Is -malign-int a usual m68k/ColdFire option?

[Chris Johns]

On 2/10/20 6:34 pm, Sebastian Huber wrote:
> Hello,
> 
> a test suite failure surfaced that we may have an issue with the alignment of
> basic data structures on ColdFire targets:
> 
> https://devel.rtems.org/ticket/4013
> 
> The chips usually have at least a 32-bit data system bus.

These days this is true however some architectures reach back to a time when a
16 bit bus was considered new. The m68K is one and the widely used 68302, 68320
etc all had 16bit buses for many years.

> I am not sure why
> RTEMS didn't use the -malign-int for the ColdFire targets before. Has anyone
> experience using this option?

The RSB set builder option `--targetcflags flags` was added to the RSB before it
became the RSB to control a tools build for this specific option. Alan asked for
a way to align ints on the MMS (runs a RAD hardened Coldfire) to test the
performance so I added this option. He would need to comment on the effect it had.

The RSB can support adding target specific options in a config with:

%define _targetcflags -g _O2 -malign-int
%define _targetcxxflags -g -O2 -malign-int

Chris