IBM PCjr Problem

Having problems with a specific game or application? Post your problems here!

Re: IBM PCjr Problem

Postby ripsaw8080 » 2012-9-23 @ 19:57

Demon Attack without mirroring must be at segment E600h. However, consider the first executed instruction in Demon Attack: a far jump to E600:0008... if the code is executing at segment E600, that is a far jump to the very next instruction, so why do that? Because it's supposed to be a far jump from E000 to E600, and that jump is evidence that the mirroring is the same as in Microsurgeon, even if the game works without it. Instead of a far jump, Microsurgeon uses a relative near jump that makes the mirroring essential. I wonder if this mirroring and jumping between the mirrored banks was supposed to be some kind of copy protection.
User avatar
ripsaw8080
DOSBox Author
 
Posts: 3394
Joined: 2006-4-25 @ 23:24

Re: IBM PCjr Problem

Postby Great Hierophant » 2012-9-23 @ 20:59

ripsaw8080 wrote:Demon Attack without mirroring must be at segment E600h. However, consider the first executed instruction in Demon Attack: a far jump to E600:0008... if the code is executing at segment E600, that is a far jump to the very next instruction, so why do that? Because it's supposed to be a far jump from E000 to E600, and that jump is evidence that the mirroring is the same as in Microsurgeon, even if the game works without it. Instead of a far jump, Microsurgeon uses a relative near jump that makes the mirroring essential. I wonder if this mirroring and jumping between the mirrored banks was supposed to be some kind of copy protection.


Probably to make it more difficult for hackers to dump the image and turn it into a com or exe file.

Here are the starting segments for all known cartridge programs which have been dumped :

IBM PCjr. Cartridge Basic - E800 32K
PCjr. Colorpaint - E000 64K
Lotus 1-2-3 Cartridge A - D000 64K
Lotus 1-2-3 Cartridge B - E000 64K
Crossfire - E000 8K
Demon Attack - E600 16K
ScubaVenture - E600 8K
Mineshaft - E600 8K
Pitfall 2 - E000 16K
River Raid - E000 16K
Mouser - E000 8K
Microsurgeon - E000 & E600 16K

There would be no need for headers for emulation purposes if all PCjr. cartridge dumps were 128KB in size to correspond to the D-E segments. This information would be necessary to people trying to make a custom cartridge.
Last edited by Great Hierophant on 2013-11-07 @ 18:58, edited 1 time in total.
User avatar
Great Hierophant
Oldbie
 
Posts: 1860
Joined: 2003-4-27 @ 08:20

Re: IBM PCjr Problem

Postby ripsaw8080 » 2012-9-24 @ 08:40

Great Hierophant wrote:There would be no need for headers for emulation purposes if all PCjr. cartridge dumps were 128KB in size to correspond to the D-E segments.

Sounds inefficient to me. The entry point is relative to the ROM segment, and without that value from the header you'd have to scan through the address space to figure out where the ROM bank is located... I prefer a header to that.

A more advanced header spec would allow a single ROM bank to be read at multiple segments; the 2x repetition in Microsurgeon (and Demon Attack if you're trying to be accurate) is a workaround for the lack of such capability.
User avatar
ripsaw8080
DOSBox Author
 
Posts: 3394
Joined: 2006-4-25 @ 23:24

Re: IBM PCjr Problem

Postby ronald_herrera » 2013-2-28 @ 07:43

Hi, I was trying everything that I can to make this cartridge img (Demon Attack) to work on the DOSBOX but I couldn't understand the hexadecimal codes for the header. Even I tried to manually (with a HEX editor) make a header of 512bytes but the run failed. Can I have the sample of the mods or the entire IMG to see what was I doing wrong? Thank You!.

Ronald.
ronald_herrera
Newbie
 
Posts: 34
Joined: 2013-2-22 @ 02:45

Re: IBM PCjr Problem

Postby Trajk Logik » 2013-11-04 @ 20:52

Hi,
I found this thread while searching for a solution to this problem with Demon Attack. I'm sorry but I'm hex-editor-deficient and was wondering if someone might be able to send me the hexed copy of Demon Attack that is compatible with DOSBox?

Thanks in advance.
Trajk Logik
Newbie
 
Posts: 4
Joined: 2013-11-04 @ 20:46

Re: IBM PCjr Problem

Postby ronald_herrera » 2013-11-05 @ 08:04

Hi, if you can see the date of my post, I still haven't a respond yet, so I'm wondering myself. Sorry, I have failed and no one seems to care. :-( I stop trying but I never let my hopes down and still watching for someone to answer our question. :-)
ronald_herrera
Newbie
 
Posts: 34
Joined: 2013-2-22 @ 02:45

Re: IBM PCjr Problem

Postby ronald_herrera » 2013-11-05 @ 21:46

Okay... following the nerdy terms and the comments that our past friends left us. I could manage to run the Demon Attack cartridge dump to a fix of the "damnated" header (pushing the code at 513 bytes location) and the editing to write the tiny byte "E6" at the 462 length byte location that was need it to run. You know what. whatever, give me a email address and I'll send what-so-far I have done. I'll give you some simple steps to run the program. But remember, I guess the game needs a joystick on less there's something wrong with the code segment. Al least the demo display beautifully the game, but I'm still working on it in order to use the keyboard; if it's possible. Somehow I feel all alone. :depressed:
ronald_herrera
Newbie
 
