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11-12-88/T\MOU03
This website contains an archive of files for the Acorn Electron, BBC Micro, Acorn Archimedes, Commodore 16 and Commodore 64 computers, which Dominic Ford has rescued from his private collection of floppy disks and cassettes.
Some of these files were originally commercial releases in the 1980s and 1990s, but they are now widely available online. I assume that copyright over them is no longer being asserted. If you own the copyright and would like files to be removed, please contact me.
| Tape/disk: | Home » CEEFAX disks » telesoftware11.adl |
| Filename: | 11-12-88/T\MOU03 |
| Read OK: | ✔ |
| File size: | 33DB bytes |
| Load address: | 0000 |
| Exec address: | 0000 |
File contents
Using a mouse with the BBC microcomputer - by - Gordon Horsington
-----------------------------------------------------------------
Module 3. Reading the mouse buttons
-----------------------------------
The status of the mouse buttons can be read from data register B (DRB,
&FE60) if the data direction register B (DDRB, &FE62) is first cleared to
zero to make DRB an input. The mouse buttons are not connected to a
handshake line and do not produce an IRQ interrupt. For this reason the
buttons are read by polling the DRB. It is quite undesirable to poll this
register continuously and far better to either poll it at set intervals or
poll it whenever the keyboard is scanned for a keypress. Both these ideas
will be demonstrated in this module.
If the DRB is polled at set intervals then the intervals should be chosen
to be most suitable for the particular application. If the mouse buttons
are to be used as an addition to the keyboard to provide, for example,
three extra function keys, then the DRB needs to be polled about four
times a second. This gives a quick response but does not repeat before the
user can take his finger off the button.
The program EVENT demonstrates how the interval timer can be used to
generate the timer crossing zero event at 0.25 second intervals. This
event is used to poll the DRB and insert an "R" into the keyboard buffer
if the right mouse button is pressed, a "C" if the centre button is
pressed and an "L" if the left button is pressed. I have used the interval
timer in this demonstration, rather than use one of the VIA timers to
produce an interrupt, because the polling routine uses an Osbyte call to
insert a character into the keyboard buffer. Operating system calls must
not be used by interrupt routines but they can be used by event handling
routines running in the I/O processor.
The interval timer uses a five byte number which is incremented every
centisecond. One centisecond after the timer reaches &FFFFFFFFFF it is
incremented and crosses zero. If the timer crossing zero event is enabled
this generates event number 5.
To find the number with which to seed the timer use BASIC to print the
negative hexadecimal value of the number of centiseconds in the required
interval. For example, if an interval of 0.25 seconds is required then
type:
PRINT ~ -25
and BASIC will give the four least significant bytes of the asnswer:
FFFFFFE7
you can then add the most significant byte which, in this application
will always be &FF, to give &FFFFFFFFE7. The interval used by the
demonstration program is 0.25 seconds and the five byte number is
specified in lines 890 and 900 of EVENT.
Event number 5 is enabled with Osbyte 14, X=5, and disabled with Osbyte
13, X=5, Y=0. Osword 4 is used to write to the timer when the routine is
initialised and again after processing event 5 when it is used to restart
the timer for the next interval.
Chain the program EVENT and press the mouse buttons. The program can be
modified to enter a string of characters into the keyboard buffer rather
than just one character and this will have the effect of producing extra
function keys.
10 REM> EVENT
20 DIM mcode &100 :REM: machine code at mcode
30 evntv=&220 :REM: event vector
40 drb=&FE60 :REM: data register B
50 ddrb=&FE62 :REM: data direction register B
60 osword=&FFF1
70 osbyte=&FFF4
80 FOR pass=0 TO 2 STEP 2
90 P%=mcode
100 [ OPT pass
110 LDX evntv
120 LDY evntv+1
130 CPY #timeout DIV 256
140 BEQ disable \ branch if event vector altered
150 STX oldevntv \ store original event vector
160 STY oldevntv+1
170 LDX #timeout MOD 256
180 LDY #timeout DIV 256
190 STX evntv \ install new event vector
200 STY evntv+1
210 LDA #0 \ user port input
220 STA ddrb \ data direction register B
230 LDA #&0E \ enable events
240 LDX #&05 \ interval timer crossing zero
250 JSR osbyte
260 .writetimer
270 LDA #&04 \ write interval timer
280 LDX #clock MOD 256
290 LDY #clock DIV 256
300 JMP osword \ Osword and return
310 .disable
320 LDA #&0D \ disable events
330 LDX #&05 \ interval timer crossing zero
340 LDY #&00
350 JSR osbyte
360 LDX oldevntv \ restore event vector
370 LDY oldevntv+1
380 STX evntv
390 STY evntv+1
400 RTS \ return to BASIC
410 .timeout
420 PHP \ push status register
430 CMP #&05 \ is this interval timer crossing zero?
440 BEQ interval \ branch if it is
450 PLP \ restore status register
460 JMP (oldevntv) \ exit via original vector
470 .interval
480 PHA \ store A
490 TXA
500 PHA \ store X
510 TYA
520 PHA \ store Y
530 LDA drb \ data register B
540 ROL A \ bit 7 into carry
550 BCC right \ branch if right button pressed
560 ROL A \ bit 6 into carry
570 BCC centre \ branch if centre button pressed
580 ROL A \ bit 5 into carry
590 BCS pullout \ exit if left button not pressed
600 LDY leftkey \ left button pressed
610 BNE intobuffer
620 .centre
630 LDY centrekey
640 BNE intobuffer
650 .right
660 LDY rightkey
670 .intobuffer
680 LDA #&8A \ insert value into buffer
690 LDX #&00 \ keyboard buffer
700 JSR osbyte
710 .pullout
720 JSR writetimer \ reset timer
730 PLA
740 TAY \ restore Y
750 PLA
760 TAX \ restore X
770 PLA
780 PLP
790 RTS
800 .leftkey
810 EQUB ASC("L")
820 .centrekey
830 EQUB ASC("C")
840 .rightkey
850 EQUB ASC("R")
860 .oldevntv
870 EQUW &00
880 .clock
890 EQUD &FFFFFFE7
900 EQUB &FF
910 ]
920 NEXT
930 CALL mcode
The program BUTTONS demonstrates a second method of polling the DRB to see
if any of the mouse buttons are pressed. In this program the INKEY
function is intercepted so that the mouse buttons can be tested as if they
are keys on the keyboard.
