Question

Assembly language (MIPS)

Let register $8 be x and register $9 be y. Write a program to evaluate:

Z = 3x - 5y+5

Leave the result in register $10. Inspect the register after running the program to check that the program works. Run the program several times, initialize x and y to different values for each run.

Answer 1

.data

x: .word 10

y: .word 2

msg: .asciiz "z = "

.text

main:

  

#load value 3 to $t0

li $2,3

#load value 5 to $t1

li $3,5

#load x value to $t8

lw $8,x

#load y value to $t9

lw $9,y

#multiply $2 and $8,result stores in $10

# 3*x

mul $10,$2,$8

# 5*y

mul $5,$9,$3

#subtract $10 and $5,result stores in $10

# 3x - 5y

sub $10,$10,$5

#add $10 and $3,result stores in $10

# z = 3x - 5y + 5

add $10,$10,$3

#print msg1

li $v0,4 #print string syscall value is 4

la $a0,msg #load address of msg to $a0

syscall

#print z value

li $v0,1 #print integer syscall value is 1

move $a0,$10 #load z value to $a0

syscall

#terminate the program

li $v0, 10

syscall

For x = 4 and y = 5

For x = 10 ,y = 2

For x = 15,y = 6