Question

Write a MIPS assembly program that asks the user first for a string, then for a character. The program should search the string for the character and print out the number of times the character appears in the string. Restrictions can be used, just be sure to list them. You must allocate space in the .data segment of your program for the user string.

Answer 1

MIPS assembly program code:

.data
promtMsg1: .asciiz "Enter a string "
promtMsg2: .asciiz "Enter a character "
count: .word 10
string: .space 50
character: .space 4
output: .asciiz "# of character found = "

main:
li $t0, 50 #end var for loop
li $t1, 0 #start var for loop
li $t2, 0 #number of occurences

la $a0, promtMsg1 #print 'enter string'
li $v0, 4
syscall

la $a0, string #input string
li $a1, 50
li $v0, 8
syscall

la $a0, promtMsg2 #print 'Enter char'
li $v0, 4
syscall

la $a0, character #input character
li $a1, 4
li $v0, 8
syscall

la $s0, character
lb $s1, ($s0)
la $t3, string
lb $a2, ($t3) #gets first char of string

loop:
beq $a2, $zero, end #once reach end of char array, prints result
beq $a2, $s1, something #if the char within string == comparing char
addi $t3, $t3, 1 #increment char array
lb $a2,($t3)
j loop

something:   
addi $t2, $t2, 1 #increments number of occurences of char
end:
la $a0, output
li $v0, 4
syscall

la $a0, character
li $v0, 11
syscall

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