Add C sample (#3698)

* Add C sample

Sample was incorrectly being identified as C++

* Changed asm.h license to the Unlicense

* Changed asm.h license to Apache 2.0

samples/C/asm.h

@@ -0,0 +1,27 @@
+/* CarbonOS System/Kernel
+ * Copyright 2015-2017 David Aylaian
+ * Licensed under Apache 2.0: https://github.com/DavidAylaian/CarbonOS/blob/master/LICENSE.md
+ */
+
+#ifndef ASM_H
+#define ASM_H
+
+#include <stdint.h>
+
+// macros for enabling and disabling interrupts
+#define enable()	asm("sti");
+#define disable()	asm("cli");
+
+// inb instruction
+uint8_t inb (uint16_t port) {
+	uint8_t val;
+	asm volatile ("inb %0, %1" : "=a"(val): "Nd"(port));
+	return val;
+}
+
+// outb instruction
+void outb (uint16_t port, uint8_t val) {
+	asm volatile ("outb %1, %0" : : "a"(val), "Nd"(port));
+}
+
+#endif