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Mod_Dis/Manual
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 » Archimedes archive » Micro User » MU 1991-04.adf » PD-Stuff |
| Filename: | Mod_Dis/Manual |
| Read OK: | ✔ |
| File size: | 44DF bytes |
| Load address: | 0000 |
| Exec address: | 0000 |
File contents
>Manual
Directory Structure
===================
MOD_DIS
|
+--------+----+-----+----+----------+-----------+-----------+---------+
| | | | | | | | |
GetStarted | Changes | Checker MODULES ORIGINALS SCRIPTS SOURCES
| | | | | |
Manual ModDis201 ---+--- ---+--- ---+--- ---+---
GetStarted Text How to start quickly without reading the manual
Manual Text The manual
Changes Text Major changes since version 1.04
ModDis201 BASIC The main program
Checker BASIC Checks the validity of a re-assembled module
MODULES Dir Newly-assembled modules are saved here
ORIGINALS Dir The module to be disassembled should be put here
SCRIPTS Dir User responses are stored here
SOURCES Dir Disassembled modules are stored here
This is version 2.01 of ModDis, and replaces those versions previously
published (0.E, 0.F and 1.04). It has various bug fixes and enhancements not
available in previous versions. If you already have version 1.04, see the
file Changes for details of important changes. If you don't want to read
this manual yet try reading GetStarted and following its instructions.
ModDis a semi-intelligent module disassembler. It will read a relocatable
module file from the ORIGINALS directory and attempt to disassemble it into
a form suitable for the BASIC assembler. If successful, the output file is
stored in the SOURCES directory, under the same filename as the module. If,
as is likely, the program cannot resolve the disassembly unaided, it will
prompt the user for help, hence the "semi-intelligent" description. These
responses can be stored in the SCRIPTS directory and played back later to
re-create the disassembly. The validity of the disassembly can be tested by
re-assembling, which makes a new version in the MODULES directory. The BASIC
program Checker can then be used to do a byte-by-byte comparison of the
original and new versions.
I had already disassembled several modules by hand, and, while it is
relatively easy, it becomes quite tedious as the module size increases. This
program started as a quick utility to do some of the mechanical
"donkey-work" aspects of disassembly, but has grown out of all proportion to
its original aims. I have successfully disassembled about 30 of the RISC OS
modules, and there are usually only a handful of errors to sort out in the
output assembler listing (see the Problems section for details). You should
be warned, however, that some of the larger RISC OS modules can produce
thousands of lines of assembler listing.
There are more enhancements in the pipeline, but it will probably be some
time before they become available.
In use
======
Start by making ModDis your current directory, and load the ModDis201
program. There is one feature which the user can change, located in
PROCinit, around line 8000:
debug%=TRUE
If debug% is TRUE, extra information is printed out in cyan while the
program is running. I find it reassuring to be able to see what the program
is doing. Setting it to FALSE will supress this printout, and there will be
sometimes be long pauses when it is not obvious if the program is doing
anything.
How the program works
=====================
The program identifies the "type" of each byte of the module, according to
the following scheme:
type description
-4 'Acorn'-format compressed string
-3 Padded string, ie a string padded with zeros up to a fixed length
-2 Carriage-return-terminated string
-1 Zero-terminated string
0 Don't know
1 A byte of data
2 A word (2 bytes of data)
3 Address, ie a 4-byte number pointing to another point in the module
4 A double word (4 bytes of data)
5 ARM code
6 Alignment bytes, 1, 2 or 3 bytes to bring us to a word boundary
7 External. See below
The first pass through the module is made armed with the entry points, eg
initialisation code, finalisation code, etc. At this stage, ModDis is just
setting the "type" of each byte it comes across, code, data or whatever. If
it finds code, it follows it, and investigates branches and subroutine calls
recursively, asking the user for help with identifying what it has found,
where necessary. The program is smart enough to spot when the code ends, so
it doesn't "fall off" into following data. It also recognises such things as
SWI "OS_Exit", the zero-terminated string which always follows SWI
"OS_WriteS", and stuff like that.
After investigating all the entry points, it does one sequential pass
through the module, searching for any bytes whose type has not yet been
identified, and asking the user what they are.
Once all the types have been sorted out, the disassembly proper starts. If
parts of the module are marked as data, they are expanded with EQU
directives. The code is disassembled with calls to the Debugger module, but
the following enhancements are made to its output:
1. Labels are placed at all necessary points, as .xABCD where ABCD is the
offset in hex from the module start.
2. Wherever possible, sensible label names are constructed, eg SWI tables,
Keyword code, etc.
3. Branches are expanded to refer to labels.
4. Subroutines are identified by sABCD, rather than xABCD
5. PC-relative addressing is expanded as the ADR macro.
6. SWI names are enclosed in quotes.
7. The 2 instructions making up a 'long ADR' are recognised and represented
by a macro, FNadrl, to aid readability.
The "What's this?" prompt
=========================
During the first pass through the module, the program will ask for help if
it finds a reference to another part of the module, asking whether this
reference is code to be disassembled, or data, in which case it wants to
know what kind of data it is. The display looks like this:
[ ] This is the line currently being disassembled
[ Block of ] and the three following, to show the context.
[ yellow text ]
[ ]
[ ]
[ Block of ] A few lines preceding the reference
[ white text ]
[ ]
[ RED LINE ] The address being referred to
[ ]
[ More ] A few lines after the reference
[ white text ]
[ ]
What's this? The prompt
The program expects a numeric response in the range -4 to 7.
It should be easy to tell if it's a string. Most strings are zero-terminated
(type -1), but OS_CLI strings may be CR-terminated (-2). RISC OS menu labels
are usually padded with zeros to 12 bytes; if you reply -3 you will be asked
for the length of the padded string. 'Acorn'-format strings contain ASCII 27
to indicate compressed dictionary entries; although zero-terminated they may
also contain ASCII 0 immediately after ASCII 27.
Try to avoid replying 0 (don't know) if at all possible, because you'll have
to answer sooner or later, and this may be your best oppertunity. There are
however, two occasions when it is useful to answer 0. One is when the offset
in question is obviously something like the module's title string, help
string, or some other known entry point which is going to be recognised by
the program later on. If you identify this offset now, it may not be fully
followed-up by the program later. The other case is when the offset is
pointing to the middle of an instruction, somewhere where a label cannnot be
placed. See 'Odd labels' in the Problems section for more details.
Byte, word and address (1,2,3) are fairly rare. Make sure that the reference
is word-aligned before replying 4 or 5 (double or code); getting this wrong
will almost certainly cause an execution error later on. It is unlikely that
a reference will be made to alignment bytes (6). See the External section
below for details of type 7.
The "bytes of unknown type" prompt
==================================
This prompt will occur during the final sequential pass through the module.
