�> SWGRAPH
� mcode &200
xcoord=&70 :�: &70-&73
(ycoord=&74 :�: &74-&77
2#fire=&78 :�: fire button status
<7savereg=&FC :�: interrupt accumulator save register
F'start=&350 :�: screen start address
P&screen=&355 :�: screen mode OS 1.2
Zsheila=&FE00
d-drb=&FE40 :�: system 6522 data register B
n5ifr=&FE4D :�: system 6522 interrupt flag register
x7ier=&FE4E :�: system 6522 interrupt enable register
�� pass=4 � 6 � 2
�O%=mcode
�P%=&8000
�
[OPT pass
�BRK
�BRK
�BRK
�&JMP service \ service entry to ROM
�6EQUB &82 \ ROM type byte indicates a service entry
�3EQUB copyright � 256 \ copyright offset pointer
�BRK
�,EQUS "Light pen Graphics" \ title string
�.copyright

BRK \ start of copyright

8EQUS "(C) Gordon Horsington 1987" \ copyright string

BRK \ copyright terminator

".out

,JMP pullout

6	.exit

@PLA

JSTA savereg

T2LDA #&05 \ unrecognised interrupt service call

^.return

hRTS

r.service

|1CMP #&05 \ is this an unrecognised interrupt?

�(BNE return \ branch if not interrupt

�:LDA savereg \ load interrupt accumulator save register

�"PHA \ and push it on the stack

�5LDA ifr \ load system VIA interrupt flag register

�"BPL exit \ exit if bit 7 clear

�� #&08 \ � with %00001000

�.BEQ exit \ exit if not light pen interrupt

�TXA

�PHA

�TYA

�PHA

�LDA drb \ clear interrupt

�PHA \ push data register B
CLD \ clear decimal flag
LDA #&00
LDX #&07
&
.initloop
0!STA xcoord,X \ &70-&77 = #&00
:DEX
DBPL initloop
N,LDY screen \ screen mode into Y register
X#CPY #&06 \ is this mode 6 or 7?
b'BCS out \ exit if non-graphics mode
lCPY #&03 \ is this mode 3?
v'BEQ out \ exit if non-graphics mode
�.LDA start \ screen start address, low byte
�STA ycoord
�1LDA start+1 \ screen start address, high byte
�STA ycoord+1
�LSR ycoord+1
�"ROR ycoord \ start address � 2
�LSR ycoord+1
�"ROR ycoord \ start address � 4
�LSR ycoord+1
�"ROR ycoord \ start address � 8
�%LDA offsetlow,Y \ trim the offset
�CLC \ prepare for addition
�#ADC ycoord \ add trim to offset
STA ycoord
LDA #&00
ADC ycoord+1
 STA ycoord+1
*<SEC \ prepare to subtract offset from light pen register
4+LDX #&11 \ light pen register, low byte
>&STX sheila \ 6845 address register
H%LDA sheila+1 \ 6845 data register
R*SBC ycoord \ subtract offset, low byte
\"STA ycoord \ low byte - offset
fDEX \ X = #&10
p&STX sheila \ 6845 address register
z%LDA sheila+1 \ 6845 data register
�-SBC ycoord+1 \ subtract offset, high byte
�%STA ycoord+1 \ high byte - offset
�	.next
�-ASL ycoord \ shift dividend/quotient left
�/ROL ycoord+1 \ shift dividend/quotient left
�1ROL xcoord \ shift bits into partial dividend
�&LDA xcoord \ load partial dividend
�!SEC \ prepare for subtraction
�"SBC width,Y \ subtract divisor
�+BCC done \ branch if dividend < divisor
�#INC ycoord \ increment quotient
�*STA xcoord \ save new partial dividend
�	.done
DEX \ decrement bit counter
!BNE next \ branch for 16 bits
,LDA xloop,Y \ prepare for multiplication
$&TAX \ X=4 modes 0-3, X=5 modes 4-7
.
.multx
8ASL xcoord \ low byte * 2
B ROL xcoord+1 \ high byte * 2
L)DEX \ count number of multiplications
V'BNE multx \ go back if not finished
`.LDA xadd,Y \ A=8 modes 0-3, A=16 modes 4-7
jCLC \ prepare for addition
tADC xcoord
~STA xcoord
�LDA #&00
�ADC xcoord+1
�STA xcoord+1
�6LDX #&05 \ prepare for y coordinate multiplication
�
.multy
�ASL ycoord \ low byte * 2
� ROL ycoord+1 \ high byte * 2
�)DEX \ count number of multiplications
�'BNE multy \ go back if not finished
�!SEC \ prepare for subtraction
�'LDA #&F0 \ low byte of decimal 1008
�SBC ycoord \ ycoord-#&F0
STA ycoord

