MIPS 32反向打印字符串

Question

输出应为“ LastName，FirstName” ...当我运行代码时，它将打印我姓氏的第一个字符，然后打印我的全名。 我不确定这是因为我需要另一个循环还是因为它没有读取我的完整姓氏。请帮助我了解为什么以及如何解决此问题。 预先感谢！

       .data
userInput: .space 400  #Make a 4 byte (32 bit) space in memory
fName:     .space 100
lName:     .space 100 

Prompt: .asciiz "Enter your name (FIRST LAST):\n 
Output: .asciiz "Your name in reverse order is:\n 
Comma: .asciiz "," 
blank: .asciiz " "

    .text  
    .globl main
main:  
    li $v0, 4 
    la $a0, Prompt #Loads address prompt from memory and stores it
    syscall #Reads register $v0 for op code, sees 4 and prints the string located in $a0

    li $v0, 8
    la $a0, userInput #sets $a0 to point to the space allocated for writing a word
    la $a1, 100 # gets the length of the space in $a1 so we cant go over the memory limit
    syscall

    li $v0, 4 #Loads the value 4 into register $v0 which is the op code for print string
    la $a0, Output # Load address Tell Output from memory and stores it into arguments register 0
    syscall #reads regsiter $v0 for op code, sees 4 and prints the string located in a$ao

    la $s0, userInput
    la $s1, fName #save int to $s0-$s2 registers to use throughout whole program
    la $s2, lName

loop: 
    lb $t0, 0($s0)
    lb $t1, 0($s1)
    beq $t0, ' ', skipBlankSpace #else 
    sb $t0, 0($s1)
    add $s0, $s0, 1 #increments the character array $s++
    add $s1, $s1, 1

    j loop  

skipBlankSpace: 
    add $s0,$s0, 1

nextName:
    lb $t1, 0($s0)
    sb $t1, 0($s2)
    addi $s2, $s2, 1 

print:  #prints the output
    li $v0, 4
    la $a0, lName
    syscall 

    li $v0, 4
    la $a0, Comma
    syscall

    li $v0 4
    la $a0, blank 
    syscall

    li $v0, 4 
    la $a0, fName
    syscall 

    li $v0, 10
    syscall