These prototypes affect functions defined by application code. Only
the implementations in libopencm3 are supposed to be weak; the
functions in application code should definitely not be. Otherwise,
you'll end up with two weak symbols being linked together, and
it's luck as to which one the linker picks.
SCB.CCR.STKALIGN enables the automatic aligning of the stack pointer to 8 bytes
on interrupt entry. Per ARM recommendations, and for AAPCS compliance, this
bit should be enabled at all times. ARMv6M has this hardcoded to 1. Cortex M3
has this broken in rev 0, optional (default off) in rev 1, and optional
(default on) in rev 2 and later. M4(f) has optional (default on) for all
revisions, M7 has hardcoded to 1.
See Section 2.3.3 in ARM document IHI0046B:
http://infocenter.arm.com/help/topic/com.arm.doc.ihi0046b/IHI0046B_ABI_Advisory_1.pdf
To ensure that all parts behave correctly, we make sure that we hardcode the
feature on, for all parts. While not _required_ for anything other than rev1
cm3, inserting it into the common reset handler ensures no-one gets any
surprises.
Fixes Github issue #516
This moves the platform specific initialization function pre_main
in front of C++ constructors. This is especially necessary for
platforms which need to setup the stack pointer (pre_main itself
is inline, hence no stack needed for this function).
Added --terse and --mailback options to the make stylecheck target. It
also does continue even if it enounters a possible error.
We decided on two exceptions from the linux kernel coding standard:
- Empty wait while loops may end with ; on the same line.
- All blocks after while, if, for have to be in brackets even if they
only contain one statement. Otherwise it is easy to introduce an
error.
Checkpatch needs to be adapted to reflect those changes.
Fixes#51
There should be no reason for manually trying to load the stack. Cortex
devices can be programmed with only C, and any code that needed this
would indicate broken vectors.
the cortex generic interrupts get moved to lib/cm3/vector.c, the
platorms' individual irq names, initialization and handler prototypes go
to platoform specific irq.h files.
as the vector.c file heavily depends on platoform specific headers, it
can't be built once-and-for-all in lib/cm3/, so there are inclusion
stubs in the various architecture dirs; this might be better solved with
Makefile / include path handling.
one particular file is lib/lpc43xx/vector.c; that platform's
initialization code contains an additional section to copy everything
from flash to ram (which probably performs better there). that code
still resides in the inclusion stub, and gets mashed in using defines.
would need a cleaner implementation together with the Makefile solution.
this commit contains some files of the upcoming efm32 branch, from which
it was cherry-picked.
the .bin files produced from before and after this commit only differ in
lpc43xx, where the startup sequence was subtly modified.