(LDA #&03 \ high byte of decimal 1008
"SBC ycoord+1 \ (ycoord+1)-#&03
STA ycoord+1
(.pullout
2PLA \ pull data register B
<� #&20 \ %00100000
F'STA fire \ store fire button status
PPLA
ZTAY \ restore Y
dPLA
nTAX \ restore X
xPLA
�#STA savereg \ restore zero page
�!LDA #&00 \ interrupt serviced
�$RTS \ return to operating system
�.offsetlow
�%EQUB &04 \ mode0, untrimmed = &06
�%EQUB &04 \ mode1, untrimmed = &06
�%EQUB &04 \ mode2, untrimmed = &06
�!EQUB &00 \ mode3, dummy value
�%EQUB &03 \ mode4, untrimmed = &04
�%EQUB &03 \ mode5, untrimmed = &04
�
.xloop
�EQUD &00040404 \ modes 3-0
�EQUW &0505 \ modes 5-4
	.xadd
EQUD &00080808 \ modes 3-0
EQUW &1010 \ modes 5-4
"
.width
,EQUD &00505050 \ modes 3-0
6EQUW &2828 \ modes 5-4
@
.lastbyte
J]
T�
^*OPT1,2
hN�("SAVE LPGRAPH "+�~(mcode)+" + "+�~(lastbyte-&8000)+" FFFF8000 FFFF8000")
r*OPT0,0
�

00000000  0d 00 0a 0e f4 3e 20 53  57 47 52 41 50 48 0d 00  |.....> SWGRAPH..|
00000010  14 10 de 20 6d 63 6f 64  65 20 26 32 30 30 0d 00  |... mcode &200..|
00000020  1e 1a 78 63 6f 6f 72 64  3d 26 37 30 20 3a f4 3a  |..xcoord=&70 :.:|
00000030  20 26 37 30 2d 26 37 33  0d 00 28 1a 79 63 6f 6f  | &70-&73..(.ycoo|
00000040  72 64 3d 26 37 34 20 3a  f4 3a 20 26 37 34 2d 26  |rd=&74 :.: &74-&|
00000050  37 37 0d 00 32 23 66 69  72 65 3d 26 37 38 20 3a  |77..2#fire=&78 :|
00000060  f4 3a 20 66 69 72 65 20  62 75 74 74 6f 6e 20 73  |.: fire button s|
00000070  74 61 74 75 73 0d 00 3c  37 73 61 76 65 72 65 67  |tatus..<7savereg|
00000080  3d 26 46 43 20 3a f4 3a  20 69 6e 74 65 72 72 75  |=&FC :.: interru|
00000090  70 74 20 61 63 63 75 6d  75 6c 61 74 6f 72 20 73  |pt accumulator s|
000000a0  61 76 65 20 72 65 67 69  73 74 65 72 0d 00 46 27  |ave register..F'|
000000b0  73 74 61 72 74 3d 26 33  35 30 20 3a f4 3a 20 73  |start=&350 :.: s|
000000c0  63 72 65 65 6e 20 73 74  61 72 74 20 61 64 64 72  |creen start addr|
000000d0  65 73 73 0d 00 50 26 73  63 72 65 65 6e 3d 26 33  |ess..P&screen=&3|
000000e0  35 35 20 3a f4 3a 20 73  63 72 65 65 6e 20 6d 6f  |55 :.: screen mo|
000000f0  64 65 20 4f 53 20 31 2e  32 0d 00 5a 10 73 68 65  |de OS 1.2..Z.she|
00000100  69 6c 61 3d 26 46 45 30  30 0d 00 64 2d 64 72 62  |ila=&FE00..d-drb|
00000110  3d 26 46 45 34 30 20 3a  f4 3a 20 73 79 73 74 65  |=&FE40 :.: syste|
00000120  6d 20 36 35 32 32 20 64  61 74 61 20 72 65 67 69  |m 6522 data regi|
00000130  73 74 65 72 20 42 0d 00  6e 35 69 66 72 3d 26 46  |ster B..n5ifr=&F|
00000140  45 34 44 20 3a f4 3a 20  73 79 73 74 65 6d 20 36  |E4D :.: system 6|
00000150  35 32 32 20 69 6e 74 65  72 72 75 70 74 20 66 6c  |522 interrupt fl|
00000160  61 67 20 72 65 67 69 73  74 65 72 0d 00 78 37 69  |ag register..x7i|
00000170  65 72 3d 26 46 45 34 45  20 3a f4 3a 20 73 79 73  |er=&FE4E :.: sys|
00000180  74 65 6d 20 36 35 32 32  20 69 6e 74 65 72 72 75  |tem 6522 interru|
00000190  70 74 20 65 6e 61 62 6c  65 20 72 65 67 69 73 74  |pt enable regist|
000001a0  65 72 0d 00 82 14 e3 20  70 61 73 73 3d 34 20 b8  |er..... pass=4 .|
000001b0  20 36 20 88 20 32 0d 00  8c 0c 4f 25 3d 6d 63 6f  | 6 . 2....O%=mco|
000001c0  64 65 0d 00 96 0c 50 25  3d 26 38 30 30 30 0d 00  |de....P%=&8000..|
000001d0  a0 0d 5b 4f 50 54 20 70  61 73 73 0d 00 aa 07 42  |..[OPT pass....B|
000001e0  52 4b 0d 00 b4 07 42 52  4b 0d 00 be 07 42 52 4b  |RK....BRK....BRK|
000001f0  0d 00 c8 26 4a 4d 50 20  73 65 72 76 69 63 65 20  |...&JMP service |
00000200  5c 20 73 65 72 76 69 63  65 20 65 6e 74 72 79 20  |\ service entry |
00000210  74 6f 20 52 4f 4d 0d 00  d2 36 45 51 55 42 20 26  |to ROM...6EQUB &|
00000220  38 32 20 5c 20 52 4f 4d  20 74 79 70 65 20 62 79  |82 \ ROM type by|
00000230  74 65 20 69 6e 64 69 63  61 74 65 73 20 61 20 73  |te indicates a s|
00000240  65 72 76 69 63 65 20 65  6e 74 72 79 0d 00 dc 33  |ervice entry...3|
