Question

Write a MIPS Assembly language program to request a file name from the user, open the file, read the contents, and write out the contents to the console.

This is what I have so far:

.data
   fileName:   .space 100
   prompt1:   .asciiz "Enter the file name: "
   prompt2:    .asciiz ""
   prompt3:   .asciiz "\n"
   buffer:    .space 4096
.text
   main:
       #
       li $v0, 4
       la $a0, prompt1
       syscall
      
       #
       li $v0, 8
       la $a0, fileName
       li $a1, 50
       syscall
      
       jal remove
      
       #
       li $v0, 13
       la $a0, fileName
       li $a1, 0
       li $a2, 0
       syscall
       move $s0, $v0
      
       #
       li $v0, 14
       move $a0, $s0
       la $a1, buffer
       li $a2, 11
       syscall
      
       #
       li $v0, 4
       la $a0, buffer
       syscall
      
       #
       li $v0, 10
       syscall

Answer 1

Note: My jar file and text file located in the same folder, please input full path for getting results

FileOperation.asm:

.data
fileName: .space 100
prompt1: .asciiz "Enter the file name: "
buffer: .space 40966
.text
main:
#
li $v0, 4
la $a0, prompt1
syscall
  
#(the file name must be full path or path from which Mars jar file is located)
li $v0, 8
la $a0, fileName
li $a1, 50
syscall


# converting the string into a null-terminated string
#replacing last character of fileName with 0 instead of \n

    la   $s0, fileName   # $s0 contains base address of str
   add   $s2, $0, $0   # $s2 = 0
   addi   $s3, $0, '\n'   # $s3 = '\n'
loop:
   lb   $s1, 0($s0)   # load character into $s0
   beq   $s1, $s3, end   # Break if byte is newline
   addi   $s2, $s2, 1   # increment counter
   addi   $s0, $s0, 1   # increment str address
   j   loop
end:
   sb   $0, 0($s0)   #replace newline with 0
  
   #now that input file name is converted to null-terminated string the remaining code is same
  
  
   # Open file for reading

   li $v0, 13 # system call for open file
   la $a0, fileName # address of null-terminated string containing filename
   li $a1, 0 # flags
   li $a2, 0 # mode
   syscall # open a file
   move $s0, $v0 # save the file descriptor
  
   # reading from file just opened

   li $v0, 14 # system call for reading from file
   move $a0, $s0 # file descriptor
   la $a1, buffer # address of input buffer
   li $a2, 100 # maximum number of characters to read
   syscall # read from file

   # Printing File Content
   li $v0, 4 # system Call for PRINT STRING
   la $a0, buffer # buffer contains the values
   syscall # print int

li $v0, 10 # Finish the Program
syscall
Output: