Home » CEEFAX disks » telesoftware8.adl » 13-08-88/T\SWR06

13-08-88/T\SWR06

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 » telesoftware8.adl
Filename: 13-08-88/T\SWR06
Read OK:
File size: 2F6E bytes
Load address: 0000
Exec address: FFFFFFFF
Duplicates

There is 1 duplicate copy of this file in the archive:

File contents
Mastering Sideways ROM & RAM - Module 06 - Osbyte
-------------------------------------------------

  In Module 5 you were shown how to read an argument which follows a *
command. The argument is always read as an ASCII string. This is fine
if the string is a word such as "ON" or "OFF" but it can be a problem
if the argument is a number. The number must be read as an ASCII
string but it has to be converted into binary before the computer can
use it as a number. The computer can store a number in the range from
&00 to &FF in one byte. In order to read just one byte as an argument
up to three ASCII characters representing the byte have to be read,
converted into binary and stored in a byte of user memory.

  You have two options if you want to read numerical arguments.

1. Write a routine to read every ASCII character in the argument and
convert the ASCII representation of the number into binary.

2. Use the MOS to do the work for you.

  The first option, not surprisingly, involves more work than the
second. If you write your own conversion routine it has to include
error handling and a check for validity. It also has to have somewhere
in memory to store the result. This will be covered in detail in
Module 9.

  The second option involves defining a new Osbyte or Osword. Osbyte
will be covered in this module and Osword in Module 7.

  Osbyte is an MOS call specified by the contents of the accumulator
taking parameters in the X and Y registers. Osbyte calls 22 (&15) to
116 (&74) are not used by MOS 1.20 and can be defined within your SWR
programs. Other operating systems use some of these unused Osbyte
calls. For example *FX 114 is used to switch shadow screen memory on
and off in the B+ and Master computers. You can use TRACE to check if
any particular Osbyte call is unused by your operating system. *FX 100
is not used by any operating system (as far as I know) and will be
used in the example program for this module.

  Load the object code generated by TRACE into SWR and press the Break
key. Type *FX 100 and press Return. You will see that service call 7
is used for an unrecognised Osbyte. Type *FX 100,1,1 and you will see
that the Osbyte X and Y parameters are not made available to the
interpreter in the X and Y registers as you might expect. Figure 6.1
shows that, whatever value you type for the Osbyte X and Y parameters,
the rom is entered with X storing the rom number and Y storing zero.



>*FX 100
 A=07 X=0F Y=00 Unrecognised Osbyte
>*FX 100,1,1
 A=07 X=0F Y=00 Unrecognised Osbyte
>*FX 100,100,100
 A=07 X=0F Y=00 Unrecognised Osbyte
>

Figure 6.1 Service trace for unrecognised Osbyte.
-------------------------------------------------



  Osbyte uses three consecutive bytes in zero page to store the values
of the A, X and Y registers. The accumulator value for the most recent
Osbyte (or Osword) is stored in &EF. The X register value is stored in
&F0 and the Y register value is stored in &F1. Both Osbyte and Osword
make the three registers available to the routine through these three
zero page locations.

  After processing an Osbyte call any values that need to be returned
to the calling routine should be stored in locations &F0 and &F1. On
return the number stored in the X register and &F0 should be the same
and the number stored in the Y register and &F1 should be the same.
&EF should store the number of your new Osbyte and the accumulator
should be reset to zero before returning to the MOS. On return to the
MOS the number stored in &EF is copied into the accumulator.

  You can use the X and Y parameters of an Osbyte call to make two
(one byte) numbers or one (two byte) number available to your new
routine. If you want to make a two byte number available store the
least significant byte in X and the most significant byte in Y. For
example,

  LDA #100              \ New osbyte
  LDX #(number MOD 256) \ Least significant byte
  LDY #(number DIV 256) \ Most significant byte
  JSR &FFF4             \ Call osbyte

  Your new Osbyte can then read the least significant byte fron &F0
and the most significant byte from &F1. It can also use these memory
locations for post-indexed indirect addressing.

  The interpreter needed to implement a new Osbyte is probably the
easiest of all interpreters to write. An outline interpreter is shown
in figure 6.2.




.service
         PHA           \ push accumulator
         CMP #7        \ is it an unrecognised Osbyte?
         BEQ newosbyte \ branch if it is
.exit
         PLA           \ pull accumulator
         RTS           \ return and give other roms the call
.newosbyte
         LDA &EF       \ load Osbyte number from &EF
         CMP #100      \ is it 100?
         BNE exit      \ branch if not Osbyte 100
         LDX &F0       \ read X from &F0
         LDY &F1       \ read Y from &F1
          .
          .            \ new routine goes in here
          .
         STX &F0       \ store result for X
         STY &F1       \ store result for Y
         PLA           \ pull A pushed by interpreter
         LDA #0        \ other roms ignore this call
         RTS           \ return to MOS

Figure 6.2 An Osbyte interpreter.
---------------------------------




  The service entry point of the outline interpreter in figure 6.2
will have a jump to the label ".service". On entering the interpreter
the accumulator is pushed on the stack and then compared with 7 to see
if the call is an unrecognised Osbyte. If it is not the accumulator is
pulled off the stack and control is returned to the MOS. If the call
is for an unrecognised Osbyte the number stored in &EF is loaded into
the accumulator and compared with the number of the new Osbyte, in
this example 100.

  If the unrecognised Osbyte number stored in &EF is not 100 the
accumulator is pulled off the stack and control is returned to the
MOS. If it is 100 then the parameters (if used) can be read from &F0
(X register) and &F1 (Y register) and the new routine can be executed.

  After completing the new routine any results are stored in &F0 (X
register) and &F1 (Y register). The index registers and their zero
page copies should be identical. Even if you don't want to write any
results you should still ensure that the index registers are identical
to their zero page copies. The accumulator was pushed on the stack by
the interpreter and it is pulled back off to balance the stack. The
accumulator is reset to zero to inform other roms that the service
call has been recognised and control is passed back to the MOS.

  The interpreter in figure 6.2 is used in the example program OSBYTE.
This program generates the object code for *FX 100,x,y in which the X
parameter is the number of a rom to be disabled and the Y parameter is
used as a flag which, if set, tells the routine to print a list of the
active roms. If the X parameter is outside the range from 0 to 15 it
is ignored. To use the program load the object code it generates into
SWR and press the Break key. You can use the new Osbyte to disable any
rom, except BASIC, until the Break key is pressed to re-enable it.

  Type *FX 100,100,1 to list the roms in your computer. This command
will be recognised as the new Osbyte but the X parameter is out of
range and it will not disable any rom. The Y parameter has a value
other than zero and the active roms will be listed.

  Type *FX 100,10 to disable rom &0A without listing the active roms.
The Y parameter is not specified and takes the default value of zero.

  Type *FX 100,8,1 to disable rom &08 and list the active roms.

  You can re-enable all the roms disabled with this new Osbyte by
pressing the Break key.

  The program uses an Osbyte interpreter (lines 310-410) similar to
the one outlined in figure 6.2. After recognising the new Osbyte
(lines 390-410) the new routine loads the X register with the X
parameter (line 420) and compares it with &10 (line 430) to see if it
is in the range from 0 to 15. If X is in range it disables the rom by
storing a zero in the rom information table byte that corresponds with
that rom (lines 450-460). The Y parameter is then loaded into the Y
register (line 480) and checked to see if it has been set (line 490).
If it has been set the active roms are listed (line 510).

  The routine does not write any results to the zero page copies of
the index registers but it still ensures that the index registers and
their copies are identical (lines 530-540). The accumulator was pushed
on the stack by the interpreter (line 320) and it is pulled back off
in line 550. It is reset to zero to inform the other roms that the
service call has been recognised (line 560) and control is returned to
the MOS (line 570).

  The subroutine romnames (lines 580-940) uses Osrdrm to list the
titles of the active roms and is similar to the routine used to print
rom titles in the program READROM (used in Module 1). The subroutine
decimal (lines 950-1110) prints the ASCII decimal equivalent of any
byte storing a number in the range from 0 to 99 (decimal). It is quite
a useful routine and can also be used to print a binary coded decimal
byte.





