[J-core] Port Idea: Little Kernel

Cedric BAIL cedric.bail at free.fr
Fri Nov 10 17:01:54 EST 2017

On Thu, Nov 9, 2017 at 4:24 PM, Rob Landley <rob at landley.net> wrote:
> Alas, nobody's made time for either yet, I've got my hands full with
> toybox and $DAYJOB, and if I did wind up with extra time I'd really need
> to add j-core SOC board and j2 -cpu emulation to qemu.
> (Qemu commit 143021b26ffe is already making a couple of instructions
> sh4a-specific. In theory the technique for adding a j2 target wouldn't
> be that different. Right now we just run qemu under an sh4 kernel with
> j2 userspace binaries when we want to test in emulation, because then
> the only j2 userspace instruction missing is cmpxchg, which means
> futexes don't work. I'm aware there's a kernel patch saying futexes need
> fixing, but unless Rich gets around to that independently it's behind
> adding qemu support on my own todo list.)

I looked at that commit and it sounds quite simple to add the same
tests for all the other instructions. I was planning to use my JSON
file for this kind of purpose and generate most of it automatically. I
will try to look at it this weekend or during next week. Would you
mind sharing the binary you are using to do your current tests with
sh2 ? I am guessing I can use a sh4 debian to test if the features
tests are enable and result in an illegal instruction.
Cedric BAIL

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