Modifying Roklan PAC-MAN source code for fujinet hi-scores. $5969 alignment hell, HELP!

[tschak909]

Am currently trying to patch the Roklan Pac-Man source code, to add FujiNet Hi-score capability.

 

I attempted to add a single JMP inside PAC1 to go to my code after VGMEND finishes, and am being hit by alignment bugs from hell:

mads -d:VERSION=1 PACMAN.ASM -o:PACMAN-ORIGINAL.xex
 ORG $5969
PAC3.ASM (119) ERROR: Can't fill from higher ($596C) to lower memory location ($5969)
make: *** [Makefile:13: pacman1] Error 2

 

Anyone have some insight? @JAC!?

[+JAC!]

The addresses have to be continously counting up. In mads that is activated with "OPT F+" (fill mode).
You cannot just place the ORG anywere, you have to adapt the source code in the right line that corresponds to the address.
Other than that it's difficult without having the source...

[tschak909]

 There's a reason I mentioned you.

 

;************************************
;*                                  *
;*            PAC-MAN               *
;*                                  *
;*   Developed for Atari Inc. by    *
;*  Roklan Corp. This Information   *
;*  is confidential and is not for  *
;*  sale or distribution.           *
;*                                  *
;* Software written by Joe Hellesen *
;*                                  *
;*            10/03/82              *
;*                                  *
;*          DISK VERSION            *
;*                                  *
;*          REVISION 3.0            *
;*                                  *
;************************************
;

; Adapted version for MADS, 2018-07-28 JAC!

 

A bit of some creative jumping later, and I got something that built and displayed, but now I realize that PAC-MAN uses a DLI after the second row of text, and switches to a dedicated multicolor charset.

 

guess I need to find a way to cram a bit more into the DLI, so I can switch to text mode in the middle there

 

-Thom

Edited October 14, 2022 by tschak909

[tschak909]

I managed to get a workable high-score display.

now need to find ways to patch into the main code. 

 

@JAC! Why the alignment restrictions? What can I do to help work around that?

 

-Thom

[JamesD]

15 hours ago, tschak909 said:

I managed to get a workable high-score display.

now need to find ways to patch into the main code. 

 

@JAC! Why the alignment restrictions? What can I do to help work around that?

 

-Thom

The Antic can't cross page boundaries

[+slx]

Would it be an option to replace the code at VGMEND with a JSR to your code (placed in a safe memory space) that first contains the instruction at VGMEND you replaced with the JSR, followed by whatever code you need and an RTS? That's a method I used when patching Shamus to create Shamus+. (Obviously does not work with code that is very time critical.)