Hi! First of all, I'm new to this, so I apologise in advance if this is a really simple thing...
I am trying to write a code in assembly MIPS, in wich the program asks the user for the name of a file where it will read the text on it and copy it to another text file.
I created this code below where the name of the file is given by the variable msg3 ( the user prompt doesn't do anything yet...) and this code seems to work (i.e. the result file presents the same text has file1.txt)
.data
msg1: .asciiz "Name of file: "
msg3: .asciiz "file1.txt" #File to read from
file: .asciiz "result.txt" # File to Write to
.align 4
str_value: .asciiz "caracas" # Variable for keyboard input
test: .space 80 # Buffer
.text
main:
la $a0, msg1
jal print_string
la $a0, str_value # Loads the name of the file
jal read_string
### File for Reading
li $v0, 13 # System call to open file
la $a0, msg3 # Name of the file
li $a1, 0 # Flags Open to Read(0: read, 1: write)
syscall
move $t0, $v0 # Saves fd in $t0
li $v0, 14 # System call to read from file
la $a1, test # Buffer where to write
li $a2, 9 # Number of characters to read
move $a0, $t0 # Saves fd in $a0
syscall
li $v0, 16 # System call to close file
move $a0, $t0 # Return fd
syscall
### File for Writing
li $v0, 13 # System to open file
la $a0, file # Name of the file
li $a1, 1 # Flags Open to Write(0: read, 1: write)
syscall
move $t0, $v0 # Saves fd
li $v0, 15 # System call to write on file
la $a1,teste # Buffer where to write
li $a2, 80 # Number of characters to read
move $a0, $t0
syscall
li $v0, 16 # System call to close file
move $a0, $s6 # Returns fd
syscall
finish:
li $v0, 10 # System call para terminar a execucao
syscall
### Functions
read_string:
li $v0, 8
la $a1, 80
syscall
jr $ra
print_string:
li $v0, 4
syscall
jr $raThen, I altered the code, so the input by the user to be saved in the str_value variable, wich is used by the program to acess the file. This time, the program, although it works, it doesn't do what it is required (i.e. the result.txt file appears empty/with spaces). I'm tired of looking at it all day long and I don't see what I'm doing wrong.....can someone help, please? (to be noted that in the prompt, the user should write "file1.txt"
.data
msg1: .asciiz "Name of file: "
msg3: .asciiz "file1.txt" #File to read from
file: .asciiz "result.txt" # File to Write to
.align 4
str_value: .asciiz "caracas" # Variable for keyboard input
test: .space 80 # Buffer
.text
main:
la $a0, msg1
jal print_string
la $a0, str_value # Loads the name of the file
jal read_string
### File for Reading
li $v0, 13 # System call to open file
la $a0, str_value # Name of the file
li $a1, 0 # Flags Open to Read(0: read, 1: write)
syscall
move $t0, $v0 # Saves fd in $t0
li $v0, 14 # System call to read from file
la $a1, test # Buffer where to write
li $a2, 9 # Number of characters to read
move $a0, $t0 # Saves fd in $a0
syscall
li $v0, 16 # System call to close file
move $a0, $t0 # Return fd
syscall
### File for Writing
li $v0, 13 # System to open file
la $a0, file # Name of the file
li $a1, 1 # Flags Open to Write(0: read, 1: write)
syscall
move $t0, $v0 # Saves fd
li $v0, 15 # System call to write on file
la $a1,teste # Buffer where to write
li $a2, 80 # Number of characters to read
move $a0, $t0
syscall
li $v0, 16 # System call to close file
move $a0, $s6 # Returns fd
syscall
finish:
li $v0, 10 # System call para terminar a execucao
syscall
### Functions
read_string:
li $v0, 8
la $a1, 80
syscall
jr $ra
print_string:
li $v0, 4
syscall
jr $ra