The BASIC function INKEY with a negative number in the brackets, eg.
INKEY(-74), can be used to test whether a particular key is pressed when
the function is called. The INKEY function is executed via the Osbyte
indirection vector using Osbyte &81 with X = the (negative) INKEY value
and Y = &FF. The function can be intercepted by redirecting the Osbyte
vector to a new INKEY routine. The program BUTTONS duplicates the negative
INKEY function for the Z, X and Return keys so that these key can be
scanned both on the keyboard and on the mouse.
The revectored Osbyte indirection vector used in BUTTONS points to the
code labeled newinkey which checks to see if a negative INKEY function is
being executed. If it is not a negative INKEY then the new routine exits
via the original Osbyte vector. If a negative INKEY is being executed then
the new routine first of all executes the original code to see if the
required keyboard button is pressed. If it is then the new routine returns
control to the operating system. If the key being scanned is not pressed
on the keyboard then the new routine checks to see if the key is one which
has been allocated to one of the mouse buttons. If it is then the DRB is
polled to see if the appropriate mouse button is pressed.
If the required mouse button is pressed then a return from Osbyte &81 is
made with both the X=&FF and Y=&FF. This has the effect of simulating a
TRUE return from the negative INKEY function. If the required mouse button
is not pressed then the return from Osbyte &81 has the X and Y registers
storing the same numbers with which they returned from the original INKEY
routine and this has the effect of a FALSE return from the function.
Chain the program BUTTONS and press either the Z, X or Return keys on the
keyboard or the mouse buttons. The technique demonstrated in the program
is probably the most useful one to use if you want to use the mouse
buttons for arcade type games. This type of game often uses the negative
INKEY or its machine code equivalent to scan the keyboard and by using the
ideas demonstrated in the program the game player will be able to use
either the keyboard or the mouse buttons or even both at the same time.
You have already been shown how to detect and record the movement of a
mouse. In module 4 I will demonstrate how the stored X and Y coordinates
can be used with a modified version of the negative INKEY technique so
that mouse movement can become a substitute for pressing the cursor keys.
10 REM> BUTTONS
20 DIM mcode &100 :REM: machine code at mcode
30 bytev=&20A :REM: Osbyte indirection vector
40 drb=&FE60 :REM: data register B
50 ddrb=&FE62 :REM: data direction register B
60 FOR pass=0 TO 2 STEP 2
70 P%=mcode
80 [ OPT pass
90 LDX bytev
100 LDY bytev+1
110 CPY #newinkey DIV 256
120 BEQ disable \ branch if Osbyte vector altered
130 STX oldbytev \ store original Osbyte vector
140 STY oldbytev+1
150 LDX #newinkey MOD 256
160 LDY #newinkey DIV 256
170 STX bytev \ install new Osbyte vector
180 STY bytev+1
190 LDA #0 \ user port input
200 STA ddrb \ data direction register B
210 RTS \ return to BASIC
220 .disable
230 LDX oldbytev \ restore Osbyte indirection vector
240 LDY oldbytev+1
250 STX bytev
260 STY bytev+1
270 RTS \ return to BASIC
280 .newinkey
290 PHP \ push status register
300 CMP #&81 \ is this Osbyte &81?
310 BNE notinkey \ branch if not Osbyte &81
320 CPY #&FF \ is this a -ve INKEY?
330 BEQ inkey \ branch if -ve INKEY
340 .notinkey
350 PLP \ pull status register
360 .oldcode
370 JMP (oldbytev) \ exit via original vector
380 .inkey
390 TXA \ -ve INKEY value in X register
400 PHA \ push X onto stack
410 LDA #&81
420 JSR oldcode \ execute original code
430 CPX #&FF \ key pressed if X and Y =&FF
440 BNE notpressed \ branch if key not pressed
450 CPY #&FF \ key pressed if X and Y =&FF
460 BNE notpressed \ branch if key not pressed
470 PLA \ pull X off stack
480 .pullout
