build.zig and memory.x as ld file for tivatm4c123g

basics/src/calc.zig

@@ -0,0 +1,16 @@
+
+pub fn add(a: i32, b: i32) i32 {
+    return a + b;
+}
+
+pub fn sub(a: i32, b: i32) i32 {
+    return a - b;
+}
+
+pub fn mul(a: i32, b: i32) i32 {
+    return a * b;
+}
+
+pub fn divFloor(a: i32, b: i32) i32 {
+    return @divFloor(a, b);
+}