
	add r4, r1, r2
	;load input
	ldw r5, 0(r4)
	;jump to instr
	brr r5

vm_eof:
	;load stack[sp-1]
	ldw r0, 0-4(r3);
	ret+;

;case *
;42
vm_mul:
	br+ vm_loop

;case +
;43
vm_add:
	;decrement sp
	subi r3, r3, 4
	;load sp
	ldw r6, 0(r3)
	;load sp-1
	ldw r7, 0-4(r3)
	;sp-1 = sp-1 + sp
	add r7, r7, r6
	;store sp-1
	stw r7, 0-4(r3)
	br+ vm_loop

;case -
;45
vm_sub:
	;decrement sp
	subi r3, r3, 4
	;load sp
	ldw r6, 0(r3)
	;load sp-1
	ldw r7, 0-4(r3)
	;sp-1 = sp-1 - sp
	sub r7, r7, r6
	;store sp-1
	stw r7, 0-4(r3)
	br+ vm_loop

;case 0 1 2 3 4 5 6 7 8 9
;48-57
vm_consts:
	;input minus offset
	subi r6, r5, 48
	;store onto stack
	stw r6, 0(r3)
	;increment stack addr
	addi r3, r3, 4
	br+ vm_loop

;case <
;60
vm_lessthan:
	;decrement sp
	subi r3, r3, 4
	;load sp
	ldw r6, 0(r3)
	;load sp-1
	ldw r7, 0-4(r3)
	;load r8 with 0
	ldi r8, 0
	;compare sp-1 with sp
	cmp r7, r6
	;set r8 to -1 if less than
	ldilt r8, 1
	;store r8 to sp-1
	stw r8, 0-4(r3)
	br+ vm_loop
	

;case D
;68
vm_dup:
	;load sp-1
	ldw r6, 0-4(r3)
	;store to sp
	stw r6, 0(r3)
	;increment stack addr
	addi r3, r3, 4
	br+ vm_loop

;case I
;73
vm_imm:
	;load new high byte
	ldb r6, 4(pc)
	;shift high byte
	lls r6, r6, 8
	;load 2nd byte
	ldb r7, 3(pc)
	;add to high byte
	add r6, r6, r7
	;shift
	lls r6, r6, 8
	;load
	ldb r7, 2(pc)
	;add
	add r6, r6, r7
	;shift
	lls r6, r6, 8
	;load
	ldb r7, 1(pc)
	;add
	add r6, r6, r7
	;store result to stack
	stw r6, 0(r3)
	;pc+4
	addi r2, r2, 4
	br+ vm_loop

;case J
;74
vm_jmp:
	;decrement sp
	sub r3, r3, 4
	;load sp
	ldw r6, 0(r3)
	;compare to 0
	cmpi r6,0
	;increment pc if == 0
	addieqD r2, r2, 4
	brnq+ vm_loop
	;if != 0
	;load pc+1 input
	ldb r6, 1(r4)
	;pc += data
	add r2, r2, r6
	br+ vm_loop

;case P
;80
vm_pop:
	;decrement stack addr
	subi r3, r3, 4
	br+ vm_loop

;case X
;88
vm_xch:
	;load sp-1
	ldw r6, 0-4(r3)
	;load sp-2
	ldw r7, 0-8(r3)
	;store sp-1 to sp-2
	stw r6, 0-8(r3)
	;store sp-2 to sp-1
	stw r7, 0-4(r3)
	br+ vm_loop

;case ~
;126
vm_not:
	ldw r6, 0-4(r3)
	not r6
	stw r6, 0-4(r3)
	br+ vm_loop