Re: [Qemu-devel] [PATCH] configure: Support QEMU cross-compiling for ARM64 host

[Peter Maydell]

On 8 January 2013 15:57, Richard Henderson <address@hidden> wrote:
> On 01/08/2013 04:08 AM, Peter Maydell wrote:
>> The translator sources (as and when we implement a
>> TCG QEMU target for this) should live under the existing target-arm.
>
> Of this I'm not certain, given that A64 is different enough from A32
> to warrant a brand new gcc backend.  I havn't tried to reverse engineer
> the encodings from the binutils sources to understand the details; I'm
> happy to wait until proper documentation is finally released.

Since an ARMv8 64 bit CPU can run both 32 bit and 64 bit binaries,
a QEMU TCG system level emulator would need the existing 32 bit
code as well as new 64 bit code, so putting them both in the same
directory seems to make sense to me. GCC backends don't need to
emit code for both modes at once (since you can only change mode
on an exception boundary) so they don't have the same requirements.

(Also, all our other "we have a 32 and a 64 bit version" tcg targets live
in a shared target-foo/ directory.)

-- PMM