尝试编写一个以MIPS汇编语言打印质数的程序 [英] Trying to write a program that prints prime numbers in MIPS Assembly language
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问题描述
该程序需要接受用户输入并打印出一定数量的质数,因此,如果用户输入"5",它将输出"2,3,5,7,11"
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"
我正在尝试这样做:
boolean isPrime(int n) {
for(int i=2;i<n;i++) {
if(n%i==0)
return false;
}
return true;
}
这是我的汇编代码.现在看来,它永远不会离开test_prime过程.
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"
推荐答案
这是问题所在行
add $a2, $a0, $zero # $a2 = $a0
程序已通过将其更改为:
program was fixed by changing that to:
addi $a2, $zero, 2 # $a2 = 2
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