diff --git a/kernel/include/portio.h b/kernel/include/portio.h
index fbf4484..9a9f762 100755
--- a/kernel/include/portio.h
+++ b/kernel/include/portio.h
@@ -13,25 +13,25 @@
 #define outportd(port, val) \
     __asm__ __volatile__ ("outl %%eax, %%dx" : : "a" (val), "d" (port));
 
-#define inportb(port) \
-    ({ \
-        u8_t val; \
-        __asm__ __volatile__ ("inb %%dx, %%al" : "=a" (val) : "d" (port)); \
-        val; \
-    });
+static inline u8_t inportb(u16_t port)
+{
+    u8_t val;
+    __asm__ __volatile__ ("inb %%dx, %%al" : "=a" (val) : "d" (port));
+    return val;
+}
 
-#define inportw(port) \
-    ({ \
-        u16_t val; \
-        __asm__ __volatile__ ("inw %%dx, %%al" : "=a" (val) : "d" (port)); \
-        val; \
-    });
+static inline u16_t inportw(u16_t port)
+{
+    u16_t val;
+    __asm__ __volatile__ ("inw %%dx, %%al" : "=a" (val) : "d" (port));
+    return val;
+}
 
-#define inportd(port) \
-    ({ \
-        u32_t val; \
-        __asm__ __volatile__ ("inl %%dx, %%al" : "=a" (val) : "d" (port)); \
-        val; \
-    });
+static inline u32_t inportd(u16_t port)
+{
+    u32_t val;
+    __asm__ __volatile__ ("inl %%dx, %%al" : "=a" (val) : "d" (port));
+    return val;
+}
 
 #endif