diff --git a/hw/mcf_intc.c b/hw/mcf_intc.c
index f01bd32..21c0f42 100644
--- a/hw/mcf_intc.c
+++ b/hw/mcf_intc.c
@@ -62,6 +62,10 @@ static uint32_t mcf_intc_read(void *opaque, target_phys_addr_t addr)
         return (uint32_t)(s->ifr >> 32);
     case 0x14:
         return (uint32_t)s->ifr;
+    /* Reading from SIMR and CIMR return 0 */
+    case 0x1c:
+    case 0x1d:
+        return 0;
     case 0xe0: /* SWIACK.  */
         return s->active_vector;
     case 0xe1: case 0xe2: case 0xe3: case 0xe4:
@@ -98,6 +102,20 @@ static void mcf_intc_write(void *opaque, target_phys_addr_t addr, uint32_t val)
     case 0x0c:
         s->imr = (s->imr & 0xffffffff00000000ull) | (uint32_t)val;
         break;
+    /* SIMR allows to easily mask interrupts */
+    case 0x1c:
+        if (val & 0x40)
+            s->imr = ~0ull;
+        else
+            s->imr |= (1 << (val & 0x3f));
+        break;
+    /* CIMR allows to easily unmask interrupts */
+    case 0x1d:
+        if (val & 0x40)
+            s->imr = 0ull;
+        else
+            s->imr &= ~(1 << (val & 0x3f));
+        break;
     default:
         hw_error("mcf_intc_write: Bad write offset %d\n", offset);
         break;