490 LDA #&81 \ restore A
500 PLP \ restore status register
510 RTS \ return to operating system
520 .notpressed
530 PLA \ pull -ve INKEY number off stack
540 CMP centre \ compare with number allocated to centre
\ mouse button
550 BNE tryright \ branch if not centre button
560 LDA drb \ data register B
570 JMP two \ check bit 6
580 .tryright
590 CMP right \ compare with number allocated to right
\ mouse button
600 BNE tryleft \ branch if not right button
610 LDA drb \ data register B
620 JMP one \ check bit 7
630 .tryleft
640 CMP left \ compare with number allocated to left
\ mouse button
650 BNE pullout \ exit if not left button
660 LDA drb \ data register B
670 ROL A \ bit 7 into carry
680 .two
690 ROL A \ bit 6/7 into carry
700 .one
710 ROL A \ bit 5/6/7 into carry
720 BCS pullout \ exit if bit 5/6/7 set
730 .found
740 LDA #&81 \ Osbyte &81
750 LDX #&FF \ X and Y = &FF when key pressed
760 LDY #&FF
770 PLP \ pull status register
780 RTS \ return to operating system
790 .oldbytev
800 EQUW &00 \ original Osbyte indirection vector
810 .right
820 EQUB -67 \ -ve INKEY for X
830 .centre
840 EQUB -74 \ -ve INKEY for <return>
850 .left
860 EQUB -98 \ -ve INKEY for Z
870 .lastbyte
880 ]
890 NEXT
900 CALL mcode :REM: enable new code
910 MODE7
920 mouse$=CHR$141+CHR$132+CHR$157+CHR$131
+"Press keyboard or mouse buttons "+CHR$156
930 PRINTTAB(0,2)mouse$
940 PRINTTAB(0,3)mouse$
950 ONERROR GOTO 1030
960 VDU23,1,0;0;0;0;
970 REPEAT
980 IF INKEY(-67) PRINTTAB(26,12)"X" ELSE PRINTTAB(26,12)" "
990 IF INKEY(-74) PRINTTAB(16,12)"Return" ELSE PRINTTAB(16,12)" "
1000 IF INKEY(-98) PRINTTAB(11,12)"Z" ELSE PRINTTAB(11,12)" "
1010 IF INKEY(-99) PRINTTAB(16,17)"Space" ELSE PRINTTAB(16,17)" "
1020 UNTIL FALSE
1030 CALL mcode :REM: disable new code
1040 VDU23,1,1;0;0;0;31,0,23
1050 END
00000000 55 73 69 6e 67 20 61 20 6d 6f 75 73 65 20 77 69 |Using a mouse wi|
00000010 74 68 20 74 68 65 20 42 42 43 20 6d 69 63 72 6f |th the BBC micro|
00000020 63 6f 6d 70 75 74 65 72 20 2d 20 62 79 20 2d 20 |computer - by - |
00000030 47 6f 72 64 6f 6e 20 48 6f 72 73 69 6e 67 74 6f |Gordon Horsingto|
00000040 6e 0d 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d |n.--------------|
00000050 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d |----------------|
*
00000080 2d 2d 2d 0d 0d 4d 6f 64 75 6c 65 20 33 2e 20 52 |---..Module 3. R|
00000090 65 61 64 69 6e 67 20 74 68 65 20 6d 6f 75 73 65 |eading the mouse|
000000a0 20 62 75 74 74 6f 6e 73 0d 2d 2d 2d 2d 2d 2d 2d | buttons.-------|
000000b0 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d |----------------|
000000c0 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d 0d 0d 54 68 |------------..Th|
000000d0 65 20 73 74 61 74 75 73 20 6f 66 20 74 68 65 20 |e status of the |
000000e0 6d 6f 75 73 65 20 62 75 74 74 6f 6e 73 20 63 61 |mouse buttons ca|
000000f0 6e 20 62 65 20 72 65 61 64 20 66 72 6f 6d 20 64 |n be read from d|
00000100 61 74 61 20 72 65 67 69 73 74 65 72 20 42 20 28 |ata register B (|
00000110 44 52 42 2c 0d 26 46 45 36 30 29 20 69 66 20 74 |DRB,.&FE60) if t|
00000120 68 65 20 64 61 74 61 20 64 69 72 65 63 74 69 6f |he data directio|
00000130 6e 20 72 65 67 69 73 74 65 72 20 42 20 28 44 44 |n register B (DD|
00000140 52 42 2c 20 26 46 45 36 32 29 20 69 73 20 66 69 |RB, &FE62) is fi|
00000150 72 73 74 20 63 6c 65 61 72 65 64 20 74 6f 0d 7a |rst cleared to.z|
00000160 65 72 6f 20 74 6f 20 6d 61 6b 65 20 44 52 42 20 |ero to make DRB |
00000170 61 6e 20 69 6e 70 75 74 2e 20 54 68 65 20 6d 6f |an input. The mo|
00000180 75 73 65 20 62 75 74 74 6f 6e 73 20 61 72 65 20 |use buttons are |
00000190 6e 6f 74 20 63 6f 6e 6e 65 63 74 65 64 20 74 6f |not connected to|
000001a0 20 61 0d 68 61 6e 64 73 68 61 6b 65 20 6c 69 6e | a.handshake lin|
000001b0 65 20 61 6e 64 20 64 6f 20 6e 6f 74 20 70 72 6f |e and do not pro|
000001c0 64 75 63 65 20 61 6e 20 49 52 51 20 69 6e 74 65 |duce an IRQ inte|
