HANOI.MIC

# Towers of Hanoi - recursive - works for up to 4 disks!
# (C) 2024 LambdaMikel
# MIC file can be read by PicoRAM 2090, Firmware v1.1 

00:fo8
01:f0e
02:f1f
03:fff
04:f02
05:1ae # A -> source
06:1cd # C -> dest
07:1bc # B -> spare 
08:f0e

09:11f # move "return marker 1" top top of return stack (F); marker 1 -> 0b
0a:c0d # goto hanoi(n, source, dest, spare); "recursive" call 

# end 

0b:f60 # stop 
0c:f00

### hanoi(n, source, dest, spare) @0d 

## f = 01?

0d:f0e # swap in value stack 
0e:91f 
0f:D15 

## = 01; base case 

10:f3d
11:ff0 # this doesn't destroy the value stack, as only 8-f has been swapped in!
12:f02 
13:f0e # swap back normal registers 
14:cb0 # goto jumpblock  ; return

## > 01; rec call and add 

# create 4 value stack entries

15:f0e # restore normal registers 
16:b70 # shift value stack down
17:b70 
18:b70 
19:b70 

# swap in upper bank to put values on value stack
# for first rec. call:
# FUNCTION MoveTower(disk, source, dest, spare):
# MoveTower(disk - 1, source, spare, dest)   // Step 1 above

1a:f0e # swap in upper values bank 
1b:0bf # copy "n" value 
1c:71f # sub 1 from n -> n-1 
1d:0ae # source -> source
1e:09c # dest -> spare 
1f:08d # spare -> dest 
20:f0e 

21:b50 # shift return stack down 
22:12f # -> move "return marker 2" top top of return stack (F); "marker 2 -> 24"

# parameters were prepared, do the call

23:c0d # goto sum(n);  recursive call

24:b60 # shift return stack up 
25:b90 # shift value stack up
26:b90
27:b90
28:b90

# output
# move disk from source to dest              // Step 2 above

29:f0e
2a:f3d 
2b:ff0
2c:f02
2d:f0e 

#
# prepare 2nd recursive call 
# 

2e:b70 # shift value stack down
2f:b70 
30:b70 
31:b70 

# swap in upper bank to put values on value stack
# for second rec. call:
# FUNCTION MoveTower(disk, source, dest, spare):
# MoveTower(disk - 1, spare, dest, source)   // Step 3 above

32:f0e # swap in upper values bank 
33:0bf # copy "n" value 
34:71f # sub 1 from n -> n-1 
35:08e # spare -> source
36:09d # dest -> dest  
37:0ac # source -> spare  
38:f0e 

39:b50 # shift return stack down 
3a:13f # -> move "return marker 3" top top of return stack (F); "marker 3 -> 3c"

# parameters were prepared, do the call

3b:c0d # goto sum(n);  recursive call

3c:b60 # shift return stack up 
3d:b90 # shift value stack up
3e:b90
3f:b90
40:b90

41:cb0 # goto jumpblock  ; return 

###

# return stack shift down: 

50:098
51:0a9
52:0ba
53:0cb
54:0dc
55:0ed
56:0fe
57:f07 

#### 

# return stack shift up: 

60:0ef
61:0de
62:0cd 
63:0bc
64:0ab
65:09a
66:089 
67:f07 

####

# value stack shift down: 

70:f0d
71:f0e 
72:010
73:021
74:032
75:043
76:054
77:065
78:076
79:087
7a:098
7b:0a9
7c:0ba
7d:0cb
7e:0dc
7f:0ed
80:0fe 
81:f0e
82:f0d 
83:f07 # ret 

#### 

# value stack shift up: 

90:f0d
91:f0e 
92:0ef
93:0de
94:0cd
95:0bc
96:0ab
97:09a
98:089
99:078
9a:067
9b:056
9c:045
9d:034
9e:023
9f:012
a0:001
a1:f0e
a2:f0d 
a3:f07 # ret 

###

# jump block

b0:91f # marker 1 ?
b1:E0b # goto 0A
b2:92f # marker 2 ?
b3:E24 # goto 24
b4:93f # marker 3 ?
b5:E3c # goto 3c
b6:F00 # error

#---------------
#
#Test run with 3 disks: 
#
#A B C
#-----
#1
#2
#3
#-----
#
#2
#3   1
#-----
#
#
#3 2 1
#-----
#
#  1
#3 2
#-----
#
#  1
#  2 3
#-----
#
#
#1 2 3
#-----
#
#    2
#1   3
#-----
#    1
#    2
#    3
#-----
# 
#7 Steps