   10 REM: OSBYTE
   20 MODE7
   30 HIMEM=&3C00
   40 DIM save 50
   50 diff=&8000-HIMEM
   60 accumulator=&EF
   70 xregister=&F0
   80 yregister=&F1
   90 rompoint=&F6
  100 table=&2A1
  110 osrdrm=&FFB9
  120 osasci=&FFE3
  130 osnewl=&FFE7
  140 osbyte=&FFF4
  150 oscli=&FFF7
  160 FOR pass = 0 TO 2 STEP 2
  170 P%=HIMEM
  180 [       OPT pass
  190         BRK
  200         BRK
  210         BRK
  220         JMP service+diff
  230         OPT FNequb(&82)
  240         OPT FNequb((copyright+diff) MOD 256)
  250         BRK
  260         OPT FNequs("OSBYTE")
  270 .copyright
  280         BRK
  290         OPT FNequs("(C) Gordon Horsington 1987")
  300         BRK
  310 .service
  320         PHA
  330         CMP #7
  340         BEQ newosbyte
  350 .exit
  360         PLA
  370         RTS
  380 .newosbyte
  390         LDA accumulator
  400         CMP #100
  410         BNE exit
  420         LDX xregister
  430         CPX #&10
  440         BCS checkyreg
  450         LDA #0
  460         STA table,X
  470 .checkyreg
  480         LDY yregister
  490         BEQ out
  500 .romlist
  510         JSR romnames+diff
  520 .out
  530         LDX xregister
  540         LDY yregister
  550         PLA
  560         LDA #0
  570         RTS
  580 .romnames
  590         JSR osnewl
  600         LDA #&F
  610         PHA
  620 .romloop
  630         TAY
  640         LDA table,Y
  650         BEQ nothere
  660         TYA
  670         JSR decimal+diff
  680         LDA #ASC(" ")
  690         JSR osasci
  700         LDA #&8
  710         STA rompoint
  720         LDA #&80
  730         STA rompoint+1
  740 .readloop
  750         INC rompoint
  760         BEQ newline
  770         PLA
  780         PHA
  790         TAY
  800         JSR osrdrm
  810         CMP #ASC(" ")
  820         BCC newline
  830         JSR osasci
  840         JMP readloop+diff
  850 .newline
  860         JSR osnewl
  870 .nothere
  880         PLA
  890         SEC
  900         SBC #1
  910         PHA
  920         BPL romloop
  930         PLA
  940         JMP osnewl
  950 .decimal
  960         SED
  970         CLC
  980         ADC #0
  990         CLD
 1000         PHA
 1010         LSR A
 1020         LSR A
 1030         LSR A
 1040         LSR A
 1050         JSR nibble+diff
 1060         PLA
 1070         AND #&F
 1080 .nibble
 1090         CLC
 1100         ADC #ASC("0")
 1110         JMP osasci
 1120 .lastbyte
 1130 ]
 1140 NEXT
 1150 INPUT'"Save filename = "filename$
 1160 IF filename$="" END
 1170 $save="SAVE "+filename$+" "+STR$~(HIMEM)+" "+STR$~(las
      tbyte)+" FFFF8000 FFFF8000"
 1180 X%=save MOD 256
 1190 Y%=save DIV 256
 1200 *OPT1,2
 1210 CALL oscli
 1220 *OPT1,0
 1230 END
 1240 DEFFNequb(byte)
 1250 ?P%=byte
 1260 P%=P%+1
 1270 =pass
 1280 DEFFNequw(word)
 1290 ?P%=word MOD 256
 1300 P%?1=word DIV 256
 1310 P%=P%+2
 1320 =pass
 1330 DEFFNequd(double)
 1340 !P%=double
 1350 P%=P%+4
 1360 =pass
 1370 DEFFNequs(string$)
 1380 $P%=string$
 1390 P%=P%+LEN(string$)
 1400 =pass
00000000  4d 61 73 74 65 72 69 6e  67 20 53 69 64 65 77 61  |Mastering Sidewa|
00000010  79 73 20 52 4f 4d 20 26  20 52 41 4d 20 2d 20 4d  |ys ROM & RAM - M|
00000020  6f 64 75 6c 65 20 30 36  20 2d 20 4f 73 62 79 74  |odule 06 - Osbyt|
00000030  65 0d 2d 2d 2d 2d 2d 2d  2d 2d 2d 2d 2d 2d 2d 2d  |e.--------------|
00000040  2d 2d 2d 2d 2d 2d 2d 2d  2d 2d 2d 2d 2d 2d 2d 2d  |----------------|
*
00000060  2d 2d 2d 0d 0d 20 20 49  6e 20 4d 6f 64 75 6c 65  |---..  In Module|
00000070  20 35 20 79 6f 75 20 77  65 72 65 20 73 68 6f 77  | 5 you were show|
00000080  6e 20 68 6f 77 20 74 6f  20 72 65 61 64 20 61 6e  |n how to read an|
00000090  20 61 72 67 75 6d 65 6e  74 20 77 68 69 63 68 20  | argument which |
000000a0  66 6f 6c 6c 6f 77 73 20  61 20 2a 0d 63 6f 6d 6d  |follows a *.comm|
000000b0  61 6e 64 2e 20 54 68 65  20 61 72 67 75 6d 65 6e  |and. The argumen|
000000c0  74 20 69 73 20 61 6c 77  61 79 73 20 72 65 61 64  |t is always read|
000000d0  20 61 73 20 61 6e 20 41  53 43 49 49 20 73 74 72  | as an ASCII str|
000000e0  69 6e 67 2e 20 54 68 69  73 20 69 73 20 66 69 6e  |ing. This is fin|
000000f0  65 0d 69 66 20 74 68 65  20 73 74 72 69 6e 67 20  |e.if the string |
00000100  69 73 20 61 20 77 6f 72  64 20 73 75 63 68 20 61  |is a word such a|
00000110  73 20 22 4f 4e 22 20 6f  72 20 22 4f 46 46 22 20  |s "ON" or "OFF" |
00000120  62 75 74 20 69 74 20 63  61 6e 20 62 65 20 61 20  |but it can be a |
00000130  70 72 6f 62 6c 65 6d 0d  69 66 20 74 68 65 20 61  |problem.if the a|
00000140  72 67 75 6d 65 6e 74 20  69 73 20 61 20 6e 75 6d  |rgument is a num|
00000150  62 65 72 2e 20 54 68 65  20 6e 75 6d 62 65 72 20  |ber. The number |
00000160  6d 75 73 74 20 62 65 20  72 65 61 64 20 61 73 20  |must be read as |
00000170  61 6e 20 41 53 43 49 49  0d 73 74 72 69 6e 67 20  |an ASCII.string |
00000180  62 75 74 20 69 74 20 68  61 73 20 74 6f 20 62 65  |but it has to be|
00000190  20 63 6f 6e 76 65 72 74  65 64 20 69 6e 74 6f 20  | converted into |
000001a0  62 69 6e 61 72 79 20 62  65 66 6f 72 65 20 74 68  |binary before th|
000001b0  65 20 63 6f 6d 70 75 74  65 72 20 63 61 6e 0d 75  |e computer can.u|
000001c0  73 65 20 69 74 20 61 73  20 61 20 6e 75 6d 62 65  |se it as a numbe|
000001d0  72 2e 20 54 68 65 20 63  6f 6d 70 75 74 65 72 20  |r. The computer |
000001e0  63 61 6e 20 73 74 6f 72  65 20 61 20 6e 75 6d 62  |can store a numb|
000001f0  65 72 20 69 6e 20 74 68  65 20 72 61 6e 67 65 20  |er in the range |
00000200  66 72 6f 6d 0d 26 30 30  20 74 6f 20 26 46 46 20  |from.&00 to &FF |
00000210  69 6e 20 6f 6e 65 20 62  79 74 65 2e 20 49 6e 20  |in one byte. In |
00000220  6f 72 64 65 72 20 74 6f  20 72 65 61 64 20 6a 75  |order to read ju|
00000230  73 74 20 6f 6e 65 20 62  79 74 65 20 61 73 20 61  |st one byte as a|
00000240  6e 20 61 72 67 75 6d 65  6e 74 0d 75 70 20 74 6f  |n argument.up to|
00000250  20 74 68 72 65 65 20 41  53 43 49 49 20 63 68 61  | three ASCII cha|
00000260  72 61 63 74 65 72 73 20  72 65 70 72 65 73 65 6e  |racters represen|
00000270  74 69 6e 67 20 74 68 65  20 62 79 74 65 20 68 61  |ting the byte ha|
00000280  76 65 20 74 6f 20 62 65  20 72 65 61 64 2c 0d 63  |ve to be read,.c|
00000290  6f 6e 76 65 72 74 65 64  20 69 6e 74 6f 20 62 69  |onverted into bi|
000002a0  6e 61 72 79 20 61 6e 64  20 73 74 6f 72 65 64 20  |nary and stored |
000002b0  69 6e 20 61 20 62 79 74  65 20 6f 66 20 75 73 65  |in a byte of use|
000002c0  72 20 6d 65 6d 6f 72 79  2e 0d 0d 20 20 59 6f 75  |r memory...  You|
000002d0  20 68 61 76 65 20 74 77  6f 20 6f 70 74 69 6f 6e  | have two option|
000002e0  73 20 69 66 20 79 6f 75  20 77 61 6e 74 20 74 6f  |s if you want to|
000002f0  20 72 65 61 64 20 6e 75  6d 65 72 69 63 61 6c 20  | read numerical |
00000300  61 72 67 75 6d 65 6e 74  73 2e 0d 0d 31 2e 20 57  |arguments...1. W|
00000310  72 69 74 65 20 61 20 72  6f 75 74 69 6e 65 20 74  |rite a routine t|
00000320  6f 20 72 65 61 64 20 65  76 65 72 79 20 41 53 43  |o read every ASC|
00000330  49 49 20 63 68 61 72 61  63 74 65 72 20 69 6e 20  |II character in |
00000340  74 68 65 20 61 72 67 75  6d 65 6e 74 20 61 6e 64  |the argument and|
00000350  0d 63 6f 6e 76 65 72 74  20 74 68 65 20 41 53 43  |.convert the ASC|
00000360  49 49 20 72 65 70 72 65  73 65 6e 74 61 74 69 6f  |II representatio|
00000370  6e 20 6f 66 20 74 68 65  20 6e 75 6d 62 65 72 20  |n of the number |
00000380  69 6e 74 6f 20 62 69 6e  61 72 79 2e 0d 0d 32 2e  |into binary...2.|
00000390  20 55 73 65 20 74 68 65  20 4d 4f 53 20 74 6f 20  | Use the MOS to |
000003a0  64 6f 20 74 68 65 20 77  6f 72 6b 20 66 6f 72 20  |do the work for |
000003b0  79 6f 75 2e 0d 0d 20 20  54 68 65 20 66 69 72 73  |you...  The firs|
000003c0  74 20 6f 70 74 69 6f 6e  2c 20 6e 6f 74 20 73 75  |t option, not su|
000003d0  72 70 72 69 73 69 6e 67  6c 79 2c 20 69 6e 76 6f  |rprisingly, invo|
000003e0  6c 76 65 73 20 6d 6f 72  65 20 77 6f 72 6b 20 74  |lves more work t|
000003f0  68 61 6e 20 74 68 65 0d  73 65 63 6f 6e 64 2e 20  |han the.second. |
00000400  49 66 20 79 6f 75 20 77  72 69 74 65 20 79 6f 75  |If you write you|
00000410  72 20 6f 77 6e 20 63 6f  6e 76 65 72 73 69 6f 6e  |r own conversion|
00000420  20 72 6f 75 74 69 6e 65  20 69 74 20 68 61 73 20  | routine it has |
00000430  74 6f 20 69 6e 63 6c 75  64 65 0d 65 72 72 6f 72  |to include.error|
00000440  20 68 61 6e 64 6c 69 6e  67 20 61 6e 64 20 61 20  | handling and a |
00000450  63 68 65 63 6b 20 66 6f  72 20 76 61 6c 69 64 69  |check for validi|
00000460  74 79 2e 20 49 74 20 61  6c 73 6f 20 68 61 73 20  |ty. It also has |
00000470  74 6f 20 68 61 76 65 20  73 6f 6d 65 77 68 65 72  |to have somewher|
00000480  65 0d 69 6e 20 6d 65 6d  6f 72 79 20 74 6f 20 73  |e.in memory to s|
00000490  74 6f 72 65 20 74 68 65  20 72 65 73 75 6c 74 2e  |tore the result.|
000004a0  20 54 68 69 73 20 77 69  6c 6c 20 62 65 20 63 6f  | This will be co|
000004b0  76 65 72 65 64 20 69 6e  20 64 65 74 61 69 6c 20  |vered in detail |
