David Laight commented;

> One this to look at is whether you have the 'misaligned access' trap
> enabled.  At least some versions of gcc for arm will do 32bit reads
> from misaligned addresses [1] in order to read 16bit quantities.

My impression is it depends on the way to invoke the target program,
not compiler option nor instrunction itself.  Although it remains mystery
for me about why "undefined instruction fault" is posted, "alignment fault
enable bit" in cp15 c1 might have been modified by unknown-unknown.

Toru Nishimura/ALKYL Technology