GCC cannot compile the existing assembly here on ARMv7-M,
claiming impossible constraints. It is actually possible to
compile if the input arguments (addresses and sizes) are
first moved to a high register so as not to conflict with
the use of r0-r7 in ldm/stm -- this is exactly what GCC does
for ARMv6, but it won't do it on ARMv7-M for some reason.
We can get a result similar to the ARMv6 code by manually
moving the inputs into temporaries, but the generated code
is a actually a bit smaller on ARMv7-M if the r0-r7 block is
shifted up to r3-r10. This only works since ARMv7-M supports
the 32-bit Thumb encoding -- 16-bit Thumb can't represent an
ldm/stm instruction of this type.
It's worth #ifdef'ing the code because although the ARMv7-M
version works on ARMv6 too, it spills a lot of registers on
the stack even though register use is mostly similar.
Change-Id: I9bc8b5c76e198aecfd0a0e7a2158b1c00f82c4df
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>