The display looks like this:
[ ]
[ Block of ] A few lines preceding the address
[ white text ]
[ ]
[ RED LINE ] The address being referred to
[ ]
[ More ] A few lines after the address
[ white text ]
[ ]
n byte(s) at ABC of unknown type The prompt
This is your last chance to work out unresolved byte types. Note that if
n is 69, this means that there is a block of more than 68 bytes whose types
are unknown. The allowed responses are the similar to those above, with the
following changes:
You must NOT reply "don't know" (0) at this prompt. If you answer 1,2,3 or 4
(byte, word, address, double) the program will ask you how many of these
items there are. If you answer 5 (code), you may get some more "What's
this?" type prompts as the program re-enters its recursive code-following
phase, but it will eventually return to where it left off. Alignment bytes
(6) are easily recognised as 1, 2 or 3 zeros at the end of a string,
bringing it to a word boundary. See the External section below for details
of type 7.
If you can see by inspection that the block of bytes contains more than one
"type", simply reply with the type number of whatever comes first, and the
program will re-prompt you for the remainder.
The external type (7)
=====================
Rather than making the program general enough to cope with anything, I have
allowed for the heading "none of the above" by creating type 7. If your
module contains something weird, you can edit the program to cope with it,
by writing your own PROCexternal, which marks the weird block as type 7,
and PROCdisexternal, which copes with the disassembly of the block.
For example, the RISC OS Desktop module contains 5 template files embedded
in it (these appear under the DeskFS filing system). The PROCexternal
supplied simply marks these 5 blocks as type 7 throughout, and
PROCdisexternal loads the files in and increments the assembler counters
O% and P% to jump over them. Something similar would be needed for the 6502
emulator module, which contains embedded the BASIC ROM from the BBC.
Another good use for PROCexternal is if you know that the module contains a
large block of, say, zero-terminated strings. rather than identifying each
one individually at run time, you could put something like this in
PROCexternal:
FOR offset%=&1234 TO &2468
type%(offset%)=-1
NEXT
This will mark the block en-masse before the program proper starts.
CHECKER
=======
To verify that the disassembly worked, you can re-assemble the module; the
new version is stored in directory MODULES. The program Checker does a
byte-by-byte comparison of the original and new module, reporting on any
differences it finds, as a disassembled instruction from each version. Any
differences should be unimportant, as outlined in the Problems section below.
PROBLEMS
========
This is a list of known problem areas with ModDis. In most cases the
problems are obscure, or difficult to correct in the program, but easy to
spot and fix in the final assembler listing.
Immediate constants
-------------------
An immediate constant is expressed as an 8-bit value with a 4-bit rotation
applied to it. This means that there can be more than one way of expressing
a constant, eg #1 can be represented as #1 with 0 rotation, #4 with a
rotation of 2, etc. The BASIC assembler hides this process from the
programmer, who merely supplies the required constant and lets the assembler
figure out how to represent it. If the original module has #1 stored as
4>>2, the disassembler will convert this to #1, and the BASIC assembler will
reassemble it as 1>>0. This is functionally identical, but a byte-by-byte
comparison of the two modules will show a difference.
Another related problem is that the program sometimes fails to expand the
constant at all, giving something like MOV R0,#0,24, ie 0 rotated by 24,
which is still 0. This format, which the program generates through the
debugger module, is not valid for the BASIC assembler and should be replaced
by MOV R0,#0. Some of these are detected and translated by the this version
of the program, but it's not foolproof, and some still slip through. This
problem is caused by a bug in the Debugger module. To solve it permanently,
you need to modify the Debugger module itself, changing offset &920 from
&1A000028 to &FA000028, effectively changing a BNE to a BNV. This seems to
solve the problem, although I haven't tested this fix exhaustively, so
proceed with caution.
The ADR directive
-----------------
ADR Rn,#address is converted by the assembler into either SUB Rn,PC,#offset
or ADD Rn,PC,#offset, depending on whether the address comes before or after
the current PC value. A problem arises in that ADD Rn,PC,#0 is functionally
identical to SUB Rn,PC,#0. The BASIC assembler always chooses the former, so
if the latter occurs in a module it will be converted from SUB to ADD
leading to an apparent difference between the modules when compared
byte-by-byte. It should have no effect on running the module.
Long labels
-----------
The assembler mnemonics start in column 20, leaving room for long labels.
Sometimes, however, the labels are too long, in which case the mnemonic is
moved to the next line, this being still syntactically correct. But if the
label is exactly 19 characters long then it 'touches' the mnemonic, and BASIC
sees this as one big label with a bad mnemonic after it. It's rare, so fix it
manually if it happens.
The comment field
-----------------
The program generates a comment field which may be useful. If, however, it
contains a colon, the BASIC assembler thinks this is a new statement
starting. It's rare, so fix it manually. I also had a case once when the
comment field contained the character &8D, which BASIC tried to tokenise. I
did consider removing the commenr field altogether, as the simplest way of
solving these problems, but overall it's too useful to lose, despite its
problems.
SWI branch table
----------------
The program attempts to match the SWI names to the SWI branch table, but it
sometimes fails to identify the branch table as belonging to the SWI
routine. In this case it substitutes labels of the type xABCD, so the
assembly is still syntactically correct (and logically) correct. I think
this is one of those things you're going to have to live with.
Embedded text
-------------
Something that cropped up in the NetPrint module was like this:
BL s1234
EQUS "A message"
More code...
where the subroutine at s1234 adjusts the return address to skip the string.
While ModDis recognises this if used with SWI "OS_WriteS", it cannot check
for a user routine which does the same. ModDis will try to interpret the
string as code, giving a warning message if this is not possible. It's up to
you to be aware of this pitfall and watch out for it.
Floating point
--------------
Although ModDis could disassemble instructions intended for the FPU, in
practice there isn't much point, since the BASIC assembler doesn't recognise
them, so you could not re-assemble the module. Instead, it assumes that any
FPU instruction it comes across is a mistake caused by an incorrect user
response, and gives a warning message. I may do something about FPU at some
time, but it's a low priority. In the meantime, if you want to disassemble a
module which contains some FPU instructions, you will have to mark them as
words (4-byte data).
Odd labels
----------
Sometimes a reference is made to, for example, the byte BEFORE a block of
data, the pointer being incremented before use. Something like:
ADR xF6F
........
MOV PC,R14
.xF70 EQUS "...."
It is not possible to place a label at &F6F, since it lies in the middle of
an instruction. Instead, you should manually substitute something like this:
ADR xF70-1
This sort of thing is usually fairly easy to spot.
ALIGN
-----
When assembling a module, the ALIGN directive is used to move to a word
boundary, simply incrementing the pointer by 1, 2 or 3. The bytes "skipped"
like this are not explicitly set to zero, and will contain whatever was
there at the time the module was originally compiled. When recompiling after
running ModDis, these 'skipped" bytes may well have different values, and the
Checker program will detect this, but since they play no part in the module,
they are unimportant.
THE END
=======
My thanks to those users who reported bugs in the previous versions of
ModDis, and to those who made suggestions on improving it. If you have any
problems or (constructive) comments about ModDis, please get in touch with
me. If you have any ideas for improving it, or if you extend it yourself,
I'd be very glad to hear from you.