00000250  45 51 55 42 20 63 6f 70  79 72 69 67 68 74 20 83  |EQUB copyright .|
00000260  20 32 35 36 20 5c 20 63  6f 70 79 72 69 67 68 74  | 256 \ copyright|
00000270  20 6f 66 66 73 65 74 20  70 6f 69 6e 74 65 72 0d  | offset pointer.|
00000280  00 e6 07 42 52 4b 0d 00  f0 2c 45 51 55 53 20 22  |...BRK...,EQUS "|
00000290  4c 69 67 68 74 20 70 65  6e 20 47 72 61 70 68 69  |Light pen Graphi|
000002a0  63 73 22 20 5c 20 74 69  74 6c 65 20 73 74 72 69  |cs" \ title stri|
000002b0  6e 67 0d 00 fa 0e 2e 63  6f 70 79 72 69 67 68 74  |ng.....copyright|
000002c0  0d 01 04 1c 42 52 4b 20  5c 20 73 74 61 72 74 20  |....BRK \ start |
000002d0  6f 66 20 63 6f 70 79 72  69 67 68 74 0d 01 0e 38  |of copyright...8|
000002e0  45 51 55 53 20 22 28 43  29 20 47 6f 72 64 6f 6e  |EQUS "(C) Gordon|
000002f0  20 48 6f 72 73 69 6e 67  74 6f 6e 20 31 39 38 37  | Horsington 1987|
00000300  22 20 5c 20 63 6f 70 79  72 69 67 68 74 20 73 74  |" \ copyright st|
00000310  72 69 6e 67 0d 01 18 1e  42 52 4b 20 5c 20 63 6f  |ring....BRK \ co|
00000320  70 79 72 69 67 68 74 20  74 65 72 6d 69 6e 61 74  |pyright terminat|
00000330  6f 72 0d 01 22 08 2e 6f  75 74 0d 01 2c 0f 4a 4d  |or.."..out..,.JM|
00000340  50 20 70 75 6c 6c 6f 75  74 0d 01 36 09 2e 65 78  |P pullout..6..ex|
00000350  69 74 0d 01 40 07 50 4c  41 0d 01 4a 0f 53 54 41  |it..@.PLA..J.STA|
00000360  20 73 61 76 65 72 65 67  0d 01 54 32 4c 44 41 20  | savereg..T2LDA |
00000370  23 26 30 35 20 5c 20 75  6e 72 65 63 6f 67 6e 69  |#&05 \ unrecogni|
00000380  73 65 64 20 69 6e 74 65  72 72 75 70 74 20 73 65  |sed interrupt se|
00000390  72 76 69 63 65 20 63 61  6c 6c 0d 01 5e 0b 2e 72  |rvice call..^..r|
000003a0  65 74 75 72 6e 0d 01 68  07 52 54 53 0d 01 72 0c  |eturn..h.RTS..r.|
000003b0  2e 73 65 72 76 69 63 65  0d 01 7c 31 43 4d 50 20  |.service..|1CMP |
000003c0  23 26 30 35 20 5c 20 69  73 20 74 68 69 73 20 61  |#&05 \ is this a|
000003d0  6e 20 75 6e 72 65 63 6f  67 6e 69 73 65 64 20 69  |n unrecognised i|
000003e0  6e 74 65 72 72 75 70 74  3f 0d 01 86 28 42 4e 45  |nterrupt?...(BNE|
000003f0  20 72 65 74 75 72 6e 20  5c 20 62 72 61 6e 63 68  | return \ branch|
00000400  20 69 66 20 6e 6f 74 20  69 6e 74 65 72 72 75 70  | if not interrup|
00000410  74 0d 01 90 3a 4c 44 41  20 73 61 76 65 72 65 67  |t...:LDA savereg|
00000420  20 5c 20 6c 6f 61 64 20  69 6e 74 65 72 72 75 70  | \ load interrup|
00000430  74 20 61 63 63 75 6d 75  6c 61 74 6f 72 20 73 61  |t accumulator sa|
00000440  76 65 20 72 65 67 69 73  74 65 72 0d 01 9a 22 50  |ve register..."P|
00000450  48 41 20 5c 20 61 6e 64  20 70 75 73 68 20 69 74  |HA \ and push it|
00000460  20 6f 6e 20 74 68 65 20  73 74 61 63 6b 0d 01 a4  | on the stack...|
00000470  35 4c 44 41 20 69 66 72  20 5c 20 6c 6f 61 64 20  |5LDA ifr \ load |
00000480  73 79 73 74 65 6d 20 56  49 41 20 69 6e 74 65 72  |system VIA inter|
