semihosting: add example

examples/semihosting/semihosting.go

@@ -0,0 +1,23 @@
+package main
+
+// A small example that demonstrates how SemiHosting can be used.
+// You could use it with a board that supports GDB, such as the BBC micro:bit:
+// 1. Compile and debug it:
+//      tinygo gdb -target=microbit -ocd-output tinygo.org/x/drivers/examples/semihosting
+// 2. Enable semihosting in the GDB shell:
+//      monitor arm semihosting enable
+// 3. Start the program:
+//      continue
+
+import (
+	"time"
+
+	"tinygo.org/x/drivers/semihosting"
+)
+
+func main() {
+	for {
+		semihosting.Stdout.Write([]byte("hello world!\n"))
+		time.Sleep(time.Second)
+	}
+}