PC DOS emulator for Picopad with Raspberry Pico and RP2040 processor 

CGA se 4 barvami byla docela bída. 16-barevná grafika u následného PCjr byla už plně dostatečná pro hry, škoda že PCjr byl propadák a neuchytil se.

Sorry, other games are a problem to emulate. The main problem is the size of the RAM memory. The emulator loads the program into Flash memory, divides the memory into 4 KB pages and reallocates the corresponding page to RAM when it is written. This ensures that programs requiring 640 KB of memory could work. However, most DOS games introduce their parts into memory additionally as overlay modules. The emulator cannot distinguish this and has to load them into RAM memory, so the internal RAM memory of the Pico processor is not sufficient for most programs. A significant part of the RAM memory is also consumed for video memory. The solution is to modify the emulated programs so that the entire code is loaded as a single file into Flash memory, then the RAM memory might be sufficient. However, the modification is quite difficult and sometimes it may be easier to write such a program again, in Pico C code.

The emulator emulates 20 basic video modes from CGA to VGA cards, so graphics should not be a limitation. To save memory, BIOS and DOS functions are emulated internally by the emulator functions, not by running DOS and BIOS code. The emulation is not exact, only the most basic functions are emulated for the savings, this is also a limitation of emulations, besides the lack of memory. The accuracy of emulation could be improved over time, e.g. emulating the video card registers more accurately.