Lorcan Mongey
56 Salisbury Court
Dublin Road
Belfast BT7 1DD
Tel: 0232 234386
I can also be reached at the following BBS:
BBS Telephone Username Number
--- --------- -------- ------
CIX 081 390 1244 lorcan@cix.uucp
The World of Cryton 0749 670030 lorcan #237
Arcade 081 654 2212 lorcan #417
00000000 3e 4d 61 6e 75 61 6c 0a 0a 44 69 72 65 63 74 6f |>Manual..Directo| 00000010 72 79 20 53 74 72 75 63 74 75 72 65 0a 3d 3d 3d |ry Structure.===| 00000020 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d |================| 00000030 0a 0a 20 20 20 20 20 20 20 20 20 20 20 20 20 20 |.. | 00000040 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 | | 00000050 20 20 20 20 20 20 4d 4f 44 5f 44 49 53 0a 20 20 | MOD_DIS. | 00000060 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 | | * 00000080 20 20 20 20 20 7c 0a 20 20 20 2b 2d 2d 2d 2d 2d | |. +-----| 00000090 2d 2d 2d 2b 2d 2d 2d 2d 2b 2d 2d 2d 2d 2d 2b 2d |---+----+-----+-| 000000a0 2d 2d 2d 2b 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d 2b 2d |---+----------+-| 000000b0 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d 2b 2d 2d 2d 2d 2d |----------+-----| 000000c0 2d 2d 2d 2d 2d 2d 2b 2d 2d 2d 2d 2d 2d 2d 2d 2d |------+---------| 000000d0 2b 0a 20 20 20 7c 20 20 20 20 20 20 20 20 7c 20 |+. | | | 000000e0 20 20 20 7c 20 20 20 20 20 7c 20 20 20 20 7c 20 | | | | | 000000f0 20 20 20 20 20 20 20 20 20 7c 20 20 20 20 20 20 | | | 00000100 20 20 20 20 20 7c 20 20 20 20 20 20 20 20 20 20 | | | 00000110 20 7c 20 20 20 20 20 20 20 20 20 7c 0a 47 65 74 | | |.Get| 00000120 53 74 61 72 74 65 64 20 20 7c 20 43 68 61 6e 67 |Started | Chang| 00000130 65 73 20 20 7c 20 43 68 65 63 6b 65 72 20 20 20 |es | Checker | 00000140 20 4d 4f 44 55 4c 45 53 20 20 20 20 4f 52 49 47 | MODULES ORIG| 00000150 49 4e 41 4c 53 20 20 20 20 53 43 52 49 50 54 53 |INALS SCRIPTS| 00000160 20 20 20 53 4f 55 52 43 45 53 0a 20 20 20 20 20 | SOURCES. | 00000170 20 20 20 20 20 20 20 7c 20 20 20 20 20 20 20 20 | | | 00000180 20 20 7c 20 20 20 20 20 20 20 20 20 20 20 20 20 | | | 00000190 20 20 7c 20 20 20 20 20 20 20 20 20 20 20 7c 20 | | | | 000001a0 20 20 20 20 20 20 20 20 20 20 7c 20 20 20 20 20 | | | 000001b0 20 20 20 20 7c 0a 20 20 20 20 20 20 20 20 4d 61 | |. Ma| 000001c0 6e 75 61 6c 20 20 20 20 20 4d 6f 64 44 69 73 32 |nual ModDis2| 000001d0 30 31 20 20 20 20 20 20 20 20 2d 2d 2d 2b 2d 2d |01 ---+--| 000001e0 2d 20 20 20 20 20 2d 2d 2d 2b 2d 2d 2d 20 20 20 |- ---+--- | 000001f0 20 20 2d 2d 2d 2b 2d 2d 2d 20 20 20 2d 2d 2d 2b | ---+--- ---+| 00000200 2d 2d 2d 0a 0a 0a 20 20 20 20 47 65 74 53 74 61 |---... GetSta| 00000210 72 74 65 64 20 20 20 20 20 54 65 78 74 20 20 20 |rted Text | 00000220 20 48 6f 77 20 74 6f 20 73 74 61 72 74 20 71 75 | How to start qu| 00000230 69 63 6b 6c 79 20 77 69 74 68 6f 75 74 20 72 65 |ickly without re| 00000240 61 64 69 6e 67 20 74 68 65 20 6d 61 6e 75 61 6c |ading the manual| 00000250 0a 20 20 20 20 4d 61 6e 75 61 6c 20 20 20 20 20 |. Manual | 00000260 20 20 20 20 54 65 78 74 20 20 20 20 54 68 65 20 | Text The | 00000270 6d 61 6e 75 61 6c 0a 20 20 20 20 43 68 61 6e 67 |manual. Chang| 00000280 65 73 20 20 20 20 20 20 20 20 54 65 78 74 20 20 |es Text | 00000290 20 20 4d 61 6a 6f 72 20 63 68 61 6e 67 65 73 20 | Major changes | 000002a0 73 69 6e 63 65 20 76 65 72 73 69 6f 6e 20 31 2e |since version 1.| 000002b0 30 34 0a 20 20 20 20 4d 6f 64 44 69 73 32 30 31 |04. ModDis201| 000002c0 20 20 20 20 20 20 42 41 53 49 43 20 20 20 54 68 | BASIC Th| 000002d0 65 20 6d 61 69 6e 20 70 72 6f 67 72 61 6d 0a 20 |e main program. | 000002e0 20 20 20 43 68 65 63 6b 65 72 20 20 20 20 20 20 | Checker | 000002f0 20 20 42 41 53 49 43 20 20 20 43 68 65 63 6b 73 | BASIC Checks| 00000300 20 74 68 65 20 76 61 6c 69 64 69 74 79 20 6f 66 | the validity of| 00000310 20 61 20 72 65 2d 61 73 73 65 6d 62 6c 65 64 20 | a re-assembled | 00000320 6d 6f 64 75 6c 65 0a 20 20 20 20 4d 4f 44 55 4c |module. MODUL| 00000330 45 53 20 20 20 20 20 20 20 20 44 69 72 20 20 20 |ES Dir | 00000340 20 20 4e 65 77 6c 79 2d 61 73 73 65 6d 62 6c 65 | Newly-assemble| 00000350 64 20 6d 6f 64 75 6c 65 73 20 61 72 65 20 73 61 |d modules are sa| 00000360 76 65 64 20 68 65 72 65 0a 20 20 20 20 4f 52 49 |ved here. ORI| 00000370 47 49 4e 41 4c 53 20 20 20 20 20 20 44 69 72 20 |GINALS Dir | 00000380 20 20 20 20 54 68 65 20 6d 6f 64 75 6c 65 20 74 | The module t| 00000390 6f 20 62 65 20 64 69 73 61 73 73 65 6d 62 6c 65 |o be disassemble| 000003a0 64 20 73 68 6f 75 6c 64 20 62 65 20 70 75 74 20 |d should be put | 000003b0 68 65 72 65 0a 20 20 20 20 53 43 52 49 50 54 53 |here. SCRIPTS| 000003c0 20 20 20 20 20 20 20 20 44 69 72 20 20 20 20 20 | Dir | 000003d0 55 73 65 72 20 72 65 73 70 6f 6e 73 65 73 20 61 |User responses a| 000003e0 72 65 20 73 74 6f 72 65 64 20 68 65 72 65 0a 20 |re stored here. | 000003f0 20 20 20 53 4f 55 52 43 45 53 20 20 20 20 20 20 | SOURCES | 00000400 20 20 44 69 72 20 20 20 20 20 44 69 73 61 73 73 | Dir Disass| 00000410 65 6d 62 6c 65 64 20 6d 6f 64 75 6c 65 73 20 61 |embled modules a| 00000420 72 65 20 73 74 6f 72 65 64 20 68 65 72 65 0a 0a |re stored here..