3 files changed, 22 insertions, 3 deletions

diff --git a/target-mips/exec.h b/target-mips/exec.h
index 5b8577eaf2..d5aadedb81 100644
--- a/target-mips/exec.h
+++ b/target-mips/exec.h
@@ -153,6 +153,8 @@ uint32_t cpu_mips_get_random (CPUState *env);
 uint32_t cpu_mips_get_count (CPUState *env);
 void cpu_mips_store_count (CPUState *env, uint32_t value);
 void cpu_mips_store_compare (CPUState *env, uint32_t value);
+void cpu_mips_start_count(CPUState *env);
+void cpu_mips_stop_count(CPUState *env);
 void cpu_mips_update_irq (CPUState *env);
 void cpu_mips_clock_init (CPUState *env);
 void cpu_mips_tlb_flush (CPUState *env, int flush_global);
diff --git a/target-mips/op.c b/target-mips/op.c
index b3536442e3..b8c5ce8d54 100644
--- a/target-mips/op.c
+++ b/target-mips/op.c
@@ -1886,9 +1886,8 @@ void op_mttc0_status(void)
 
 void op_mtc0_intctl (void)
 {
-    /* vectored interrupts not implemented, timer on int 7,
-       no performance counters. */
-    env->CP0_IntCtl |= T0 & 0x000002e0;
+    /* vectored interrupts not implemented, no performance counters. */
+    env->CP0_IntCtl = (env->CP0_IntCtl & ~0x000002e0) | (T0 & 0x000002e0);
     RETURN();
 }
 
@@ -1908,12 +1907,20 @@ void op_mtc0_srsmap (void)
 void op_mtc0_cause (void)
 {
     uint32_t mask = 0x00C00300;
+    uint32_t old = env->CP0_Cause;
 
     if (env->insn_flags & ISA_MIPS32R2)
         mask |= 1 << CP0Ca_DC;
 
     env->CP0_Cause = (env->CP0_Cause & ~mask) | (T0 & mask);
 
+    if ((old ^ env->CP0_Cause) & (1 << CP0Ca_DC)) {
+        if (env->CP0_Cause & (1 << CP0Ca_DC))
+            CALL_FROM_TB1(cpu_mips_stop_count, env);
+        else
+            CALL_FROM_TB1(cpu_mips_start_count, env);
+    }
+
     /* Handle the software interrupt as an hardware one, as they
        are very similar */
     if (T0 & CP0Ca_IP_mask) {
diff --git a/target-mips/op_helper.c b/target-mips/op_helper.c
index 6405f80666..6b007a6be0 100644
--- a/target-mips/op_helper.c
+++ b/target-mips/op_helper.c
@@ -265,6 +265,16 @@ void cpu_mips_store_compare(CPUState *env, uint32_t value)
     cpu_abort(env, "mtc0 compare\n");
 }
 
+void cpu_mips_start_count(CPUState *env)
+{
+    cpu_abort(env, "start count\n");
+}
+
+void cpu_mips_stop_count(CPUState *env)
+{
+    cpu_abort(env, "stop count\n");
+}
+
 void cpu_mips_update_irq(CPUState *env)
 {
     cpu_abort(env, "mtc0 status / mtc0 cause\n");