Bridge. Handic. Vic20. Get it now.

nbla000 · Post by **nbla000** » Wed Oct 29, 2008 10:04 am

I got it, forget the previous post.

The key is to change pointers on $a71f 21 a7 (pointer to $a721 routine)

The $a721 routine is executed to check the key pressed after the screen is positioned on start.

Code: Select all

a721   86 0A      STX $0A
a723   20 E4 FF   JSR $FFE4
a726   F0 FB      BEQ $A723
a728   A6 0A      LDX $0A
a72a   4C C2 A1   JMP $A1C2

I may change pointers to a free space location in $6d50/$6fff and write a routine that set correct screen for both PAL/NTSC machines before to jump to $a721 with just one fix for both systems

Stay tuned...

orion70 · Post by **orion70** » Wed Oct 29, 2008 11:21 am

Mayhem wrote:Given the game is pretty much the same as its C64 counterpart, then I figure the manual on my site should cover it well enough.

Hope you don't mind if I created a PDF version of the manual. Thanks for Bridge, it will be my chance to learn the basics of this game.

nbla000 · Post by **nbla000** » Wed Oct 29, 2008 5:12 pm

Here we are...

This is my solution to center screen for both PAL/NTSC machines in just one fix:

Code: Select all

a71f  00 6F   ;CHANGE POINTERS TO $6F00 (FIX ROUTINE)


6f00   48         PHA
6f01   8A         TXA
6f02   48         PHA        ; STORE A/X VALUES  

6f03   A9 DD      LDA #$DD   ; CHECK BYTE 
6f05   CD FF 03   CMP $03FF  ; CHECK LOCATION
6f08   F0 08      BEQ $6F12  ; ROUTINE ALREADY EXECUTED, SKIP                     
6f0a   8D FF 03   STA $03FF  ; WRITE CHECK BYTE   

6f0d   A2 02      LDX #$02
6f0f   20 C5 E5   JSR $E5C5  ; WRITE DEFAULT X/Y COORDINATES
                             ; ($05/$19 NTSC, $0C/26 PAL)
6f12   68         PLA
6f13   AA         TAX
6f14   68         PLA        ; RESTORE A/X VALUES

6f15   4C 21 A7   JMP $A721  ; CONTINUE NORMAL ROUTINES

I need to use the check byte because the $a721 routine is recalled from $a71f pointers each time you press a key on Title screen so without a check byte you cannot use manual screen centering with cursor keys because my code rewrite X/Y coordinates.
The check byte is required to execute the fix routine just once.

Any other solution to substitute the check byte routine portion and to execute the X/Y centering routine portion just once is welcome.

A/X store/restore code is required to prevent game crash.

The solution is a little bit strange especially if compared with my other easy fixes but this game is the most hard to fix that i've found.

Enjoy it

pelleb · Post by **pelleb** » Thu Oct 30, 2008 3:30 am

Hello!

I am the Per Backman Mayhem got the ROM-dumps from.

As people seem to have studied these files maybe someone could explain a strange behaviour this game shows, it won't start on a VIC with scandinavian ROMs. The irony in this is that, if I remember correctly, it was Handic that marketed the scandinavian conversion...

Mayhem · Post by **Mayhem** » Thu Oct 30, 2008 4:14 am

Welcome Per... as you can see, people are enjoying the fruits of labour heh...

carlsson · Post by **carlsson** » Thu Oct 30, 2008 6:19 am

Hm, are you sure you're not using a memory expansion in parallel with the game cartridge? I tried in VICE and if I have +8K or more, the game bails out no matter which version of the Kernel ROM I have installed.

If I change to unexpanded VIC + cartridge like it is supposed to. I tried both VIC-1001, VIC-20 NTSC, VIC-20 PAL and VIC-20 Swedish.

Unfortunately I don't think I own any localized VIC-20 at the moment, I've sold the two ones I got. How far do you come on a real machine: start-up picture, the "set number" screen, the display of cards...

nbla000 · Post by **nbla000** » Thu Oct 30, 2008 8:03 am

pelleb wrote:Hello!

I am the Per Backman Mayhem got the ROM-dumps from.