000004c0  69 6e 0d 4d 6f 64 75 6c  65 20 39 2e 0d 0d 20 20  |in.Module 9...  |
000004d0  54 68 65 20 73 65 63 6f  6e 64 20 6f 70 74 69 6f  |The second optio|
000004e0  6e 20 69 6e 76 6f 6c 76  65 73 20 64 65 66 69 6e  |n involves defin|
000004f0  69 6e 67 20 61 20 6e 65  77 20 4f 73 62 79 74 65  |ing a new Osbyte|
00000500  20 6f 72 20 4f 73 77 6f  72 64 2e 20 4f 73 62 79  | or Osword. Osby|
00000510  74 65 0d 77 69 6c 6c 20  62 65 20 63 6f 76 65 72  |te.will be cover|
00000520  65 64 20 69 6e 20 74 68  69 73 20 6d 6f 64 75 6c  |ed in this modul|
00000530  65 20 61 6e 64 20 4f 73  77 6f 72 64 20 69 6e 20  |e and Osword in |
00000540  4d 6f 64 75 6c 65 20 37  2e 0d 0d 20 20 4f 73 62  |Module 7...  Osb|
00000550  79 74 65 20 69 73 20 61  6e 20 4d 4f 53 20 63 61  |yte is an MOS ca|
00000560  6c 6c 20 73 70 65 63 69  66 69 65 64 20 62 79 20  |ll specified by |
00000570  74 68 65 20 63 6f 6e 74  65 6e 74 73 20 6f 66 20  |the contents of |
00000580  74 68 65 20 61 63 63 75  6d 75 6c 61 74 6f 72 0d  |the accumulator.|
00000590  74 61 6b 69 6e 67 20 70  61 72 61 6d 65 74 65 72  |taking parameter|
000005a0  73 20 69 6e 20 74 68 65  20 58 20 61 6e 64 20 59  |s in the X and Y|
000005b0  20 72 65 67 69 73 74 65  72 73 2e 20 4f 73 62 79  | registers. Osby|
000005c0  74 65 20 63 61 6c 6c 73  20 32 32 20 28 26 31 35  |te calls 22 (&15|
000005d0  29 20 74 6f 0d 31 31 36  20 28 26 37 34 29 20 61  |) to.116 (&74) a|
000005e0  72 65 20 6e 6f 74 20 75  73 65 64 20 62 79 20 4d  |re not used by M|
000005f0  4f 53 20 31 2e 32 30 20  61 6e 64 20 63 61 6e 20  |OS 1.20 and can |
00000600  62 65 20 64 65 66 69 6e  65 64 20 77 69 74 68 69  |be defined withi|
00000610  6e 20 79 6f 75 72 20 53  57 52 0d 70 72 6f 67 72  |n your SWR.progr|
00000620  61 6d 73 2e 20 4f 74 68  65 72 20 6f 70 65 72 61  |ams. Other opera|
00000630  74 69 6e 67 20 73 79 73  74 65 6d 73 20 75 73 65  |ting systems use|
00000640  20 73 6f 6d 65 20 6f 66  20 74 68 65 73 65 20 75  | some of these u|
00000650  6e 75 73 65 64 20 4f 73  62 79 74 65 0d 63 61 6c  |nused Osbyte.cal|
00000660  6c 73 2e 20 46 6f 72 20  65 78 61 6d 70 6c 65 20  |ls. For example |
00000670  2a 46 58 20 31 31 34 20  69 73 20 75 73 65 64 20  |*FX 114 is used |
00000680  74 6f 20 73 77 69 74 63  68 20 73 68 61 64 6f 77  |to switch shadow|
00000690  20 73 63 72 65 65 6e 20  6d 65 6d 6f 72 79 20 6f  | screen memory o|
000006a0  6e 0d 61 6e 64 20 6f 66  66 20 69 6e 20 74 68 65  |n.and off in the|
000006b0  20 42 2b 20 61 6e 64 20  4d 61 73 74 65 72 20 63  | B+ and Master c|
000006c0  6f 6d 70 75 74 65 72 73  2e 20 59 6f 75 20 63 61  |omputers. You ca|
000006d0  6e 20 75 73 65 20 54 52  41 43 45 20 74 6f 20 63  |n use TRACE to c|
000006e0  68 65 63 6b 20 69 66 0d  61 6e 79 20 70 61 72 74  |heck if.any part|
000006f0  69 63 75 6c 61 72 20 4f  73 62 79 74 65 20 63 61  |icular Osbyte ca|
00000700  6c 6c 20 69 73 20 75 6e  75 73 65 64 20 62 79 20  |ll is unused by |
00000710  79 6f 75 72 20 6f 70 65  72 61 74 69 6e 67 20 73  |your operating s|
00000720  79 73 74 65 6d 2e 20 2a  46 58 20 31 30 30 0d 69  |ystem. *FX 100.i|
00000730  73 20 6e 6f 74 20 75 73  65 64 20 62 79 20 61 6e  |s not used by an|
00000740  79 20 6f 70 65 72 61 74  69 6e 67 20 73 79 73 74  |y operating syst|
00000750  65 6d 20 28 61 73 20 66  61 72 20 61 73 20 49 20  |em (as far as I |
00000760  6b 6e 6f 77 29 20 61 6e  64 20 77 69 6c 6c 20 62  |know) and will b|
00000770  65 0d 75 73 65 64 20 69  6e 20 74 68 65 20 65 78  |e.used in the ex|
00000780  61 6d 70 6c 65 20 70 72  6f 67 72 61 6d 20 66 6f  |ample program fo|
00000790  72 20 74 68 69 73 20 6d  6f 64 75 6c 65 2e 0d 0d  |r this module...|
000007a0  20 20 4c 6f 61 64 20 74  68 65 20 6f 62 6a 65 63  |  Load the objec|
000007b0  74 20 63 6f 64 65 20 67  65 6e 65 72 61 74 65 64  |t code generated|
000007c0  20 62 79 20 54 52 41 43  45 20 69 6e 74 6f 20 53  | by TRACE into S|
000007d0  57 52 20 61 6e 64 20 70  72 65 73 73 20 74 68 65  |WR and press the|
000007e0  20 42 72 65 61 6b 0d 6b  65 79 2e 20 54 79 70 65  | Break.key. Type|
000007f0  20 2a 46 58 20 31 30 30  20 61 6e 64 20 70 72 65  | *FX 100 and pre|
00000800  73 73 20 52 65 74 75 72  6e 2e 20 59 6f 75 20 77  |ss Return. You w|
00000810  69 6c 6c 20 73 65 65 20  74 68 61 74 20 73 65 72  |ill see that ser|
00000820  76 69 63 65 20 63 61 6c  6c 20 37 0d 69 73 20 75  |vice call 7.is u|
00000830  73 65 64 20 66 6f 72 20  61 6e 20 75 6e 72 65 63  |sed for an unrec|
00000840  6f 67 6e 69 73 65 64 20  4f 73 62 79 74 65 2e 20  |ognised Osbyte. |
00000850  54 79 70 65 20 2a 46 58  20 31 30 30 2c 31 2c 31  |Type *FX 100,1,1|
00000860  20 61 6e 64 20 79 6f 75  20 77 69 6c 6c 20 73 65  | and you will se|
00000870  65 0d 74 68 61 74 20 74  68 65 20 4f 73 62 79 74  |e.that the Osbyt|
00000880  65 20 58 20 61 6e 64 20  59 20 70 61 72 61 6d 65  |e X and Y parame|
00000890  74 65 72 73 20 61 72 65  20 6e 6f 74 20 6d 61 64  |ters are not mad|
000008a0  65 20 61 76 61 69 6c 61  62 6c 65 20 74 6f 20 74  |e available to t|
000008b0  68 65 0d 69 6e 74 65 72  70 72 65 74 65 72 20 69  |he.interpreter i|
000008c0  6e 20 74 68 65 20 58 20  61 6e 64 20 59 20 72 65  |n the X and Y re|
000008d0  67 69 73 74 65 72 73 20  61 73 20 79 6f 75 20 6d  |gisters as you m|
000008e0  69 67 68 74 20 65 78 70  65 63 74 2e 20 46 69 67  |ight expect. Fig|
000008f0  75 72 65 20 36 2e 31 0d  73 68 6f 77 73 20 74 68  |ure 6.1.shows th|
00000900  61 74 2c 20 77 68 61 74  65 76 65 72 20 76 61 6c  |at, whatever val|
00000910  75 65 20 79 6f 75 20 74  79 70 65 20 66 6f 72 20  |ue you type for |
00000920  74 68 65 20 4f 73 62 79  74 65 20 58 20 61 6e 64  |the Osbyte X and|
00000930  20 59 20 70 61 72 61 6d  65 74 65 72 73 2c 0d 74  | Y parameters,.t|
00000940  68 65 20 72 6f 6d 20 69  73 20 65 6e 74 65 72 65  |he rom is entere|
00000950  64 20 77 69 74 68 20 58  20 73 74 6f 72 69 6e 67  |d with X storing|
00000960  20 74 68 65 20 72 6f 6d  20 6e 75 6d 62 65 72 20  | the rom number |
00000970  61 6e 64 20 59 20 73 74  6f 72 69 6e 67 20 7a 65  |and Y storing ze|
00000980  72 6f 2e 0d 0d 0d 0d 3e  2a 46 58 20 31 30 30 0d  |ro.....>*FX 100.|
00000990  20 41 3d 30 37 20 58 3d  30 46 20 59 3d 30 30 20  | A=07 X=0F Y=00 |
000009a0  55 6e 72 65 63 6f 67 6e  69 73 65 64 20 4f 73 62  |Unrecognised Osb|
000009b0  79 74 65 0d 3e 2a 46 58  20 31 30 30 2c 31 2c 31  |yte.>*FX 100,1,1|
000009c0  0d 20 41 3d 30 37 20 58  3d 30 46 20 59 3d 30 30  |. A=07 X=0F Y=00|
000009d0  20 55 6e 72 65 63 6f 67  6e 69 73 65 64 20 4f 73  | Unrecognised Os|
000009e0  62 79 74 65 0d 3e 2a 46  58 20 31 30 30 2c 31 30  |byte.>*FX 100,10|
000009f0  30 2c 31 30 30 0d 20 41  3d 30 37 20 58 3d 30 46  |0,100. A=07 X=0F|
00000a00  20 59 3d 30 30 20 55 6e  72 65 63 6f 67 6e 69 73  | Y=00 Unrecognis|
00000a10  65 64 20 4f 73 62 79 74  65 0d 3e 0d 0d 46 69 67  |ed Osbyte.>..Fig|
00000a20  75 72 65 20 36 2e 31 20  53 65 72 76 69 63 65 20  |ure 6.1 Service |
00000a30  74 72 61 63 65 20 66 6f  72 20 75 6e 72 65 63 6f  |trace for unreco|
00000a40  67 6e 69 73 65 64 20 4f  73 62 79 74 65 2e 0d 2d  |gnised Osbyte..-|
00000a50  2d 2d 2d 2d 2d 2d 2d 2d  2d 2d 2d 2d 2d 2d 2d 2d  |----------------|
*
00000a80  0d 0d 0d 0d 20 20 4f 73  62 79 74 65 20 75 73 65  |....  Osbyte use|
00000a90  73 20 74 68 72 65 65 20  63 6f 6e 73 65 63 75 74  |s three consecut|
00000aa0  69 76 65 20 62 79 74 65  73 20 69 6e 20 7a 65 72  |ive bytes in zer|
00000ab0  6f 20 70 61 67 65 20 74  6f 20 73 74 6f 72 65 20  |o page to store |
00000ac0  74 68 65 20 76 61 6c 75  65 73 0d 6f 66 20 74 68  |the values.of th|
00000ad0  65 20 41 2c 20 58 20 61  6e 64 20 59 20 72 65 67  |e A, X and Y reg|
00000ae0  69 73 74 65 72 73 2e 20  54 68 65 20 61 63 63 75  |isters. The accu|
00000af0  6d 75 6c 61 74 6f 72 20  76 61 6c 75 65 20 66 6f  |mulator value fo|
00000b00  72 20 74 68 65 20 6d 6f  73 74 20 72 65 63 65 6e  |r the most recen|
00000b10  74 0d 4f 73 62 79 74 65  20 28 6f 72 20 4f 73 77  |t.Osbyte (or Osw|
00000b20  6f 72 64 29 20 69 73 20  73 74 6f 72 65 64 20 69  |ord) is stored i|
00000b30  6e 20 26 45 46 2e 20 54  68 65 20 58 20 72 65 67  |n &EF. The X reg|
00000b40  69 73 74 65 72 20 76 61  6c 75 65 20 69 73 20 73  |ister value is s|
00000b50  74 6f 72 65 64 20 69 6e  0d 26 46 30 20 61 6e 64  |tored in.&F0 and|
00000b60  20 74 68 65 20 59 20 72  65 67 69 73 74 65 72 20  | the Y register |
00000b70  76 61 6c 75 65 20 69 73  20 73 74 6f 72 65 64 20  |value is stored |
00000b80  69 6e 20 26 46 31 2e 20  42 6f 74 68 20 4f 73 62  |in &F1. Both Osb|
00000b90  79 74 65 20 61 6e 64 20  4f 73 77 6f 72 64 0d 6d  |yte and Osword.m|
00000ba0  61 6b 65 20 74 68 65 20  74 68 72 65 65 20 72 65  |ake the three re|
00000bb0  67 69 73 74 65 72 73 20  61 76 61 69 6c 61 62 6c  |gisters availabl|
00000bc0  65 20 74 6f 20 74 68 65  20 72 6f 75 74 69 6e 65  |e to the routine|
00000bd0  20 74 68 72 6f 75 67 68  20 74 68 65 73 65 20 74  | through these t|
00000be0  68 72 65 65 0d 7a 65 72  6f 20 70 61 67 65 20 6c  |hree.zero page l|
00000bf0  6f 63 61 74 69 6f 6e 73  2e 0d 0d 20 20 41 66 74  |ocations...  Aft|
