# This version replaces direct invocation of the OS to do output
# with calls to the standard C-- runtime (which provides
# methods printString(char* str) and printInt(int val), among others)

.data                                    # begin data section
N:       .word    5                      # reserve and initialize a word
result:  .space   4                      # reserve but don't initalize a word
msg:     .asciiz  "The factorial is: "   # message string
newline: .asciiz "\n"
        
.text                                   # begin program text
    .global main
main:
	addi    $sp, $sp, -8            # procedure entry (as main has no local variables)
	sw      $ra, 0($sp)
	sw	$fp, 4($sp)
	
        addi    $t0, $0, 1              # $t0 will hold result, initially 1
        lw      $t1, N($gp)             # $t1 will hold N, initially 9
    
top:    beq     $t1, $0, bottom
        mult    $t0, $t0, $t1           # result = result * N
        addi    $t1, $t1, -1            # decrement N
        j       top                     # goto top
    
bottom:
        sw      $t0, result($gp)        # we'd better save result

	addi    $sp, $sp, -4            # make room for arg to printString
	addi	$t0, $gp, msg           # compute argument address
	sw      $t0, 0($sp)             # push argument
	jal     printString

	lw      $t0, result($gp)
	sw      $t0, 0($sp)
	jal     printInt

	addi	$t0, $gp, newline
	sw	$t0, 0($sp)
	jal	printString
	addi	$sp, $sp, 4

	lw	$ra, 0($sp)             # fetch caller's return address
	lw      $fp, 4($sp)		# restore $fp to what it was on entry
	addi    $sp, $sp, 8             # restore $sp to what it was on entry
        jr      $ra