Welcome on Denial and many many thanks for your ROM-dump.

As people seem to have studied these files maybe someone could explain a strange behaviour this game shows, it won't start on a VIC with scandinavian ROMs.

As Carlsson suggested maybe a Memory matter at least if you talk of file images, if you use a standard 32K expansion it doesn't work, you see the title screen but when you press F1, you got a garbage screen.
You need to use a switchable Memory expansion and set BLK3 and BLK5 ON, BLK1 must be off.
You may use the Eslapion's Expander too, set 32K switch Enabled, Power ON the Vic, Load the file images then set 32K switch disabled and reset or SYS64802.

Another way is to use the MegaCart RAM expander without any switch but since i've added it on the MegaCart Cartridge games section, you just need to start it.
If you want you may add it in the first MegaCart menu page to start it quickly after each boot.

MegaCart, what else ?

gklinger · Post by **gklinger** » Thu Oct 30, 2008 9:40 am

Nice to have you with us, pelleb, and again, thanks for sharing.

nbla000 · Post by **nbla000** » Thu Oct 30, 2008 12:11 pm

OK, in addition to my previous fix this is my solution to allow loading from standard 32k, BLK1 not switchable, memory expansions.

Code: Select all

a4f9   20 20 6f   JSR $6f20

6f20   A9 1E      LDA #$1E
6f22   8D 88 02   STA $0288
6f25   20 18 E5   JSR $E518
6f28   60         RTS

If required i may send full fixed BLK3/BLK5 files to Mayhem for sharing.

*** edit *** it's my 1000th post on Denial

orion70 · Post by **orion70** » Thu Oct 30, 2008 12:35 pm

@Nicola:

pelleb · Post by **pelleb** » Fri Oct 31, 2008 2:18 am

carlsson wrote:Hm, are you sure you're not using a memory expansion in parallel with the game cartridge? I tried in VICE and if I have +8K or more, the game bails out no matter which version of the Kernel ROM I have installed.

To clarify, I just plug the actual cartridge into my VIC, no expansions.

nbla000 · Post by **nbla000** » Fri Oct 31, 2008 3:17 am

pelleb wrote:To clarify, I just plug the actual cartridge into my VIC, no expansions.

I've tested Bridge roms on VICE by attaching cartridge images at $a000 and $6000 with swedish kernal and chargen in PAL mode.

They worked without problems, i don't know if is a VICE bug or it's a specific problem of your board, if you have a 32k memory expansion or any switchable expansion for blk3 and blk5 i may send you a disk image with your original dump but in prg 4k+8k image format and my BLK1 fixed version with screen centered so you may try these files.
Give me your Email in a PM for file sending.

Have you tested other 16k cartridges like MsPacMan, MoonPatrol, PolePosition ?

PS:Thanks Orion for your cake

carlsson · Post by **carlsson** » Fri Oct 31, 2008 3:58 am

Yes, as NBLA000 writes the setup works fine in emulation. Please try one of the other 16K cartridges in case something is bad on your Scandinavian VIC-20. Perhaps one of the lines on the cartridge port does not get proper contact. If you do have a suitable memory expansion, you could try that as well, e.g. if you can obtain a 24K mode or not.

As Bridge (and A World at War, in case you own that one too) uses a fair bit of RAM (i.e. zeropage and stack), in worst case it could be something bad with the interior RAM which should be observed even if you load tape games. It sounds a bit unlikely, but never knows...

nbla000 · Post by **nbla000** » Fri Oct 31, 2008 4:15 am

carlsson wrote:Perhaps one of the lines on the cartridge port does not get proper contact.

I thought on this but since i suppose that pelleb grubbed the file images from this machine and since file images work, i discarded this hypothesis.

Btw in case pelleb grubbed file images from another vic he may try this way too.

pelleb · Post by **pelleb** » Fri Oct 31, 2008 9:43 am

nbla000 wrote: Btw in case pelleb grubbed file images from another vic he may try this way too.

Actually, I pulled the socketed EPROMS from the cartridge and read them with my EPROMMER...

Bridge. Handic. Vic20. Get it now.

Re: Bridge. Handic. Vic20. Get it now.