317 lines
7.4 KiB
Plaintext
317 lines
7.4 KiB
Plaintext
; LIFE FOR APPLE-1
|
|
; UNKNOWN AUTHOR
|
|
; DISASSEMBLED BY ANTONINO PORCINO, 14TH SEP 2022
|
|
|
|
ECHO = $FFEF ; character echo routine in woz monitor
|
|
KEY_DATA = $D010 ; read key
|
|
KEY_CTRL = $D011 ; control port
|
|
DSP_DATA = $D012 ; write ascii
|
|
DSP_CTRL = $D013 ; control port
|
|
|
|
; zero page variables
|
|
|
|
PTR1 = $F0 ; $F0-$F1
|
|
PTR2 = $F2 ; $F2-$F3
|
|
PTR3 = $F6 ; $F6-$F7
|
|
PTR4 = $F8 ; $F8-$F9
|
|
CELLCOUNT = $F9 ; also PTR4 high byte
|
|
RND = $FA ; $FA-$FB random seed
|
|
|
|
; board geometry is 40x24 = 960 bytes
|
|
; primary board: $2440-$27FF
|
|
; secondary board: $2840-$2BFF
|
|
|
|
ROW0 = $2440
|
|
ROW1 = $2468
|
|
ROW22 = $27B0
|
|
ROW23 = $27D8
|
|
|
|
DEADCELL = $A0 ; " " (space character)
|
|
ALIVECELL = $AA ; "*"
|
|
FRAMECELL = $AD ; "-"
|
|
|
|
|
|
ORG $2000
|
|
|
|
;
|
|
; quickly resets the primary board ($2400-$27FF)
|
|
;
|
|
LDX #$00
|
|
LDA #DEADCELL ; dead cell character
|
|
L2004 STA $2400,X ; bug: this should be $2440
|
|
STA $2500,X
|
|
STA $2600,X
|
|
STA $2700,X
|
|
INX
|
|
BNE L2004
|
|
|
|
;
|
|
; prints welcome message (56 characters)
|
|
; X is zero from previous BNE
|
|
|
|
L2013 LDA MESSAGE,X
|
|
JSR ECHO
|
|
INX
|
|
CPX #$38 ; prints 56 chars
|
|
BNE L2013
|
|
|
|
; read and print string from keyboard until ENTER is pressed
|
|
; string is simply discarded, the purpose is to increment the
|
|
; random seed in $FA-RND+1
|
|
|
|
L201E JSR RDKEY
|
|
CMP #$8D ; enter key
|
|
BNE L201E
|
|
|
|
;
|
|
; fills the board with a random number of cells (from 32 to 95)
|
|
; bug: also fills out of screen area between $2400 and $243F
|
|
;
|
|
|
|
JSR GETRAND ; gets a random number
|
|
AND #$3F ; ranges it $00-$3F
|
|
ADC #$20 ; ranges it $20-$5F (TODO: why carry is not cleared?)