00000c00  65 72 20 70 72 6f 63 65  73 73 69 6e 67 20 61 6e  |er processing an|
00000c10  20 4f 73 62 79 74 65 20  63 61 6c 6c 20 61 6e 79  | Osbyte call any|
00000c20  20 76 61 6c 75 65 73 20  74 68 61 74 20 6e 65 65  | values that nee|
00000c30  64 20 74 6f 20 62 65 20  72 65 74 75 72 6e 65 64  |d to be returned|
00000c40  0d 74 6f 20 74 68 65 20  63 61 6c 6c 69 6e 67 20  |.to the calling |
00000c50  72 6f 75 74 69 6e 65 20  73 68 6f 75 6c 64 20 62  |routine should b|
00000c60  65 20 73 74 6f 72 65 64  20 69 6e 20 6c 6f 63 61  |e stored in loca|
00000c70  74 69 6f 6e 73 20 26 46  30 20 61 6e 64 20 26 46  |tions &F0 and &F|
00000c80  31 2e 20 4f 6e 0d 72 65  74 75 72 6e 20 74 68 65  |1. On.return the|
00000c90  20 6e 75 6d 62 65 72 20  73 74 6f 72 65 64 20 69  | number stored i|
00000ca0  6e 20 74 68 65 20 58 20  72 65 67 69 73 74 65 72  |n the X register|
00000cb0  20 61 6e 64 20 26 46 30  20 73 68 6f 75 6c 64 20  | and &F0 should |
00000cc0  62 65 20 74 68 65 20 73  61 6d 65 0d 61 6e 64 20  |be the same.and |
00000cd0  74 68 65 20 6e 75 6d 62  65 72 20 73 74 6f 72 65  |the number store|
00000ce0  64 20 69 6e 20 74 68 65  20 59 20 72 65 67 69 73  |d in the Y regis|
00000cf0  74 65 72 20 61 6e 64 20  26 46 31 20 73 68 6f 75  |ter and &F1 shou|
00000d00  6c 64 20 62 65 20 74 68  65 20 73 61 6d 65 2e 0d  |ld be the same..|
00000d10  26 45 46 20 73 68 6f 75  6c 64 20 73 74 6f 72 65  |&EF should store|
00000d20  20 74 68 65 20 6e 75 6d  62 65 72 20 6f 66 20 79  | the number of y|
00000d30  6f 75 72 20 6e 65 77 20  4f 73 62 79 74 65 20 61  |our new Osbyte a|
00000d40  6e 64 20 74 68 65 20 61  63 63 75 6d 75 6c 61 74  |nd the accumulat|
00000d50  6f 72 0d 73 68 6f 75 6c  64 20 62 65 20 72 65 73  |or.should be res|
00000d60  65 74 20 74 6f 20 7a 65  72 6f 20 62 65 66 6f 72  |et to zero befor|
00000d70  65 20 72 65 74 75 72 6e  69 6e 67 20 74 6f 20 74  |e returning to t|
00000d80  68 65 20 4d 4f 53 2e 20  4f 6e 20 72 65 74 75 72  |he MOS. On retur|
00000d90  6e 20 74 6f 20 74 68 65  0d 4d 4f 53 20 74 68 65  |n to the.MOS the|
00000da0  20 6e 75 6d 62 65 72 20  73 74 6f 72 65 64 20 69  | number stored i|
00000db0  6e 20 26 45 46 20 69 73  20 63 6f 70 69 65 64 20  |n &EF is copied |
00000dc0  69 6e 74 6f 20 74 68 65  20 61 63 63 75 6d 75 6c  |into the accumul|
00000dd0  61 74 6f 72 2e 0d 0d 20  20 59 6f 75 20 63 61 6e  |ator...  You can|
00000de0  20 75 73 65 20 74 68 65  20 58 20 61 6e 64 20 59  | use the X and Y|
00000df0  20 70 61 72 61 6d 65 74  65 72 73 20 6f 66 20 61  | parameters of a|
00000e00  6e 20 4f 73 62 79 74 65  20 63 61 6c 6c 20 74 6f  |n Osbyte call to|
00000e10  20 6d 61 6b 65 20 74 77  6f 0d 28 6f 6e 65 20 62  | make two.(one b|
00000e20  79 74 65 29 20 6e 75 6d  62 65 72 73 20 6f 72 20  |yte) numbers or |
00000e30  6f 6e 65 20 28 74 77 6f  20 62 79 74 65 29 20 6e  |one (two byte) n|
00000e40  75 6d 62 65 72 20 61 76  61 69 6c 61 62 6c 65 20  |umber available |
00000e50  74 6f 20 79 6f 75 72 20  6e 65 77 0d 72 6f 75 74  |to your new.rout|
00000e60  69 6e 65 2e 20 49 66 20  79 6f 75 20 77 61 6e 74  |ine. If you want|
00000e70  20 74 6f 20 6d 61 6b 65  20 61 20 74 77 6f 20 62  | to make a two b|
00000e80  79 74 65 20 6e 75 6d 62  65 72 20 61 76 61 69 6c  |yte number avail|
00000e90  61 62 6c 65 20 73 74 6f  72 65 20 74 68 65 0d 6c  |able store the.l|
00000ea0  65 61 73 74 20 73 69 67  6e 69 66 69 63 61 6e 74  |east significant|
00000eb0  20 62 79 74 65 20 69 6e  20 58 20 61 6e 64 20 74  | byte in X and t|
00000ec0  68 65 20 6d 6f 73 74 20  73 69 67 6e 69 66 69 63  |he most signific|
00000ed0  61 6e 74 20 62 79 74 65  20 69 6e 20 59 2e 20 46  |ant byte in Y. F|
00000ee0  6f 72 0d 65 78 61 6d 70  6c 65 2c 0d 0d 20 20 4c  |or.example,..  L|
00000ef0  44 41 20 23 31 30 30 20  20 20 20 20 20 20 20 20  |DA #100         |
00000f00  20 20 20 20 20 5c 20 4e  65 77 20 6f 73 62 79 74  |     \ New osbyt|
00000f10  65 0d 20 20 4c 44 58 20  23 28 6e 75 6d 62 65 72  |e.  LDX #(number|
00000f20  20 4d 4f 44 20 32 35 36  29 20 5c 20 4c 65 61 73  | MOD 256) \ Leas|
00000f30  74 20 73 69 67 6e 69 66  69 63 61 6e 74 20 62 79  |t significant by|
00000f40  74 65 0d 20 20 4c 44 59  20 23 28 6e 75 6d 62 65  |te.  LDY #(numbe|
00000f50  72 20 44 49 56 20 32 35  36 29 20 5c 20 4d 6f 73  |r DIV 256) \ Mos|
00000f60  74 20 73 69 67 6e 69 66  69 63 61 6e 74 20 62 79  |t significant by|
00000f70  74 65 0d 20 20 4a 53 52  20 26 46 46 46 34 20 20  |te.  JSR &FFF4  |
00000f80  20 20 20 20 20 20 20 20  20 20 20 5c 20 43 61 6c  |           \ Cal|
00000f90  6c 20 6f 73 62 79 74 65  0d 0d 20 20 59 6f 75 72  |l osbyte..  Your|
00000fa0  20 6e 65 77 20 4f 73 62  79 74 65 20 63 61 6e 20  | new Osbyte can |
00000fb0  74 68 65 6e 20 72 65 61  64 20 74 68 65 20 6c 65  |then read the le|
00000fc0  61 73 74 20 73 69 67 6e  69 66 69 63 61 6e 74 20  |ast significant |
00000fd0  62 79 74 65 20 66 72 6f  6e 20 26 46 30 0d 61 6e  |byte fron &F0.an|
00000fe0  64 20 74 68 65 20 6d 6f  73 74 20 73 69 67 6e 69  |d the most signi|
00000ff0  66 69 63 61 6e 74 20 62  79 74 65 20 66 72 6f 6d  |ficant byte from|
00001000  20 26 46 31 2e 20 49 74  20 63 61 6e 20 61 6c 73  | &F1. It can als|
00001010  6f 20 75 73 65 20 74 68  65 73 65 20 6d 65 6d 6f  |o use these memo|
00001020  72 79 0d 6c 6f 63 61 74  69 6f 6e 73 20 66 6f 72  |ry.locations for|
00001030  20 70 6f 73 74 2d 69 6e  64 65 78 65 64 20 69 6e  | post-indexed in|
00001040  64 69 72 65 63 74 20 61  64 64 72 65 73 73 69 6e  |direct addressin|
00001050  67 2e 0d 0d 20 20 54 68  65 20 69 6e 74 65 72 70  |g...  The interp|
00001060  72 65 74 65 72 20 6e 65  65 64 65 64 20 74 6f 20  |reter needed to |
00001070  69 6d 70 6c 65 6d 65 6e  74 20 61 20 6e 65 77 20  |implement a new |
00001080  4f 73 62 79 74 65 20 69  73 20 70 72 6f 62 61 62  |Osbyte is probab|
00001090  6c 79 20 74 68 65 0d 65  61 73 69 65 73 74 20 6f  |ly the.easiest o|
000010a0  66 20 61 6c 6c 20 69 6e  74 65 72 70 72 65 74 65  |f all interprete|
000010b0  72 73 20 74 6f 20 77 72  69 74 65 2e 20 41 6e 20  |rs to write. An |
000010c0  6f 75 74 6c 69 6e 65 20  69 6e 74 65 72 70 72 65  |outline interpre|
000010d0  74 65 72 20 69 73 20 73  68 6f 77 6e 0d 69 6e 20  |ter is shown.in |
000010e0  66 69 67 75 72 65 20 36  2e 32 2e 0d 0d 0d 0d 0d  |figure 6.2......|
000010f0  2e 73 65 72 76 69 63 65  0d 20 20 20 20 20 20 20  |.service.       |
00001100  20 20 50 48 41 20 20 20  20 20 20 20 20 20 20 20  |  PHA           |
00001110  5c 20 70 75 73 68 20 61  63 63 75 6d 75 6c 61 74  |\ push accumulat|
00001120  6f 72 0d 20 20 20 20 20  20 20 20 20 43 4d 50 20  |or.         CMP |
00001130  23 37 20 20 20 20 20 20  20 20 5c 20 69 73 20 69  |#7        \ is i|
00001140  74 20 61 6e 20 75 6e 72  65 63 6f 67 6e 69 73 65  |t an unrecognise|
00001150  64 20 4f 73 62 79 74 65  3f 0d 20 20 20 20 20 20  |d Osbyte?.      |
00001160  20 20 20 42 45 51 20 6e  65 77 6f 73 62 79 74 65  |   BEQ newosbyte|
00001170  20 5c 20 62 72 61 6e 63  68 20 69 66 20 69 74 20  | \ branch if it |
00001180  69 73 0d 2e 65 78 69 74  0d 20 20 20 20 20 20 20  |is..exit.       |
00001190  20 20 50 4c 41 20 20 20  20 20 20 20 20 20 20 20  |  PLA           |
000011a0  5c 20 70 75 6c 6c 20 61  63 63 75 6d 75 6c 61 74  |\ pull accumulat|
000011b0  6f 72 0d 20 20 20 20 20  20 20 20 20 52 54 53 20  |or.         RTS |
000011c0  20 20 20 20 20 20 20 20  20 20 5c 20 72 65 74 75  |          \ retu|
000011d0  72 6e 20 61 6e 64 20 67  69 76 65 20 6f 74 68 65  |rn and give othe|
000011e0  72 20 72 6f 6d 73 20 74  68 65 20 63 61 6c 6c 0d  |r roms the call.|
000011f0  2e 6e 65 77 6f 73 62 79  74 65 0d 20 20 20 20 20  |.newosbyte.     |
00001200  20 20 20 20 4c 44 41 20  26 45 46 20 20 20 20 20  |    LDA &EF     |
00001210  20 20 5c 20 6c 6f 61 64  20 4f 73 62 79 74 65 20  |  \ load Osbyte |
00001220  6e 75 6d 62 65 72 20 66  72 6f 6d 20 26 45 46 0d  |number from &EF.|
00001230  20 20 20 20 20 20 20 20  20 43 4d 50 20 23 31 30  |         CMP #10|
00001240  30 20 20 20 20 20 20 5c  20 69 73 20 69 74 20 31  |0      \ is it 1|
00001250  30 30 3f 0d 20 20 20 20  20 20 20 20 20 42 4e 45  |00?.         BNE|
00001260  20 65 78 69 74 20 20 20  20 20 20 5c 20 62 72 61  | exit      \ bra|
00001270  6e 63 68 20 69 66 20 6e  6f 74 20 4f 73 62 79 74  |nch if not Osbyt|
00001280  65 20 31 30 30 0d 20 20  20 20 20 20 20 20 20 4c  |e 100.         L|
00001290  44 58 20 26 46 30 20 20  20 20 20 20 20 5c 20 72  |DX &F0       \ r|
000012a0  65 61 64 20 58 20 66 72  6f 6d 20 26 46 30 0d 20  |ead X from &F0. |
000012b0  20 20 20 20 20 20 20 20  4c 44 59 20 26 46 31 20  |        LDY &F1 |
000012c0  20 20 20 20 20 20 5c 20  72 65 61 64 20 59 20 66  |      \ read Y f|
000012d0  72 6f 6d 20 26 46 31 0d  20 20 20 20 20 20 20 20  |rom &F1.        |
000012e0  20 20 2e 0d 20 20 20 20  20 20 20 20 20 20 2e 20  |  ..          . |
000012f0  20 20 20 20 20 20 20 20  20 20 20 5c 20 6e 65 77  |           \ new|
00001300  20 72 6f 75 74 69 6e 65  20 67 6f 65 73 20 69 6e  | routine goes in|
