[J-core] linuxconf.au talk proposal.

Rob Landley rob at landley.net
Fri Aug 5 19:13:57 EDT 2016

FYI, here's the description I just hit send on. No idea if they'll want


When the last patents on the SuperH architecture started expiring in
2014, the http://j-core.org project released a new BSD-licensed clean
room VHDL implementation of an SOC compatible with the sh2 instruction
set already capable of booting Linux to a shell prompt on a $50 FPGA
board. Linux Weekly news covered this at https://lwn.net/Articles/647636/

Now we'd like to talk about the things we've done to speed up linux,
gcc, musl-libc, and the VHDL itself since we first got Linux booted on
the thing ~3 years ago. We've doubled the MHZ, added SMP support,
implemented futexes, ported everything to device tree, tracked down
kernel and toolchain bugs of the "how did this ever work" variety
(spoiler: it didn't), and even have a native compiler working on the
board. We'll explain why we selected this architecture instead of
i386/sparc/m68k (whose patents have had just as long to expire), scaling
the processor design up to 64 bit and down to Arduino country at the
same time, when the best way to go isn't clear because of tradeoffs
(with a "prefetch vs cache" example), decisions about compatibility (sh2
vs sh3 system call numbers, should 64 bit mode have branch delay slots),
issues with interrupts and clocks and futexes we hit modernizing an
older architecture, and so on.

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