A GNU extension that returns dst + size instead of dst. It's a nice
shortcut when copying strings with a known size or back-to-back blocks
and you have to do it often.

May of course be called directly or alternately through
__builtin_mempcpy in some compiler versions.

For ASM on native targets, it is implemented as an alternate entrypoint
to memcpy which adds minimal code and overhead.

Change-Id: I4cbb3483f6df3c1007247fe0a95fd7078737462b

Abstracts threading from itself a bit, changes the way its queues are
handled and does type hiding for that as well.

Do alot here due to already required major brain surgery.

Threads may now be on a run queue and a wait queue simultaneously so
that the expired timer only has to wake the thread but not remove it
from the wait queue which simplifies the implicit wake handling.

List formats change for wait queues-- doubly-linked, not circular.
Timeout queue is now singly-linked. The run queue is still circular
as before.

Adds a better thread slot allocator that may keep the slot marked as
used regardless of the thread state. Assists in dumping special tasks
that switch_thread was tasked to perform (blocking tasks).

Deletes alot of code yet surprisingly, gets larger than expected.
Well, I'm not not minding that for the time being-- omlettes and break
a few eggs and all that.

Change-Id: I0834d7bb16b2aecb2f63b58886eeda6ae4f29d59

Save only once if emac is used in ISR and restore only once per ISR
call if already saved.

Change-Id: I0e40db5d4aab2a8552480f76873f59ff6ccd9977
Reviewed-on: http://gerrit.rockbox.org/176
Tested-by: Michael Sevakis <jethead71@rockbox.org>
Reviewed-by: Michael Sevakis <jethead71@rockbox.org>

Additional status callback is added to pcm_play/rec_data instead of
using a special function to set it. Status includes DMA error
reporting to the status callback. Playback and recording callback
become more alike except playback uses "const void **addr" (because
the data should not be altered) and recording  uses "void **addr".
"const" is put in place throughout where appropriate.

Most changes are fairly trivial. One that should be checked in
particular because it isn't so much is telechips, if anyone cares to
bother. PP5002 is not so trivial either but that tested as working.

Change-Id: I4928d69b3b3be7fb93e259f81635232df9bd1df2
Reviewed-on: http://gerrit.rockbox.org/166
Reviewed-by: Michael Sevakis <jethead71@rockbox.org>
Tested-by: Michael Sevakis <jethead71@rockbox.org>

For now due to current lack of an apps/asm, place the ASM/generic code in the
firmware/asm directory.

Additionally, make generic beep code more generic.

Change-Id: I4a69b6ffcbb97d9e6dfde2209c5a118de19e5638

Correct sizing in m68k asm.
Make the gerneric version far more generic.

Change-Id: I32945f7431771979b3fe0da5472bdb110fd054ae

Change-Id: I5e7bdc8be7de50ef604c16078857fff1b84650dc

using the new automatic-asm-picking infrastructure.

This dir is suitable for stuff that doesn't fit the target tree, e.g. because
it also builds on hosted or otherwise. It also has a generic subfolder for
fallback C implementations so that not all archs need to provide asm files.

SOURCES should only contain "foo.c" where foo.c includes the specific
<arch>/foo.c files from the subdirs using the preprocessor. This way automatic
selection of asm versions or generic C verion is possible.

For the start, the thread support files are moved, since ASM threads can
be used on hosted platforms as well. Since core_sleep() remains platform
specific it's moved to the corresponding system.h headers.

Change-Id: Iebff272f3407a6eaafeb7656ceb0ae9eca3f7cb9