00001310  20 68 65 72 65 0d 20 20  20 20 20 20 20 20 20 20  | here.          |
00001320  2e 0d 20 20 20 20 20 20  20 20 20 53 54 58 20 26  |..         STX &|
00001330  46 30 20 20 20 20 20 20  20 5c 20 73 74 6f 72 65  |F0       \ store|
00001340  20 72 65 73 75 6c 74 20  66 6f 72 20 58 0d 20 20  | result for X.  |
00001350  20 20 20 20 20 20 20 53  54 59 20 26 46 31 20 20  |       STY &F1  |
00001360  20 20 20 20 20 5c 20 73  74 6f 72 65 20 72 65 73  |     \ store res|
00001370  75 6c 74 20 66 6f 72 20  59 0d 20 20 20 20 20 20  |ult for Y.      |
00001380  20 20 20 50 4c 41 20 20  20 20 20 20 20 20 20 20  |   PLA          |
00001390  20 5c 20 70 75 6c 6c 20  41 20 70 75 73 68 65 64  | \ pull A pushed|
000013a0  20 62 79 20 69 6e 74 65  72 70 72 65 74 65 72 0d  | by interpreter.|
000013b0  20 20 20 20 20 20 20 20  20 4c 44 41 20 23 30 20  |         LDA #0 |
000013c0  20 20 20 20 20 20 20 5c  20 6f 74 68 65 72 20 72  |       \ other r|
000013d0  6f 6d 73 20 69 67 6e 6f  72 65 20 74 68 69 73 20  |oms ignore this |
000013e0  63 61 6c 6c 0d 20 20 20  20 20 20 20 20 20 52 54  |call.         RT|
000013f0  53 20 20 20 20 20 20 20  20 20 20 20 5c 20 72 65  |S           \ re|
00001400  74 75 72 6e 20 74 6f 20  4d 4f 53 0d 0d 46 69 67  |turn to MOS..Fig|
00001410  75 72 65 20 36 2e 32 20  41 6e 20 4f 73 62 79 74  |ure 6.2 An Osbyt|
00001420  65 20 69 6e 74 65 72 70  72 65 74 65 72 2e 0d 2d  |e interpreter..-|
00001430  2d 2d 2d 2d 2d 2d 2d 2d  2d 2d 2d 2d 2d 2d 2d 2d  |----------------|
*
00001450  0d 0d 0d 0d 0d 20 20 54  68 65 20 73 65 72 76 69  |.....  The servi|
00001460  63 65 20 65 6e 74 72 79  20 70 6f 69 6e 74 20 6f  |ce entry point o|
00001470  66 20 74 68 65 20 6f 75  74 6c 69 6e 65 20 69 6e  |f the outline in|
00001480  74 65 72 70 72 65 74 65  72 20 69 6e 20 66 69 67  |terpreter in fig|
00001490  75 72 65 20 36 2e 32 0d  77 69 6c 6c 20 68 61 76  |ure 6.2.will hav|
000014a0  65 20 61 20 6a 75 6d 70  20 74 6f 20 74 68 65 20  |e a jump to the |
000014b0  6c 61 62 65 6c 20 22 2e  73 65 72 76 69 63 65 22  |label ".service"|
000014c0  2e 20 4f 6e 20 65 6e 74  65 72 69 6e 67 20 74 68  |. On entering th|
000014d0  65 20 69 6e 74 65 72 70  72 65 74 65 72 0d 74 68  |e interpreter.th|
000014e0  65 20 61 63 63 75 6d 75  6c 61 74 6f 72 20 69 73  |e accumulator is|
000014f0  20 70 75 73 68 65 64 20  6f 6e 20 74 68 65 20 73  | pushed on the s|
00001500  74 61 63 6b 20 61 6e 64  20 74 68 65 6e 20 63 6f  |tack and then co|
00001510  6d 70 61 72 65 64 20 77  69 74 68 20 37 20 74 6f  |mpared with 7 to|
00001520  20 73 65 65 0d 69 66 20  74 68 65 20 63 61 6c 6c  | see.if the call|
00001530  20 69 73 20 61 6e 20 75  6e 72 65 63 6f 67 6e 69  | is an unrecogni|
00001540  73 65 64 20 4f 73 62 79  74 65 2e 20 49 66 20 69  |sed Osbyte. If i|
00001550  74 20 69 73 20 6e 6f 74  20 74 68 65 20 61 63 63  |t is not the acc|
00001560  75 6d 75 6c 61 74 6f 72  20 69 73 0d 70 75 6c 6c  |umulator is.pull|
00001570  65 64 20 6f 66 66 20 74  68 65 20 73 74 61 63 6b  |ed off the stack|
00001580  20 61 6e 64 20 63 6f 6e  74 72 6f 6c 20 69 73 20  | and control is |
00001590  72 65 74 75 72 6e 65 64  20 74 6f 20 74 68 65 20  |returned to the |
000015a0  4d 4f 53 2e 20 49 66 20  74 68 65 20 63 61 6c 6c  |MOS. If the call|
000015b0  0d 69 73 20 66 6f 72 20  61 6e 20 75 6e 72 65 63  |.is for an unrec|
000015c0  6f 67 6e 69 73 65 64 20  4f 73 62 79 74 65 20 74  |ognised Osbyte t|
000015d0  68 65 20 6e 75 6d 62 65  72 20 73 74 6f 72 65 64  |he number stored|
000015e0  20 69 6e 20 26 45 46 20  69 73 20 6c 6f 61 64 65  | in &EF is loade|
000015f0  64 20 69 6e 74 6f 0d 74  68 65 20 61 63 63 75 6d  |d into.the accum|
00001600  75 6c 61 74 6f 72 20 61  6e 64 20 63 6f 6d 70 61  |ulator and compa|
00001610  72 65 64 20 77 69 74 68  20 74 68 65 20 6e 75 6d  |red with the num|
00001620  62 65 72 20 6f 66 20 74  68 65 20 6e 65 77 20 4f  |ber of the new O|
00001630  73 62 79 74 65 2c 20 69  6e 0d 74 68 69 73 20 65  |sbyte, in.this e|
00001640  78 61 6d 70 6c 65 20 31  30 30 2e 0d 0d 20 20 49  |xample 100...  I|
00001650  66 20 74 68 65 20 75 6e  72 65 63 6f 67 6e 69 73  |f the unrecognis|
00001660  65 64 20 4f 73 62 79 74  65 20 6e 75 6d 62 65 72  |ed Osbyte number|
00001670  20 73 74 6f 72 65 64 20  69 6e 20 26 45 46 20 69  | stored in &EF i|
00001680  73 20 6e 6f 74 20 31 30  30 20 74 68 65 0d 61 63  |s not 100 the.ac|
00001690  63 75 6d 75 6c 61 74 6f  72 20 69 73 20 70 75 6c  |cumulator is pul|
000016a0  6c 65 64 20 6f 66 66 20  74 68 65 20 73 74 61 63  |led off the stac|
000016b0  6b 20 61 6e 64 20 63 6f  6e 74 72 6f 6c 20 69 73  |k and control is|
000016c0  20 72 65 74 75 72 6e 65  64 20 74 6f 20 74 68 65  | returned to the|
000016d0  0d 4d 4f 53 2e 20 49 66  20 69 74 20 69 73 20 31  |.MOS. If it is 1|
000016e0  30 30 20 74 68 65 6e 20  74 68 65 20 70 61 72 61  |00 then the para|
000016f0  6d 65 74 65 72 73 20 28  69 66 20 75 73 65 64 29  |meters (if used)|
00001700  20 63 61 6e 20 62 65 20  72 65 61 64 20 66 72 6f  | can be read fro|
00001710  6d 20 26 46 30 0d 28 58  20 72 65 67 69 73 74 65  |m &F0.(X registe|
00001720  72 29 20 61 6e 64 20 26  46 31 20 28 59 20 72 65  |r) and &F1 (Y re|
00001730  67 69 73 74 65 72 29 20  61 6e 64 20 74 68 65 20  |gister) and the |
00001740  6e 65 77 20 72 6f 75 74  69 6e 65 20 63 61 6e 20  |new routine can |
00001750  62 65 20 65 78 65 63 75  74 65 64 2e 0d 0d 20 20  |be executed...  |
00001760  41 66 74 65 72 20 63 6f  6d 70 6c 65 74 69 6e 67  |After completing|
00001770  20 74 68 65 20 6e 65 77  20 72 6f 75 74 69 6e 65  | the new routine|
00001780  20 61 6e 79 20 72 65 73  75 6c 74 73 20 61 72 65  | any results are|
00001790  20 73 74 6f 72 65 64 20  69 6e 20 26 46 30 20 28  | stored in &F0 (|
000017a0  58 0d 72 65 67 69 73 74  65 72 29 20 61 6e 64 20  |X.register) and |
000017b0  26 46 31 20 28 59 20 72  65 67 69 73 74 65 72 29  |&F1 (Y register)|
000017c0  2e 20 54 68 65 20 69 6e  64 65 78 20 72 65 67 69  |. The index regi|
000017d0  73 74 65 72 73 20 61 6e  64 20 74 68 65 69 72 20  |sters and their |
000017e0  7a 65 72 6f 0d 70 61 67  65 20 63 6f 70 69 65 73  |zero.page copies|
000017f0  20 73 68 6f 75 6c 64 20  62 65 20 69 64 65 6e 74  | should be ident|
00001800  69 63 61 6c 2e 20 45 76  65 6e 20 69 66 20 79 6f  |ical. Even if yo|
00001810  75 20 64 6f 6e 27 74 20  77 61 6e 74 20 74 6f 20  |u don't want to |
00001820  77 72 69 74 65 20 61 6e  79 0d 72 65 73 75 6c 74  |write any.result|
00001830  73 20 79 6f 75 20 73 68  6f 75 6c 64 20 73 74 69  |s you should sti|
00001840  6c 6c 20 65 6e 73 75 72  65 20 74 68 61 74 20 74  |ll ensure that t|
00001850  68 65 20 69 6e 64 65 78  20 72 65 67 69 73 74 65  |he index registe|
00001860  72 73 20 61 72 65 20 69  64 65 6e 74 69 63 61 6c  |rs are identical|
00001870  0d 74 6f 20 74 68 65 69  72 20 7a 65 72 6f 20 70  |.to their zero p|
00001880  61 67 65 20 63 6f 70 69  65 73 2e 20 54 68 65 20  |age copies. The |
00001890  61 63 63 75 6d 75 6c 61  74 6f 72 20 77 61 73 20  |accumulator was |
000018a0  70 75 73 68 65 64 20 6f  6e 20 74 68 65 20 73 74  |pushed on the st|
000018b0  61 63 6b 20 62 79 0d 74  68 65 20 69 6e 74 65 72  |ack by.the inter|
000018c0  70 72 65 74 65 72 20 61  6e 64 20 69 74 20 69 73  |preter and it is|
000018d0  20 70 75 6c 6c 65 64 20  62 61 63 6b 20 6f 66 66  | pulled back off|
000018e0  20 74 6f 20 62 61 6c 61  6e 63 65 20 74 68 65 20  | to balance the |
000018f0  73 74 61 63 6b 2e 20 54  68 65 0d 61 63 63 75 6d  |stack. The.accum|
00001900  75 6c 61 74 6f 72 20 69  73 20 72 65 73 65 74 20  |ulator is reset |
00001910  74 6f 20 7a 65 72 6f 20  74 6f 20 69 6e 66 6f 72  |to zero to infor|
00001920  6d 20 6f 74 68 65 72 20  72 6f 6d 73 20 74 68 61  |m other roms tha|
00001930  74 20 74 68 65 20 73 65  72 76 69 63 65 0d 63 61  |t the service.ca|
00001940  6c 6c 20 68 61 73 20 62  65 65 6e 20 72 65 63 6f  |ll has been reco|
00001950  67 6e 69 73 65 64 20 61  6e 64 20 63 6f 6e 74 72  |gnised and contr|
00001960  6f 6c 20 69 73 20 70 61  73 73 65 64 20 62 61 63  |ol is passed bac|
00001970  6b 20 74 6f 20 74 68 65  20 4d 4f 53 2e 0d 0d 20  |k to the MOS... |
00001980  20 54 68 65 20 69 6e 74  65 72 70 72 65 74 65 72  | The interpreter|
00001990  20 69 6e 20 66 69 67 75  72 65 20 36 2e 32 20 69  | in figure 6.2 i|
000019a0  73 20 75 73 65 64 20 69  6e 20 74 68 65 20 65 78  |s used in the ex|
000019b0  61 6d 70 6c 65 20 70 72  6f 67 72 61 6d 20 4f 53  |ample program OS|
000019c0  42 59 54 45 2e 0d 54 68  69 73 20 70 72 6f 67 72  |BYTE..This progr|
000019d0  61 6d 20 67 65 6e 65 72  61 74 65 73 20 74 68 65  |am generates the|
000019e0  20 6f 62 6a 65 63 74 20  63 6f 64 65 20 66 6f 72  | object code for|
000019f0  20 2a 46 58 20 31 30 30  2c 78 2c 79 20 69 6e 20  | *FX 100,x,y in |
00001a00  77 68 69 63 68 20 74 68  65 20 58 0d 70 61 72 61  |which the X.para|
00001a10  6d 65 74 65 72 20 69 73  20 74 68 65 20 6e 75 6d  |meter is the num|
00001a20  62 65 72 20 6f 66 20 61  20 72 6f 6d 20 74 6f 20  |ber of a rom to |
00001a30  62 65 20 64 69 73 61 62  6c 65 64 20 61 6e 64 20  |be disabled and |
