Exception Prefix High (EPH) control bit of the Supervision Register
(SR).
The significant bits (31-12) of the vector offset address for each
exception depend on the setting of the Supervision Register (SR)'s EPH
bit and the Exception Vector Base Address Register (EVBAR).
If SR[EPH] is set, the vector offset is logically ORed with the offset
0xF0000000.
This means if EPH is;
* 0 - Exceptions vectors start at EVBAR
* 1 - Exception vectors start at EVBAR | 0xF0000000
Signed-off-by: Tim 'mithro' Ansell <mithro@mithis.com>
Signed-off-by: Stafford Horne <shorne@gmail.com>