FE3_2_SUPER_ROM_BUG?

[srowe]

I'm playing around with code to use the various modes of the FE3 and noticed the following in the VICE code base

Code: Select all

/* emulate Final Expansion v3.2 Super ROM write bug */
/*#define FE3_2_SUPER_ROM_BUG*/

I think it refers some discrepancy in whether writes go to bank 0 or 1 in Super ROM mode but I can't find any further details.

I'd like to understand this better before I write too much code that assumes the behaviour described in the original manual (which states writes go to bank 1).

[tlr]

I'm playing around with code to use the various modes of the FE3 and noticed the following in the VICE code base

Code: Select all

/* emulate Final Expansion v3.2 Super ROM write bug */
/*#define FE3_2_SUPER_ROM_BUG*/

I think it refers some discrepancy in whether writes go to bank 0 or 1 in Super ROM mode but I can't find any further details.

I'd like to understand this better before I write too much code that assumes the behaviour described in the original manual (which states writes go to bank 1).

I wrote that code. It refers to a bug in the preliminary CPLD for v3.2 which I found when reverse engineering the CUPL code to implement emulation of the cartridge. This bug is AFAIK not present in any released v3.2 CPLD versions.

[srowe]

I wrote that code. It refers to a bug in the preliminary CPLD for v3.2 which I found when reverse engineering the CUPL code to implement emulation of the cartridge. This bug is AFAIK not present in any released v3.2 CPLD versions.

Thanks for the confirmation, I noticed this is commented out so there's no way to build VICE with it. I'm amazed that all the behaviour of FE3 seems to be so faithfully implemented in VICE. A lot easier to debug with than the real thing.

[tlr]

I wrote that code. It refers to a bug in the preliminary CPLD for v3.2 which I found when reverse engineering the CUPL code to implement emulation of the cartridge. This bug is AFAIK not present in any released v3.2 CPLD versions.

Thanks for the confirmation, I noticed this is commented out so there's no way to build VICE with it. I'm amazed that all the behaviour of FE3 seems to be so faithfully implemented in VICE. A lot easier to debug with than the real thing.

Thanks, I guess.

I had the CUPL source to work from, but there was also a decent test program by Thomas Winkler to run on the vic20 to verify the bulk of the functionality.