Complete code where \" XXXXXXXXXXXXXXX \" is placed. ###########################

Question

Complete code where " XXXXXXXXXXXXXXX" is placed.

##########################################################################

1st finds & shows position-weight of the rightmost 1 of a non-0 integer, # then finds & shows the resulting value when that rightmost 1 is cleared.

############################ data segment ################################

.data

inPrompt: .asciiz "Enter a non-zero integer: "

outLab1: .asciiz " has rightmost 1 @ weight position "

outLab2: .asciiz " Clearing the rightmost 1 makes it "

############################ code segment ################################

.text

.globl main

main:

li $v0, 4

la $a0, inPrompt

syscall # print input prompt

li $v0, 5

syscall # read input integer x

##########################################################

# Replace each "hole" indicated with "********" with an # an instruction so that the program

# will work just like # the sample runs shown at the bottom. # The last 3 instructions (replacing the last 3 "holes")

# MUST involve bitwise operations. # You MUST test your completed program for AT LEAST the # test cases shown

#(and include the result in hardcopy)

. ##########################################################

xxxxxxxxxxxxxxxx # $t0 gets copy of input x

xxxxxxxxxxxxxxxxx # $t1 gets mask1 that is "-x"

li $v0, 1 move $a0, $t0

syscall

li $v0, 4 la $a0, outLab1

syscall # print output label 1

li $v0, 1

xxxxxxxxxxxxxxxxxx # $a0 gets "all bits of x cleared except the rightmost 1"

syscall

xxxxxxxxxxxxxxxxx # $t2 gets mask2 that is "$a0 with all its bits toggled"

li $v0, 4

la $a0, outLab2

syscall # print output label 2

li $v0, 1

xxxxxxxxxxxxxxxx # $a0 gets "all bits of x with the rightmost 1 cleared"

syscall

li $v0, 10 # exit syscall

########################## sample test runs ##############################
# Enter a non-zero integer: 1
# 1 has rightmost 1 @ weight position 1
# Clearing the rightmost 1 renders it 0
# -- program is finished running --
#
#
# Reset: reset completed.
# Enter a non-zero integer: -1
# -1 has rightmost 1 @ weight position 1
# Clearing the rightmost 1 makes it -2
# -- program is finished running --
#
#
# Reset: reset completed.
# Enter a non-zero integer: 3456
# 3456 has rightmost 1 @ weight position 128
# Clearing the rightmost 1 makes it 3328
# -- program is finished running --
#
#
# Reset: reset completed.
# Enter a non-zero integer: -123456
# -123456 has rightmost 1 @ weight position 64
# Clearing the rightmost 1 makes it -123520
# -- program is finished running --
#
#
# Reset: reset completed.
# Enter a non-zero integer: 1073741824
# 1073741824 has rightmost 1 @ weight position 1073741824
# Clearing the rightmost 1 makes it 0
# -- program is finished running --
#
#
# Reset: reset completed.
# Enter a non-zero integer: -2147483647
# -2147483647 has rightmost 1 @ weight position 1
# Clearing the rightmost 1 makes it -2147483648
# -- program is finished running --
######################## end sample test runs ############################

Explanation / Answer

1)move $t0,$v0 #$t0 gets copy of input x

2)neg $t1,$t0 #$t1 gets mask1 that is "-x"

3)andi $a0,$t0,1 #$a0 gets "all bits of x cleared except the rightmost 1"

4)not $t2,$a0 #$t2 gets mask2 that is "$a0 with all its bits toggled"

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