| 00000430 0a 54 68 69 73 20 69 73 20 76 65 72 73 69 6f 6e |.This is version| 00000440 20 32 2e 30 31 20 6f 66 20 4d 6f 64 44 69 73 2c | 2.01 of ModDis,| 00000450 20 61 6e 64 20 72 65 70 6c 61 63 65 73 20 74 68 | and replaces th| 00000460 6f 73 65 20 76 65 72 73 69 6f 6e 73 20 70 72 65 |ose versions pre| 00000470 76 69 6f 75 73 6c 79 0a 70 75 62 6c 69 73 68 65 |viously.publishe| 00000480 64 20 28 30 2e 45 2c 20 30 2e 46 20 61 6e 64 20 |d (0.E, 0.F and | 00000490 31 2e 30 34 29 2e 20 49 74 20 68 61 73 20 76 61 |1.04). It has va| 000004a0 72 69 6f 75 73 20 62 75 67 20 66 69 78 65 73 20 |rious bug fixes | 000004b0 61 6e 64 20 65 6e 68 61 6e 63 65 6d 65 6e 74 73 |and enhancements| 000004c0 20 6e 6f 74 0a 61 76 61 69 6c 61 62 6c 65 20 69 | not.available i| 000004d0 6e 20 70 72 65 76 69 6f 75 73 20 76 65 72 73 69 |n previous versi| 000004e0 6f 6e 73 2e 20 49 66 20 79 6f 75 20 61 6c 72 65 |ons. If you alre| 000004f0 61 64 79 20 68 61 76 65 20 76 65 72 73 69 6f 6e |ady have version| 00000500 20 31 2e 30 34 2c 20 73 65 65 20 74 68 65 0a 66 | 1.04, see the.f| 00000510 69 6c 65 20 43 68 61 6e 67 65 73 20 66 6f 72 20 |ile Changes for | 00000520 64 65 74 61 69 6c 73 20 6f 66 20 69 6d 70 6f 72 |details of impor| 00000530 74 61 6e 74 20 63 68 61 6e 67 65 73 2e 20 49 66 |tant changes. If| 00000540 20 79 6f 75 20 64 6f 6e 27 74 20 77 61 6e 74 20 | you don't want | 00000550 74 6f 20 72 65 61 64 0a 74 68 69 73 20 6d 61 6e |to read.this man| 00000560 75 61 6c 20 79 65 74 20 74 72 79 20 72 65 61 64 |ual yet try read| 00000570 69 6e 67 20 47 65 74 53 74 61 72 74 65 64 20 61 |ing GetStarted a| 00000580 6e 64 20 66 6f 6c 6c 6f 77 69 6e 67 20 69 74 73 |nd following its| 00000590 20 69 6e 73 74 72 75 63 74 69 6f 6e 73 2e 0a 0a | instructions...| 000005a0 4d 6f 64 44 69 73 20 61 20 73 65 6d 69 2d 69 6e |ModDis a semi-in| 000005b0 74 65 6c 6c 69 67 65 6e 74 20 6d 6f 64 75 6c 65 |telligent module| 000005c0 20 64 69 73 61 73 73 65 6d 62 6c 65 72 2e 20 49 | disassembler. I| 000005d0 74 20 77 69 6c 6c 20 72 65 61 64 20 61 20 72 65 |t will read a re| 000005e0 6c 6f 63 61 74 61 62 6c 65 0a 6d 6f 64 75 6c 65 |locatable.module| 000005f0 20 66 69 6c 65 20 66 72 6f 6d 20 74 68 65 20 4f | file from the O| 00000600 52 49 47 49 4e 41 4c 53 20 64 69 72 65 63 74 6f |RIGINALS directo| 00000610 72 79 20 61 6e 64 20 61 74 74 65 6d 70 74 20 74 |ry and attempt t| 00000620 6f 20 64 69 73 61 73 73 65 6d 62 6c 65 20 69 74 |o disassemble it| 00000630 20 69 6e 74 6f 0a 61 20 66 6f 72 6d 20 73 75 69 | into.a form sui| 00000640 74 61 62 6c 65 20 66 6f 72 20 74 68 65 20 42 41 |table for the BA| 00000650 53 49 43 20 61 73 73 65 6d 62 6c 65 72 2e 20 49 |SIC assembler. I| 00000660 66 20 73 75 63 63 65 73 73 66 75 6c 2c 20 74 68 |f successful, th| 00000670 65 20 6f 75 74 70 75 74 20 66 69 6c 65 20 69 73 |e output file is| 00000680 0a 73 74 6f 72 65 64 20 69 6e 20 74 68 65 20 53 |.stored in the S| 00000690 4f 55 52 43 45 53 20 64 69 72 65 63 74 6f 72 79 |OURCES directory| 000006a0 2c 20 75 6e 64 65 72 20 74 68 65 20 73 61 6d 65 |, under the same| 000006b0 20 66 69 6c 65 6e 61 6d 65 20 61 73 20 74 68 65 | filename as the| 000006c0 20 6d 6f 64 75 6c 65 2e 20 49 66 2c 0a 61 73 20 | module. If,.as | 000006d0 69 73 20 6c 69 6b 65 6c 79 2c 20 74 68 65 20 70 |is likely, the p| 000006e0 72 6f 67 72 61 6d 20 63 61 6e 6e 6f 74 20 72 65 |rogram cannot re| 000006f0 73 6f 6c 76 65 20 74 68 65 20 64 69 73 61 73 73 |solve the disass| 00000700 65 6d 62 6c 79 20 75 6e 61 69 64 65 64 2c 20 69 |embly unaided, i| 00000710 74 20 77 69 6c 6c 0a 70 72 6f 6d 70 74 20 74 68 |t will.prompt th| 00000720 65 20 75 73 65 72 20 66 6f 72 20 68 65 6c 70 2c |e user for help,| 00000730 20 68 65 6e 63 65 20 74 68 65 20 22 73 65 6d 69 | hence the "semi| 00000740 2d 69 6e 74 65 6c 6c 69 67 65 6e 74 22 20 64 65 |-intelligent" de| 00000750 73 63 72 69 70 74 69 6f 6e 2e 20 54 68 65 73 65 |scription. These| 00000760 0a 72 65 73 70 6f 6e 73 65 73 20 63 61 6e 20 62 |.responses can b| 00000770 65 20 73 74 6f 72 65 64 20 69 6e 20 74 68 65 20 |e stored in the | 00000780 53 43 52 49 50 54 53 20 64 69 72 65 63 74 6f 72 |SCRIPTS director| 00000790 79 20 61 6e 64 20 70 6c 61 79 65 64 20 62 61 63 |y and