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Norman Sword

Member Since 08 Mar 2017
Offline Last Active Apr 16 2019 12:48 PM
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Posts I've Made

In Topic: Restart without recollection

12 April 2019 - 07:35 AM

Slight edit. Due to the original wording, which refers to five bytes. A figure I did not question and repeated ad verbatim.

However the figure should be six bytes. So an edit to correct and also change/delete some words which are misleading.


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The code is monitoring 32884 (#8074) for the release of angry Eugene. This can be changed to monitor one of the objects directly,  and the best choice is the object closest to the portal. Since the order of collection is well known, this is probably not going to be noticed by the normal player. This suggested change is aimed more at a new room design and pushing towards your original goal of resetting the room in Manic Miner, but not the objects. 

You can change both the references to 32884(#8074) to one of the following, or even change either reference to one of the following. (mix and match)

Object 1 stored at 32885 (#8075)   position (1,30)
Object 2 stored at 32890                position (6,10)

Object 3 stored at 32895                position (7,29)

Object 4 stored at 32900                position (12,7)

Object 5 stored at 32905                position (12,9)

The logical change is to point at 32905 which is the object closest to the portal.

The reason for the suggested change is that it would indicate which object triggers the anger of Eugene and collecting that object, would make Eugene change colour and descend. Collecting the trigger object before the other objects are collected would send a powerful message that that object must be left till last.

This suggested change was so a room reset, would only need to reset the last object and the room would be re playable. This suggested change unfortunately does not achieve that goal. The player could ignore Eugene and carry on collecting objects. Then the last object collected would no longer be the trigger object and we are back to square one.

 

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Still might be interesting to change the logic so it monitors just one object and not wait till all objects collected. 


In Topic: Restart without recollection

10 April 2019 - 02:00 PM

Modifying Angry Eugene

Minimum needed to modify both routines is 2 bytes

 

------------------ The first one byte modification ---------------------------------

The first six byte routine, only needs the last JR Z,XX  offset changing to 0  

S.P. Version: The six bytes in question are 36355 to 36360

36355 LD A , (32884)
36358 OR A
36359 JR Z , 36378 >>>> Poke 36360,0  ---- This changes the code to JR Z,36361

B.B. Version: The six bytes are at 36344 to 36349

36344 LD A , (32884)
36347 OR A
36348 JR Z , 36367 >>>> Poke 36349,0 ---- This changes the code to JR Z,36350

 

This above just changes how far the relative branch has to jump. 

-------------  The second one byte modification --------------------------

The second modification is as you stated (slightly edited)


Change the byte at 36449 from 32 to 24, this changes the instruction at 36449 from

      JR NZ,XXX              (Jump Relative Non Zero,offset)
to   JR  XXX                  (Jump Relative, offset)

Original:    36449    JR NZ , 36458
Changed:  36449    JR 36458

B.B. Version: Again the same thing just in a slightly different place change the byte at 36438 from 32 to 24 to effect a change from a JR NZ to a JR:

Original:   36438    JR NZ , 36447
Changed: 36438    JR 36447

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Total modification 2 bytes

 


In Topic: Free space and code optimisation in "JSW"

04 March 2019 - 12:41 AM

The way the logo is stored is poor design. It is possible (i have done so) to reduce the size of the title screen and its data by around 200+ bytes, it might be nearer 300 bytes.



 


In Topic: How Fast Can Willy Play

25 January 2019 - 08:15 AM

The remnants of a deleted post.Simply because its content was misinterpreted. 

A simpler response.


The game file included at the end of POST #1 is the only version.


All other versions of JSW VL5 DEMO and the slight revisions have been deleted.



 


In Topic: Cheat Table in CPC amstrad version of JSW2

25 January 2019 - 07:48 AM

Amsrad CPC Jet Set Willy.

Cheat invocation. Any room and stood on the lower floor. This will be reset by any key that is not part of the cheat code.

I have invoked this several times recently. All done in the bathroom. The easiest way to invoke. (but it will freeze the game) is to make the assumption that it could be either of the cheat codes I have mentioned. 

press <space> this will clear the cheat buffer

 

then type in the longer of the two cheat codes-   <HIEMMRAIDNAPRRRTT>

 

From this point onward, game abort, will take you to the cartography room. This was designed as a cheat, To actually abort the game you need to loose all your lives. Break while playing the game will draw the cartography room.

A big if here. If the cheat mode worked, the cursor on the screen can be moved around the map. When over a room on the map that is the target/designated room that it is desired to go to, press <enter>

 

The cartography room will disappear and the selected room will be displayed.