000001d0 72 72 75 70 74 2e 20 46 6f 72 20 74 68 69 73 20 |rrupt. For this |
000001e0 72 65 61 73 6f 6e 20 74 68 65 0d 62 75 74 74 6f |reason the.butto|
000001f0 6e 73 20 61 72 65 20 72 65 61 64 20 62 79 20 70 |ns are read by p|
00000200 6f 6c 6c 69 6e 67 20 74 68 65 20 44 52 42 2e 20 |olling the DRB. |
00000210 49 74 20 69 73 20 71 75 69 74 65 20 75 6e 64 65 |It is quite unde|
00000220 73 69 72 61 62 6c 65 20 74 6f 20 70 6f 6c 6c 20 |sirable to poll |
00000230 74 68 69 73 0d 72 65 67 69 73 74 65 72 20 63 6f |this.register co|
00000240 6e 74 69 6e 75 6f 75 73 6c 79 20 61 6e 64 20 66 |ntinuously and f|
00000250 61 72 20 62 65 74 74 65 72 20 74 6f 20 65 69 74 |ar better to eit|
00000260 68 65 72 20 70 6f 6c 6c 20 69 74 20 61 74 20 73 |her poll it at s|
00000270 65 74 20 69 6e 74 65 72 76 61 6c 73 20 6f 72 0d |et intervals or.|
00000280 70 6f 6c 6c 20 69 74 20 77 68 65 6e 65 76 65 72 |poll it whenever|
00000290 20 74 68 65 20 6b 65 79 62 6f 61 72 64 20 69 73 | the keyboard is|
000002a0 20 73 63 61 6e 6e 65 64 20 66 6f 72 20 61 20 6b | scanned for a k|
000002b0 65 79 70 72 65 73 73 2e 20 42 6f 74 68 20 74 68 |eypress. Both th|
000002c0 65 73 65 20 69 64 65 61 73 0d 77 69 6c 6c 20 62 |ese ideas.will b|
000002d0 65 20 64 65 6d 6f 6e 73 74 72 61 74 65 64 20 69 |e demonstrated i|
000002e0 6e 20 74 68 69 73 20 6d 6f 64 75 6c 65 2e 0d 0d |n this module...|
000002f0 49 66 20 74 68 65 20 44 52 42 20 69 73 20 70 6f |If the DRB is po|
00000300 6c 6c 65 64 20 61 74 20 73 65 74 20 69 6e 74 65 |lled at set inte|
00000310 72 76 61 6c 73 20 74 68 65 6e 20 74 68 65 20 69 |rvals then the i|
00000320 6e 74 65 72 76 61 6c 73 20 73 68 6f 75 6c 64 20 |ntervals should |
00000330 62 65 20 63 68 6f 73 65 6e 0d 74 6f 20 62 65 20 |be chosen.to be |
00000340 6d 6f 73 74 20 73 75 69 74 61 62 6c 65 20 66 6f |most suitable fo|
00000350 72 20 74 68 65 20 70 61 72 74 69 63 75 6c 61 72 |r the particular|
00000360 20 61 70 70 6c 69 63 61 74 69 6f 6e 2e 20 49 66 | application. If|
00000370 20 74 68 65 20 6d 6f 75 73 65 20 62 75 74 74 6f | the mouse butto|
00000380 6e 73 0d 61 72 65 20 74 6f 20 62 65 20 75 73 65 |ns.are to be use|
00000390 64 20 61 73 20 61 6e 20 61 64 64 69 74 69 6f 6e |d as an addition|
000003a0 20 74 6f 20 74 68 65 20 6b 65 79 62 6f 61 72 64 | to the keyboard|
000003b0 20 74 6f 20 70 72 6f 76 69 64 65 2c 20 66 6f 72 | to provide, for|
000003c0 20 65 78 61 6d 70 6c 65 2c 0d 74 68 72 65 65 20 | example,.three |
000003d0 65 78 74 72 61 20 66 75 6e 63 74 69 6f 6e 20 6b |extra function k|
000003e0 65 79 73 2c 20 74 68 65 6e 20 74 68 65 20 44 52 |eys, then the DR|
000003f0 42 20 6e 65 65 64 73 20 74 6f 20 62 65 20 70 6f |B needs to be po|
00000400 6c 6c 65 64 20 61 62 6f 75 74 20 66 6f 75 72 0d |lled about four.|
00000410 74 69 6d 65 73 20 61 20 73 65 63 6f 6e 64 2e 20 |times a second. |
00000420 54 68 69 73 20 67 69 76 65 73 20 61 20 71 75 69 |This gives a qui|
00000430 63 6b 20 72 65 73 70 6f 6e 73 65 20 62 75 74 20 |ck response but |
00000440 64 6f 65 73 20 6e 6f 74 20 72 65 70 65 61 74 20 |does not repeat |
00000450 62 65 66 6f 72 65 20 74 68 65 0d 75 73 65 72 20 |before the.user |
00000460 63 61 6e 20 74 61 6b 65 20 68 69 73 20 66 69 6e |can take his fin|
00000470 67 65 72 20 6f 66 66 20 74 68 65 20 62 75 74 74 |ger off the butt|
00000480 6f 6e 2e 0d 0d 54 68 65 20 70 72 6f 67 72 61 6d |on...The program|
00000490 20 45 56 45 4e 54 20 64 65 6d 6f 6e 73 74 72 61 | EVENT demonstra|
000004a0 74 65 73 20 68 6f 77 20 74 68 65 20 69 6e 74 65 |tes how the inte|
000004b0 72 76 61 6c 20 74 69 6d 65 72 20 63 61 6e 20 62 |rval timer can b|
000004c0 65 20 75 73 65 64 20 74 6f 0d 67 65 6e 65 72 61 |e used to.genera|
000004d0 74 65 20 74 68 65 20 74 69 6d 65 72 20 63 72 6f |te the timer cro|
000004e0 73 73 69 6e 67 20 7a 65 72 6f 20 65 76 65 6e 74 |ssing zero event|
000004f0 20 61 74 20 30 2e 32 35 20 73 65 63 6f 6e 64 20 | at 0.25 second |
