I did have both of these in NTSC version when I was a kid and played them but they cannot be found on Zimmer's.
Only the PAL version of these games are there.
Anybody has them for archival ?
MIA: Spider of Mars and Mosquito Infestation NTSC
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Mayhem
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I might have an NTSC Spiders of Mars too. Again, it will take me a while to check into it, and figure out how to dump it....so please remind me in a few weeks if you haven't found anything.
As for Mosquito Infestation, it would be nice to get an NTSC version, as it's one of the better VIC-20 cartridges out there.
As for Mosquito Infestation, it would be nice to get an NTSC version, as it's one of the better VIC-20 cartridges out there.
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Mayhem
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Quick course how to find those changes:
1. Load cartridge image into emulation (or real computer if you prefer, but then you need a machine code monitor connected as well). You should enable RAM in the block(s) the image loads into and load it manually instead of attaching cartridge image, since cartridge images are write protected in the memory map.
2. Enter the monitor (in VICE: Alt+M). Issue a command like this:
> H A000 C000 00 90
The first two are start and end addresses of the memory area you want to search through, in this case equals to 8K in block 5. The last two bytes is the hexadecimal representation of 36864 in low-byte, high-byte (little endian order?).
You will probably get a few matching memory addresses. Sometimes a lot, sometimes only one.
3. Issue a command to disassemble memory, starting a bit prior to the matching addresses. For example, if the search matched at $AB91:
> D AB88 (or AB80 if it is easier to type)
AB88 STX $FD
AB8A RTS
AB8B LDX #$05
AB8D LDA $AC11,X
AB90 STA $9000,X
AB93 DEX
AB94 BNE $AB8D
... and so on
This looks like a typical example of setting up screen from an array of values, stored at $AC11 (44049) and onwards. We would like to confirm this is the case:
> M AC11
0C 26 96 2E ... and so on
Yep, those values look like PAL screen positioning.
4. Try to change those values. It can be done from the monitor:
> > AC11 05 19
Note that the command is ">", as opposed to the prompt that I represent as a ">" in the example. One could also change those values from Basic:
POKE 44049,5:POKE 44050,25
Exit the monitor by giving the X command.
5. It is possible that the memory disassembled in step 3 looks like this instead:
AB88 STX $FD
AB8A RTS
AB8B JSR $AC11
AB8E LDA #$0C
AB90 STA $9000
AB93 LDA #$26
AB95 STA $9001
... and so on
In those cases, it is the content of memory at $AB8F and $AB94 that would need to be altered, but the principle is the same.
6. If one would want to make the game playable irregarding of video mode, one needs to confirm that the screen positioning equals default, which in 80% of the games is the case. In that case, one could simply overwrite each STA with another LDA (or NOP out the whole instruction). It would be done like this, assuming the last example:
> A AB90 LDA $9000
> AB93 LDA #$26
> AB95 LDA $9001
As many of these games use a standard 22x23 screen resolution and center the display at the default position as defined by Commodore themselves, I don't quite understand why so many cartridge games are hard coded to position the screen themselves. As far as I know, the Kernel routines to set up the screen are executed even when a cartridge is about to autostart. Perhaps in an early draft of the VIC-20 specs, this wasn't guaranteed to happen so software houses made sure to set up the screen themselves.
7. In some cases, one might find more obscure ways to configure screen, by using relative values, rests of another calculation and so on. Those cases would need to be covered individually, and we haven't yet started on games which rely on raster beam timing or other pecularities.
1. Load cartridge image into emulation (or real computer if you prefer, but then you need a machine code monitor connected as well). You should enable RAM in the block(s) the image loads into and load it manually instead of attaching cartridge image, since cartridge images are write protected in the memory map.
2. Enter the monitor (in VICE: Alt+M). Issue a command like this:
> H A000 C000 00 90
The first two are start and end addresses of the memory area you want to search through, in this case equals to 8K in block 5. The last two bytes is the hexadecimal representation of 36864 in low-byte, high-byte (little endian order?).
You will probably get a few matching memory addresses. Sometimes a lot, sometimes only one.
3. Issue a command to disassemble memory, starting a bit prior to the matching addresses. For example, if the search matched at $AB91:
> D AB88 (or AB80 if it is easier to type)
AB88 STX $FD
AB8A RTS
AB8B LDX #$05
AB8D LDA $AC11,X
AB90 STA $9000,X
AB93 DEX
AB94 BNE $AB8D
... and so on
This looks like a typical example of setting up screen from an array of values, stored at $AC11 (44049) and onwards. We would like to confirm this is the case:
> M AC11
0C 26 96 2E ... and so on
Yep, those values look like PAL screen positioning.
4. Try to change those values. It can be done from the monitor:
> > AC11 05 19
Note that the command is ">", as opposed to the prompt that I represent as a ">" in the example. One could also change those values from Basic:
POKE 44049,5:POKE 44050,25
Exit the monitor by giving the X command.
