This is a 32-bit UEFI firmware based on UEFI EDK. As per UEFI specification - unpaged protected mode. This is was around 3.5 years ago, before the time of OVMF, and involved filling in all the missing bits to make the Nt32 simulator real firmware - low-level code, chipset support, patched build tools to properly relocate execute-in-place PE32 binaries for SEC/PEI phases. Sure, I'd done it all before, but this time I did everything carefully and non-hacky. And this time it took me no more than 5 all-nighters, ignored lectures and "work" at my then job...but that's a stark comparison to the month/month and a half it took me to realize the same for x64 before =).
I had followed the same pattern of Tiano porting - maintaining separate SEC, PEI and DXE phases, even though in the context of a virtual machine, the PEI phase had nothing to do but load the DXE core...
The platform changes have been lost forever, while the tool patches to generate proper ROMs (fitting to my own specification as to how it should work, given lack of functioning code provided by Intel) have carried on with me into my more official EFI endeavors, but as actual code are also either gone or bit rotting on some harddrive in one of my old boxes... I've never gone past booting to the EFI shell - I think my plans were to test ELILO, but given my senior year at UIC and other concerns, I never came around to it.
P.S.: Ignore the silly SVN commit comment. You definitely don't want to use the TSC for the timer calibration, given that the TSC may fluctuate depending on CPU power savings....
Maybe I should do a port for ARMv5 Integrator/CP in QEMU...
AoE is @ prominent position on your taskbar. cool :)
ReplyDeleteThose were the good old days :).
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