00000500 69 6e 74 65 72 76 61 6c 73 2e 20 54 68 69 73 0d |intervals. This.|
00000510 65 76 65 6e 74 20 69 73 20 75 73 65 64 20 74 6f |event is used to|
00000520 20 70 6f 6c 6c 20 74 68 65 20 44 52 42 20 61 6e | poll the DRB an|
00000530 64 20 69 6e 73 65 72 74 20 61 6e 20 22 52 22 20 |d insert an "R" |
00000540 69 6e 74 6f 20 74 68 65 20 6b 65 79 62 6f 61 72 |into the keyboar|
00000550 64 20 62 75 66 66 65 72 0d 69 66 20 74 68 65 20 |d buffer.if the |
00000560 72 69 67 68 74 20 6d 6f 75 73 65 20 62 75 74 74 |right mouse butt|
00000570 6f 6e 20 69 73 20 70 72 65 73 73 65 64 2c 20 61 |on is pressed, a|
00000580 20 22 43 22 20 69 66 20 74 68 65 20 63 65 6e 74 | "C" if the cent|
00000590 72 65 20 62 75 74 74 6f 6e 20 69 73 0d 70 72 65 |re button is.pre|
000005a0 73 73 65 64 20 61 6e 64 20 61 6e 20 22 4c 22 20 |ssed and an "L" |
000005b0 69 66 20 74 68 65 20 6c 65 66 74 20 62 75 74 74 |if the left butt|
000005c0 6f 6e 20 69 73 20 70 72 65 73 73 65 64 2e 20 49 |on is pressed. I|
000005d0 20 68 61 76 65 20 75 73 65 64 20 74 68 65 20 69 | have used the i|
000005e0 6e 74 65 72 76 61 6c 0d 74 69 6d 65 72 20 69 6e |nterval.timer in|
000005f0 20 74 68 69 73 20 64 65 6d 6f 6e 73 74 72 61 74 | this demonstrat|
00000600 69 6f 6e 2c 20 72 61 74 68 65 72 20 74 68 61 6e |ion, rather than|
00000610 20 75 73 65 20 6f 6e 65 20 6f 66 20 74 68 65 20 | use one of the |
00000620 56 49 41 20 74 69 6d 65 72 73 20 74 6f 0d 70 72 |VIA timers to.pr|
00000630 6f 64 75 63 65 20 61 6e 20 69 6e 74 65 72 72 75 |oduce an interru|
00000640 70 74 2c 20 62 65 63 61 75 73 65 20 74 68 65 20 |pt, because the |
00000650 70 6f 6c 6c 69 6e 67 20 72 6f 75 74 69 6e 65 20 |polling routine |
00000660 75 73 65 73 20 61 6e 20 4f 73 62 79 74 65 20 63 |uses an Osbyte c|
00000670 61 6c 6c 20 74 6f 0d 69 6e 73 65 72 74 20 61 20 |all to.insert a |
00000680 63 68 61 72 61 63 74 65 72 20 69 6e 74 6f 20 74 |character into t|
00000690 68 65 20 6b 65 79 62 6f 61 72 64 20 62 75 66 66 |he keyboard buff|
000006a0 65 72 2e 20 4f 70 65 72 61 74 69 6e 67 20 73 79 |er. Operating sy|
000006b0 73 74 65 6d 20 63 61 6c 6c 73 20 6d 75 73 74 0d |stem calls must.|
000006c0 6e 6f 74 20 62 65 20 75 73 65 64 20 62 79 20 69 |not be used by i|
000006d0 6e 74 65 72 72 75 70 74 20 72 6f 75 74 69 6e 65 |nterrupt routine|
000006e0 73 20 62 75 74 20 74 68 65 79 20 63 61 6e 20 62 |s but they can b|
000006f0 65 20 75 73 65 64 20 62 79 20 65 76 65 6e 74 20 |e used by event |
00000700 68 61 6e 64 6c 69 6e 67 0d 72 6f 75 74 69 6e 65 |handling.routine|
00000710 73 20 72 75 6e 6e 69 6e 67 20 69 6e 20 74 68 65 |s running in the|
00000720 20 49 2f 4f 20 70 72 6f 63 65 73 73 6f 72 2e 0d | I/O processor..|
00000730 0d 54 68 65 20 69 6e 74 65 72 76 61 6c 20 74 69 |.The interval ti|
00000740 6d 65 72 20 75 73 65 73 20 61 20 66 69 76 65 20 |mer uses a five |
00000750 62 79 74 65 20 6e 75 6d 62 65 72 20 77 68 69 63 |byte number whic|
00000760 68 20 69 73 20 69 6e 63 72 65 6d 65 6e 74 65 64 |h is incremented|
00000770 20 65 76 65 72 79 0d 63 65 6e 74 69 73 65 63 6f | every.centiseco|
00000780 6e 64 2e 20 4f 6e 65 20 63 65 6e 74 69 73 65 63 |nd. One centisec|
00000790 6f 6e 64 20 61 66 74 65 72 20 74 68 65 20 74 69 |ond after the ti|
000007a0 6d 65 72 20 72 65 61 63 68 65 73 20 26 46 46 46 |mer reaches &FFF|
000007b0 46 46 46 46 46 46 46 20 69 74 20 69 73 0d 69 6e |FFFFFFF it is.in|
000007c0 63 72 65 6d 65 6e 74 65 64 20 61 6e 64 20 63 72 |cremented and cr|
000007d0 6f 73 73 65 73 20 7a 65 72 6f 2e 20 49 66 20 74 |osses zero. If t|
000007e0 68 65 20 74 69 6d 65 72 20 63 72 6f 73 73 69 6e |he timer crossin|
000007f0 67 20 7a 65 72 6f 20 65 76 65 6e 74 20 69 73 20 |g zero event is |
00000800 65 6e 61 62 6c 65 64 0d 74 68 69 73 20 67 65 6e |enabled.this gen|
00000810 65 72 61 74 65 73 20 65 76 65 6e 74 20 6e 75 6d |erates event num|
00000820 62 65 72 20 35 2e 0d 0d 54 6f 20 66 69 6e 64 20 |ber 5...To find |
00000830 74 68 65 20 6e 75 6d 62 65 72 20 77 69 74 68 20 |the number with |