|
|
STA CELLCOUNT ; number of cells to write betwen $20-$5F (32-95)
|
|
|
|
LDY #$00
|
|
L2030 JSR GETRAND ; gets a random number
|
|
AND #$03 ; ranges it 0-3
|
|
CLC
|
|
ADC #$24
|
|
STA PTR1+1 ; high byte ranges from $24-$27
|
|
LDA RND
|
|
STA PTR1 ; PTR1 points randomly $2400-$27FF
|
|
LDA #ALIVECELL ; alive cell character ("*")
|
|
STA (PTR1),Y ; set cell "ON"
|
|
DEC CELLCOUNT ; decrement cell count
|
|
BNE L2030 ; loop until all cells are written
|
|
|
|
;$2046
|
|
; main game loop
|
|
MAINLOOP LDA #$24
|
|
STA PTR4+1
|
|
LDA #$40
|
|
STA PTR4 ; PTR4 = $2440
|
|
|
|
;
|
|
; marks top and bottom lines of the board to avoid out of bound checks
|
|
;
|
|
|
|
LDX #$27 ; $27=39, counts 40 characters backward
|
|
LDA #FRAMECELL ; $AD = board limit character ("-")
|
|
L2052 STA $27D8,X ; write bottom line of the board
|
|
STA $2440,X ; write top line of the board
|
|
DEX ; decrement 40 charc counter
|
|
BPL L2052 ; loop if X >= 0
|
|
|
|
; loop that prints the whole board from $2440 to $2800
|
|
|
|
L205B LDA (PTR4),Y
|
|
JSR ECHO
|
|
INC PTR4
|
|
BNE L205B
|
|
INC PTR4+1
|
|
LDA PTR4+1
|
|
CMP #$28
|
|
BNE L205B
|
|
|
|
; reads the keyboard between each screen printout
|
|
JSR RDKEY
|
|
|
|
; copy true board into "working" board (copies $2440-$2800 into $2840-...)
|
|
LDY #$00
|
|
JSR SETPTRS ; PTR1=$2440, PTR2=$2840
|
|
L2074 LDA (PTR1),Y
|
|
STA (PTR2),Y
|
|
INC PTR1
|
|
INC PTR2
|
|
BNE L2074
|
|
INC PTR1+1
|
|
INC PTR2+1
|
|
LDA PTR1+1
|
|
CMP #$28
|
|
BNE L2074
|
|
|
|
JSR ZEROBOARD ; fills the primary board all with zeros
|
|
|
|
;
|
|
; scans the secondary board does some computation and writes on the primary board
|
|
;
|
|
|
|
L208B LDY #$00
|
|
LDA (PTR2),Y
|
|
CMP #ALIVECELL ; is cell alive?
|
|
BNE L209D ; if no go next cell
|
|
LDY #$27 ; yes it's alive
|
|
JSR L2114 ; ??
|
|
LDY #$01
|
|
JSR L211D ; ??
|
|
|
|
; increment PTR1 and PTR2 to next cell
|
|
L209D INC PTR1
|
|
INC PTR2
|
|
BNE L208B
|
|
INC PTR1+1
|
|
INC PTR2+1
|
|
LDA PTR1+1
|
|
CMP #$28 ; check end of the board
|
|
BNE L208B
|
|
|
|
;
|
|
; ??? does something with top and bottom rows of the board
|
|
; ROW1 = ROW1 + ROW23
|
|
; ROW22 = ROW22 + ROW0
|
|
; why??
|
|
;
|
|
CLC
|
|
LDX #$27 ; count 40 characters (1 row)
|
|
L20B0 LDA ROW23,X
|
|
ADC ROW1,X
|
|
STA ROW1,X
|
|
LDA ROW0,X
|
|
ADC ROW22,X
|
|
STA ROW22,X
|
|
DEX
|
|
BPL L20B0
|
|
|
|
JSR SETPTRS
|
|
L20C8 LDY #$00
|
|
LDA (PTR1),Y
|
|
CMP #$02 ; ? two cells around
|
|
BNE L20D4
|
|
LDA (PTR2),Y
|
|
BNE L20DE
|
|
L20D4 CMP #$03 ; ? three cells around
|
|
BNE L20DC
|
|
LDA #ALIVECELL ; set next cell alive
|
|
BNE L20DE
|
|
L20DC LDA #DEADCELL ; set next cell dead
|
|
L20DE STA (PTR1),Y
|
|
INC PTR1
|
|
INC PTR2
|
|
BNE L20C8
|
|
INC PTR1+1
|
|
INC PTR2+1
|
|
LDA PTR2+1
|
|
CMP #$2C
|
|
BNE L20C8
|
|
JMP MAINLOOP
|
|
|
|
; set pointers to:
|
|
; PTR1 = $2440
|
|
; PTR2 = $2840
|
|
; $20F3
|
|
SETPTRS LDA #$24
|
|
STA PTR1+1
|
|
LDA #$28
|
|
STA PTR2+1
|
|
LDA #$40
|
|
STA PTR1
|
|
STA PTR2
|
|
RTS
|
|
|
|
; $2102
|
|
; reads a key and displays it on the terminal
|
|
; returns key in A
|
|
; increments a time counter $FA-$FB
|
|
;
|
|
RDKEY INC RND
|
|
BNE L2108
|
|
INC RND+1
|
|
L2108 LDA KEY_CTRL
|
|
BPL RDKEY
|
|
LDA KEY_DATA
|
|
JSR ECHO
|
|
RTS
|
|
|
|
; ???
