Cartridge games

[arnoldemu]

GX4000, 64KB ram + 512KB cartridge ROM, this is similar to CPC464 + X-MEM.

So this means in theory that games made for GX4000 and 512KB cart should be equal to games made for 128K computers.

The memory map would look different:

Cart memory map:

common RAM/code, Screen 1 /Asic page, Screen 2, Cart page (code and graphics).

Screens could be at &4000-&7fff and &8000-&c000 for double buffer.
Graphics could be located at &c000-&ffff. Page in the ROM to access the full 512KB space.
&0000-&3fff could be common and always RAM.
&c000-&ffff in RAM could be used for another screen (e.g. panel).

128K game:

common ram/code, graphics and access to extra RAM, Screen 1, Screen 2.

See, cartridge game with 64KB ram is the same as a 128KB pure ram game.

[TFM]

Weird banking!

[andycadley]

I'd probably be more inclined to put the screens at &0000 and &C000, especially if the display routines only need write access to them, since that gives you an effective 96K flat address space (because of ROM write-through). Memory from &8000 to &BFFF obviously being the best place for stack space and other core requirements, since it's the only place that never gets paged.

But yes, cart games on a 64K machine can easily match 128K tape or disk titles, even before you consider the additional hardware benefits of the machines.