played bac| 000007a0 6b 20 6c 61 74 65 72 20 74 6f 0a 72 65 2d 63 72 |k later to.re-cr| 000007b0 65 61 74 65 20 74 68 65 20 64 69 73 61 73 73 65 |eate the disasse| 000007c0 6d 62 6c 79 2e 20 54 68 65 20 76 61 6c 69 64 69 |mbly. The validi| 000007d0 74 79 20 6f 66 20 74 68 65 20 64 69 73 61 73 73 |ty of the disass| 000007e0 65 6d 62 6c 79 20 63 61 6e 20 62 65 20 74 65 73 |embly can be tes| 000007f0 74 65 64 20 62 79 0a 72 65 2d 61 73 73 65 6d 62 |ted by.re-assemb| 00000800 6c 69 6e 67 2c 20 77 68 69 63 68 20 6d 61 6b 65 |ling, which make| 00000810 73 20 61 20 6e 65 77 20 76 65 72 73 69 6f 6e 20 |s a new version | 00000820 69 6e 20 74 68 65 20 4d 4f 44 55 4c 45 53 20 64 |in the MODULES d| 00000830 69 72 65 63 74 6f 72 79 2e 20 54 68 65 20 42 41 |irectory. The BA| 00000840 53 49 43 0a 70 72 6f 67 72 61 6d 20 43 68 65 63 |SIC.program Chec| 00000850 6b 65 72 20 63 61 6e 20 74 68 65 6e 20 62 65 20 |ker can then be | 00000860 75 73 65 64 20 74 6f 20 64 6f 20 61 20 62 79 74 |used to do a byt| 00000870 65 2d 62 79 2d 62 79 74 65 20 63 6f 6d 70 61 72 |e-by-byte compar| 00000880 69 73 6f 6e 20 6f 66 20 74 68 65 0a 6f 72 69 67 |ison of the.orig| 00000890 69 6e 61 6c 20 61 6e 64 20 6e 65 77 20 76 65 72 |inal and new ver| 000008a0 73 69 6f 6e 73 2e 0a 0a 49 20 68 61 64 20 61 6c |sions...I had al| 000008b0 72 65 61 64 79 20 64 69 73 61 73 73 65 6d 62 6c |ready disassembl| 000008c0 65 64 20 73 65 76 65 72 61 6c 20 6d 6f 64 75 6c |ed several modul| 000008d0 65 73 20 62 79 20 68 61 6e 64 2c 20 61 6e 64 2c |es by hand, and,| 000008e0 20 77 68 69 6c 65 20 69 74 20 69 73 0a 72 65 6c | while it is.rel| 000008f0 61 74 69 76 65 6c 79 20 65 61 73 79 2c 20 69 74 |atively easy, it| 00000900 20 62 65 63 6f 6d 65 73 20 71 75 69 74 65 20 74 | becomes quite t| 00000910 65 64 69 6f 75 73 20 61 73 20 74 68 65 20 6d 6f |edious as the mo| 00000920 64 75 6c 65 20 73 69 7a 65 20 69 6e 63 72 65 61 |dule size increa| 00000930 73 65 73 2e 20 54 68 69 73 0a 70 72 6f 67 72 61 |ses. This.progra| 00000940 6d 20 73 74 61 72 74 65 64 20 61 73 20 61 20 71 |m started as a q| 00000950 75 69 63 6b 20 75 74 69 6c 69 74 79 20 74 6f 20 |uick utility to | 00000960 64 6f 20 73 6f 6d 65 20 6f 66 20 74 68 65 20 6d |do some of the m| 00000970 65 63 68 61 6e 69 63 61 6c 0a 22 64 6f 6e 6b 65 |echanical."donke| 00000980 79 2d 77 6f 72 6b 22 20 61 73 70 65 63 74 73 20 |y-work" aspects | 00000990 6f 66 20 64 69 73 61 73 73 65 6d 62 6c 79 2c 20 |of disassembly, | 000009a0 62 75 74 20 68 61 73 20 67 72 6f 77 6e 20 6f 75 |but has grown ou| 000009b0 74 20 6f 66 20 61 6c 6c 20 70 72 6f 70 6f 72 74 |t of all proport| 000009c0 69 6f 6e 20 74 6f 0a 69 74 73 20 6f 72 69 67 69 |ion to.its origi| 000009d0 6e 61 6c 20 61 69 6d 73 2e 20 49 20 68 61 76 65 |nal aims. I have| 000009e0 20 73 75 63 63 65 73 73 66 75 6c 6c 79 20 64 69 | successfully di| 000009f0 73 61 73 73 65 6d 62 6c 65 64 20 61 62 6f 75 74 |sassembled about| 00000a00 20 33 30 20 6f 66 20 74 68 65 20 52 49 53 43 20 | 30 of the RISC | 00000a10 4f 53 0a 6d 6f 64 75 6c 65 73 2c 20 61 6e 64 20 |OS.modules, and | 00000a20 74 68 65 72 65 20 61 72 65 20 75 73 75 61 6c 6c |there are usuall| 00000a30 79 20 6f 6e 6c 79 20 61 20 68 61 6e 64 66 75 6c |y only a handful| 00000a40 20 6f 66 20 65 72 72 6f 72 73 20 74 6f 20 73 6f | of errors to so| 00000a50 72 74 20 6f 75 74 20 69 6e 20 74 68 65 0a 6f 75 |rt out in the.ou| 00000a60 74 70 75 74 20 61 73 73 65 6d 62 6c 65 72 20 6c |tput assembler l| 00000a70 69 73 74 69 6e 67 20 28 73 65 65 20 74 68 65 20 |isting (see the | 00000a80 50 72 6f 62 6c 65 6d 73 20 73 65 63 74 69 6f 6e |Problems section| 00000a90 20 66 6f 72 20 64 65 74 61 69 6c 73 29 2e 20 59 | for details). 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I | 00000cb0 66 69 6e 64 20 69 74 20 72 65 61 73 73 75 72 69 |find it reassuri| 00000cc0 6e 67 20 74 6f 20 62 65 20 61 62 6c 65 20 74 6f |ng to be able to| 00000cd0 20 73 65 65 20 77 68 61 74 20 74 68 65 20 70 72 | see what the pr| 00000ce0 6f 67 72 61 6d 0a 69 73 20 64 6f 69 6e 67 2e 20 |ogram.is doing. | 00000cf0 53 65 74 74 69 6e 67 20 69 74 20 74 6f 20 46 41 |Setting it to FA| 00000d00 4c 53 45 20 77 69 6c 6c 20 73 75 70 72 65 73 73 |LSE will supress| 00000d10 20 74 68 69 73 20 70 72 69 6e 74 6f 75 74 2c 20 | this printout, | 00000d20 61 6e 64 20 74 68 65 72 65 20 77 69 6c 6c 20 62 |and there will b| 00000d30 65 0a 73 6f 6d 65 74 69 6d 65 73 20 62 65 20 6c |e.sometimes be l| 00000d40 6f 6e 67 20 70 61 75 73 65 73 20 77 68 65 6e 20 |ong pauses when | 00000d50 69 74 20 69 73 20 6e 6f 74 20 6f 62 76 69 6f 75 |it is not obviou| 00000d60 73 20 69 66 20 74 68 65 20 70 72 6f 67 72 61 6d |s if the program| 00000d70 20 69 73 20 64 6f 69 6e 67 0a 61 6e 79 74 68 69 | is doing.anythi| 00000d80 6e 67 2e 0a 0a 48 6f 77 20 74 68 65 20 70 72 6f |ng...How the pro| 00000d90 67 72 61 6d 20 77 6f 72 6b 73 0a 3d 3d 3d 3d 3d |gram works.