Define kernel entry-points in Go

boot.go

@@ -0,0 +1,18 @@
+package main
+
+import "github.com/achilleasa/gopher-os/kernel"
+
+// main is the only Go symbol that is visible (exported) from the rt0 initialization
+// code. This function works as a trampoline for calling the actual kernel entrypoint
+// (kernel.Kmain) and its intentionally defined to prevent the Go compiler from
+// optimizing away the actual kernel code as its not aware of the presence of the
+// rt0 code.
+//
+// The main function is invoked by the rt0 assembly code after setting up the GDT
+// and setting up a a minimal g0 struct that allows Go code using the 4K stack
+// allocated by the assembly code.
+//
+// main is not expected to return. If it does, the rt0 code will halt the CPU.
+func main() {
+	kernel.Kmain()
+}

kernel/kmain.go

@@ -0,0 +1,5 @@
+package kernel
+
+// Kmain is invoked by the boot.go and implements the actual kernel entrypoint.
+func Kmain() {
+}