1 files changed, 32 insertions, 0 deletions
diff --git a/kernel/include/arch/x86_64/io.h b/kernel/include/arch/x86_64/io.h
new file mode 100644
index 0000000..b99f0ef
--- /dev/null
+++ b/kernel/include/arch/x86_64/io.h
@@ -0,0 +1,32 @@
+#ifndef HW_IO_H
+#define HW_IO_H
+
+#include <stdint.h>
+
+// Used for io access
+
+static inline void outb(uint16_t port, uint8_t val)
+{
+    asm volatile ( "outb %0, %1" : : "a"(val), "Nd"(port) :"memory");
+    /* There's an outb %al, $imm8  encoding, for compile-time constant port numbers that fit in 8b.  (N constraint).
+     * Wider immediate constants would be truncated at assemble-time (e.g. "i" constraint).
+     * The  outb  %al, %dx  encoding is the only option for all other cases.
+     * %1 expands to %dx because  port  is a uint16_t.  %w1 could be used if we had the port number a wider C type */
+}
+
+static inline uint8_t inb(uint16_t port)
+{
+    uint8_t ret;
+    asm volatile ( "inb %1, %0"
+                   : "=a"(ret)
+                   : "Nd"(port)
+                   : "memory");
+    return ret;
+}
+
+static inline void io_wait(void)
+{
+    outb(0x80, 0);
+}
+
+#endif
+\ No newline at end of file