=====| 00000da0 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d |================| 00000db0 0a 54 68 65 20 70 72 6f 67 72 61 6d 20 69 64 65 |.The program ide| 00000dc0 6e 74 69 66 69 65 73 20 74 68 65 20 22 74 79 70 |ntifies the "typ| 00000dd0 65 22 20 6f 66 20 65 61 63 68 20 62 79 74 65 20 |e" of each byte | 00000de0 6f 66 20 74 68 65 20 6d 6f 64 75 6c 65 2c 20 61 |of the module, a| 00000df0 63 63 6f 72 64 69 6e 67 20 74 6f 0a 74 68 65 20 |ccording to.the | 00000e00 66 6f 6c 6c 6f 77 69 6e 67 20 73 63 68 65 6d 65 |following scheme| 00000e10 3a 0a 0a 74 79 70 65 20 20 20 20 20 20 64 65 73 |:..type des| 00000e20 63 72 69 70 74 69 6f 6e 0a 2d 34 20 20 20 20 20 |cription.-4 | 00000e30 20 20 20 27 41 63 6f 72 6e 27 2d 66 6f 72 6d 61 | 'Acorn'-forma| 00000e40 74 20 63 6f 6d 70 72 65 73 73 65 64 20 73 74 72 |t compressed str| 00000e50 69 6e 67 0a 2d 33 20 20 20 20 20 20 20 20 50 61 |ing.-3 Pa| 00000e60 64 64 65 64 20 73 74 72 69 6e 67 2c 20 69 65 20 |dded string, ie | 00000e70 61 20 73 74 72 69 6e 67 20 70 61 64 64 65 64 20 |a string padded | 00000e80 77 69 74 68 20 7a 65 72 6f 73 20 75 70 20 74 6f |with zeros up to| 00000e90 20 61 20 66 69 78 65 64 20 6c 65 6e 67 74 68 0a | a fixed length.| 00000ea0 2d 32 20 20 20 20 20 20 20 20 43 61 72 72 69 61 |-2 Carria| 00000eb0 67 65 2d 72 65 74 75 72 6e 2d 74 65 72 6d 69 6e |ge-return-termin| 00000ec0 61 74 65 64 20 73 74 72 69 6e 67 0a 2d 31 20 20 |ated string.-1 | 00000ed0 20 20 20 20 20 20 5a 65 72 6f 2d 74 65 72 6d 69 | Zero-termi| 00000ee0 6e 61 74 65 64 20 73 74 72 69 6e 67 0a 20 30 20 |nated string. 0 | 00000ef0 20 20 20 20 20 20 20 44 6f 6e 27 74 20 6b 6e 6f | Don't kno| 00000f00 77 0a 20 31 20 20 20 20 20 20 20 20 41 20 62 79 |w. 1 A by| 00000f10 74 65 20 6f 66 20 64 61 74 61 0a 20 32 20 20 20 |te of data. 2 | 00000f20 20 20 20 20 20 41 20 77 6f 72 64 20 28 32 20 62 | A word (2 b| 00000f30 79 74 65 73 20 6f 66 20 64 61 74 61 29 0a 20 33 |ytes of data). 3| 00000f40 20 20 20 20 20 20 20 20 41 64 64 72 65 73 73 2c | Address,| 00000f50 20 69 65 20 61 20 34 2d 62 79 74 65 20 6e 75 6d | ie a 4-byte num| 00000f60 62 65 72 20 70 6f 69 6e 74 69 6e 67 20 74 6f 20 |ber pointing to | 00000f70 61 6e 6f 74 68 65 72 20 70 6f 69 6e 74 20 69 6e |another point in| 00000f80 20 74 68 65 20 6d 6f 64 75 6c 65 0a 20 34 20 20 | the module. 4 | 00000f90 20 20 20 20 20 20 41 20 64 6f 75 62 6c 65 20 77 | A double w| 00000fa0 6f 72 64 20 28 34 20 62 79 74 65 73 20 6f 66 20 |ord (4 bytes of | 00000fb0 64 61 74 61 29 0a 20 35 20 20 20 20 20 20 20 20 |data). 5 | 00000fc0 41 52 4d 20 63 6f 64 65 0a 20 36 20 20 20 20 20 |ARM code. 6 | 00000fd0 20 20 20 41 6c 69 67 6e 6d 65 6e 74 20 62 79 74 | Alignment byt| 00000fe0 65 73 2c 20 31 2c 20 32 20 6f 72 20 33 20 62 79 |es, 1, 2 or 3 by| 00000ff0 74 65 73 20 74 6f 20 62 72 69 6e 67 20 75 73 20 |tes to bring us | 00001000 74 6f 20 61 20 77 6f 72 64 20 62 6f 75 6e 64 61 |to a word bounda| 00001010 72 79 0a 20 37 20 20 20 20 20 20 20 20 45 78 74 |ry. 7 Ext| 00001020 65 72 6e 61 6c 2e 20 53 65 65 20 62 65 6c 6f 77 |ernal. 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The code is di| 00001410 73 61 73 73 65 6d 62 6c 65 64 20 77 69 74 68 20 |sassembled with | 00001420 63 61 6c 6c 73 20 74 6f 20 74 68 65 20 44 65 62 |calls to the Deb| 00001430 75 67 67 65 72 20 6d 6f 64 75 6c 65 2c 20 62 75 |ugger module, bu| 00001440 74 0a 74 68 65 20 66 6f 6c 6c 6f 77 69 6e 67 20 |t.the following | 00001450 65 6e 68 61 6e 63 65 6d 65 6e 74 73 20 61 72 65 |enhancements are| 00001460 20 6d 61 64 65 20 74 6f 20 69 74 73 20 6f 75 74 | made to its out| 00001470 70 75 74 3a 0a 0a 31 2e 20 4c 61 62 65 6c 73 20 |put:..1. 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SWI n| 000015f0 61 6d 65 73 20 61 72 65 20 65 6e 63 6c 6f 73 65 |ames are enclose| 00001600 64 20 69 6e 20 71 75 6f 74 65 73 2e 0a 37 2e 20 |d in quotes..7. | 00001610 54 68 65 20 32 20 69 6e 73 74 72 75 63 74 69 6f |The 2 instructio| 00001620 6e 73 20 6d 61 6b 69 6e 67 20 75 70 20 61 20 27 |ns making up a '| 00001630 6c 6f 6e 67 20 41 44 52 27 20 61 72 65 20 72 65 |long ADR' are re| 00001640 63 6f 67 6e 69 73 65 64 20 61 6e 64 20 72 65 70 |cognised and rep| 00001650 72 65 73 65 6e 74 65 64 0a 20 20 20 62 79 20 61 |resented. by a| 00001660 20 6d 61 63 72 6f 2c 20 46 4e 61 64 72 6c 2c 20 | macro, FNadrl, | 00001670 74 6f 20 61 69 64 20 72 65 61 64 61 62 69 6c 69 |to aid readabili| 00001680 74 79 2e 0a 0a 0a 54 68 65 20 22 57 68 61 74 27 |ty....The "What'| 00001690 73 20 74 68 69 73 3f 22 20 70 72 6f 6d 70 74 0a |s this?" prompt.