00000840 77 68 69 63 68 20 74 6f 20 73 65 65 64 20 74 68 |which to seed th|
00000850 65 20 74 69 6d 65 72 20 75 73 65 20 42 41 53 49 |e timer use BASI|
00000860 43 20 74 6f 20 70 72 69 6e 74 20 74 68 65 0d 6e |C to print the.n|
00000870 65 67 61 74 69 76 65 20 68 65 78 61 64 65 63 69 |egative hexadeci|
00000880 6d 61 6c 20 76 61 6c 75 65 20 6f 66 20 74 68 65 |mal value of the|
00000890 20 6e 75 6d 62 65 72 20 6f 66 20 63 65 6e 74 69 | number of centi|
000008a0 73 65 63 6f 6e 64 73 20 69 6e 20 74 68 65 20 72 |seconds in the r|
000008b0 65 71 75 69 72 65 64 0d 69 6e 74 65 72 76 61 6c |equired.interval|
000008c0 2e 20 46 6f 72 20 65 78 61 6d 70 6c 65 2c 20 69 |. For example, i|
000008d0 66 20 61 6e 20 69 6e 74 65 72 76 61 6c 20 6f 66 |f an interval of|
000008e0 20 30 2e 32 35 20 73 65 63 6f 6e 64 73 20 69 73 | 0.25 seconds is|
000008f0 20 72 65 71 75 69 72 65 64 20 74 68 65 6e 0d 74 | required then.t|
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00002ac0 20 20 50 4c 50 20 20 20 20 20 20 20 20 20 20 20 | PLP |
00002ad0 5c 20 72 65 73 74 6f 72 65 20 73 74 61 74 75 73 |\ restore status|
00002ae0 20 72 65 67 69 73 74 65 72 0d 20 20 35 31 30 20 | register. 510 |
00002af0 20 20 20 20 20 20 20 20 52 54 53 20 20 20 20 20 | RTS |
00002b00 20 20 20 20 20 20 5c 20 72 65 74 75 72 6e 20 74 | \ return t|
00002b10 6f 20 6f 70 65 72 61 74 69 6e 67 20 73 79 73 74 |o operating syst|
00002b20 65 6d 0d 20 20 35 32 30 20 2e 6e 6f 74 70 72 65 |em. 520 .notpre|
00002b30 73 73 65 64 0d 20 20 35 33 30 20 20 20 20 20 20 |ssed. 530 |
00002b40 20 20 20 50 4c 41 20 20 20 20 20 20 20 20 20 20 | PLA |
00002b50 20 5c 20 70 75 6c 6c 20 2d 76 65 20 49 4e 4b 45 | \ pull -ve INKE|
00002b60 59 20 6e 75 6d 62 65 72 20 6f 66 66 20 73 74 61 |Y number off sta|
00002b70 63 6b 0d 20 20 35 34 30 20 20 20 20 20 20 20 20 |ck. 540 |
00002b80 20 43 4d 50 20 63 65 6e 74 72 65 20 20 20 20 5c | CMP centre \|
00002b90 20 63 6f 6d 70 61 72 65 20 77 69 74 68 20 6e 75 | compare with nu|
00002ba0 6d 62 65 72 20 61 6c 6c 6f 63 61 74 65 64 20 74 |mber allocated t|
00002bb0 6f 20 63 65 6e 74 72 65 0d 20 20 20 20 20 20 20 |o centre. |
00002bc0 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 | |
00002bd0 20 20 20 20 20 5c 20 6d 6f 75 73 65 20 62 75 74 | \ mouse but|
00002be0 74 6f 6e 0d 20 20 35 35 30 20 20 20 20 20 20 20 |ton. 550 |
00002bf0 20 20 42 4e 45 20 74 72 79 72 69 67 68 74 20 20 | BNE tryright |
00002c00 5c 20 62 72 61 6e 63 68 20 69 66 20 6e 6f 74 20 |\ branch if not |
00002c10 63 65 6e 74 72 65 20 62 75 74 74 6f 6e 0d 20 20 |centre button. |
00002c20 35 36 30 20 20 20 20 20 20 20 20 20 4c 44 41 20 |560 LDA |
00002c30 64 72 62 20 20 20 20 20 20 20 5c 20 64 61 74 61 |drb \ data|
00002c40 20 72 65 67 69 73 74 65 72 20 42 0d 20 20 35 37 | register B. 57|
00002c50 30 20 20 20 20 20 20 20 20 20 4a 4d 50 20 74 77 |0 JMP tw|
00002c60 6f 20 20 20 20 20 20 20 5c 20 63 68 65 63 6b 20 |o \ check |
00002c70 62 69 74 20 36 0d 20 20 35 38 30 20 2e 74 72 79 |bit 6. 580 .try|
00002c80 72 69 67 68 74 0d 20 20 35 39 30 20 20 20 20 20 |right. 590 |
00002c90 20 20 20 20 43 4d 50 20 72 69 67 68 74 20 20 20 | CMP right |
00002ca0 20 20 5c 20 63 6f 6d 70 61 72 65 20 77 69 74 68 | \ compare with|
00002cb0 20 6e 75 6d 62 65 72 20 61 6c 6c 6f 63 61 74 65 | number allocate|
00002cc0 64 20 74 6f 20 72 69 67 68 74 0d 20 20 20 20 20 |d to right. |
00002cd0 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 | |
00002ce0 20 20 20 20 20 20 20 5c 20 6d 6f 75 73 65 20 62 | \ mouse b|
00002cf0 75 74 74 6f 6e 0d 20 20 36 30 30 20 20 20 20 20 |utton. 600 |
00002d00 20 20 20 20 42 4e 45 20 74 72 79 6c 65 66 74 20 | BNE tryleft |
00002d10 20 20 5c 20 62 72 61 6e 63 68 20 69 66 20 6e 6f | \ branch if no|
00002d20 74 20 72 69 67 68 74 20 62 75 74 74 6f 6e 0d 20 |t right button. |
00002d30 20 36 31 30 20 20 20 20 20 20 20 20 20 4c 44 41 | 610 LDA|
00002d40 20 64 72 62 20 20 20 20 20 20 20 5c 20 64 61 74 | drb \ dat|
