New version with more tests: Int 15h AH=83h, AH=86, AH=88h, AH=C0h and AH=C1h Int 16h AH=0h...3h, AH=5h, AH=9h, AH=Ah and AH=10h...12h Int 1Ah AH=0h, AH=2h, AH=4h, AH=7h and AH=Ah I tested it with four computers: 286 with AMI bios 486 with Award bios Celeron with AMI bios AthlonXP with Phoenix bios …

I wrote a small program that tests if bios functions will enable interrupts. It tests Int 11h, 12h and many 13h functions. Known values (with interrupts disabled) will be pushed to stack and loaded to flags before simulating iret with far call. Flags will be printed after bios function returns. I …

Some int 13h functions need interrupts to be able to work and some do not. For example read and write functions need to enable interrupts and AH=8h, Get Drive Parameters does not. What i meant before was that should all int 13h functions return with interrupts enabled or only those that really needs …

From http://www.microsoft.com/whdc/archive/Lf.mspx : "If a ROM BIOS API is documented to modify the flags--for example, it is documented to return with the CARRY flag set or cleared--this restriction does not apply to individual arithmetic bits in the flags register. Any ROM BIOS API that is …

Interrupts are needed during many int 13h functions. When returned with iret, interrupts will be disabled if they were disabled when bios function was called. Diag seems to have pushed some dummy word before calling int 13h with far call. This dummy word disables interrupts when popped with iret. …

I have now fixed lot of bugs but many still remains. I'm still testing with Diag and now i have problems with hard disk benchmark. It starts but never finishes. It seems that it polls timer tick variable from bios data area. It just never changes because interrupts are disabled. Diag calls int 13h …

Thanks for help. That Diag required at least 386 for some processor tests. Many other tests worked fine on 286 and i found out that i have some bugs in RTC and keyboard emulation. I'll fix those before trying to find the CPU bug. I would still like to know about other test utilities that would work …

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 …