[coreboot] Time for a new project
segher at kernel.crashing.org
Sun Apr 13 19:03:12 CEST 2008
> The problem is that the loader code will not change.
> When the loader reads the type value, it will differ depending on
> endianism. As an example, 'CODE' will be equivalent to
> 0x45444F43 on a little endian machine, and 0x434F4445 on
> a big endian machine. This causes obvious issues in the code.
> By dictating that all the header values should be in little endian
> we avoid this problem.
Either the code will use u32 everywhere, or it will use u8
(or char) everywhere. Either way, it works fine; the second
option is better of course, since the binary will be more readable
(in a hexdump).
You have to be careful in your tools, so that cross-builds work
> Thats true. But again, like I said, what concerns us is that endianism
> affects the order in which the bytes will be stored in the header
That depends on how *exactly* you define the SELF format. Writing
a *proper* specification is a lot of work, indeed!
> The endianism is specified by the processor, not the software.
Not true. There are *many* processors that can run either
little-endian or correct-endian: ARM, MIPS, PowerPC, ...
> A x86 is little endian, forever more.
Yeah, poor x86.
> And since v3 only works on an x86,
I hope to change that soon.
> we could ignore it for now.
No you cannot, if you're defining this new binary format. Yet
another reason why you really shouldn't.
> we know that the problem exists, and we might as well account for it
> now. By specifying it as little endian, we do put other architectures
> at a disadvantage. But none of those other architectures are in play
> for a very long time. You have to play to your strengths.
What are you saying here?
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