[add] laos using xv6-riscv thought

laos/include/asm.h

@@ -0,0 +1,8 @@
+#include "defs.h"
+
+#ifndef ASM_H__
+#define ASM_H__
+
+#define CPUID   0x020
+
+#endif

laos/include/common.h

@@ -1,5 +1,10 @@
+#include "defs.h"
+
 #ifndef COMMON_H__
 #define COMMON_H__
 
+void main();
+void start();
+void _entry() __attribute__ ((section (".entry")));
 
 #endif // COMMON_H__

laos/include/defs.h

@@ -0,0 +1,6 @@
+#ifndef DEFS_H__
+#define DEFS_H__
+
+#define NCPU    1
+
+#endif