# Purpose: Practice using XOR, random #------------------------------------------------------------------- # The left c

[answerhappygod]

# Purpose: Practice using XOR, random
#-------------------------------------------------------------------

# The left column is random keys depressed on a keyboard.
# A zero means the key is not pressed, a one means the key is
pressed.
# You need to determine the CHANGES from one left-hand row to the
next.
# PREVIOUS ==> 0
1 1
0
# NEW ==> 0
1 0
1
# MEANING ==> No Key
Still Key
New Key
# Change
Pressed Released
Depressed
# If a New Key is depressed, that bit should apprear on the
Right.
#-------------------------------------------------------------------

# SAMPLE OUTPUT:
# 00000000000000000000000001101011
00000000000000000000000001101011
# 00000000000000000000000000100111
00000000000000000000000000000100
# 00000000000000000000000000110001
00000000000000000000000000010000
# 00000000000000000000000011011111
00000000000000000000000011001110
# 00000000000000000000000011001001
00000000000000000000000000000000
# 00000000000000000000000010101100
00000000000000000000000000100100
# 00000000000000000000000010000111
00000000000000000000000000000011
# 00000000000000000000000010001001
00000000000000000000000000001000
# 00000000000000000000000011001011
00000000000000000000000001000010
# 00000000000000000000000010110110
00000000000000000000000000110100
# 00000000000000000000000011100111
00000000000000000000000001000001
# 00000000000000000000000011110110
00000000000000000000000000010000
# 00000000000000000000000001001000
00000000000000000000000000001000
# 00000000000000000000000001101011
00000000000000000000000000100011
# 00000000000000000000000000011010
00000000000000000000000000010000
# 00000000000000000000000011001101
00000000000000000000000011000101
.data
.eqv SYS_PRINT_WORD 1
#word, byte, character
.eqv SYS_PRINT_FLOAT 2
#float
.eqv SYS_PRINT_DOUBLE 3
#double
.eqv SYS_PRINT_TEXT 4 #text
(zero terminated)
.eqv SYS_EXIT
10 #terminate
.eqv SYS_PRINT_CHAR 11
#print char
.eqv SYS_READ_CHAR 12 #read
char
.eqv SYS_TIME
30 #system time to a1,a0
.eqv SYS_SLEEP 32
#delay a0 msec
.eqv SYS_PRINT_BIN 35
#print binary
.eqv SYS_SET_SEED 40
#set random seed
.eqv SYS_RAND_INT 42
#get random int

wait: .word 1000
#1 second
max: .word 16
#max loops
tab: .asciiz "\t"
endl: .asciiz "\n"
last: .word 0
#last random
.text
.globl main
main:
# get system time
li $v0, SYS_TIME
#get system time
syscall
# use system time lsb for seed a1, a0=0 for id
move $a1, $a0
#time lsw will be seed
li $a0, 0
#generator id 0
li $v0, SYS_SET_SEED
syscall
# initialize main loop: s7=max, s6=0 (loop
counter)
# main loop
loop:
# pause 'wait' msec using SYS_SLEEP
# get random integer in a0
# load 'last' into s0
# zero top 24 bits of a0 random
# save a0 new random lsb into 'last' and move a0
into s1
# print a0 random lsb as binary
# print a tab
# XOR s0 'last' with s1 new random lsb, save in a
register
# AND the XOR results with s1 new random lsb,
print as binary
# print a new line
# end loop: s6++, if s6==s7 then branch to
exit:
# else branch to
loop:
#------------------------
# terminate program.
exit:
li $v0, SYS_EXIT # call code for
terminate
syscall #
system call
#.end main