Question

Write a procedure that accepts a byte string(base address in $a0, length in $ a1)
and returns its XOR checksum, defined as the exclusive-OR of all its bytes, in $v0.

(by MiniMIPS)

Answer 1

Greetings!!

Code:

#DATA SEGMENT

.data

string: .ascii "Hello Welcome!!"

#CODE SEGMENT

.text

#MAIN STARTS HERE

main:

la $a0,string                #load address of the string in a0 as 1st parameter

li $a1,14                      #load length-1 to a1 as 2nd parameter

#FUNCTION CALL

jal checksum               #function call

#RETURN FROM MAIN

#STANDARD TERMINATION

li $v0,10                      #parameter for termination

syscall                         #system call

#END OF MAIN

#FUNCTION DEFINITION

checksum:

lb $t0,0($a0)               #read first byte

loop:

beq $a1,$0,end            #check the length is 0 or not. if 0 go to end

addi $a0,$a0,1             #increment array index for accessing next element

lb $t1,0($a0)               #read next byte

xor $t0,$t0,$t1             #calculating checksum

addi $a1,$a1,-1           #decrement the length

j loop                           #repeat

end:

add $v0,$0,$t0             #loading the checksum in v0 for return

jr $ra                           #return to main

#END OF FUNCTION

Output screenshot:

Hope this helps

Thank You