|
|
|
|
L2114 JSR L211D
|
|
INY
|
|
CPY #$2A
|
|
BNE L2114
|
|
RTS
|
|
|
|
L211D ; increment cell at (PTR1),Y
|
|
CLC
|
|
LDA (PTR1),Y
|
|
ADC #$01
|
|
STA (PTR1),Y
|
|
|
|
STY CELLCOUNT ; save Y into CELLCOUNT
|
|
|
|
; PTR3 = PTR1 - Y
|
|
SEC
|
|
LDA PTR1
|
|
SBC CELLCOUNT
|
|
STA PTR3
|
|
LDA PTR1+1
|
|
SBC #$00
|
|
STA PTR3+1
|
|
|
|
; increment cell at (PTR3),Y e.g. (PTR1),-Y
|
|
LDY #$00
|
|
LDA (PTR3),Y
|
|
CLC
|
|
ADC #$01
|
|
STA (PTR3),Y
|
|
LDY CELLCOUNT ; restores Y
|
|
RTS
|
|
;
|
|
;$213F
|
|
; (possibly) advances the random number generator
|
|
; and loads a random number into A
|
|
; uses PTR3 as temporary variable?
|
|
GETRAND LDA RND+1
|
|
STA PTR3
|
|
LDA RND
|
|
ASL A
|
|
ROL PTR3
|
|
ASL A
|
|
ROL PTR3
|
|
CLC
|
|
ADC RND
|
|
PHA
|
|
LDA PTR3
|
|
ADC RND+1
|
|
STA RND+1
|
|
PLA
|
|
ADC #$11
|
|
STA RND
|
|
LDA RND+1
|
|
ADC #$36
|
|
STA RND+1
|
|
RTS
|
|
|
|
;$2161
|
|
;fills the primary board ($2440-$27FF) all with $00
|
|
ZEROBOARD JSR SETPTRS
|
|
LDA #$00
|
|
TAY
|
|
L2167 STA (PTR1),Y
|
|
INC PTR1
|
|
BNE L2167
|
|
INC PTR1+1
|
|
LDX PTR1+1
|
|
CPX #$28 ; check end of the board
|
|
BNE L2167
|
|
JSR SETPTRS ; reset correct pointers on exit
|
|
RTS
|
|
|
|
L2179:
|
|
DB A0 ; unused byte
|
|
|
|
; $2180
|
|
MESSAGE:
|
|
DB $A0,$A0,$A0,$A0,$A0,$A0,$8D,$8D
|
|
DB $8D,$8D,$C3,$CF,$CE,$D7,$C1,$D9
|
|
DB $A7,$D3,$A0,$C7,$C1,$CD,$C5,$A0
|
|
DB $CF,$C6,$A0,$CC,$C9,$C6,$C5,$8D
|
|
DB $8D,$D0,$CC,$C5,$C1,$D3,$C5,$A0
|
|
DB $D4,$D9,$D0,$C5,$A0,$D9,$CF,$D5
|
|
DB $D2,$A0,$C6,$D5,$CC,$CC,$A0,$CE
|
|
DB $C1,$CD,$C5,$AE,$8D,$8D,$00
|
|
|
|
// $21B9
|
|
|