00001a40  74 68 65 20 59 20 70 61  72 61 6d 65 74 65 72 20  |the Y parameter |
00001a50  69 73 0d 75 73 65 64 20  61 73 20 61 20 66 6c 61  |is.used as a fla|
00001a60  67 20 77 68 69 63 68 2c  20 69 66 20 73 65 74 2c  |g which, if set,|
00001a70  20 74 65 6c 6c 73 20 74  68 65 20 72 6f 75 74 69  | tells the routi|
00001a80  6e 65 20 74 6f 20 70 72  69 6e 74 20 61 20 6c 69  |ne to print a li|
00001a90  73 74 20 6f 66 20 74 68  65 0d 61 63 74 69 76 65  |st of the.active|
00001aa0  20 72 6f 6d 73 2e 20 49  66 20 74 68 65 20 58 20  | roms. If the X |
00001ab0  70 61 72 61 6d 65 74 65  72 20 69 73 20 6f 75 74  |parameter is out|
00001ac0  73 69 64 65 20 74 68 65  20 72 61 6e 67 65 20 66  |side the range f|
00001ad0  72 6f 6d 20 30 20 74 6f  20 31 35 20 69 74 0d 69  |rom 0 to 15 it.i|
00001ae0  73 20 69 67 6e 6f 72 65  64 2e 20 54 6f 20 75 73  |s ignored. To us|
00001af0  65 20 74 68 65 20 70 72  6f 67 72 61 6d 20 6c 6f  |e the program lo|
00001b00  61 64 20 74 68 65 20 6f  62 6a 65 63 74 20 63 6f  |ad the object co|
00001b10  64 65 20 69 74 20 67 65  6e 65 72 61 74 65 73 20  |de it generates |
00001b20  69 6e 74 6f 0d 53 57 52  20 61 6e 64 20 70 72 65  |into.SWR and pre|
00001b30  73 73 20 74 68 65 20 42  72 65 61 6b 20 6b 65 79  |ss the Break key|
00001b40  2e 20 59 6f 75 20 63 61  6e 20 75 73 65 20 74 68  |. You can use th|
00001b50  65 20 6e 65 77 20 4f 73  62 79 74 65 20 74 6f 20  |e new Osbyte to |
00001b60  64 69 73 61 62 6c 65 20  61 6e 79 0d 72 6f 6d 2c  |disable any.rom,|
00001b70  20 65 78 63 65 70 74 20  42 41 53 49 43 2c 20 75  | except BASIC, u|
00001b80  6e 74 69 6c 20 74 68 65  20 42 72 65 61 6b 20 6b  |ntil the Break k|
00001b90  65 79 20 69 73 20 70 72  65 73 73 65 64 20 74 6f  |ey is pressed to|
00001ba0  20 72 65 2d 65 6e 61 62  6c 65 20 69 74 2e 0d 0d  | re-enable it...|
00001bb0  20 20 54 79 70 65 20 2a  46 58 20 31 30 30 2c 31  |  Type *FX 100,1|
00001bc0  30 30 2c 31 20 74 6f 20  6c 69 73 74 20 74 68 65  |00,1 to list the|
00001bd0  20 72 6f 6d 73 20 69 6e  20 79 6f 75 72 20 63 6f  | roms in your co|
00001be0  6d 70 75 74 65 72 2e 20  54 68 69 73 20 63 6f 6d  |mputer. This com|
00001bf0  6d 61 6e 64 0d 77 69 6c  6c 20 62 65 20 72 65 63  |mand.will be rec|
00001c00  6f 67 6e 69 73 65 64 20  61 73 20 74 68 65 20 6e  |ognised as the n|
00001c10  65 77 20 4f 73 62 79 74  65 20 62 75 74 20 74 68  |ew Osbyte but th|
00001c20  65 20 58 20 70 61 72 61  6d 65 74 65 72 20 69 73  |e X parameter is|
00001c30  20 6f 75 74 20 6f 66 0d  72 61 6e 67 65 20 61 6e  | out of.range an|
00001c40  64 20 69 74 20 77 69 6c  6c 20 6e 6f 74 20 64 69  |d it will not di|
00001c50  73 61 62 6c 65 20 61 6e  79 20 72 6f 6d 2e 20 54  |sable any rom. T|
00001c60  68 65 20 59 20 70 61 72  61 6d 65 74 65 72 20 68  |he Y parameter h|
00001c70  61 73 20 61 20 76 61 6c  75 65 0d 6f 74 68 65 72  |as a value.other|
00001c80  20 74 68 61 6e 20 7a 65  72 6f 20 61 6e 64 20 74  | than zero and t|
00001c90  68 65 20 61 63 74 69 76  65 20 72 6f 6d 73 20 77  |he active roms w|
00001ca0  69 6c 6c 20 62 65 20 6c  69 73 74 65 64 2e 0d 0d  |ill be listed...|
00001cb0  20 20 54 79 70 65 20 2a  46 58 20 31 30 30 2c 31  |  Type *FX 100,1|
00001cc0  30 20 74 6f 20 64 69 73  61 62 6c 65 20 72 6f 6d  |0 to disable rom|
00001cd0  20 26 30 41 20 77 69 74  68 6f 75 74 20 6c 69 73  | &0A without lis|
00001ce0  74 69 6e 67 20 74 68 65  20 61 63 74 69 76 65 20  |ting the active |
00001cf0  72 6f 6d 73 2e 0d 54 68  65 20 59 20 70 61 72 61  |roms..The Y para|
00001d00  6d 65 74 65 72 20 69 73  20 6e 6f 74 20 73 70 65  |meter is not spe|
00001d10  63 69 66 69 65 64 20 61  6e 64 20 74 61 6b 65 73  |cified and takes|
00001d20  20 74 68 65 20 64 65 66  61 75 6c 74 20 76 61 6c  | the default val|
00001d30  75 65 20 6f 66 20 7a 65  72 6f 2e 0d 0d 20 20 54  |ue of zero...  T|
00001d40  79 70 65 20 2a 46 58 20  31 30 30 2c 38 2c 31 20  |ype *FX 100,8,1 |
00001d50  74 6f 20 64 69 73 61 62  6c 65 20 72 6f 6d 20 26  |to disable rom &|
00001d60  30 38 20 61 6e 64 20 6c  69 73 74 20 74 68 65 20  |08 and list the |
00001d70  61 63 74 69 76 65 20 72  6f 6d 73 2e 0d 0d 20 20  |active roms...  |
00001d80  59 6f 75 20 63 61 6e 20  72 65 2d 65 6e 61 62 6c  |You can re-enabl|
00001d90  65 20 61 6c 6c 20 74 68  65 20 72 6f 6d 73 20 64  |e all the roms d|
00001da0  69 73 61 62 6c 65 64 20  77 69 74 68 20 74 68 69  |isabled with thi|
00001db0  73 20 6e 65 77 20 4f 73  62 79 74 65 20 62 79 0d  |s new Osbyte by.|
00001dc0  70 72 65 73 73 69 6e 67  20 74 68 65 20 42 72 65  |pressing the Bre|
00001dd0  61 6b 20 6b 65 79 2e 0d  0d 20 20 54 68 65 20 70  |ak key...  The p|
00001de0  72 6f 67 72 61 6d 20 75  73 65 73 20 61 6e 20 4f  |rogram uses an O|
00001df0  73 62 79 74 65 20 69 6e  74 65 72 70 72 65 74 65  |sbyte interprete|
00001e00  72 20 28 6c 69 6e 65 73  20 33 31 30 2d 34 31 30  |r (lines 310-410|
00001e10  29 20 73 69 6d 69 6c 61  72 20 74 6f 0d 74 68 65  |) similar to.the|
00001e20  20 6f 6e 65 20 6f 75 74  6c 69 6e 65 64 20 69 6e  | one outlined in|
00001e30  20 66 69 67 75 72 65 20  36 2e 32 2e 20 41 66 74  | figure 6.2. Aft|
00001e40  65 72 20 72 65 63 6f 67  6e 69 73 69 6e 67 20 74  |er recognising t|
00001e50  68 65 20 6e 65 77 20 4f  73 62 79 74 65 0d 28 6c  |he new Osbyte.(l|
00001e60  69 6e 65 73 20 33 39 30  2d 34 31 30 29 20 74 68  |ines 390-410) th|
00001e70  65 20 6e 65 77 20 72 6f  75 74 69 6e 65 20 6c 6f  |e new routine lo|
00001e80  61 64 73 20 74 68 65 20  58 20 72 65 67 69 73 74  |ads the X regist|
00001e90  65 72 20 77 69 74 68 20  74 68 65 20 58 0d 70 61  |er with the X.pa|
00001ea0  72 61 6d 65 74 65 72 20  28 6c 69 6e 65 20 34 32  |rameter (line 42|
00001eb0  30 29 20 61 6e 64 20 63  6f 6d 70 61 72 65 73 20  |0) and compares |
00001ec0  69 74 20 77 69 74 68 20  26 31 30 20 28 6c 69 6e  |it with &10 (lin|
00001ed0  65 20 34 33 30 29 20 74  6f 20 73 65 65 20 69 66  |e 430) to see if|
00001ee0  20 69 74 0d 69 73 20 69  6e 20 74 68 65 20 72 61  | it.is in the ra|
00001ef0  6e 67 65 20 66 72 6f 6d  20 30 20 74 6f 20 31 35  |nge from 0 to 15|
00001f00  2e 20 49 66 20 58 20 69  73 20 69 6e 20 72 61 6e  |. If X is in ran|
00001f10  67 65 20 69 74 20 64 69  73 61 62 6c 65 73 20 74  |ge it disables t|
00001f20  68 65 20 72 6f 6d 20 62  79 0d 73 74 6f 72 69 6e  |he rom by.storin|
00001f30  67 20 61 20 7a 65 72 6f  20 69 6e 20 74 68 65 20  |g a zero in the |
00001f40  72 6f 6d 20 69 6e 66 6f  72 6d 61 74 69 6f 6e 20  |rom information |
00001f50  74 61 62 6c 65 20 62 79  74 65 20 74 68 61 74 20  |table byte that |
00001f60  63 6f 72 72 65 73 70 6f  6e 64 73 20 77 69 74 68  |corresponds with|
00001f70  0d 74 68 61 74 20 72 6f  6d 20 28 6c 69 6e 65 73  |.that rom (lines|
00001f80  20 34 35 30 2d 34 36 30  29 2e 20 54 68 65 20 59  | 450-460). The Y|
00001f90  20 70 61 72 61 6d 65 74  65 72 20 69 73 20 74 68  | parameter is th|
00001fa0  65 6e 20 6c 6f 61 64 65  64 20 69 6e 74 6f 20 74  |en loaded into t|
00001fb0  68 65 20 59 0d 72 65 67  69 73 74 65 72 20 28 6c  |he Y.register (l|
00001fc0  69 6e 65 20 34 38 30 29  20 61 6e 64 20 63 68 65  |ine 480) and che|
00001fd0  63 6b 65 64 20 74 6f 20  73 65 65 20 69 66 20 69  |cked to see if i|
00001fe0  74 20 68 61 73 20 62 65  65 6e 20 73 65 74 20 28  |t has been set (|
00001ff0  6c 69 6e 65 20 34 39 30  29 2e 0d 49 66 20 69 74  |line 490)..If it|
00002000  20 68 61 73 20 62 65 65  6e 20 73 65 74 20 74 68  | has been set th|
00002010  65 20 61 63 74 69 76 65  20 72 6f 6d 73 20 61 72  |e active roms ar|
00002020  65 20 6c 69 73 74 65 64  20 28 6c 69 6e 65 20 35  |e listed (line 5|
00002030  31 30 29 2e 0d 0d 20 20  54 68 65 20 72 6f 75 74  |10)...  The rout|
00002040  69 6e 65 20 64 6f 65 73  20 6e 6f 74 20 77 72 69  |ine does not wri|
00002050  74 65 20 61 6e 79 20 72  65 73 75 6c 74 73 20 74  |te any results t|
00002060  6f 20 74 68 65 20 7a 65  72 6f 20 70 61 67 65 20  |o the zero page |
00002070  63 6f 70 69 65 73 20 6f  66 0d 74 68 65 20 69 6e  |copies of.the in|
00002080  64 65 78 20 72 65 67 69  73 74 65 72 73 20 62 75  |dex registers bu|
00002090  74 20 69 74 20 73 74 69  6c 6c 20 65 6e 73 75 72  |t it still ensur|
000020a0  65 73 20 74 68 61 74 20  74 68 65 20 69 6e 64 65  |es that the inde|
000020b0  78 20 72 65 67 69 73 74  65 72 73 20 61 6e 64 0d  |x registers and.|
000020c0  74 68 65 69 72 20 63 6f  70 69 65 73 20 61 72 65  |their copies are|
000020d0  20 69 64 65 6e 74 69 63  61 6c 20 28 6c 69 6e 65  | identical (line|
000020e0  73 20 35 33 30 2d 35 34  30 29 2e 20 54 68 65 20  |s 530-540). The |
000020f0  61 63 63 75 6d 75 6c 61  74 6f 72 20 77 61 73 20  |accumulator was |
00002100  70 75 73 68 65 64 0d 6f  6e 20 74 68 65 20 73 74  |pushed.on the st|
00002110  61 63 6b 20 62 79 20 74  68 65 20 69 6e 74 65 72  |ack by the inter|
00002120  70 72 65 74 65 72 20 28  6c 69 6e 65 20 33 32 30  |preter (line 320|
00002130  29 20 61 6e 64 20 69 74  20 69 73 20 70 75 6c 6c  |) and it is pull|
00002140  65 64 20 62 61 63 6b 20  6f 66 66 0d 69 6e 20 6c  |ed back off.in l|
