# fact2main.mips
# Read a number n from standard input, then print n!
# (n factorial) on standard output.  Uses fact2
# to calculate the factorial.
#
# Register Usage:
# $1 - I/O, pass information to/from fact2
# $2 - Standard input value
# $4 - Argument for trap

.globl main

main:   trap 5          # Get n into $2
        add $1, $0, $2  # Copy n into $1

        jal fact2       # Calculate n! in $1

        add $4, $0, $1  # Copy result to $4
        trap 1          # Print result (in $4)

        
        addi $4, $0, 10
        trap 101        # Print newline character

        trap 10         # Quit program