[U-Boot] merge arm64 to arm

[Tom Rini]

On Mon, Aug 19, 2013 at 08:50:24PM +0100, M?ns Rullg?rd wrote:
> Tom Rini <trini at ti.com> writes:
> 
> > On 08/19/2013 01:33 PM, M?ns Rullg?rd wrote:
> >> Scott Wood <scottwood at freescale.com> writes:
> > [snip]
> >>> i960 is a bad analogy.  It's often possible to turn arm32 asm
> >>> into arm64 asm with some search and replace and minor manual
> >>> fixups.
> >>
> >> Only if the original uses none of the distinguishing features of
> >> ARM like predicated instructions or variably shifted operands.
> >> Once you limit yourself to the remaining basic operations, every
> >> (RISC) architecture looks the same.
> > [snip]
> >> AArch64 of course shares certain non-ISA aspects with AArch32.
> >> Page table formats and other architecturally defined system control
> >> features are the same, and code for managing these things should of
> >> course be shared.  Some other features, e.g. exception handling,
> >> are different enough that sharing code is probably difficult.
> >>
> >> There is a tendency to see arm64/aarch64 as yet another 64-bit
> >> extension of a 32-bit architecture, which it is not.  Assuming that
> >> software support will or can follow the model used by the others
> >> mentioned is thus a mistake.
> >
> > We don't have lots of hand-crafted assembly, and what we do, we
> > largely have split out already into the cpu directories.  I really
> > think we just need to try this and see how it goes.
> 
> Fine, let's see what it ends up looking like.
> 
> That said, please consider naming things in a way that armv8 does not
> imply 64-bit.

Agreed, thanks!

-- 
Tom
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