Program

This program demonstrates use of the stack and tests the JALR operation.

R1	first argument
R2	second argument
R3	return value
R6	stack pointer
R7	return address

	LI	R6 30	; R6 is the stack
	LI	R1 10	; first argument
	LI	R2 5	; second argument
	LI	R3 8	; address of function (L)
	JALR	R7 R3	; call function
	SWI	R3 31	; save return value
	HALT
	NOP
L:	ADD	R6 R6 R0	; push R6 (stack pointer)
	ADDI	R6 R6 -1
	ADD	R6 R7 R0	; push R7 (return address)
	ADDI	R6 R6 -1
	ADD	R3 R1 R2	; body of function f(a,b) returns a+b
	ADDI	R6 R6 1	; pop R7 from stack
	ADD	R7 R6 R0
	ADDI	R6 R6 1	; pop R6 from stack
	ADD	R6 R6 R0
	JALR	R0 R7 0	; return from function

Simulation Results

#	pc	op	rd	qd	immed
1	00	LI	6	001E	001E
2	01	LI	1	000A	000A
3	02	LI	2	0005	0005
4	03	LI	3	0008	0008
5	04	JALR	7	0005	0060
6	08	ADD	6	001E	00C0
7	09	ADDI	6	001D	00DF
8	0A	ADD	6	0005	00E0
9	0B	ADDI	6	0004	00DF
10	0C	ADD	3	000F	0028
11	0D	ADDI	6	0005	00C1
12	0E	ADD	7	0005	00C0
13	0F	ADDI	6	0006	00C1
14	10	ADD	6	0006	00C0
15	11	JALR	0	0012	00E0
16	05	SWI	0	001F	001F

Registers

format	r1	r2	r3	r4	r5	r6	r7
hex	000A	0005	000F	4444	5555	0006	0005
decimal	10	5	15	17476	21845	6	5

Memory

addr	0	1	2	3	4	5	6	7	8	9	A	B	C	D	E	F
0000	1E1E	190A	1A05	1B08	5F60	131F	0000	0000	46C0	3EDF	46E0	3EDF	4328	3EC1	47C0	3EC1
0010	46C0	58E0	0000	0000	0000	0000	0000	0000	0000	0000	0000	0000	0000	0000	0000	000F