From ccc7eeff60d41b9f740ff9c879efb56b7e683749 Mon Sep 17 00:00:00 2001
From: Eryn Wells <eryn@erynwells.me>
Date: Wed, 2 Mar 2016 02:48:25 -0500
Subject: [PATCH] Add low-level I/O functions

---
 src/IO.hh | 83 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 83 insertions(+)
 create mode 100644 src/IO.hh

diff --git a/src/IO.hh b/src/IO.hh
new file mode 100644
index 0000000..3b64bfb
--- /dev/null
+++ b/src/IO.hh
@@ -0,0 +1,83 @@
+/* IO.hh
+ * vim: set tw=80:
+ * Eryn Wells <eryn@erynwells.me>
+ */
+/**
+ * Low-level hardware I/O functions.
+ */
+
+#ifndef __IO_HH__
+#define __IO_HH__
+
+#include <stdint.h>
+
+namespace kernel {
+namespace io {
+    
+/*
+ * Input
+ */
+
+inline uint8_t
+inb(uint16_t port)
+{
+    uint8_t ret;
+    asm volatile("inb %[port], %[ret]",
+                 : [result] "=a"(ret)
+                 : [port] "Nd"(port));
+    return ret;
+}
+
+
+inline uint16_t
+inw(uint16_t port)
+{
+    uint16_t ret;
+    asm volatile("inw %[port], %[ret]",
+                 : [result] "=a"(ret)
+                 : [port] "Nd"(port));
+    return ret;
+}
+
+
+inline uint32_t
+inl(uint16_t port)
+{
+    uint32_t ret;
+    asm volatile("inl %[port], %[ret]",
+                 : [result] "=a"(ret)
+                 : [port] "Nd"(port));
+    return ret;
+}
+
+/*
+ * Output
+ */
+
+inline void
+outb(uint16_t port,
+     uint8_t value)
+{
+    asm volatile("outb %0, %1" : : "a"(value), "Nd"(port));
+}
+
+
+inline void
+outw(uint16_t port,
+     uint16_t value)
+{
+    asm volatile("outw %0, %1" : : "a"(value), "Nd"(port));
+}
+
+
+inline void
+outl(uint16_t port,
+     uint32_t value)
+{
+    asm volatile("outl %0, %1" : : "a"(value), "Nd"(port));
+}
+
+} /* namespace io */
+} /* namespace kernel */
+
+#endif /* __IO_HH__ */