Initial checkin.
diff --git a/src/ioport.h b/src/ioport.h
new file mode 100644
index 0000000..344803e
--- /dev/null
+++ b/src/ioport.h
@@ -0,0 +1,56 @@
+// Definitions for X86 IO port access.
+//
+// Copyright (C) 2008  Kevin O'Connor <kevin@koconnor.net>
+//
+// This file may be distributed under the terms of the GNU GPLv3 license.
+#ifndef __IOPORT_H
+#define __IOPORT_H
+
+#include "types.h" // u8
+
+#define PORT_DMA_ADDR_2        0x0004
+#define PORT_DMA_CNT_2         0x0005
+#define PORT_DMA1_MASK_REG     0x000a
+#define PORT_DMA1_MODE_REG     0x000b
+#define PORT_DMA1_CLEAR_FF_REG 0x000c
+#define PORT_DMA1_MASTER_CLEAR 0x000d
+#define PORT_PIC1              0x0020
+#define PORT_PIC1_DATA         0x0021
+#define PORT_PIT_COUNTER0      0x0040
+#define PORT_PIT_COUNTER1      0x0041
+#define PORT_PIT_COUNTER2      0x0042
+#define PORT_PIT_MODE          0x0043
+#define PORT_KBD_CTRLB         0x0061
+#define PORT_CMOS_INDEX        0x0070
+#define PORT_CMOS_DATA         0x0071
+#define PORT_DMA_PAGE_2        0x0081
+#define PORT_A20               0x0092
+#define PORT_PIC2              0x00a0
+#define PORT_PIC2_DATA         0x00a1
+#define PORT_DMA2_MASK_REG     0x00d4
+#define PORT_DMA2_MODE_REG     0x00d6
+#define PORT_DMA2_MASTER_CLEAR 0x00da
+#define PORT_FD_DOR            0x03f2
+#define PORT_FD_STATUS         0x03f4
+#define PORT_FD_DATA           0x03f5
+
+// PORT_PIC1 bitdefs
+#define PIC1_IRQ5  (1<<5)
+// PORT_PIC2 bitdefs
+#define PIC2_IRQ8  (1<<0)
+#define PIC2_IRQ13 (1<<5)
+
+// PORT_KBD_CTRLB bitdefs
+#define KBD_REFRESH (1<<4)
+
+
+static inline void outb(u8 value, u16 port) {
+    __asm__ __volatile__("outb %b0, %w1" : : "a"(value), "Nd"(port));
+}
+static inline u8 inb(u16 port) {
+    u8 value;
+    __asm__ __volatile__("inb %w1, %b0" : "=a"(value) : "Nd"(port));
+    return value;
+}
+
+#endif // ioport.h