Posts: 34
Joined: 2013-2-22 @ 02:45

Re: IBM PCjr Problem

Postby Trajk Logik » 2013-11-06 @ 16:49

Hey, it's better than nothing. I'm PMing my email to you. Thanks for what you've done so far.
Trajk Logik
Newbie
 
Posts: 4
Joined: 2013-11-04 @ 20:46

Re: IBM PCjr Problem

Postby ronald_herrera » 2013-11-06 @ 19:18

I have already sent you the image: DemonAttack.jrc and some info that maybe you will need.
ronald_herrera
Newbie
 
Posts: 34
Joined: 2013-2-22 @ 02:45

Re: IBM PCjr Problem

Postby collector » 2013-11-06 @ 19:37

Just a note, you should not be distributing copyrighted openly on this forum.
User avatar
collector
l33t
 
Posts: 2841
Joined: 2003-1-15 @ 10:39

Re: IBM PCjr Problem

Postby ronald_herrera » 2013-11-06 @ 19:44

Oh! Okay I thought the ware in question was copyright abandoned. I stand correct.
ronald_herrera
Newbie
 
Posts: 34
Joined: 2013-2-22 @ 02:45

Re: IBM PCjr Problem

Postby collector » 2013-11-06 @ 19:50

Abandonware has no legal meaning.
User avatar
collector
l33t
 
Posts: 2841
Joined: 2003-1-15 @ 10:39

Re: IBM PCjr Problem

Postby VileRancour » 2013-11-06 @ 21:34

ronald_herrera wrote:But remember, I guess the game needs a joystick on less there's something wrong with the code segment. Al least the demo display beautifully the game, but I'm still working on it in order to use the keyboard; if it's possible. Somehow I feel all alone. :depressed:

Use the internal DOSBox keymapper to assign joystick events to keys -- works very nicely with most games. I do this even for games where keyboard support exists but is horrible/broken (e.g. Shamus).
The comments about timed=true and low cycles apply to this game as well.
Software gets slower more rapidly than hardware gets faster. Believe it, comrade.
User avatar
VileRancour
Oldbie
 
Posts: 1152
Joined: 2003-5-14 @ 22:11
Location: B800:0000

Re: IBM PCjr Problem

Postby ronald_herrera » 2013-11-06 @ 21:48

Thank you! for sharing this. :-)
ronald_herrera
Newbie
 
Posts: 34
Joined: 2013-2-22 @ 02:45

Re: IBM PCjr Problem

Postby ronald_herrera » 2013-11-07 @ 00:06

As in the config: usescancodes=true ... and... timed=true ..and... joysticktype=auto ... How can I use keymapper to assign the cursors keys without a physical joystick? I also tried to bind the cursors keys to act as a joystick but do not know the scancodes in the mapper file. (e.g.: key_up "key 273" to key_up "jaxis_0_1-" ???). What should I do?
ronald_herrera
Newbie
 
Posts: 34
Joined: 2013-2-22 @ 02:45

Re: IBM PCjr Problem

Postby VileRancour » 2013-11-07 @ 01:22

joysticktype=auto needs a physical joystick to detect - if you don't have one just set it to 2axis.

As for the mapper file, it's the other way around - the entries you want to modify are "jaxis_0_*", not "key_up" etc. You can view my example here (I use the numpad for movement + ctrl and alt for the buttons, but you can easily replace "key ###" with whatever you need).
Software gets slower more rapidly than hardware gets faster. Believe it, comrade.
User avatar
VileRancour
Oldbie
 
Posts: 1152
Joined: 2003-5-14 @ 22:11
Location: B800:0000

Re: IBM PCjr Problem

Postby ronald_herrera » 2013-11-07 @ 07:06

That's great! Thank you for your kindness!
ronald_herrera
Newbie
 
Posts: 34
Joined: 2013-2-22 @ 02:45

Re: IBM PCjr Problem

Postby ronald_herrera » 2013-11-07 @ 16:00

The mapper mods has been done and game has been responded well. But the firing-ship tends to move automatically to the right without pressing any key. It actually goes to the left if I press the left key until I stop holding it. Which, again, drifts to the right by itself.
Can I calibrate or stabilize the virtual-joystick in order to be able to maintain a hold of the ship at any sides?

Note: If I choose to make the change to "timed=false" then what happen is that it goes to the right side, but can't be able to move it again.

Considering my relevant config:
[SDL, DOSBOX]: usescancodes=true; machine=pcjr
[CPU]: core=auto; cputype=auto; cycles=fixed 150
[JOYSTICK]: joysticktype=2axis; timed=true; autofire=false; swap34=false; buttonwrap=false
ronald_herrera
Newbie
 
Posts: 34
Joined: 2013-2-22 @ 02:45

Re: IBM PCjr Problem

Postby VileRancour » 2013-11-07 @ 16:14

With timed=true the joystick's "drift" is related to the cycle count - too low and it drifts to the left, too high and it goes right. Cycles=300 or so works for me.
Software gets slower more rapidly than hardware gets faster. Believe it, comrade.
User avatar
VileRancour
Oldbie
 
Posts: 1152
Joined: 2003-5-14 @ 22:11
Location: B800:0000

Re: IBM PCjr Problem

Postby Trajk Logik » 2013-11-07 @ 16:34

Awesome! Thanks for all the help from everyone. I was able to get it booted and working with the numpad instead of the joystick. :happy: :happy: :happy:
Trajk Logik
Newbie
 
Posts: 4
Joined: 2013-11-04 @ 20:46

PreviousNext

Return to DOSBox Games/Apps

Who is online

Users browsing this forum: Bing [Bot] and 0 guests