#############################################################
#
# mystery.mal
# CMPE12C Lab 2 (version 2)
#
# Richard Hughey 10/4/99
# rph@cse.ucsc.edu    
#
# A program that does something slightly mysterious!
#
#
# Registers:	The registers labeled $s0...$s8 are the safest to use!
#		$t0...$t9 are also safe to use if you don't do any
#		procedure calls.        
#		The register labeled $0 is always zero!
#		Don't use any other registers until you know what they mean!
#
# Instructions:	 You will find in xspimsal that several of the MAL
#	         instructions expand into more than one TAL instruction
#		 when run in the simulator.  For example, the I/O
#		 commands first copy appropriate arguments into a couple
#		 of registers, then execute a syscall to get to the OS,
#		 and then move the return value (if present) to the
#		 appropriate register.    

.text
__start:
    la $s6, greeting
    puts $s6
    la $s6, prompt
    la $s7, resultprompt
    la $s8, andprompt
    li $s5, 0x30
loop:
    li $s2, 0x20
    puts $s6
    getc $s0
    blt  $s0, $s2, finish
    getc $s1
    blt  $s1, $s2, finish
    add $s2, $s0, $s1
    sub $s2, $s2, $s5
    puts $s7
    putc $s2
    sub $s3, $s0, $s1
    add $s3, $s3, $s5   # version 1 had:     add $s3, $s2, $s5
    puts $s8
    putc $s3
    b loop
finish:	
    la $s6, endprompt
    puts $s6
    done


# A section of data.  You can have as many .data segments as you
# would like, intermixed with as many .text segments as you would like.    
.data
greeting: 
    .asciiz "Welcome to the CE12C slightly mysterious program!\n"
prompt:   
    .asciiz "\n\nPlease type something:  "
resultprompt:   
    .asciiz "\nThe results are:	   "
andprompt:      
    .asciiz "  and  "
endprompt:
    .asciiz "\n\nThank you for using this slightly mysterious program!\n"