[Qemu-devel] [PATCH 2/2] target/openrisc: Implement EPH bit

[Tim 'mithro' Ansell <mithro@mithis.com>]

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>
---
 target/openrisc/interrupt.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/target/openrisc/interrupt.c b/target/openrisc/interrupt.c
index 78f0ba9421..2c91fab380 100644
--- a/target/openrisc/interrupt.c
+++ b/target/openrisc/interrupt.c
@@ -69,6 +69,9 @@ void openrisc_cpu_do_interrupt(CPUState *cs)
         if (env->cpucfgr & CPUCFGR_EVBARP) {
             vect_pc |= env->evbar;
         }
+        if (env->sr & SR_EPH) {
+            vect_pc |= 0xf0000000;
+        }
         env->pc = vect_pc;
     } else {
         cpu_abort(cs, "Unhandled exception 0x%x\n", cs->exception_index);
-- 
2.12.1