 

The cursor will again be flashing and again it can be moved. The cursor this time is indicating the position Willy will be drawn in the room. Press <ENTER> and the game will resume with Willy at the designated position.

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The above is what is supposed to happen.  (after invocation of the cartography room and its cheat)

The first problem concerns the inaction of the keyboard to input. This could be just configuration problems. But since I could not on my brief test get the cursor in the cartography room to move, the game was locked onto that screen. (so progress to the next part did not happen) 

The next problem, one I did not get as far as testing. Is that table of corrupt data. The code in the cartography room uses the data to find what room you are selecting as you move around the map. Very simple code. The little squares on the map are simply counted off (the squares indicating rooms) by starting in the top left hand corner and scanning each line to find a room square. If it finds a square it then steps one byte through the cheat table. If the cursor is flashing over the square picked and <enter> is pressed, it takes the value in the cheat table, and uses that as the new room number. Otherwise it just keeps scanning through the cartography room and stepping each time it finds a marked square indicating a mapped room. When it reaches the end of the screen, it knows you did not select a room, and loops through the movement code again.

The cheat table is a list of the rooms as defined in the cartography room. Without that table, the data is random. What happens is the room is selected and the selected room should be drawn. The code looks up the room number and (in most cases) draws a pile of junk on the screen. Which indicates to me that the room number extracted from the cheat table is higher than the room count. So in most cases the cheat table must have values over 140ish , which are room numbers outside of the game data.

At other times if it finds data that is within the room number total it draws the room that corresponds to that number. Since this is basically a random room number. We get shown a random room in the game. This mismatch between the map and the room shown, makes the cheat worthless. 


The problems I am encountering now, seem to be greater than the problems encountered five of six years ago. Which is why I assume that the inability to move in the cartography room is a configuration problem only.

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Its not Escape that quits to the title screen! :D , will retest with various other keys although the fact he says "another key or two" is going to make it more difficult. Praise for snapshots for quick reloading!

 

As an aside there is talk of memory constraints, although it would potentially only save a 'few bytes' both the AMS and ZX versions with keypad intact have a blank page with a 'Press enter to continue' line, rather than like say other games with keypad protection (ZX at least) that immediately take you to the entry page. All I'm saying here is a few precious bytes *could* of been saved by not having this slightly un-needed page/pause before code entry ? :)

 

The only sensible next test I can think of is to try it on my real CPC464 although I'd need to sort out the tape image (tzx/cdt to mp3/wav or something) and use that rather than use my original but re-release tape, mind you that would be quicker. This way I can rule out key mapping concerns, as its not ESC it may be CLR but that does not  work either.

 

 As stated above it is indeed the break key, that invokes the cheat jump into the cartography room.

One of the many flaws of Matthew Smith's game  (spectrum) is the way it asks for a colour code. If you run the game in an emulator you will find that it will ask for the same code on every single game that is played. It will even ask for the same code on the second attempt. Every time the game is played. This is due to usage of one of the spectrum's variables as its random number seed. Since this is fixed on every load of the game when using an emulator, that is why you get asked the same input code. This problem is not a new problem, it existed back in the 80's. You can save a snapshot of the game. If the snapshot saves the system variable, then the game will ask for the same code every time it is loaded via a snapshot.

The simplest method of stopping that simple problem is to force the user to have some interaction with the game before asking for the input code. So to update the variable it would have been better if the simple question/statement had been presented to the game player. Which is <Press enter to continue> or something similar. To stop this question being negated by pressing enter as the game is loading,. Which would immediately upon completion of loading  bypass the question, because the <enter> key is being pressed. You set up the loop to wait for its release as well. The wait for key and wait for key release will generate a better random number, and a snapshot will still ask for a new colour code on every run. Even the modern versions run on an emulator would give a new number on each run of the game...

The above is why the Amstrad version asks for the user to press a key. All the time the question is on the screen the games code is changing the value of the code to ask. If the end user has enough skill to bypass this code  (asking for enter to be pressed), you can assume that he is or she is already delving into the code. 


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Searching for the cheat code activation text. Derrick thinks that the code might be written backwards, and even have a simple addition of setting bit 7 on the letters. Any decent debug/monitor allows the toggling of ASCII in its output display. The setting of bit 7 on ASCII is a common practice, and the debug/monitor should  permit you to see the ASCII from values over 128 by toggling the display output.  


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footnote:-

The hacking of the game for infinite lives will also make it impossible to exit the game once cheat is invoked.
(if it worked)