5. It is possible that the memory disassembled in step 3 looks like this instead:
AB88 STX $FD
AB8A RTS
AB8B JSR $AC11
AB8E LDA #$0C
AB90 STA $9000
AB93 LDA #$26
AB95 STA $9001
... and so on
In those cases, it is the content of memory at $AB8F and $AB94 that would need to be altered, but the principle is the same.
6. If one would want to make the game playable irregarding of video mode, one needs to confirm that the screen positioning equals default, which in 80% of the games is the case. In that case, one could simply overwrite each STA with another LDA (or NOP out the whole instruction). It would be done like this, assuming the last example:
> A AB90 LDA $9000
> AB93 LDA #$26
> AB95 LDA $9001
As many of these games use a standard 22x23 screen resolution and center the display at the default position as defined by Commodore themselves, I don't quite understand why so many cartridge games are hard coded to position the screen themselves. As far as I know, the Kernel routines to set up the screen are executed even when a cartridge is about to autostart. Perhaps in an early draft of the VIC-20 specs, this wasn't guaranteed to happen so software houses made sure to set up the screen themselves.
7. In some cases, one might find more obscure ways to configure screen, by using relative values, rests of another calculation and so on. Those cases would need to be covered individually, and we haven't yet started on games which rely on raster beam timing or other pecularities.
Anders Carlsson
hmmm, think you can send it to me for inclusion on the multicart eslapion?
I tried to dump my sofm cart but the resulting image didnt work. Im sure carlsson could get it to work but I arent that charmed. unfortunately.
Anders do you think you could fix some of the pal only games in my cart archive to work with ntsc and vice versa? I dont know if that would be a good thing or not, to fix all the games or leave them as the devs intended them to be, but gimme some opinions people. We dont need all of them done, just the rare and non ntsc available games like amidar,arcadia, deadskys,ET,Flipper,Mosquito infestation,Quackers,tank atak and wacky waiters. I would really appreciate it. Thanks
Cart archive is here and the games are in the PAL folder within.
http://members.shaw.ca/vic20/VicCartRoms.zip
Leo
I tried to dump my sofm cart but the resulting image didnt work. Im sure carlsson could get it to work but I arent that charmed. unfortunately.
Anders do you think you could fix some of the pal only games in my cart archive to work with ntsc and vice versa? I dont know if that would be a good thing or not, to fix all the games or leave them as the devs intended them to be, but gimme some opinions people. We dont need all of them done, just the rare and non ntsc available games like amidar,arcadia, deadskys,ET,Flipper,Mosquito infestation,Quackers,tank atak and wacky waiters. I would really appreciate it. Thanks
Cart archive is here and the games are in the PAL folder within.
http://members.shaw.ca/vic20/VicCartRoms.zip
Leo
Ok, first things first:
Flipper (Pinball Wizard) and Wacky Waiters are defintely not cartridges, just poor attempts of archiving an oversized unexpanded game before Pucrunch was available. I'm responsible for Flipper myself, but Marko eventually succeeded in packing it. I'm quite sure Arcadia and Quackers also fall into this category, unless someone can prove me wrong.
Amidar and ET seem like homebrewn games, which is OK if they really run as ROM images and not just copy themselves down to RAM.
Currently I'm busy on many levels, but perhaps I can have a look by the next weekend or so.
Flipper (Pinball Wizard) and Wacky Waiters are defintely not cartridges, just poor attempts of archiving an oversized unexpanded game before Pucrunch was available. I'm responsible for Flipper myself, but Marko eventually succeeded in packing it. I'm quite sure Arcadia and Quackers also fall into this category, unless someone can prove me wrong.
Amidar and ET seem like homebrewn games, which is OK if they really run as ROM images and not just copy themselves down to RAM.
Currently I'm busy on many levels, but perhaps I can have a look by the next weekend or so.
Anders Carlsson
carlsson wrote:Ok, first things first:
Flipper (Pinball Wizard) and Wacky Waiters are defintely not cartridges, just poor attempts of archiving an oversized unexpanded game before Pucrunch was available. I'm responsible for Flipper myself, but Marko eventually succeeded in packing it. I'm quite sure Arcadia and Quackers also fall into this category, unless someone can prove me wrong.
Amidar and ET seem like homebrewn games, which is OK if they really run as ROM images and not just copy themselves down to RAM.
Currently I'm busy on many levels, but perhaps I can have a look by the next weekend or so.
AH HA! I had my doubts about all of those games as in all my years, Ive never heard of any of them on cartridge. Although I had never heard of witchway until recently too but thats another thing.
Ok well I am going to see about excluding those files from the cart as they really dont fit in then. Thanks for the clarification Anders. If you can have a look some of the other games , please do. Thanks
Some games like Alien Blitz and a few others, however do exist as both 4K cartridges and 3.5K unexpanded versions. As far as I know, they look and play in the same way, just the code that is different. It is possible that one or two software houses did issue cartridges that simply contained unexpanded games that copies itself down to RAM, but given the manufacturing costs of a cartridge vs recording a tape, I think very few took that approach.
Anders Carlsson
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Mayhem
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