00000490  72 75 70 74 20 66 6c 61  67 20 72 65 67 69 73 74  |rupt flag regist|
000004a0  65 72 0d 01 ae 22 42 50  4c 20 65 78 69 74 20 5c  |er..."BPL exit \|
000004b0  20 65 78 69 74 20 69 66  20 62 69 74 20 37 20 63  | exit if bit 7 c|
000004c0  6c 65 61 72 0d 01 b8 1d  80 20 23 26 30 38 20 5c  |lear..... #&08 \|
000004d0  20 80 20 77 69 74 68 20  25 30 30 30 30 31 30 30  | . with %0000100|
000004e0  30 0d 01 c2 2e 42 45 51  20 65 78 69 74 20 5c 20  |0....BEQ exit \ |
000004f0  65 78 69 74 20 69 66 20  6e 6f 74 20 6c 69 67 68  |exit if not ligh|
00000500  74 20 70 65 6e 20 69 6e  74 65 72 72 75 70 74 0d  |t pen interrupt.|
00000510  01 cc 07 54 58 41 0d 01  d6 07 50 48 41 0d 01 e0  |...TXA....PHA...|
00000520  07 54 59 41 0d 01 ea 07  50 48 41 0d 01 f4 1d 4c  |.TYA....PHA....L|
00000530  44 41 20 64 72 62 20 5c  20 63 6c 65 61 72 20 69  |DA drb \ clear i|
00000540  6e 74 65 72 72 75 70 74  0d 01 fe 1e 50 48 41 20  |nterrupt....PHA |
00000550  5c 20 70 75 73 68 20 64  61 74 61 20 72 65 67 69  |\ push data regi|
00000560  73 74 65 72 20 42 0d 02  08 1c 43 4c 44 20 5c 20  |ster B....CLD \ |
00000570  63 6c 65 61 72 20 64 65  63 69 6d 61 6c 20 66 6c  |clear decimal fl|
00000580  61 67 0d 02 12 0c 4c 44  41 20 23 26 30 30 0d 02  |ag....LDA #&00..|
00000590  1c 0c 4c 44 58 20 23 26  30 37 0d 02 26 0d 2e 69  |..LDX #&07..&..i|
000005a0  6e 69 74 6c 6f 6f 70 0d  02 30 21 53 54 41 20 78  |nitloop..0!STA x|
000005b0  63 6f 6f 72 64 2c 58 20  5c 20 26 37 30 2d 26 37  |coord,X \ &70-&7|
000005c0  37 20 3d 20 23 26 30 30  0d 02 3a 07 44 45 58 0d  |7 = #&00..:.DEX.|
000005d0  02 44 10 42 50 4c 20 69  6e 69 74 6c 6f 6f 70 0d  |.D.BPL initloop.|
000005e0  02 4e 2c 4c 44 59 20 73  63 72 65 65 6e 20 5c 20  |.N,LDY screen \ |
000005f0  73 63 72 65 65 6e 20 6d  6f 64 65 20 69 6e 74 6f  |screen mode into|
00000600  20 59 20 72 65 67 69 73  74 65 72 0d 02 58 23 43  | Y register..X#C|
00000610  50 59 20 23 26 30 36 20  5c 20 69 73 20 74 68 69  |PY #&06 \ is thi|
00000620  73 20 6d 6f 64 65 20 36  20 6f 72 20 37 3f 0d 02  |s mode 6 or 7?..|
00000630  62 27 42 43 53 20 6f 75  74 20 5c 20 65 78 69 74  |b'BCS out \ exit|
00000640  20 69 66 20 6e 6f 6e 2d  67 72 61 70 68 69 63 73  | if non-graphics|
00000650  20 6d 6f 64 65 0d 02 6c  1e 43 50 59 20 23 26 30  | mode..l.CPY #&0|
00000660  33 20 5c 20 69 73 20 74  68 69 73 20 6d 6f 64 65  |3 \ is this mode|
00000670  20 33 3f 0d 02 76 27 42  45 51 20 6f 75 74 20 5c  | 3?..v'BEQ out \|
00000680  20 65 78 69 74 20 69 66  20 6e 6f 6e 2d 67 72 61  | exit if non-gra|
00000690  70 68 69 63 73 20 6d 6f  64 65 0d 02 80 2e 4c 44  |phics mode....LD|
000006a0  41 20 73 74 61 72 74 20  5c 20 73 63 72 65 65 6e  |A start \ screen|
000006b0  20 73 74 61 72 74 20 61  64 64 72 65 73 73 2c 20  | start address, |
000006c0  6c 6f 77 20 62 79 74 65  0d 02 8a 0e 53 54 41 20  |low byte....STA |
000006d0  79 63 6f 6f 72 64 0d 02  94 31 4c 44 41 20 73 74  |ycoord...1LDA st|
