Philipp Stanner wrote:
Why would I want to address memory in RM with 32 Bits? I don't see any difference to using PM without Paging enabled.
In a bootloader (after coreboot) you often want to call BIOS interrupt services which assume real mode, because that was the only mode, when the interrupt services were created.
For coreboot itself, I think there is little if any advantage to big
Wait. Coreboot doesn't implement BIOS-Interrupt-Services.
Sure, but a payload can. SeaBIOS aims to provide a complete BIOS with all neccessary interrupt services for legacy compatibility.
So no payload started by cb should ever try to call BIOS, should it?
That depends. A *payload* can not assume interrupt services, but a bootloader (e.g. in MBR) can very well assume interrupt services, especially since MBR is a BIOS paradigm.
And you can't use the 32-Bit-Instructionset anymore, can you?
That's orthogonal. You can use 32-bit instructions in 16-bit mode and vice versa. The 0x66 and 0x67 opcode prefixes can be used to set an instruction mode for a single instruction.