00002d50 61 20 72 65 67 69 73 74 65 72 20 42 0d 20 20 36 |a register B. 6|
00002d60 32 30 20 20 20 20 20 20 20 20 20 4a 4d 50 20 6f |20 JMP o|
00002d70 6e 65 20 20 20 20 20 20 20 5c 20 63 68 65 63 6b |ne \ check|
00002d80 20 62 69 74 20 37 0d 20 20 36 33 30 20 2e 74 72 | bit 7. 630 .tr|
00002d90 79 6c 65 66 74 0d 20 20 36 34 30 20 20 20 20 20 |yleft. 640 |
00002da0 20 20 20 20 43 4d 50 20 6c 65 66 74 20 20 20 20 | CMP left |
00002db0 20 20 5c 20 63 6f 6d 70 61 72 65 20 77 69 74 68 | \ compare with|
00002dc0 20 6e 75 6d 62 65 72 20 61 6c 6c 6f 63 61 74 65 | number allocate|
00002dd0 64 20 74 6f 20 6c 65 66 74 0d 20 20 20 20 20 20 |d to left. |
00002de0 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 | |
00002df0 20 20 20 20 20 20 5c 20 6d 6f 75 73 65 20 62 75 | \ mouse bu|
00002e00 74 74 6f 6e 0d 20 20 36 35 30 20 20 20 20 20 20 |tton. 650 |
00002e10 20 20 20 42 4e 45 20 70 75 6c 6c 6f 75 74 20 20 | BNE pullout |
00002e20 20 5c 20 65 78 69 74 20 69 66 20 6e 6f 74 20 6c | \ exit if not l|
00002e30 65 66 74 20 62 75 74 74 6f 6e 0d 20 20 36 36 30 |eft button. 660|
00002e40 20 20 20 20 20 20 20 20 20 4c 44 41 20 64 72 62 | LDA drb|
00002e50 20 20 20 20 20 20 20 5c 20 64 61 74 61 20 72 65 | \ data re|
00002e60 67 69 73 74 65 72 20 42 0d 20 20 36 37 30 20 20 |gister B. 670 |
00002e70 20 20 20 20 20 20 20 52 4f 4c 20 41 20 20 20 20 | ROL A |
00002e80 20 20 20 20 20 5c 20 62 69 74 20 37 20 69 6e 74 | \ bit 7 int|
00002e90 6f 20 63 61 72 72 79 0d 20 20 36 38 30 20 2e 74 |o carry. 680 .t|
00002ea0 77 6f 0d 20 20 36 39 30 20 20 20 20 20 20 20 20 |wo. 690 |
00002eb0 20 52 4f 4c 20 41 20 20 20 20 20 20 20 20 20 5c | ROL A \|
00002ec0 20 62 69 74 20 36 2f 37 20 69 6e 74 6f 20 63 61 | bit 6/7 into ca|
00002ed0 72 72 79 0d 20 20 37 30 30 20 2e 6f 6e 65 0d 20 |rry. 700 .one. |
00002ee0 20 37 31 30 20 20 20 20 20 20 20 20 20 52 4f 4c | 710 ROL|
00002ef0 20 41 20 20 20 20 20 20 20 20 20 5c 20 62 69 74 | A \ bit|
00002f00 20 35 2f 36 2f 37 20 69 6e 74 6f 20 63 61 72 72 | 5/6/7 into carr|
00002f10 79 0d 20 20 37 32 30 20 20 20 20 20 20 20 20 20 |y. 720 |
00002f20 42 43 53 20 70 75 6c 6c 6f 75 74 20 20 20 5c 20 |BCS pullout \ |
00002f30 65 78 69 74 20 69 66 20 62 69 74 20 35 2f 36 2f |exit if bit 5/6/|
00002f40 37 20 73 65 74 0d 20 20 37 33 30 20 2e 66 6f 75 |7 set. 730 .fou|
00002f50 6e 64 0d 20 20 37 34 30 20 20 20 20 20 20 20 20 |nd. 740 |
00002f60 20 4c 44 41 20 23 26 38 31 20 20 20 20 20 20 5c | LDA #&81 \|
00002f70 20 4f 73 62 79 74 65 20 26 38 31 0d 20 20 37 35 | Osbyte &81. 75|
00002f80 30 20 20 20 20 20 20 20 20 20 4c 44 58 20 23 26 |0 LDX #&|
00002f90 46 46 20 20 20 20 20 20 5c 20 58 20 61 6e 64 20 |FF \ X and |
00002fa0 59 20 3d 20 26 46 46 20 77 68 65 6e 20 6b 65 79 |Y = &FF when key|
00002fb0 20 70 72 65 73 73 65 64 0d 20 20 37 36 30 20 20 | pressed. 760 |
00002fc0 20 20 20 20 20 20 20 4c 44 59 20 23 26 46 46 0d | LDY #&FF.|
00002fd0 20 20 37 37 30 20 20 20 20 20 20 20 20 20 50 4c | 770 PL|
00002fe0 50 20 20 20 20 20 20 20 20 20 20 20 5c 20 70 75 |P \ pu|
00002ff0 6c 6c 20 73 74 61 74 75 73 20 72 65 67 69 73 74 |ll status regist|
00003000 65 72 0d 20 20 37 38 30 20 20 20 20 20 20 20 20 |er. 780 |
00003010 20 52 54 53 20 20 20 20 20 20 20 20 20 20 20 5c | RTS \|
00003020 20 72 65 74 75 72 6e 20 74 6f 20 6f 70 65 72 61 | return to opera|
00003030 74 69 6e 67 20 73 79 73 74 65 6d 0d 20 20 37 39 |ting system. 79|
00003040 30 20 2e 6f 6c 64 62 79 74 65 76 0d 20 20 38 30 |0 .oldbytev. 80|
00003050 30 20 20 20 20 20 20 20 20 20 45 51 55 57 20 26 |0 EQUW &|
00003060 30 30 20 20 20 20 20 20 5c 20 6f 72 69 67 69 6e |00 \ origin|
00003070 61 6c 20 4f 73 62 79 74 65 20 69 6e 64 69 72 65 |al Osbyte indire|
00003080 63 74 69 6f 6e 20 76 65 63 74 6f 72 0d 20 20 38 |ction vector. 8|
00003090 31 30 20 2e 72 69 67 68 74 0d 20 20 38 32 30 20 |10 .right. 820 |
000030a0 20 20 20 20 20 20 20 20 45 51 55 42 20 2d 36 37 | EQUB -67|
