update_readme

README.md

@@ -13,3 +13,21 @@ B:     backpack??<br>
 
 Map will be randomly generate every time
 
+# Call C function in Assembly
+
+## generate a *.o file
+> $gcc -c test.c -o test.o
+
+or add pragma to tell IDE not to link
+>  #pragma src </br>
+
+
+## generate a *.a file
+
+>ar rcs libtst.a test.o
+
+
+## Gcc tips
+add this directive to notify gas using Intel syntax
+>.intel_syntax noprefix
+