diff --git a/hello.c b/hello.c
index 6631ada..75514e4 100644
--- a/hello.c
+++ b/hello.c
@@ -2,5 +2,6 @@
 
 int kernelmain(void) {
   init_uart();
+  puts("Hello world\n");
   return 0;
 }
diff --git a/mmio.h b/mmio.h
index 3f98913..88f7034 100644
--- a/mmio.h
+++ b/mmio.h
@@ -3,11 +3,32 @@
 // IO mapping
 #define IO_BASE 0x3f000000
 
-// Mini-UART mapping
-#define MU_BASE (IO_BASE + 0x215000)
+// System Timer
+#define TIMER_BASE (IO_BASE + 0x3000)
+
+// Intr mapping
+#define INTERUPT_BASE (IO_BASE + 0xB000)
+
+// Videocore mbox system
+#define VCORE_MBOX (IO_BASE + 0x0000B880)
+
+// Power manager
+#define POWER_BASE (IO_BASE + 0x100000)
+
+//Random gen
+#define RANDOM_BASE (IO_BASE + 0x104000)
 
 // GPIO mapping
 #define GP_BASE (IO_BASE + 0x200000)
 
-// videocore mbox system
-#define VCORE_MBOX (IO_BASE + 0x0000B880)
+// UART0
+#define UART0_BASE (IO_BASE + 0x201000)
+
+// Mini-UART mapping or UART1
+#define MU_BASE (IO_BASE + 0x215000)
+
+// External Mass Media Controller
+#define SD_BASE (IO_BASE + 0x300000)
+
+// USB
+#define USB_BASE (IO_BASE + 0x980000)
diff --git a/uart.c b/uart.c
index e3d1ca9..838708b 100644
--- a/uart.c
+++ b/uart.c
@@ -43,3 +43,8 @@ void putc(char c){
 
 	UART0_DR = c;
 }
+
+void puts(const char *s){
+	while(*s)
+		putc(*s++);
+}
diff --git a/uart.h b/uart.h
index c0d4777..2fa910e 100644
--- a/uart.h
+++ b/uart.h
@@ -2,14 +2,15 @@
 #include "mmio.h"
 
 /* PL011 UART */
-#define UART0_DR (*(volatile unsigned *)(IO_BASE + 0x00201000))
-#define UART0_FR (*(volatile unsigned *)(IO_BASE + 0x00201018))
-#define UART0_IBRD (*(volatile unsigned *)(IO_BASE + 0x00201024))
-#define UART0_FBRD (*(volatile unsigned *)(IO_BASE + 0x00201028))
-#define UART0_LCRH (*(volatile unsigned *)(IO_BASE + 0x0020102C))
-#define UART0_CR (*(volatile unsigned *)(IO_BASE + 0x00201030))
-#define UART0_IMSC (*(volatile unsigned *)(IO_BASE + 0x00201038))
-#define UART0_ICR (*(volatile unsigned *)(IO_BASE + 0x00201044))
+#define UART0_DR (*(volatile unsigned *)(UART0_BASE + 0x0))
+#define UART0_FR (*(volatile unsigned *)(UART0_BASE + 0x18))
+#define UART0_IBRD (*(volatile unsigned *)(UART0_BASE + 0x24))
+#define UART0_FBRD (*(volatile unsigned *)(UART0_BASE + 0x28))
+#define UART0_LCRH (*(volatile unsigned *)(UART0_BASE + 0x2C))
+#define UART0_CR (*(volatile unsigned *)(UART0_BASE + 0x30))
+#define UART0_IMSC (*(volatile unsigned *)(UART0_BASE + 0x38))
+#define UART0_ICR (*(volatile unsigned *)(UART0_BASE + 0x44))
 
 void init_uart(void);
 void putc(char c);
+void puts(const char *s);