When writing a value to PC, execution continues at that location,
so subtracting 4 returns to the next instruction. Previously, two
instructions after the faulting instruction were being skipped, causing
safe_read functions to return true even if a data abort happened.
Change-Id: I3fd02d54646323ea2050d0504e38f6d22f09c749
Implement functions to read from a memory location and indicate
failure in case this is not possible. Since we do not have a MMU,
intercept the data abort handler and simply return when the abort
comes from the safe read routines.
Change-Id: I08f2e59898dcac893319a8150d4cf626f3adabbd
Reviewed-on: http://gerrit.rockbox.org/207
Reviewed-by: Marcin Bukat <marcin.bukat@gmail.com>