Reputation:
I am currently learning MIPS and while doing some exercises I came across one which is to write the Fibonacci sequence first in Java then convert it to MIPS Assembly. I only can use beq
, bne
and slt
My Java code is the following:
int n = 50; F_MAX v
int t1 = 0;
int t2 = 1;
int sum = 0;
while(t1 <= n)
{
System.out.print(t1 + " ")
sum = t1 + t2
t1 = t2
t2 = sum;
}
Meaning that if n = 50 if should print all the numbers before 50 (0; 1; 1; 2; 3; 5; 8; 13; 21; 34)
My MIPS Assembly code is:
la $s0, F_MAX
lw $s0, 0($s0) #$s0 = int n = F_MAX (50);
addi $t1, $zero, 0 # $t1 = int t1 = 0;
addi $t2, $zero, 1 # $t2 = int t2 = 1;
addi $t3, $zero, 0 # $t3 = int sum = 0
while:
beq $t1, $s0, Exit #if t1 == 50 exit the program
addi $v0, $zero, 1 # syscall code to print integer
add $a0, $zero, $t1 # t1 to be printed
syscall # print t1
add $t3, $t1, $t2
addi $t1, $t2, 0
addi $t2, $t3, 0
addi $v0, $zero, 4 # syscall code to print a string
la $a0, COMMA
syscall # print a comma (and a space)
j while
Exit:
li $v0, 10
syscall
But for some reason, it gives me overflow and prints all the possible positive numbers and I cannot figure out why.
Upvotes: 1
Views: 3592
Reputation:
So here is the updated code:
As the condition t1== 50 never was met it alwasys was false I had to use slt
and bne
instructions.
la $s0, F_MAX
lw $s0, 0($s0) #$s0 = int n = F_MAX (50);
addi $t1, $zero, 0 # $t1 = int t1 = 0;
addi $t2, $zero, 1 # $t2 = int t2 = 1;
addi $t3, $zero, 0 # $t3 = int sum = 0
while:
addi $v0, $zero, 1 # syscall code to print integer
add $a0, $zero, $t1 # t1 to be printed
syscall # print t1
add $t3, $t1, $t2
addi $t1, $t2, 0
addi $t2, $t3, 0
addi $v0, $zero, 4 # syscall code to print a string
la $a0, COMMA
syscall # print a comma (and a space)
slt $t4, $t1, $s0 #if t1 < 50 $t4 = 1
bne $t4, $zero, while #if $t4 != $zero goto while
slt $t4, $s0, $t1 #if 50 < $t1 $t4 = 1
bne $t4, $zero, Exit #if $t4 != $zero goto Exit
Exit:
li $v0, 10
syscall
Upvotes: 1