00002150  69 6e 65 20 35 35 30 2e  20 49 74 20 69 73 20 72  |ine 550. It is r|
00002160  65 73 65 74 20 74 6f 20  7a 65 72 6f 20 74 6f 20  |eset to zero to |
00002170  69 6e 66 6f 72 6d 20 74  68 65 20 6f 74 68 65 72  |inform the other|
00002180  20 72 6f 6d 73 20 74 68  61 74 20 74 68 65 0d 73  | roms that the.s|
00002190  65 72 76 69 63 65 20 63  61 6c 6c 20 68 61 73 20  |ervice call has |
000021a0  62 65 65 6e 20 72 65 63  6f 67 6e 69 73 65 64 20  |been recognised |
000021b0  28 6c 69 6e 65 20 35 36  30 29 20 61 6e 64 20 63  |(line 560) and c|
000021c0  6f 6e 74 72 6f 6c 20 69  73 20 72 65 74 75 72 6e  |ontrol is return|
000021d0  65 64 20 74 6f 0d 74 68  65 20 4d 4f 53 20 28 6c  |ed to.the MOS (l|
000021e0  69 6e 65 20 35 37 30 29  2e 0d 0d 20 20 54 68 65  |ine 570)...  The|
000021f0  20 73 75 62 72 6f 75 74  69 6e 65 20 72 6f 6d 6e  | subroutine romn|
00002200  61 6d 65 73 20 28 6c 69  6e 65 73 20 35 38 30 2d  |ames (lines 580-|
00002210  39 34 30 29 20 75 73 65  73 20 4f 73 72 64 72 6d  |940) uses Osrdrm|
00002220  20 74 6f 20 6c 69 73 74  20 74 68 65 0d 74 69 74  | to list the.tit|
00002230  6c 65 73 20 6f 66 20 74  68 65 20 61 63 74 69 76  |les of the activ|
00002240  65 20 72 6f 6d 73 20 61  6e 64 20 69 73 20 73 69  |e roms and is si|
00002250  6d 69 6c 61 72 20 74 6f  20 74 68 65 20 72 6f 75  |milar to the rou|
00002260  74 69 6e 65 20 75 73 65  64 20 74 6f 20 70 72 69  |tine used to pri|
00002270  6e 74 0d 72 6f 6d 20 74  69 74 6c 65 73 20 69 6e  |nt.rom titles in|
00002280  20 74 68 65 20 70 72 6f  67 72 61 6d 20 52 45 41  | the program REA|
00002290  44 52 4f 4d 20 28 75 73  65 64 20 69 6e 20 4d 6f  |DROM (used in Mo|
000022a0  64 75 6c 65 20 31 29 2e  20 54 68 65 20 73 75 62  |dule 1). The sub|
000022b0  72 6f 75 74 69 6e 65 0d  64 65 63 69 6d 61 6c 20  |routine.decimal |
000022c0  28 6c 69 6e 65 73 20 39  35 30 2d 31 31 31 30 29  |(lines 950-1110)|
000022d0  20 70 72 69 6e 74 73 20  74 68 65 20 41 53 43 49  | prints the ASCI|
000022e0  49 20 64 65 63 69 6d 61  6c 20 65 71 75 69 76 61  |I decimal equiva|
000022f0  6c 65 6e 74 20 6f 66 20  61 6e 79 0d 62 79 74 65  |lent of any.byte|
00002300  20 73 74 6f 72 69 6e 67  20 61 20 6e 75 6d 62 65  | storing a numbe|
00002310  72 20 69 6e 20 74 68 65  20 72 61 6e 67 65 20 66  |r in the range f|
00002320  72 6f 6d 20 30 20 74 6f  20 39 39 20 28 64 65 63  |rom 0 to 99 (dec|
00002330  69 6d 61 6c 29 2e 20 49  74 20 69 73 20 71 75 69  |imal). It is qui|
00002340  74 65 0d 61 20 75 73 65  66 75 6c 20 72 6f 75 74  |te.a useful rout|
00002350  69 6e 65 20 61 6e 64 20  63 61 6e 20 61 6c 73 6f  |ine and can also|
00002360  20 62 65 20 75 73 65 64  20 74 6f 20 70 72 69 6e  | be used to prin|
00002370  74 20 61 20 62 69 6e 61  72 79 20 63 6f 64 65 64  |t a binary coded|
00002380  20 64 65 63 69 6d 61 6c  0d 62 79 74 65 2e 0d 0d  | decimal.byte...|
00002390  0d 0d 0d 0d 20 20 20 31  30 20 52 45 4d 3a 20 4f  |....   10 REM: O|
000023a0  53 42 59 54 45 0d 20 20  20 32 30 20 4d 4f 44 45  |SBYTE.   20 MODE|
000023b0  37 0d 20 20 20 33 30 20  48 49 4d 45 4d 3d 26 33  |7.   30 HIMEM=&3|
000023c0  43 30 30 0d 20 20 20 34  30 20 44 49 4d 20 73 61  |C00.   40 DIM sa|
000023d0  76 65 20 35 30 0d 20 20  20 35 30 20 64 69 66 66  |ve 50.   50 diff|
000023e0  3d 26 38 30 30 30 2d 48  49 4d 45 4d 0d 20 20 20  |=&8000-HIMEM.   |
000023f0  36 30 20 61 63 63 75 6d  75 6c 61 74 6f 72 3d 26  |60 accumulator=&|
00002400  45 46 0d 20 20 20 37 30  20 78 72 65 67 69 73 74  |EF.   70 xregist|
00002410  65 72 3d 26 46 30 0d 20  20 20 38 30 20 79 72 65  |er=&F0.   80 yre|
00002420  67 69 73 74 65 72 3d 26  46 31 0d 20 20 20 39 30  |gister=&F1.   90|
00002430  20 72 6f 6d 70 6f 69 6e  74 3d 26 46 36 0d 20 20  | rompoint=&F6.  |
00002440  31 30 30 20 74 61 62 6c  65 3d 26 32 41 31 0d 20  |100 table=&2A1. |
00002450  20 31 31 30 20 6f 73 72  64 72 6d 3d 26 46 46 42  | 110 osrdrm=&FFB|
00002460  39 0d 20 20 31 32 30 20  6f 73 61 73 63 69 3d 26  |9.  120 osasci=&|
00002470  46 46 45 33 0d 20 20 31  33 30 20 6f 73 6e 65 77  |FFE3.  130 osnew|
00002480  6c 3d 26 46 46 45 37 0d  20 20 31 34 30 20 6f 73  |l=&FFE7.  140 os|
00002490  62 79 74 65 3d 26 46 46  46 34 0d 20 20 31 35 30  |byte=&FFF4.  150|
000024a0  20 6f 73 63 6c 69 3d 26  46 46 46 37 0d 20 20 31  | oscli=&FFF7.  1|
000024b0  36 30 20 46 4f 52 20 70  61 73 73 20 3d 20 30 20  |60 FOR pass = 0 |
000024c0  54 4f 20 32 20 53 54 45  50 20 32 0d 20 20 31 37  |TO 2 STEP 2.  17|
000024d0  30 20 50 25 3d 48 49 4d  45 4d 0d 20 20 31 38 30  |0 P%=HIMEM.  180|
000024e0  20 5b 20 20 20 20 20 20  20 4f 50 54 20 70 61 73  | [       OPT pas|
000024f0  73 0d 20 20 31 39 30 20  20 20 20 20 20 20 20 20  |s.  190         |
00002500  42 52 4b 0d 20 20 32 30  30 20 20 20 20 20 20 20  |BRK.  200       |
00002510  20 20 42 52 4b 0d 20 20  32 31 30 20 20 20 20 20  |  BRK.  210     |
00002520  20 20 20 20 42 52 4b 0d  20 20 32 32 30 20 20 20  |    BRK.  220   |
00002530  20 20 20 20 20 20 4a 4d  50 20 73 65 72 76 69 63  |      JMP servic|
00002540  65 2b 64 69 66 66 0d 20  20 32 33 30 20 20 20 20  |e+diff.  230    |
00002550  20 20 20 20 20 4f 50 54  20 46 4e 65 71 75 62 28  |     OPT FNequb(|
00002560  26 38 32 29 0d 20 20 32  34 30 20 20 20 20 20 20  |&82).  240      |
00002570  20 20 20 4f 50 54 20 46  4e 65 71 75 62 28 28 63  |   OPT FNequb((c|
00002580  6f 70 79 72 69 67 68 74  2b 64 69 66 66 29 20 4d  |opyright+diff) M|
00002590  4f 44 20 32 35 36 29 0d  20 20 32 35 30 20 20 20  |OD 256).  250   |
000025a0  20 20 20 20 20 20 42 52  4b 0d 20 20 32 36 30 20  |      BRK.  260 |
000025b0  20 20 20 20 20 20 20 20  4f 50 54 20 46 4e 65 71  |        OPT FNeq|
000025c0  75 73 28 22 4f 53 42 59  54 45 22 29 0d 20 20 32  |us("OSBYTE").  2|
000025d0  37 30 20 2e 63 6f 70 79  72 69 67 68 74 0d 20 20  |70 .copyright.  |
000025e0  32 38 30 20 20 20 20 20  20 20 20 20 42 52 4b 0d  |280         BRK.|
000025f0  20 20 32 39 30 20 20 20  20 20 20 20 20 20 4f 50  |  290         OP|
00002600  54 20 46 4e 65 71 75 73  28 22 28 43 29 20 47 6f  |T FNequs("(C) Go|
00002610  72 64 6f 6e 20 48 6f 72  73 69 6e 67 74 6f 6e 20  |rdon Horsington |
00002620  31 39 38 37 22 29 0d 20  20 33 30 30 20 20 20 20  |1987").  300    |
00002630  20 20 20 20 20 42 52 4b  0d 20 20 33 31 30 20 2e  |     BRK.  310 .|
00002640  73 65 72 76 69 63 65 0d  20 20 33 32 30 20 20 20  |service.  320   |
00002650  20 20 20 20 20 20 50 48  41 0d 20 20 33 33 30 20  |      PHA.  330 |
00002660  20 20 20 20 20 20 20 20  43 4d 50 20 23 37 0d 20  |        CMP #7. |
00002670  20 33 34 30 20 20 20 20  20 20 20 20 20 42 45 51  | 340         BEQ|
00002680  20 6e 65 77 6f 73 62 79  74 65 0d 20 20 33 35 30  | newosbyte.  350|
00002690  20 2e 65 78 69 74 0d 20  20 33 36 30 20 20 20 20  | .exit.  360    |
000026a0  20 20 20 20 20 50 4c 41  0d 20 20 33 37 30 20 20  |     PLA.  370  |
000026b0  20 20 20 20 20 20 20 52  54 53 0d 20 20 33 38 30  |       RTS.  380|
000026c0  20 2e 6e 65 77 6f 73 62  79 74 65 0d 20 20 33 39  | .newosbyte.  39|
000026d0  30 20 20 20 20 20 20 20  20 20 4c 44 41 20 61 63  |0         LDA ac|
000026e0  63 75 6d 75 6c 61 74 6f  72 0d 20 20 34 30 30 20  |cumulator.  400 |
000026f0  20 20 20 20 20 20 20 20  43 4d 50 20 23 31 30 30  |        CMP #100|
00002700  0d 20 20 34 31 30 20 20  20 20 20 20 20 20 20 42  |.  410         B|
00002710  4e 45 20 65 78 69 74 0d  20 20 34 32 30 20 20 20  |NE exit.  420   |
00002720  20 20 20 20 20 20 4c 44  58 20 78 72 65 67 69 73  |      LDX xregis|
00002730  74 65 72 0d 20 20 34 33  30 20 20 20 20 20 20 20  |ter.  430       |
00002740  20 20 43 50 58 20 23 26  31 30 0d 20 20 34 34 30  |  CPX #&10.  440|
00002750  20 20 20 20 20 20 20 20  20 42 43 53 20 63 68 65  |         BCS che|
00002760  63 6b 79 72 65 67 0d 20  20 34 35 30 20 20 20 20  |ckyreg.  450    |
00002770  20 20 20 20 20 4c 44 41  20 23 30 0d 20 20 34 36  |     LDA #0.  46|
00002780  30 20 20 20 20 20 20 20  20 20 53 54 41 20 74 61  |0         STA ta|
00002790  62 6c 65 2c 58 0d 20 20  34 37 30 20 2e 63 68 65  |ble,X.  470 .che|
000027a0  63 6b 79 72 65 67 0d 20  20 34 38 30 20 20 20 20  |ckyreg.  480    |
000027b0  20 20 20 20 20 4c 44 59  20 79 72 65 67 69 73 74  |     LDY yregist|
000027c0  65 72 0d 20 20 34 39 30  20 20 20 20 20 20 20 20  |er.  490        |
000027d0  20 42 45 51 20 6f 75 74  0d 20 20 35 30 30 20 2e  | BEQ out.  500 .|
000027e0  72 6f 6d 6c 69 73 74 0d  20 20 35 31 30 20 20 20  |romlist.  510   |
000027f0  20 20 20 20 20 20 4a 53  52 20 72 6f 6d 6e 61 6d  |      JSR romnam|
00002800  65 73 2b 64 69 66 66 0d  20 20 35 32 30 20 2e 6f  |es+diff.  520 .o|
00002810  75 74 0d 20 20 35 33 30  20 20 20 20 20 20 20 20  |ut.  530        |
00002820  20 4c 44 58 20 78 72 65  67 69 73 74 65 72 0d 20  | LDX xregister. |
00002830  20 35 34 30 20 20 20 20  20 20 20 20 20 4c 44 59  | 540         LDY|
00002840  20 79 72 65 67 69 73 74  65 72 0d 20 20 35 35 30  | yregister.  550|
00002850  20 20 20 20 20 20 20 20  20 50 4c 41 0d 20 20 35  |         PLA.  5|
00002860  36 30 20 20 20 20 20 20  20 20 20 4c 44 41 20 23  |60         LDA #|
