\ The Towers Of Hanoi
\ ABC Implementation
\ Copyright (C) 2003 Amit Singh. All Rights Reserved.
\ http://hanoi.kernelthread.com
\
\ Tested under ABC Release 1.05.02 (central workspace)
\

HOW TO HANOI n:
    PUT {} IN stack
    PUT n  IN stack[1]
    PUT 1  IN stack[2]
    PUT 3  IN stack[3]
    PUT 0  IN stack[4]
    PUT 4  IN esp
    WHILE esp > 0:
        PUT stack[esp] IN processed
        PUT esp - 1 IN esp
        PUT stack[esp] IN dto
        PUT esp - 1 IN esp
        PUT stack[esp] IN dfrom
        PUT esp - 1 IN esp
        PUT stack[esp] IN dn
        PUT esp - 1 IN esp
        PUT 6 - dfrom - dto IN dleft
        IF processed = 0:
            IF dn = 1:
                WRITE dfrom, " --> ", dto /
            IF NOT dn = 1:
                PUT esp + 1 IN esp
                PUT dn IN stack[esp]
                PUT esp + 1 IN esp
                PUT dfrom IN stack[esp]
                PUT esp + 1 IN esp
                PUT dto IN stack[esp]
                PUT esp + 1 IN esp
                PUT 1 IN stack[esp]
                PUT esp + 1 IN esp
                PUT dn - 1 IN stack[esp]
                PUT esp + 1 IN esp
                PUT dfrom IN stack[esp]
                PUT esp + 1 IN esp
                PUT dleft IN stack[esp]
                PUT esp + 1 IN esp
                PUT 0 IN stack[esp]
        IF NOT processed = 0:
                WRITE dfrom, " --> ", dto /
                PUT esp + 1 IN esp
                PUT dn - 1 IN stack[esp]
                PUT esp + 1 IN esp
                PUT dleft IN stack[esp]
                PUT esp + 1 IN esp
                PUT dto IN stack[esp]
                PUT esp + 1 IN esp
                PUT 0 IN stack[esp]

\ HANOI n runs this for n disks
HANOI 3