diff --git a/target-avr/helper.c b/target-avr/helper.c
index ed22b37..450f598 100644
--- a/target-avr/helper.c
+++ b/target-avr/helper.c
@@ -155,6 +155,23 @@ void                tlb_fill(
 
     tlb_set_page_with_attrs(cs, vaddr, paddr, attrs, prot, mmu_idx, page_size);
 }
+void                helper_sleep(
+                                CPUAVRState        *env)
+{
+    CPUState   *cs = CPU(avr_env_get_cpu(env));
+
+    cs->exception_index = EXCP_HLT;
+    cpu_loop_exit(cs);
+}
+void                helper_unsupported(
+                                CPUAVRState        *env)
+{
+    CPUState   *cs = CPU(avr_env_get_cpu(env));
+
+    cs->exception_index = EXCP_DEBUG;
+    cpu_dump_state(cs, stderr, fprintf, 0);
+    cpu_loop_exit(cs);
+}
 
 void                helper_debug(
                                 CPUAVRState        *env)
@@ -165,3 +182,89 @@ void                helper_debug(
     cpu_loop_exit(cs);
 }
 
+void                helper_wdr(
+                                CPUAVRState        *env)
+{
+    CPUState   *cs = CPU(avr_env_get_cpu(env));
+
+    cs->exception_index = EXCP_DEBUG;
+    cpu_loop_exit(cs);
+}
+
+target_ulong        helper_inb(
+                                CPUAVRState        *env,
+                                uint32_t            port)
+{
+    printf("in: io[%02x]\n", port);
+
+    switch (port) {
+        case    0x3b: {
+            return  env->rampZ;         /*  RAMPZ */
+        }
+        case    0x3d: {                 /*  SPL */
+            return  env->sp & 0x00ff;
+        }
+        case    0x3e: {                 /*  SPH */
+            return  env->sp >> 8;
+        }
+        case    0x3f: {                 /*  SREG */
+            uint8_t sreg;
+            sreg    =   (env->sregC & 0x01) << 0
+                    |   (env->sregZ & 0x01) << 1
+                    |   (env->sregN & 0x01) << 2
+                    |   (env->sregV & 0x01) << 3
+                    |   (env->sregS & 0x01) << 4
+                    |   (env->sregH & 0x01) << 5
+                    |   (env->sregT & 0x01) << 6
+                    |   (env->sregI & 0x01) << 7;
+            return  sreg;
+        }
+    }
+    return  0;
+}
+
+void                helper_outb(
+                                CPUAVRState        *env,
+                                uint32_t            port,
+                                uint32_t            data)
+{
+    printf("out:%02x -> io[%02x]\n", data, port);
+
+    data    &= 0x000000ff;
+
+    switch (port) {
+        case    0x04: {
+            qemu_irq    irq;
+            CPUState   *cpu = CPU(avr_env_get_cpu(env));
+            irq     = qdev_get_gpio_in(DEVICE(cpu), 3);
+            qemu_set_irq(irq, 1);
+            break;
+        }
+        case    0x3b: {
+            env->rampZ  = data & 0x01;  /*  RAMPZ */
+            break;
+        }
+        case    0x3d: {                 /*  SPL */
+            if (avr_feature(env, AVR_FEATURE_2_BYTE_SP)) {
+                env->sp = (env->sp & 0xff00) | (data);
+            }
+            break;
+        }
+        case    0x3e: {                  /*  SPH */
+            env->sp = (env->sp & 0x00ff) | (data << 8);
+            break;
+        }
+        case    0x3f: {                 /*  SREG */
+            env->sregC  = (data >> 0) & 0x01;
+            env->sregZ  = (data >> 1) & 0x01;
+            env->sregN  = (data >> 2) & 0x01;
+            env->sregV  = (data >> 3) & 0x01;
+            env->sregS  = (data >> 4) & 0x01;
+            env->sregH  = (data >> 5) & 0x01;
+            env->sregT  = (data >> 6) & 0x01;
+            env->sregI  = (data >> 7) & 0x01;
+            break;
+        }
+    }
+}
+
diff --git a/target-avr/helper.h b/target-avr/helper.h
index 017e076..5a08cfd 100644
--- a/target-avr/helper.h
+++ b/target-avr/helper.h
@@ -18,4 +18,9 @@
  * <http://www.gnu.org/licenses/lgpl-2.1.html>
  */
 
+DEF_HELPER_1(wdr,           void,   env)
 DEF_HELPER_1(debug,         void,   env)
+DEF_HELPER_1(sleep,         void,   env)
+DEF_HELPER_1(unsupported,   void,   env)
+DEF_HELPER_3(outb,          void,   env, i32, i32)
+DEF_HELPER_2(inb,           tl,     env, i32)