| 000016a0 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d |================| 000016b0 3d 3d 3d 3d 3d 3d 3d 3d 3d 0a 44 75 72 69 6e 67 |=========.During| 000016c0 20 74 68 65 20 66 69 72 73 74 20 70 61 73 73 20 | the first pass | 000016d0 74 68 72 6f 75 67 68 20 74 68 65 20 6d 6f 64 75 |through the modu| 000016e0 6c 65 2c 20 74 68 65 20 70 72 6f 67 72 61 6d 20 |le, the program | 000016f0 77 69 6c 6c 20 61 73 6b 20 66 6f 72 20 68 65 6c |will ask for hel| 00001700 70 20 69 66 0a 69 74 20 66 69 6e 64 73 20 61 20 |p if.it finds a | 00001710 72 65 66 65 72 65 6e 63 65 20 74 6f 20 61 6e 6f |reference to ano| 00001720 74 68 65 72 20 70 61 72 74 20 6f 66 20 74 68 65 |ther part of the| 00001730 20 6d 6f 64 75 6c 65 2c 20 61 73 6b 69 6e 67 20 | module, asking | 00001740 77 68 65 74 68 65 72 20 74 68 69 73 0a 72 65 66 |whether this.ref| 00001750 65 72 65 6e 63 65 20 69 73 20 63 6f 64 65 20 74 |erence is code t| 00001760 6f 20 62 65 20 64 69 73 61 73 73 65 6d 62 6c 65 |o be disassemble| 00001770 64 2c 20 6f 72 20 64 61 74 61 2c 20 69 6e 20 77 |d, or data, in w| 00001780 68 69 63 68 20 63 61 73 65 20 69 74 20 77 61 6e |hich case it wan| 00001790 74 73 20 74 6f 0a 6b 6e 6f 77 20 77 68 61 74 20 |ts to.know what | 000017a0 6b 69 6e 64 20 6f 66 20 64 61 74 61 20 69 74 20 |kind of data it | 000017b0 69 73 2e 20 54 68 65 20 64 69 73 70 6c 61 79 20 |is. 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See 'Odd la| 00001e50 62 65 6c 73 27 20 69 6e 20 74 68 65 20 50 72 6f |bels' in the Pro| 00001e60 62 6c 65 6d 73 20 73 65 63 74 69 6f 6e 20 66 6f |blems section fo| 00001e70 72 20 6d 6f 72 65 20 64 65 74 61 69 6c 73 2e 0a |r more details..| 00001e80 0a 42 79 74 65 2c 20 77 6f 72 64 20 61 6e 64 20 |.Byte, word and | 00001e90 61 64 64 72 65 73 73 20 28 31 2c 32 2c 33 29 20 |address (1,2,3) | 00001ea0 61 72 65 20 66 61 69 72 6c 79 20 72 61 72 65 2e |are fairly rare.| 00001eb0 20 4d 61 6b 65 20 73 75 72 65 20 74 68 61 74 20 | Make sure that | 00001ec0 74 68 65 20 72 65 66 65 72 65 6e 63 65 0a 69 73 |the reference.is| 00001ed0 20 77 6f 72 64 2d 61 6c 69 67 6e 65 64 20 62 65 | word-aligned be| 00001ee0 66 6f 72 65 20 72 65 70 6c 79 69 6e 67 20 34 20 |fore replying 4 | 00001ef0 6f 72 20 35 20 28 64 6f 75 62 6c 65 20 6f 72 20 |or 5 (double or | 00001f00 63 6f 64 65 29 3b 20 67 65 74 74 69 6e 67 20 74 |code); getting t| 00001f10 68 69 73 20 77 72 6f 6e 67 0a 77 69 6c 6c 20 61 |his wrong.will a| 00001f20 6c 6d 6f 73 74 20 63 65 72 74 61 69 6e 6c 79 20 |lmost certainly | 00001f30 63 61 75 73 65 20 61 6e 20 65 78 65 63 75 74 69 |cause an executi| 00001f40 6f 6e 20 65 72 72 6f 72 20 6c 61 74 65 72 20 6f |on error later o| 00001f50 6e 2e 20 49 74 20 69 73 20 75 6e 6c 69 6b 65 6c |n. It is unlikel| 00001f60 79 20 74 68 61 74 0a 61 20 72 65 66 65 72 65 6e |y that.a referen| 00001f70 63 65 20 77 69 6c 6c 20 62 65 20 6d 61 64 65 20 |ce will be made | 00001f80 74 6f 20 61 6c 69 67 6e 6d 65 6e 74 20 62 79 74 |to alignment byt| 00001f90 65 73 20 28 36 29 2e 20 53 65 65 20 74 68 65 20 |es (6). See the | 00001fa0 45 78 74 65 72 6e 61 6c 20 73 65 63 74 69 6f 6e |External section| 00001fb0 0a 62 65 6c 6f 77 20 66 6f 72 20 64 65 74 61 69 |.below for detai| 00001fc0 6c 73 20 6f 66 20 74 79 70 65 20 37 2e 0a 0a 54 |ls of type 7...T| 00001fd0 68 65 20 22 62 79 74 65 73 20 6f 66 20 75 6e 6b |he "bytes of unk| 00001fe0 6e 6f 77 6e 20 74 79 70 65 22 20 70 72 6f 6d 70 |nown type" promp| 00001ff0 74 0a 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d |t.==============| 00002000 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d |================| 00002010 3d 3d 3d 3d 0a 54 68 69 73 20 70 72 6f 6d 70 74 |====.This prompt| 00002020 20 77 69 6c 6c 20 6f 63 63 75 72 20 64 75 72 69 | will occur duri| 00002030 6e 67 20 74 68 65 20 66 69 6e 61 6c 20 73 65 71 |ng the final seq| 00002040 75 65 6e 74 69 61 6c 20 70 61 73 73 20 74 68 72 |uential pass thr| 00002050 6f 75 67 68 20 74 68 65 20 6d 6f 64 75 6c 65 2e |ough the module.| 00002060 0a 54 68 65 20 64 69 73 70 6c 61 79 20 6c 6f 6f |.The display loo| 00002070 6b 73 20 6c 69 6b 65 20 74 68 69 73 3a 0a 0a 5b |ks like this:..[| 00002080 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 | | 00002090 20 5d 0a 5b 20 20 20 20 42 6c 6f 63 6b 20 6f 66 | ].[ Block of| 000020a0 20 20 20 20 20 5d 20 20 20 20 20 20 20 20 20 20 | ] | 000020b0 20 20 20 20 20 20 41 20 66 65 77 20 6c 69 6e 65 | A few line| 000020c0 73 20 70 72 65 63 65 64 69 6e 67 20 74 68 65 20 |s preceding the | 000020d0 61 64 64 72 65 73 73 0a 5b 20 20 20 20 77 68 69 |address.