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27_11_87/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.

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Filename: 27_11_87/T\SWR06
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File size: 2F6E bytes
Load address: 0000
Exec address: 0000
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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|
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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    |
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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|
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00002d00  31 30 20 20 20 20 20 20  20 20 20 4a 4d 50 20 6f  |10         JMP o|
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00002d30  31 34 30 20 4e 45 58 54  0d 20 31 31 35 30 20 49  |140 NEXT. 1150 I|
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00002d80  20 24 73 61 76 65 3d 22  53 41 56 45 20 22 2b 66  | $save="SAVE "+f|
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00002da0  24 7e 28 48 49 4d 45 4d  29 2b 22 20 22 2b 53 54  |$~(HIMEM)+" "+ST|
00002db0  52 24 7e 28 6c 61 73 0d  20 20 20 20 20 20 74 62  |R$~(las.      tb|
00002dc0  79 74 65 29 2b 22 20 46  46 46 46 38 30 30 30 20  |yte)+" FFFF8000 |
00002dd0  46 46 46 46 38 30 30 30  22 0d 20 31 31 38 30 20  |FFFF8000". 1180 |
00002de0  58 25 3d 73 61 76 65 20  4d 4f 44 20 32 35 36 0d  |X%=save MOD 256.|
00002df0  20 31 31 39 30 20 59 25  3d 73 61 76 65 20 44 49  | 1190 Y%=save DI|
00002e00  56 20 32 35 36 0d 20 31  32 30 30 20 2a 4f 50 54  |V 256. 1200 *OPT|
00002e10  31 2c 32 0d 20 31 32 31  30 20 43 41 4c 4c 20 6f  |1,2. 1210 CALL o|
00002e20  73 63 6c 69 0d 20 31 32  32 30 20 2a 4f 50 54 31  |scli. 1220 *OPT1|
00002e30  2c 30 0d 20 31 32 33 30  20 45 4e 44 0d 20 31 32  |,0. 1230 END. 12|
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00002e50  65 29 0d 20 31 32 35 30  20 3f 50 25 3d 62 79 74  |e). 1250 ?P%=byt|
00002e60  65 0d 20 31 32 36 30 20  50 25 3d 50 25 2b 31 0d  |e. 1260 P%=P%+1.|
00002e70  20 31 32 37 30 20 3d 70  61 73 73 0d 20 31 32 38  | 1270 =pass. 128|
00002e80  30 20 44 45 46 46 4e 65  71 75 77 28 77 6f 72 64  |0 DEFFNequw(word|
00002e90  29 0d 20 31 32 39 30 20  3f 50 25 3d 77 6f 72 64  |). 1290 ?P%=word|
00002ea0  20 4d 4f 44 20 32 35 36  0d 20 31 33 30 30 20 50  | MOD 256. 1300 P|
00002eb0  25 3f 31 3d 77 6f 72 64  20 44 49 56 20 32 35 36  |%?1=word DIV 256|
00002ec0  0d 20 31 33 31 30 20 50  25 3d 50 25 2b 32 0d 20  |. 1310 P%=P%+2. |
00002ed0  31 33 32 30 20 3d 70 61  73 73 0d 20 31 33 33 30  |1320 =pass. 1330|
00002ee0  20 44 45 46 46 4e 65 71  75 64 28 64 6f 75 62 6c  | DEFFNequd(doubl|
00002ef0  65 29 0d 20 31 33 34 30  20 21 50 25 3d 64 6f 75  |e). 1340 !P%=dou|
00002f00  62 6c 65 0d 20 31 33 35  30 20 50 25 3d 50 25 2b  |ble. 1350 P%=P%+|
00002f10  34 0d 20 31 33 36 30 20  3d 70 61 73 73 0d 20 31  |4. 1360 =pass. 1|
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00002f30  72 69 6e 67 24 29 0d 20  31 33 38 30 20 24 50 25  |ring$). 1380 $P%|
00002f40  3d 73 74 72 69 6e 67 24  0d 20 31 33 39 30 20 50  |=string$. 1390 P|
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00002f60  29 0d 20 31 34 30 30 20  3d 70 61 73 73 0d        |). 1400 =pass.|
00002f6e
27_11_87/T\SWR06.m0
27_11_87/T\SWR06.m1
27_11_87/T\SWR06.m2
27_11_87/T\SWR06.m4
27_11_87/T\SWR06.m5