First post, by aitotat
I am developing my own PC-emulator and i have been trying to find and fix some bugs for weeks. 286, motherboard components, text modes and floppy controller (IDE as well but it does not work properly yet) are currently emulated. I have written my own bios for motherboard and VGA. They should contain all functions related to currently emulated hardware.
MS-DOS boots fine (several versions) and many ASCII-games also work fine. There are two games that give me trouble. They are Pac-Gal and The Queen of Hearts Maze Game. Pac-Gal sometimes doesn’t draw all characters to screen. Both of them occasionally give some error messages, like String formula too complex or Out of string space. I think that there might be bug in CPU-emulation.
I have found (and fixed) some bugs by using PC Diagnostics 95 but it does not have any CPU tests. I would like to know where i can find any similar testing utilities that might also have CPU tests.
I have another question as well. Are BIOS-functions allowed to enable interrupts? Some BIOS-functions, like INT 16h/AH=00h (keyboard, get keystroke), need to enable interrupts but what about some (possibly slow) display bios functions? Should they enable interrupts even if it is not necessary?