000006e0  61 72 74 2b 31 20 5c 20  73 63 72 65 65 6e 20 73  |art+1 \ screen s|
000006f0  74 61 72 74 20 61 64 64  72 65 73 73 2c 20 68 69  |tart address, hi|
00000700  67 68 20 62 79 74 65 0d  02 9e 10 53 54 41 20 79  |gh byte....STA y|
00000710  63 6f 6f 72 64 2b 31 0d  02 a8 10 4c 53 52 20 79  |coord+1....LSR y|
00000720  63 6f 6f 72 64 2b 31 0d  02 b2 22 52 4f 52 20 79  |coord+1..."ROR y|
00000730  63 6f 6f 72 64 20 5c 20  73 74 61 72 74 20 61 64  |coord \ start ad|
00000740  64 72 65 73 73 20 81 20  32 0d 02 bc 10 4c 53 52  |dress . 2....LSR|
00000750  20 79 63 6f 6f 72 64 2b  31 0d 02 c6 22 52 4f 52  | ycoord+1..."ROR|
00000760  20 79 63 6f 6f 72 64 20  5c 20 73 74 61 72 74 20  | ycoord \ start |
00000770  61 64 64 72 65 73 73 20  81 20 34 0d 02 d0 10 4c  |address . 4....L|
00000780  53 52 20 79 63 6f 6f 72  64 2b 31 0d 02 da 22 52  |SR ycoord+1..."R|
00000790  4f 52 20 79 63 6f 6f 72  64 20 5c 20 73 74 61 72  |OR ycoord \ star|
000007a0  74 20 61 64 64 72 65 73  73 20 81 20 38 0d 02 e4  |t address . 8...|
000007b0  25 4c 44 41 20 6f 66 66  73 65 74 6c 6f 77 2c 59  |%LDA offsetlow,Y|
000007c0  20 5c 20 74 72 69 6d 20  74 68 65 20 6f 66 66 73  | \ trim the offs|
000007d0  65 74 0d 02 ee 1e 43 4c  43 20 5c 20 70 72 65 70  |et....CLC \ prep|
000007e0  61 72 65 20 66 6f 72 20  61 64 64 69 74 69 6f 6e  |are for addition|
000007f0  0d 02 f8 23 41 44 43 20  79 63 6f 6f 72 64 20 5c  |...#ADC ycoord \|
00000800  20 61 64 64 20 74 72 69  6d 20 74 6f 20 6f 66 66  | add trim to off|
00000810  73 65 74 0d 03 02 0e 53  54 41 20 79 63 6f 6f 72  |set....STA ycoor|
00000820  64 0d 03 0c 0c 4c 44 41  20 23 26 30 30 0d 03 16  |d....LDA #&00...|
00000830  10 41 44 43 20 79 63 6f  6f 72 64 2b 31 0d 03 20  |.ADC ycoord+1.. |
00000840  10 53 54 41 20 79 63 6f  6f 72 64 2b 31 0d 03 2a  |.STA ycoord+1..*|
00000850  3c 53 45 43 20 5c 20 70  72 65 70 61 72 65 20 74  |<SEC \ prepare t|
00000860  6f 20 73 75 62 74 72 61  63 74 20 6f 66 66 73 65  |o subtract offse|
00000870  74 20 66 72 6f 6d 20 6c  69 67 68 74 20 70 65 6e  |t from light pen|
00000880  20 72 65 67 69 73 74 65  72 0d 03 34 2b 4c 44 58  | register..4+LDX|
00000890  20 23 26 31 31 20 5c 20  6c 69 67 68 74 20 70 65  | #&11 \ light pe|
000008a0  6e 20 72 65 67 69 73 74  65 72 2c 20 6c 6f 77 20  |n register, low |
000008b0  62 79 74 65 0d 03 3e 26  53 54 58 20 73 68 65 69  |byte..>&STX shei|
000008c0  6c 61 20 5c 20 36 38 34  35 20 61 64 64 72 65 73  |la \ 6845 addres|
000008d0  73 20 72 65 67 69 73 74  65 72 0d 03 48 25 4c 44  |s register..H%LD|
000008e0  41 20 73 68 65 69 6c 61  2b 31 20 5c 20 36 38 34  |A sheila+1 \ 684|
000008f0  35 20 64 61 74 61 20 72  65 67 69 73 74 65 72 0d  |5 data register.|
00000900  03 52 2a 53 42 43 20 79  63 6f 6f 72 64 20 5c 20  |.R*SBC ycoord \ |
00000910  73 75 62 74 72 61 63 74  20 6f 66 66 73 65 74 2c  |subtract offset,|
