issues with e7-style bank switching

[deater78]

so I've been working on Myst which uses E7 bank-switching.  It works great under Stella, but it turns out it doesn't work elsewhere.

 

Mame: the ROM and 1k bank switches seem to work, but the 256 byte RAM at $1800/$1900 doesn't seem to work right

javatari: works for a bit but at some point things get corrupted, so badly that a power cycle doesn't fix it

harmony cartridge: appears to just lock up on the first bank switch (I've named the rom file with an .e7 extension)

 

has anyone else successfully used the E7 bank-switch method before?

[+splendidnut]

 

[deater78]

3 hours ago, deater78 said:

 

Mame: the ROM and 1k bank switches seem to work, but the 256 byte RAM at $1800/$1900 doesn't seem to work right

 

OK, after adding a lot of printf()s to the MAME code I figured out that it just ignores "-cartslot a26_e7" on the command line and tries to auto-detect anyway.  So I put one of the E7 magic numbers into the rom image and now things work on MAME at least.

 

I'm using LDA to switch banks, but looking at the MAME code it looks like using STA might be preferred?  I can try that I guess, though I thought the r/w signal didn't make it to the cartridge

[+splendidnut]

Both LDA or STA should work, since there is no R/W signal to the cartridge.

 

STA is probably preferred since it won't affect the contents of the Accumulator.

[deater78]

I made a lot of changes to my code while trying to sort things out, and the Harmony cartridge appears to be working now!

 

javatari is still broken.  I'm not sure if there's a good way to debug it.  You can save the game state, but I'm not sure if there's a way to turn that into a hexdump style memory dump to try to figure out what's going on.