mjb/altos/src/kernel/ao_list.h, branch debian/1.8.2-1AltOS - the operating system for Altus Metrum products
https://git.ethernal.org/mjb/altos/atom?h=debian%2F1.8.2-12017-01-25T19:21:43+00:00altos/arm: Align data so that gcc 5.4 doesn't do byte-accesses. Add -Wcast-align2017-01-25T19:21:43+00:00Keith Packardkeithp@keithp.com2016-12-18T04:58:36+00:00urn:sha1:fe25510fc23031f1a3c1b42edd37067d1989a9f6
Gcc 5.4.1 tracks alignment of data through assignments, so that a
uint32_t pointer which comes from byte-aligned uint8_t data:
extern uint8_t foo[];
uint32_t *q = (void *) foo;
Fetches and stores through this pointer are done bytewise. This is
slow (meh), but if q references a device register, things to bad very
quickly.
This patch works around this bug in the compiler by adding
__attribute__((aligned(4))) tags to some variables, or changing them
from uint8_t to uint32_t. Places doing this will now be caught as I've
added -Wcast-align to the compiler flags. That required adding (void
*) casts, after the relevant code was checked to make sure the
compiler could tell that the addresses were aligned.
Signed-off-by: Keith Packard <keithp@keithp.com>
Switch from GPLv2 to GPLv2+2016-07-12T22:41:41+00:00Keith Packardkeithp@keithp.com2016-07-05T16:03:49+00:00urn:sha1:1085ec5d57e0ed5d132f2bbdac1a0b6a32c0ab4a
Signed-off-by: Keith Packard <keithp@keithp.com>
altos: Rename 'core' to 'kernel'2014-04-05T07:22:29+00:00Keith Packardkeithp@keithp.com2014-04-05T06:34:48+00:00urn:sha1:24167015705ae831692b95735968b04a876f935e
core remains a bad name to use -- dirvish skips files (and
directories, it seems) with that name.
Signed-off-by: Keith Packard <keithp@keithp.com>