Im trying to make a random integer generator from $-31$ to $32$ from mips but I encounter an error "Runtime exception at $0$x$00400020$: Upper bound of range cannot be negative $($syscall $42)"$ Here is my code in MIPS Assembly

$.$data

BingoArray: $.$word $-31,-30,-29,-28,-27,-26,-25,-24,-23,-22,-21,-20,-19,-18,-17,-16,-15,-14,-13,-12,-11,-10,-9,-8,-7,-6,-5,-4,-3,-2,-1,0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32$

ArraySize: $.$word $64$ # Total elements in BingoArray

$.$text

$.$globl main

main:

# Load the array size

lw $a$0,$ ArraySize

# Fisher$-$Yates Shuffle Algorithm

addi $a$0,$ $a$0,-1$ # Adjust size for $0$ indexing

move $t$1,$ $a$0$ # $t$1$ will be used for $\text{'}$i$\text{'}$ in the loop, starting from n$-1$

shuffle$\_$loop:

bltz $t$1,$ print$\_$random # If $t$1<0,$ we've shuffled the array; go to print

# Generate random number, $0<=$ j $<=$ i$,$ using syscall $42$

li $v$0,42$ # Syscall code for random int in range

li $a$1,0$ # Lower bound of the range

move $a$2,$ $t$1$ # Upper bound is $\text{'}$i$\text{'}$

syscall # Perform syscall, result is in $a$0($random index j$)$

move $a$1,$ $a$0$ # Move random index to $a$1$ for SWAP procedure

# Call SWAP with indices i $($$t$1)$ and j $($$a$1)$

move $a$2,$ $t$1$

jal SWAP

# Decrement i for next iteration

addi $t$1,$ $t$1,-1$

j shuffle$\_$loop

SWAP:

# Input: $a$2=$ i$,$ $a$1=$ j

# Swap BingoArray$[$i$]$ and BingoArray$[$j$]$

# Calculate addresses

sll $t$2,$ $a$2,2$ # $t$2=$ i $*4$

sll $t$3,$ $a$1,2$ # $t$3=$ j $*4$

add $t$2,$ $t$2,$ $gp # Address of BingoArray$[$i$]$

add $t$3,$ $t$3,$ $gp # Address of BingoArray$[$j$]$

# Swap values

lw $t$4,0($$t$2)$ # Temporarily store BingoArray$[$i$]$

lw $t$5,0($$t$3)$ # Temporarily store BingoArray$[$j$]$

sw $t$5,0($$t$2)$ # BingoArray$[$i$]=$ BingoArray$[$j$]$

sw $t$4,0($$t$3)$ # BingoArray$[$j$]=$ BingoArray$[$i$]$

jr $ra # Return to caller

print$\_$random:

# Printing the first element of the shuffled array

lw $a$0,$ BingoArray # Load the first element of the array

li $v$0,1$ # syscall for print integer

syscall

# End of program

li $v$0,10$ # exit syscall

syscall

The Swap procedure work like this

Store any variables you will use on your procedure on the stack

$$ Inputs: i$,$ j

$$ Exchange BingoArray$[$i$]$ and BingoArray$[$j$]$

$$ Restore the used variables from the stack

And the psuedocode for shuffle work like this

To shuffle an array a of n elements $($indices $0..$n$-1)$:

for i from n$1$ down to $1$ do

j $$ random integer such that $0<=$ j $<=$ i

exchange a$[$j$]$ and a$[$i$]$