# NOTE - THIS IS NOT A THOROUGH TEST.  YOURS SHOULD BE MORE THOROUGH THAN THIS.
# THE FACT THAT WE WERE ABLE TO CATCH ERRORS WITH THIS PROGRAM IMPLIES THAT
# MANY OF YOU DIDN'T TEST ENOUGH.
# It would be wise to have one partner think of crazy test cases if s/he
# is ever sitting idly while the other partner works.

This is the code:

0x00000000 addiu	$1, $0, 1	# $1 <- 1
0x00000004 addiu	$2, $0, 2	# $2 <- 2
0x00000008 beq		$1, $2, L1	# Shouldn't branch (not equal)
0x0000000c addiu	$1, $0, 3	# $1 <- 3
0x00000010 addiu	$2, $0, 3	# $1 <- 3
0x00000014 beq		$1, $2, L2	# Should branch (equal) (forward)
L1:
0x00000018 addiu	$5, $0, 42	# Should never reach here.
L2:
0x0000001c addiu	$1, $0, 1	# $1 <- 1
0x00000020 addiu	$2, $0, 1	# $2 <- 1
0x00000024 bne		$1, $2, L3	# Shouldn't branch (equal)
0x00000028 addiu	$1, $0, 2	# $1 <- 2
0x0000002c addiu	$2, $0, 3	# $1 <- 3
0x00000030 bne		$1, $2, L4	# Should branch (not equal) (forward)
L3:
0x00000034 addiu	$5, $0, 43	# Should never reach here
L4:
0x00000038 jal		L5		# Jump. $31 <- 0x0000003c
0x0000003c addiu	$5, $0, 44	# Should never reach here
0x00000040 beq		$0, $0, L8	# 0 == 0 so branch to L8
L5:
0x00000044 addiu	$4, $31, 0	# $4 <- 0x0000003c
0x00000048 addiu	$31, $31, 4	# $31 <- 0x00000040
0x0000004c jr		$31		# Jump back to 0x00000040
0x00000050 addiu	$5, $0, 45	# Should never reach here
L6:
0x00000054 beq		$0, $0, L6	# 0 == 0 so branch to L6 (infinite)
L7:
0x00000058 bne		$0, $1, L6	# 0 != 3 so branch to L6 (backward)
0x0000005c addiu	$5, $0, 47	# Should never reach here
L8:
0x00000060 beq		$0, $0, L7	# 0 == 0 so branch to L7 (backward)
0x00000064 addiu	$5, $0, 46	# Should never reach here


What to watch for:

$5 should *never* change.  If it does, there was a problem.
The following sequence should occur.

PC = 0x00000000
PC = 0x00000004		$1 <- 1
PC = 0x00000008		$2 <- 2
PC = 0x0000000c
PC = 0x00000010		$1 <- 3
PC = 0x00000014		$2 <- 3
PC = 0x0000001c
PC = 0x00000020		$1 <- 1
PC = 0x00000024		$2 <- 1
PC = 0x00000028
PC = 0x0000002c		$1 <- 2
PC = 0x00000030		$2 <- 3
PC = 0x00000038
PC = 0x00000044
PC = 0x00000048		$4 <- 0x0000003c
PC = 0x0000004c
PC = 0x00000040
PC = 0x00000060
PC = 0x00000058
PC = 0x00000054
(repeat on 0x00000054 forever)