mips string copy: error in spim

Question

Q1. In my class ppt, that codes are written, but the MIPS code does not work in SPIM. How can I revise the MIPS code?

Q2. Assume that address of x and y are 100 and 200, respectively, and i = 10 and sp = 500. How can I revise MIPS code with that MIPS source code?

//strcpy C code

void strcpy (char x[], char y[]) 
{ 
    int i;
    i = 0;

  while ((x[i]=y[i])!='\0')
   i += 1; 
}

//strcpy MIPS code

.data

 Array: .space 10

.text

strcpy:
  addi $sp, $sp, -4
  sw $s0, 0($sp)
  add $s0, $zero, $zero

L1: 
  add $t1, $s0, $a1
  lbu $t2, 0($t1)
  add $t3, $s0, $a0
  sb $t2, 0($t3)
  beq $t2, $zero, L2
  addi $s0, $s0, 1
  j L1

L2:
  lw $s0, 0($sp)
  addi $sp, $sp, 4
  jr $ra

score 0 · Answer 1 · answered Apr 07 '18 at 07:09

you undefined "main" symbols, and you should pass arguments for strcpy.

for example:

main:
    la      $a0, str1       # first args
    la      $a1, str2       # second args
    jal     strcpy          # jump and save return address

    li      $v0, 4          # print_string
    add     $a0, $a0, $zero 
    syscall

    li      $v0, 4
    add     $a0, $a1, $zero 
    syscall

    li      $v0, 10          # exit program

mips string copy: error in spim

1 Answers1