00002870  30 0d 20 20 35 37 30 20  20 20 20 20 20 20 20 20  |0.  570         |
00002880  52 54 53 0d 20 20 35 38  30 20 2e 72 6f 6d 6e 61  |RTS.  580 .romna|
00002890  6d 65 73 0d 20 20 35 39  30 20 20 20 20 20 20 20  |mes.  590       |
000028a0  20 20 4a 53 52 20 6f 73  6e 65 77 6c 0d 20 20 36  |  JSR osnewl.  6|
000028b0  30 30 20 20 20 20 20 20  20 20 20 4c 44 41 20 23  |00         LDA #|
000028c0  26 46 0d 20 20 36 31 30  20 20 20 20 20 20 20 20  |&F.  610        |
000028d0  20 50 48 41 0d 20 20 36  32 30 20 2e 72 6f 6d 6c  | PHA.  620 .roml|
000028e0  6f 6f 70 0d 20 20 36 33  30 20 20 20 20 20 20 20  |oop.  630       |
000028f0  20 20 54 41 59 0d 20 20  36 34 30 20 20 20 20 20  |  TAY.  640     |
00002900  20 20 20 20 4c 44 41 20  74 61 62 6c 65 2c 59 0d  |    LDA table,Y.|
00002910  20 20 36 35 30 20 20 20  20 20 20 20 20 20 42 45  |  650         BE|
00002920  51 20 6e 6f 74 68 65 72  65 0d 20 20 36 36 30 20  |Q nothere.  660 |
00002930  20 20 20 20 20 20 20 20  54 59 41 0d 20 20 36 37  |        TYA.  67|
00002940  30 20 20 20 20 20 20 20  20 20 4a 53 52 20 64 65  |0         JSR de|
00002950  63 69 6d 61 6c 2b 64 69  66 66 0d 20 20 36 38 30  |cimal+diff.  680|
00002960  20 20 20 20 20 20 20 20  20 4c 44 41 20 23 41 53  |         LDA #AS|
00002970  43 28 22 20 22 29 0d 20  20 36 39 30 20 20 20 20  |C(" ").  690    |
00002980  20 20 20 20 20 4a 53 52  20 6f 73 61 73 63 69 0d  |     JSR osasci.|
00002990  20 20 37 30 30 20 20 20  20 20 20 20 20 20 4c 44  |  700         LD|
000029a0  41 20 23 26 38 0d 20 20  37 31 30 20 20 20 20 20  |A #&8.  710     |
000029b0  20 20 20 20 53 54 41 20  72 6f 6d 70 6f 69 6e 74  |    STA rompoint|
000029c0  0d 20 20 37 32 30 20 20  20 20 20 20 20 20 20 4c  |.  720         L|
000029d0  44 41 20 23 26 38 30 0d  20 20 37 33 30 20 20 20  |DA #&80.  730   |
000029e0  20 20 20 20 20 20 53 54  41 20 72 6f 6d 70 6f 69  |      STA rompoi|
000029f0  6e 74 2b 31 0d 20 20 37  34 30 20 2e 72 65 61 64  |nt+1.  740 .read|
00002a00  6c 6f 6f 70 0d 20 20 37  35 30 20 20 20 20 20 20  |loop.  750      |
00002a10  20 20 20 49 4e 43 20 72  6f 6d 70 6f 69 6e 74 0d  |   INC rompoint.|
00002a20  20 20 37 36 30 20 20 20  20 20 20 20 20 20 42 45  |  760         BE|
00002a30  51 20 6e 65 77 6c 69 6e  65 0d 20 20 37 37 30 20  |Q newline.  770 |
00002a40  20 20 20 20 20 20 20 20  50 4c 41 0d 20 20 37 38  |        PLA.  78|
00002a50  30 20 20 20 20 20 20 20  20 20 50 48 41 0d 20 20  |0         PHA.  |
00002a60  37 39 30 20 20 20 20 20  20 20 20 20 54 41 59 0d  |790         TAY.|
00002a70  20 20 38 30 30 20 20 20  20 20 20 20 20 20 4a 53  |  800         JS|
00002a80  52 20 6f 73 72 64 72 6d  0d 20 20 38 31 30 20 20  |R osrdrm.  810  |
00002a90  20 20 20 20 20 20 20 43  4d 50 20 23 41 53 43 28  |       CMP #ASC(|
00002aa0  22 20 22 29 0d 20 20 38  32 30 20 20 20 20 20 20  |" ").  820      |
00002ab0  20 20 20 42 43 43 20 6e  65 77 6c 69 6e 65 0d 20  |   BCC newline. |
00002ac0  20 38 33 30 20 20 20 20  20 20 20 20 20 4a 53 52  | 830         JSR|
00002ad0  20 6f 73 61 73 63 69 0d  20 20 38 34 30 20 20 20  | osasci.  840   |
00002ae0  20 20 20 20 20 20 4a 4d  50 20 72 65 61 64 6c 6f  |      JMP readlo|
00002af0  6f 70 2b 64 69 66 66 0d  20 20 38 35 30 20 2e 6e  |op+diff.  850 .n|
00002b00  65 77 6c 69 6e 65 0d 20  20 38 36 30 20 20 20 20  |ewline.  860    |
00002b10  20 20 20 20 20 4a 53 52  20 6f 73 6e 65 77 6c 0d  |     JSR osnewl.|
00002b20  20 20 38 37 30 20 2e 6e  6f 74 68 65 72 65 0d 20  |  870 .nothere. |
00002b30  20 38 38 30 20 20 20 20  20 20 20 20 20 50 4c 41  | 880         PLA|
00002b40  0d 20 20 38 39 30 20 20  20 20 20 20 20 20 20 53  |.  890         S|
00002b50  45 43 0d 20 20 39 30 30  20 20 20 20 20 20 20 20  |EC.  900        |
00002b60  20 53 42 43 20 23 31 0d  20 20 39 31 30 20 20 20  | SBC #1.  910   |
00002b70  20 20 20 20 20 20 50 48  41 0d 20 20 39 32 30 20  |      PHA.  920 |
00002b80  20 20 20 20 20 20 20 20  42 50 4c 20 72 6f 6d 6c  |        BPL roml|
00002b90  6f 6f 70 0d 20 20 39 33  30 20 20 20 20 20 20 20  |oop.  930       |
00002ba0  20 20 50 4c 41 0d 20 20  39 34 30 20 20 20 20 20  |  PLA.  940     |
00002bb0  20 20 20 20 4a 4d 50 20  6f 73 6e 65 77 6c 0d 20  |    JMP osnewl. |
00002bc0  20 39 35 30 20 2e 64 65  63 69 6d 61 6c 0d 20 20  | 950 .decimal.  |
00002bd0  39 36 30 20 20 20 20 20  20 20 20 20 53 45 44 0d  |960         SED.|
00002be0  20 20 39 37 30 20 20 20  20 20 20 20 20 20 43 4c  |  970         CL|
00002bf0  43 0d 20 20 39 38 30 20  20 20 20 20 20 20 20 20  |C.  980         |
00002c00  41 44 43 20 23 30 0d 20  20 39 39 30 20 20 20 20  |ADC #0.  990    |
00002c10  20 20 20 20 20 43 4c 44  0d 20 31 30 30 30 20 20  |     CLD. 1000  |
00002c20  20 20 20 20 20 20 20 50  48 41 0d 20 31 30 31 30  |       PHA. 1010|
00002c30  20 20 20 20 20 20 20 20  20 4c 53 52 20 41 0d 20  |         LSR A. |
00002c40  31 30 32 30 20 20 20 20  20 20 20 20 20 4c 53 52  |1020         LSR|
00002c50  20 41 0d 20 31 30 33 30  20 20 20 20 20 20 20 20  | A. 1030        |
00002c60  20 4c 53 52 20 41 0d 20  31 30 34 30 20 20 20 20  | LSR A. 1040    |
00002c70  20 20 20 20 20 4c 53 52  20 41 0d 20 31 30 35 30  |     LSR A. 1050|
00002c80  20 20 20 20 20 20 20 20  20 4a 53 52 20 6e 69 62  |         JSR nib|
00002c90  62 6c 65 2b 64 69 66 66  0d 20 31 30 36 30 20 20  |ble+diff. 1060  |
00002ca0  20 20 20 20 20 20 20 50  4c 41 0d 20 31 30 37 30  |       PLA. 1070|
00002cb0  20 20 20 20 20 20 20 20  20 41 4e 44 20 23 26 46  |         AND #&F|
00002cc0  0d 20 31 30 38 30 20 2e  6e 69 62 62 6c 65 0d 20  |. 1080 .nibble. |
00002cd0  31 30 39 30 20 20 20 20  20 20 20 20 20 43 4c 43  |1090         CLC|
00002ce0  0d 20 31 31 30 30 20 20  20 20 20 20 20 20 20 41  |. 1100         A|
00002cf0  44 43 20 23 41 53 43 28  22 30 22 29 0d 20 31 31  |DC #ASC("0"). 11|
00002d00  31 30 20 20 20 20 20 20  20 20 20 4a 4d 50 20 6f  |10         JMP o|
00002d10  73 61 73 63 69 0d 20 31  31 32 30 20 2e 6c 61 73  |sasci. 1120 .las|
00002d20  74 62 79 74 65 0d 20 31  31 33 30 20 5d 0d 20 31  |tbyte. 1130 ]. 1|
00002d30  31 34 30 20 4e 45 58 54  0d 20 31 31 35 30 20 49  |140 NEXT. 1150 I|
00002d40  4e 50 55 54 27 22 53 61  76 65 20 66 69 6c 65 6e  |NPUT'"Save filen|
00002d50  61 6d 65 20 3d 20 22 66  69 6c 65 6e 61 6d 65 24  |ame = "filename$|
00002d60  0d 20 31 31 36 30 20 49  46 20 66 69 6c 65 6e 61  |. 1160 IF filena|
00002d70  6d 65 24 3d 22 22 20 45  4e 44 0d 20 31 31 37 30  |me$="" END. 1170|
00002d80  20 24 73 61 76 65 3d 22  53 41 56 45 20 22 2b 66  | $save="SAVE "+f|
00002d90  69 6c 65 6e 61 6d 65 24  2b 22 20 22 2b 53 54 52  |ilename$+" "+STR|
00002da0  24 7e 28 48 49 4d 45 4d  29 2b 22 20 22 2b 53 54  |$~(HIMEM)+" "+ST|
00002db0  52 24 7e 28 6c 61 73 0d  20 20 20 20 20 20 74 62  |R$~(las.      tb|
00002dc0  79 74 65 29 2b 22 20 46  46 46 46 38 30 30 30 20  |yte)+" FFFF8000 |
00002dd0  46 46 46 46 38 30 30 30  22 0d 20 31 31 38 30 20  |FFFF8000". 1180 |
00002de0  58 25 3d 73 61 76 65 20  4d 4f 44 20 32 35 36 0d  |X%=save MOD 256.|
00002df0  20 31 31 39 30 20 59 25  3d 73 61 76 65 20 44 49  | 1190 Y%=save DI|
00002e00  56 20 32 35 36 0d 20 31  32 30 30 20 2a 4f 50 54  |V 256. 1200 *OPT|
00002e10  31 2c 32 0d 20 31 32 31  30 20 43 41 4c 4c 20 6f  |1,2. 1210 CALL o|
00002e20  73 63 6c 69 0d 20 31 32  32 30 20 2a 4f 50 54 31  |scli. 1220 *OPT1|
00002e30  2c 30 0d 20 31 32 33 30  20 45 4e 44 0d 20 31 32  |,0. 1230 END. 12|
00002e40  34 30 20 44 45 46 46 4e  65 71 75 62 28 62 79 74  |40 DEFFNequb(byt|
00002e50  65 29 0d 20 31 32 35 30  20 3f 50 25 3d 62 79 74  |e). 1250 ?P%=byt|
00002e60  65 0d 20 31 32 36 30 20  50 25 3d 50 25 2b 31 0d  |e. 1260 P%=P%+1.|
00002e70  20 31 32 37 30 20 3d 70  61 73 73 0d 20 31 32 38  | 1270 =pass. 128|
00002e80  30 20 44 45 46 46 4e 65  71 75 77 28 77 6f 72 64  |0 DEFFNequw(word|
00002e90  29 0d 20 31 32 39 30 20  3f 50 25 3d 77 6f 72 64  |). 1290 ?P%=word|
00002ea0  20 4d 4f 44 20 32 35 36  0d 20 31 33 30 30 20 50  | MOD 256. 1300 P|
00002eb0  25 3f 31 3d 77 6f 72 64  20 44 49 56 20 32 35 36  |%?1=word DIV 256|
00002ec0  0d 20 31 33 31 30 20 50  25 3d 50 25 2b 32 0d 20  |. 1310 P%=P%+2. |
00002ed0  31 33 32 30 20 3d 70 61  73 73 0d 20 31 33 33 30  |1320 =pass. 1330|
00002ee0  20 44 45 46 46 4e 65 71  75 64 28 64 6f 75 62 6c  | DEFFNequd(doubl|
00002ef0  65 29 0d 20 31 33 34 30  20 21 50 25 3d 64 6f 75  |e). 1340 !P%=dou|
00002f00  62 6c 65 0d 20 31 33 35  30 20 50 25 3d 50 25 2b  |ble. 1350 P%=P%+|
00002f10  34 0d 20 31 33 36 30 20  3d 70 61 73 73 0d 20 31  |4. 1360 =pass. 1|
00002f20  33 37 30 20 44 45 46 46  4e 65 71 75 73 28 73 74  |370 DEFFNequs(st|
00002f30  72 69 6e 67 24 29 0d 20  31 33 38 30 20 24 50 25  |ring$). 1380 $P%|
00002f40  3d 73 74 72 69 6e 67 24  0d 20 31 33 39 30 20 50  |=string$. 1390 P|
00002f50  25 3d 50 25 2b 4c 45 4e  28 73 74 72 69 6e 67 24  |%=P%+LEN(string$|
00002f60  29 0d 20 31 34 30 30 20  3d 70 61 73 73 0d        |). 1400 =pass.|
00002f6e
13-08-88/T\SWR06.m0
13-08-88/T\SWR06.m1
13-08-88/T\SWR06.m2
13-08-88/T\SWR06.m4
13-08-88/T\SWR06.m5