# An example of a recursive function 

main:
    #int main()
    #{
    #   int max;
    #   print("Enter +ve integer: ");
    #   scanf("%d", &max); ****
    #   int tmp = sumTo(max);
    #   printf("Sum 1..%d = %d\n", max, tmp); ***
    #   return 0;
    #}
    #prolog
	push $ra            
    push $s0
	
    li $v0, 4               # print("Enter +ve integer: ");
    la $a0, ask
    syscall
	
    li $v0, 5               # scanf("%d", &max); 
    syscall
    move $s0, $v0           # I need max after the function call
                            # I need to store it safely
	
    move $a0, $v0
    jal sumTo               # sumTo(max);
	
    move $t0, $v0           # tmp = sumTo(max)
	
    li $v0, 4               # printf("Sum 1..")
    la $a0, out1
    syscall
	
    li $v0, 1               # printf(max)
    move $a0, $s0
    syscall
	
    li $v0, 4               # printf(" = ")
    la $a0, out2
    syscall
	
    li $v0, 1               # printf(tmp)
    move $a0, $t0
    syscall
	
    li $v0, 11              # printf("\n")
    li $a0, '\n'
    syscall
	
    li  $v0, 0
    #epilog
    pop $s0
    pop $ra
    jr $ra 
   
#$v0       $a0   
#int sumTo(int n) {          
# if(n == 0){
#     return 0;
# } 
# tmp = sumTo(n-1)           
# return n + tmp;            
#}   
sumTo:
    push $ra
    push $s0

    move $s0, $a0            # $s0 = n
    bnez $s0, else           # if(n != 0) goto else
    li $v0, 0                # returnValue = 0
    j epilog
else:    
    
    addi $a0, $s0, -1        # $a0 = n - 1
    jal sumTo                # $v0 = sumTo(n-1)
    add $v0, $s0, $v0        # returnValue = n + $v0

epilog:   
    pop $s0
    pop $ra
    jr $ra
    

    .data
ask:
    .asciiz "Enter +ve integer: "
out1:
    .asciiz "Sum 1.."
out2:
    .asciiz " = "