[ whi| 000020e0 74 65 20 74 65 78 74 20 20 20 5d 0a 5b 20 20 20 |te text ].[ | 000020f0 20 20 20 20 20 20 20 20 20 20 20 20 20 20 5d 0a | ].| 00002100 0a 5b 20 20 20 20 20 52 45 44 20 4c 49 4e 45 20 |.[ RED LINE | 00002110 20 20 20 5d 20 20 20 20 20 20 20 20 20 20 20 20 | ] | 00002120 20 20 20 20 54 68 65 20 61 64 64 72 65 73 73 20 | The address | 00002130 62 65 69 6e 67 20 72 65 66 65 72 72 65 64 20 74 |being referred t| 00002140 6f 0a 0a 5b 20 20 20 20 20 20 20 20 20 20 20 20 |o..[ | 00002150 20 20 20 20 20 5d 0a 5b 20 20 20 20 20 20 4d 6f | ].[ Mo| 00002160 72 65 20 20 20 20 20 20 20 5d 20 20 20 20 20 20 |re ] | 00002170 20 20 20 20 20 20 20 20 20 20 41 20 66 65 77 20 | A few | 00002180 6c 69 6e 65 73 20 61 66 74 65 72 20 74 68 65 20 |lines after the | 00002190 61 64 64 72 65 73 73 0a 5b 20 20 20 20 77 68 69 |address.[ whi| 000021a0 74 65 20 74 65 78 74 20 20 20 5d 0a 5b 20 20 20 |te text ].[ | 000021b0 20 20 20 20 20 20 20 20 20 20 20 20 20 20 5d 0a | ].| 000021c0 0a 6e 20 62 79 74 65 28 73 29 20 61 74 20 41 42 |.n byte(s) at AB| 000021d0 43 20 6f 66 20 75 6e 6b 6e 6f 77 6e 20 74 79 70 |C of unknown typ| 000021e0 65 20 20 20 54 68 65 20 70 72 6f 6d 70 74 0a 0a |e The prompt..| 000021f0 54 68 69 73 20 69 73 20 79 6f 75 72 20 6c 61 73 |This is your las| 00002200 74 20 63 68 61 6e 63 65 20 74 6f 20 77 6f 72 6b |t chance to work| 00002210 20 6f 75 74 20 75 6e 72 65 73 6f 6c 76 65 64 20 | out unresolved | 00002220 62 79 74 65 20 74 79 70 65 73 2e 20 4e 6f 74 65 |byte types. 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If you | 00002320 61 6e 73 77 65 72 20 31 2c 32 2c 33 20 6f 72 20 |answer 1,2,3 or | 00002330 34 0a 28 62 79 74 65 2c 20 77 6f 72 64 2c 20 61 |4.(byte, word, a| 00002340 64 64 72 65 73 73 2c 20 64 6f 75 62 6c 65 29 20 |ddress, double) | 00002350 74 68 65 20 70 72 6f 67 72 61 6d 20 77 69 6c 6c |the program will| 00002360 20 61 73 6b 20 79 6f 75 20 68 6f 77 20 6d 61 6e | ask you how man| 00002370 79 20 6f 66 20 74 68 65 73 65 0a 69 74 65 6d 73 |y of these.items| 00002380 20 74 68 65 72 65 20 61 72 65 2e 20 49 66 20 79 | there are. 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If | 000042d0 79 6f 75 20 68 61 76 65 20 61 6e 79 20 69 64 65 |you have any ide| 000042e0 61 73 20 66 6f 72 20 69 6d 70 72 6f 76 69 6e 67 |as for improving| 000042f0 20 69 74 2c 20 6f 72 20 69 66 20 79 6f 75 20 65 | it, or if you e| 00004300 78 74 65 6e 64 20 69 74 20 79 6f 75 72 73 65 6c |xtend it yoursel| 00004310 66 2c 0a 49 27 64 20 62 65 20 76 65 72 79 20 67 |f,.I'd be very g| 00004320 6c 61 64 20 74 6f 20 68 65 61 72 20 66 72 6f 6d |lad to hear from| 00004330 20 79 6f 75 2e 0a 0a 4c 6f 72 63 61 6e 20 4d 6f | you...Lorcan Mo| 00004340 6e 67 65 79 0a 35 36 20 53 61 6c 69 73 62 75 72 |ngey.56 Salisbur| 00004350 79 20 43 6f 75 72 74 0a 44 75 62 6c 69 6e 20 52 |y Court.Dublin R| 00004360 6f 61 64 0a 42 65 6c 66 61 73 74 20 42 54 37 20 |oad.Belfast BT7 | 00004370 31 44 44 0a 54 65 6c 3a 20 30 32 33 32 20 32 33 |1DD.Tel: 0232 23| 00004380 34 33 38 36 0a 0a 49 20 63 61 6e 20 61 6c 73 6f |4386..I can also| 00004390 20 62 65 20 72 65 61 63 68 65 64 20 61 74 20 74 | be reached at t| 000043a0 68 65 20 66 6f 6c 6c 6f 77 69 6e 67 20 42 42 53 |he following BBS| 000043b0 3a 0a 0a 42 42 53 20 20 20 20 20 20 20 20 20 20 |:..BBS | 000043c0 20 20 20 20 20 20 20 20 20 20 54 65 6c 65 70 68 | Teleph| 000043d0 6f 6e 65 20 20 20 20 20 20 55 73 65 72 6e 61 6d |one Usernam| 000043e0 65 20 20 20 20 20 20 20 20 20 4e 75 6d 62 65 72 |e Number| 000043f0 0a 2d 2d 2d 20 20 20 20 20 20 20 20 20 20 20 20 |.--- | 00004400 20 20 20 20 20 20 20 20 2d 2d 2d 2d 2d 2d 2d 2d | --------| 00004410 2d 20 20 20 20 20 20 2d 2d 2d 2d 2d 2d 2d 2d 20 |- -------- | 00004420 20 20 20 20 20 20 20 20 2d 2d 2d 2d 2d 2d 0a 43 | ------.C| 00004430 49 58 20 20 20 20 20 20 20 20 20 20 20 20 20 20 |IX | 00004440 20 20 20 20 20 20 30 38 31 20 33 39 30 20 31 32 | 081 390 12| 00004450 34 34 20 20 20 6c 6f 72 63 61 6e 40 63 69 78 2e |44 lorcan@cix.| 00004460 75 75 63 70 20 20 0a 54 68 65 20 57 6f 72 6c 64 |uucp .The World| 00004470 20 6f 66 20 43 72 79 74 6f 6e 20 20 20 20 30 37 | of Cryton 07| 00004480 34 39 20 36 37 30 30 33 30 20 20 20 20 6c 6f 72 |49 670030 lor| 00004490 63 61 6e 20 20 20 20 20 20 20 20 20 20 20 23 32 |can #2| 000044a0 33 37 0a 41 72 63 61 64 65 20 20 20 20 20 20 20 |37.Arcade | 000044b0 20 20 20 20 20 20 20 20 20 20 30 38 31 20 36 35 | 081 65| 000044c0 34 20 32 32 31 32 20 20 20 6c 6f 72 63 61 6e 20 |4 2212 lorcan | 000044d0 20 20 20 20 20 20 20 20 20 20 23 34 31 37 0a | #417.| 000044df
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