Rom hex file help

Discussion about ZX80 / ZX81 Software
Moggy
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Joined: Wed Jun 18, 2008 2:00 pm

Re: Rom hex file help

Post by Moggy »

Tried debug.exe in W-XP and no matter what I entered all I got was error error error!!

As I said before I'm terminally fu*&%!ng stupid so I'll leave this to those that know what they're doing.
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stefano
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Re: Rom hex file help

Post by stefano »

My fault, I try to suggest few steps, let me know where when things get too hard, I'll give more detail.

1) You need the "command prompt". Put a copy of the ROM file you want to modify in a new folder (in example c:\myroms).

2) use the command prompt and change directory to that folder (cd \myroms)

3) now the command prompt should show "c:\myroms).

4) To copy "Tree4th.rom" into "h4.rom" and make it compatible to 50 hz:
c:\myroms> copy Tree4th.rom h4.rom
c:\myroms> debug h4.rom
-e 172 4A <-- the '-' symbol is the prompt !
-w
(debug will say "Writing 02000 bytes")
-q
c:\myroms>

5) To patch any of the forth roms and shift the display left:

c:\myroms> copy originalrom.rom newrom.rom
c:\myroms> debug newrom.rom
-e 183 CD 8d 00 D3 FE D1 C1 F1 E1 C9 3E EA 76 D3 FD
(debug will say "Writing 02000 bytes")
-w
-q
c:\myroms>
Moggy
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Re: Rom hex file help

Post by Moggy »

Hi Stefano.

Many thanks for turning on the light!!! :lol:

I patched the ROM and it runs fine in eighty one though now it is about 3 columns too much to the left and also needs to come down by about 3 lines!
The reverse mask is also correct but then it always was in eighty one.

Ho and by the way I mistakenly said there was a fault in the editor preventing editing/deletion of furthermost right column, well I forgot that the editor does not delete the chr that the cursor is positioned directly on, you have to put the cursor to the left of any chr to delete so my mistake. :oops: :oops:

I now need to find some 25v 2764 EPROMs to burn this image to to try on the real thing. Sir Morris has the 12v versions that he uses for the ZXpand I may need to beg a favour from him!! :lol:

Once again great work Stefano many thanks.

Regards.

Moggy.
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stefano
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Re: Rom hex file help

Post by stefano »

I'm so glad we undestood each other :)

I know the picture shift is not optimal; being so difficult to get it centered makes me doubt it is possible at all, but obviously I cannot be sure of it :geek:
Moggy
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Re: Rom hex file help

Post by Moggy »

Ok I now need to lay my hands on some EPROMS and see if this works with real zeddy. :D
sirmorris
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Re: Rom hex file help

Post by sirmorris »

Do you have a ROM expansion board which takes 2764s, Mr. Moggy? Email me the ROM file and I'll whizz you one over.

C
Moggy
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Re: Rom hex file help

Post by Moggy »

sirmorris wrote:Do you have a ROM expansion board which takes 2764s, Mr. Moggy? Email me the ROM file and I'll whizz you one over.

C
Charlie I've said it before and I'll say it again you're an absolute star :D

I use the 2764's direct into the zeddies rom socket after a bit of pin jiggling.
I could burn em myself but as you know my burner for the speccy only does the old 21/25 volt devices and not the 12.5 volt 27c64s.

Anyhow email (and elevation to baron Morris) on it's way :lol:

Cheers Charlie.

Moggy.
sirmorris
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Re: Rom hex file help

Post by sirmorris »

28 2 days for delivery..
Moggy
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Re: Rom hex file help

Post by Moggy »

Managed to lay my hands on some EPROMS and tried Stefanos's patch for the H4th ROM.
Sorry to say It doesn't work, well not for me at least, great in eighty one but not on a real zeddy.
the following pictures say it all really, screen still up and to the right plus inverse mask still missing furthest right attribute, the top lines now corrupted and bend markedly to the left.
Other than that the ROM actually works as it should just a corrupted display.

I burnt two separate EPROMS just to be sure one wasn't faulty still no joy, I then burnt original H4th image and and that worked ok apart from the screen position and inverse mask problem mentioned earlier in the thread, so assume EPROMS ok.

Please excuse poor pic quality I'm not too good at this but they show what I mean.
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PokeMon
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Re: Rom hex file help

Post by PokeMon »

This looks like a simple timing error of about 3 chars / 12 t-states missing when starting the first line. ;)
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