00000920  20 6c 6f 77 20 62 79 74  65 0d 03 5c 22 53 54 41  | low byte..\"STA|
00000930  20 79 63 6f 6f 72 64 20  5c 20 6c 6f 77 20 62 79  | ycoord \ low by|
00000940  74 65 20 2d 20 6f 66 66  73 65 74 0d 03 66 12 44  |te - offset..f.D|
00000950  45 58 20 5c 20 58 20 3d  20 23 26 31 30 0d 03 70  |EX \ X = #&10..p|
00000960  26 53 54 58 20 73 68 65  69 6c 61 20 5c 20 36 38  |&STX sheila \ 68|
00000970  34 35 20 61 64 64 72 65  73 73 20 72 65 67 69 73  |45 address regis|
00000980  74 65 72 0d 03 7a 25 4c  44 41 20 73 68 65 69 6c  |ter..z%LDA sheil|
00000990  61 2b 31 20 5c 20 36 38  34 35 20 64 61 74 61 20  |a+1 \ 6845 data |
000009a0  72 65 67 69 73 74 65 72  0d 03 84 2d 53 42 43 20  |register...-SBC |
000009b0  79 63 6f 6f 72 64 2b 31  20 5c 20 73 75 62 74 72  |ycoord+1 \ subtr|
000009c0  61 63 74 20 6f 66 66 73  65 74 2c 20 68 69 67 68  |act offset, high|
000009d0  20 62 79 74 65 0d 03 8e  25 53 54 41 20 79 63 6f  | byte...%STA yco|
000009e0  6f 72 64 2b 31 20 5c 20  68 69 67 68 20 62 79 74  |ord+1 \ high byt|
000009f0  65 20 2d 20 6f 66 66 73  65 74 0d 03 98 09 2e 6e  |e - offset.....n|
00000a00  65 78 74 0d 03 a2 2d 41  53 4c 20 79 63 6f 6f 72  |ext...-ASL ycoor|
00000a10  64 20 5c 20 73 68 69 66  74 20 64 69 76 69 64 65  |d \ shift divide|
00000a20  6e 64 2f 71 75 6f 74 69  65 6e 74 20 6c 65 66 74  |nd/quotient left|
00000a30  0d 03 ac 2f 52 4f 4c 20  79 63 6f 6f 72 64 2b 31  |.../ROL ycoord+1|
00000a40  20 5c 20 73 68 69 66 74  20 64 69 76 69 64 65 6e  | \ shift dividen|
00000a50  64 2f 71 75 6f 74 69 65  6e 74 20 6c 65 66 74 0d  |d/quotient left.|
00000a60  03 b6 31 52 4f 4c 20 78  63 6f 6f 72 64 20 5c 20  |..1ROL xcoord \ |
00000a70  73 68 69 66 74 20 62 69  74 73 20 69 6e 74 6f 20  |shift bits into |
00000a80  70 61 72 74 69 61 6c 20  64 69 76 69 64 65 6e 64  |partial dividend|
00000a90  0d 03 c0 26 4c 44 41 20  78 63 6f 6f 72 64 20 5c  |...&LDA xcoord \|
00000aa0  20 6c 6f 61 64 20 70 61  72 74 69 61 6c 20 64 69  | load partial di|
00000ab0  76 69 64 65 6e 64 0d 03  ca 21 53 45 43 20 5c 20  |vidend...!SEC \ |
00000ac0  70 72 65 70 61 72 65 20  66 6f 72 20 73 75 62 74  |prepare for subt|
00000ad0  72 61 63 74 69 6f 6e 0d  03 d4 22 53 42 43 20 77  |raction..."SBC w|
00000ae0  69 64 74 68 2c 59 20 5c  20 73 75 62 74 72 61 63  |idth,Y \ subtrac|
00000af0  74 20 64 69 76 69 73 6f  72 0d 03 de 2b 42 43 43  |t divisor...+BCC|
00000b00  20 64 6f 6e 65 20 5c 20  62 72 61 6e 63 68 20 69  | done \ branch i|
00000b10  66 20 64 69 76 69 64 65  6e 64 20 3c 20 64 69 76  |f dividend < div|
00000b20  69 73 6f 72 0d 03 e8 23  49 4e 43 20 79 63 6f 6f  |isor...#INC ycoo|
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00000b40  75 6f 74 69 65 6e 74 0d  03 f2 2a 53 54 41 20 78  |uotient...*STA x|
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00001200  2c 30 0d ff                                       |,0..|
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