Do core interrupt masking in a less general fashion and save some instructions to decrease size and speed things up a little bit. Small fix to a few places where interrupts would get enabled again where they shouldn't have been (context switching calls when disabled).

git-svn-id: svn://svn.rockbox.org/rockbox/trunk@16811 a1c6a512-1295-4272-9138-f99709370657
61 files changed