Additional bios routines

[maman]

I really wish to make an additional bios routine that will show up by means of trapping certain keyboard character similar to pressing "del" during power up on award bioses. I've already able to embed certain routine in the bios as an isa expansion rom, but I wish to extend it to show some menu through trapping certain keyboard message during powerup so that the routine that I add would be programmable, and the setting it uses will be stored in the cmos. Then , my first question is this possible while still using an isa expansion rom or should I make the PCI expansion rom version of my routine. The second is how to trap keyboard message during power up, I know that those expansion roms are initialized after the main bios (original.tmp) loads, I wish somebody could point me to the right direction . The last one how to save certain data to the cmos in a save manner without disturbing the other setting that already there, as I know not all of the cmos registers used by the bios routine. Any suggestion will be very help full

[tomuf]

maybe you could try hooking interrupts if it works; you can read CMOS map from BIOS, the best thing would be to find CKCMOS utility somewhere, which scans BIOS and finds conflicting CMOS addresses and free addresses; but there is usually only few bytes free in CMOS... and I don't know anyone who has CKCMOS

[Rainbow]

To read keyboard: see ports.lst in Ralf Brown's Interrupt list. You don't need interrupts, only some reads from keyboard data port. The keyboard handler in UniFlash does not use interrupts at all. And works.
Better don't write anything to CMOS - usage of CMOS depends on BIOS version. So it can work with one BIOS but will overwrite settings in another one.