On 04/07/2011 03:22 AM, Bei Guan wrote:
Hi,
I have some questions about the qemu's bios. How does the QEMU load
the binary files bios.bin and vgabios-cirrus.bin? Which function or
code file need I to pay more attention to?
For the loading of vgabios-cirrus.bin and bios.bin, I just trace them
into the same funciton rom_add_file() in hw/loader.c. Is it the
right function, which loads the bioses?
And then another question, how qemu give the control to bios when the
bios file is loaded? Maybe this question is not in the scope of qemu,
however, can you give me some cue point.
I had some stuff written up locally so I posted it to the wiki at
http://wiki.qemu.org/Documentation/Platforms/PC
The x86 architecture defines the initial state of the chip to have the
CS register have a base of 0xF000 and an IP of 0xFFF0. The result is
that the actual memory address of the first instruction falls at the end
of the BIOS ROM segment. This is the entry point to the BIOS.
The VGABIOS is treated like any other option ROM and is initialized
during option ROM scanning.
Regards,
Anthony Liguori
Any reply are appreciated. Thanks.
Gavin
