Trying to write a program that prints prime numbers in MIPS Assembly language

问题

This program needs to take user input and print out that quantity of prime numbers, so if the user in puts "5" it will output "2,3,5,7,11"

I'm trying to do it like so:

    boolean isPrime(int n) {
for(int i=2;i<n;i++) {
    if(n%i==0)
        return false;
}
return true;
}

This is my assembly code. Right now it appears to never leave the test_prime procedure.

    .globl main
.text
main:
li $v0, 4               # print welcome message
la $a0, welcome
syscall

la $a0, prompt          # prompt for user input
syscall         

#receive input
li $v0, 5               
syscall
add $s1, $v0, $zero     # $s1 = user input

beq $s1, $zero, quit    # if input == zero, quit

#print 1st prime
li $v0, 1               # print int
addi $a0, $zero, 2      # argument = 2
syscall

li $v0, 4               # print new line
la $a0, line
syscall

addi $s2, $s2, 1        # $s2 = 1 (prime counter)
add $a2, $a0, $zero     # $a2 = $a0

loop:
addi $a2, $a2, 1        # argument++
#beq $s2, $s1, quit     # if prime counter == input, quit
jal test_prime
beq $v1, $zero, loop    # if test_prime returns false, repeat
addi $s2, $s2, 1        # else $s2++
#print next prime
li $v0, 1               # print int
add $a0, $a2, $zero     # argument = $a2
syscall

li $v0, 4               # print new line
la $a0, line
syscall

beq $s2, $s1, quit      # if prime counter == input, quit
j loop

test_prime:
add $t1, $a2, $zero     # $t1 = argument
addi $t2, $zero, 1      # $t2 = 1
loop2:
addi $t2, $t2, 1        # $t2++
beq $t2, $t1, true      # if $t2 == $t1, return
div $t3, $t1, $t2       # $t3 = $t1 / $t2
mfhi $t4                # $t4 = remainder
beq $t4, $zero, false
j loop2
false:
li $v1, 0       # $v1 = false
jr $ra
true:
li $v1, 1       # $v1 = true
jr $ra

quit:
# program exit
li $v0, 10
syscall


.data
welcome:    .asciiz "Prime Numbers\n"   
prompt:     .asciiz "How many primes? "
line:       .asciiz "\n"

回答1:

this was the problem line

add $a2, $a0, $zero     # $a2 = $a0

program was fixed by changing that to:

addi $a2, $zero, 2      # $a2 = 2

来源：https://stackoverflow.com/questions/33068056/trying-to-write-a-program-that-prints-prime-numbers-in-mips-assembly-language