000030b0 20 20 20 20 20 20 5c 20 2d 76 65 20 49 4e 4b 45 | \ -ve INKE|
000030c0 59 20 66 6f 72 20 58 0d 20 20 38 33 30 20 2e 63 |Y for X. 830 .c|
000030d0 65 6e 74 72 65 0d 20 20 38 34 30 20 20 20 20 20 |entre. 840 |
000030e0 20 20 20 20 45 51 55 42 20 2d 37 34 20 20 20 20 | EQUB -74 |
000030f0 20 20 5c 20 2d 76 65 20 49 4e 4b 45 59 20 66 6f | \ -ve INKEY fo|
00003100 72 20 3c 72 65 74 75 72 6e 3e 0d 20 20 38 35 30 |r <return>. 850|
00003110 20 2e 6c 65 66 74 0d 20 20 38 36 30 20 20 20 20 | .left. 860 |
00003120 20 20 20 20 20 45 51 55 42 20 2d 39 38 20 20 20 | EQUB -98 |
00003130 20 20 20 5c 20 2d 76 65 20 49 4e 4b 45 59 20 66 | \ -ve INKEY f|
00003140 6f 72 20 5a 0d 20 20 38 37 30 20 2e 6c 61 73 74 |or Z. 870 .last|
00003150 62 79 74 65 0d 20 20 38 38 30 20 5d 0d 20 20 38 |byte. 880 ]. 8|
00003160 39 30 20 4e 45 58 54 0d 20 20 39 30 30 20 43 41 |90 NEXT. 900 CA|
00003170 4c 4c 20 6d 63 6f 64 65 20 3a 52 45 4d 3a 20 65 |LL mcode :REM: e|
00003180 6e 61 62 6c 65 20 6e 65 77 20 63 6f 64 65 0d 20 |nable new code. |
00003190 20 39 31 30 20 4d 4f 44 45 37 0d 20 20 39 32 30 | 910 MODE7. 920|
000031a0 20 6d 6f 75 73 65 24 3d 43 48 52 24 31 34 31 2b | mouse$=CHR$141+|
000031b0 43 48 52 24 31 33 32 2b 43 48 52 24 31 35 37 2b |CHR$132+CHR$157+|
000031c0 43 48 52 24 31 33 31 0d 20 20 20 20 20 20 2b 22 |CHR$131. +"|
000031d0 50 72 65 73 73 20 6b 65 79 62 6f 61 72 64 20 6f |Press keyboard o|
000031e0 72 20 6d 6f 75 73 65 20 62 75 74 74 6f 6e 73 20 |r mouse buttons |
000031f0 20 22 2b 43 48 52 24 31 35 36 0d 20 20 39 33 30 | "+CHR$156. 930|
00003200 20 50 52 49 4e 54 54 41 42 28 30 2c 32 29 6d 6f | PRINTTAB(0,2)mo|
00003210 75 73 65 24 0d 20 20 39 34 30 20 50 52 49 4e 54 |use$. 940 PRINT|
00003220 54 41 42 28 30 2c 33 29 6d 6f 75 73 65 24 0d 20 |TAB(0,3)mouse$. |
00003230 20 39 35 30 20 4f 4e 45 52 52 4f 52 20 47 4f 54 | 950 ONERROR GOT|
00003240 4f 20 31 30 33 30 0d 20 20 39 36 30 20 56 44 55 |O 1030. 960 VDU|
00003250 32 33 2c 31 2c 30 3b 30 3b 30 3b 30 3b 0d 20 20 |23,1,0;0;0;0;. |
00003260 39 37 30 20 52 45 50 45 41 54 0d 20 20 39 38 30 |970 REPEAT. 980|
00003270 20 49 46 20 49 4e 4b 45 59 28 2d 36 37 29 20 50 | IF INKEY(-67) P|
00003280 52 49 4e 54 54 41 42 28 32 36 2c 31 32 29 22 58 |RINTTAB(26,12)"X|
00003290 22 20 45 4c 53 45 20 50 52 49 4e 54 54 41 42 28 |" ELSE PRINTTAB(|
000032a0 32 36 2c 31 32 29 22 20 22 0d 20 20 39 39 30 20 |26,12)" ". 990 |
000032b0 49 46 20 49 4e 4b 45 59 28 2d 37 34 29 20 50 52 |IF INKEY(-74) PR|
000032c0 49 4e 54 54 41 42 28 31 36 2c 31 32 29 22 52 65 |INTTAB(16,12)"Re|
000032d0 74 75 72 6e 22 20 45 4c 53 45 20 50 52 49 4e 54 |turn" ELSE PRINT|
000032e0 54 41 42 28 31 36 2c 31 32 29 22 20 20 20 20 20 |TAB(16,12)" |
000032f0 20 22 0d 20 31 30 30 30 20 49 46 20 49 4e 4b 45 | ". 1000 IF INKE|
00003300 59 28 2d 39 38 29 20 50 52 49 4e 54 54 41 42 28 |Y(-98) PRINTTAB(|
00003310 31 31 2c 31 32 29 22 5a 22 20 45 4c 53 45 20 50 |11,12)"Z" ELSE P|
00003320 52 49 4e 54 54 41 42 28 31 31 2c 31 32 29 22 20 |RINTTAB(11,12)" |
00003330 22 0d 20 31 30 31 30 20 49 46 20 49 4e 4b 45 59 |". 1010 IF INKEY|
00003340 28 2d 39 39 29 20 50 52 49 4e 54 54 41 42 28 31 |(-99) PRINTTAB(1|
00003350 36 2c 31 37 29 22 53 70 61 63 65 22 20 45 4c 53 |6,17)"Space" ELS|
00003360 45 20 50 52 49 4e 54 54 41 42 28 31 36 2c 31 37 |E PRINTTAB(16,17|
00003370 29 22 20 20 20 20 20 22 0d 20 31 30 32 30 20 55 |)" ". 1020 U|
00003380 4e 54 49 4c 20 46 41 4c 53 45 0d 20 31 30 33 30 |NTIL FALSE. 1030|
00003390 20 43 41 4c 4c 20 6d 63 6f 64 65 20 3a 52 45 4d | CALL mcode :REM|
000033a0 3a 20 64 69 73 61 62 6c 65 20 6e 65 77 20 63 6f |: disable new co|
000033b0 64 65 0d 20 31 30 34 30 20 56 44 55 32 33 2c 31 |de. 1040 VDU23,1|
000033c0 2c 31 3b 30 3b 30 3b 30 3b 33 31 2c 30 2c 32 33 |,1;0;0;0;31,0,23|
000033d0 0d 20 31 30 35 30 20 45 4e 44 0d |. 1050 END.|
000033db 
11-12-88/T\MOU03.m0
11-12-88/T\MOU03.m1
11-12-88/T\MOU03.m2
11-12-88/T\MOU03.m4
11-12-88/T\MOU03.m5
.