From 91923430c498110b4e60b750bf9cb5a17726c4d1 Mon Sep 17 00:00:00 2001
From: "E. Almqvist" <elalmqvist@gmail.com>
Date: Wed, 18 Aug 2021 22:09:04 +0200
Subject: [PATCH] Headers

---
 kernel/io.c | 18 +++++++++++++++++-
 kernel/io.h |  5 +++++
 2 files changed, 22 insertions(+), 1 deletion(-)

diff --git a/kernel/io.c b/kernel/io.c
index 9b630ef..4bdffb8 100644
--- a/kernel/io.c
+++ b/kernel/io.c
@@ -1,3 +1,4 @@
+// Function to read a byte from port
 unsigned char port_byte_in(unsigned short port) {
 	unsigned char res;
 	__asm__("in %%dx, %%al" : "=a" (res) : "d" (port));
@@ -5,6 +6,21 @@ unsigned char port_byte_in(unsigned short port) {
 	return res;
 }
 
+// to write a byte to port
 void port_byte_out(unsigned short port, unsigned char data) {
-	
+	__asm__("out %%al, %%dx" : :"a" (data), "d" (port));	
+}
+
+
+// Read word from port
+unsigned short port_word_in(unsigned short port) {
+	unsigned short res;
+	__asm__("in %%dx, %%ax" : "=a" (res) : "d" (port));
+
+	return res;
+}
+
+// write word to port
+void port_word_out(unsigned short port, unsigned short data) {
+	__asm__("out %%ax, %%dx" : :"a" (data), "d" (port));
 }
diff --git a/kernel/io.h b/kernel/io.h
index e69de29..87c3e5c 100644
--- a/kernel/io.h
+++ b/kernel/io.h
@@ -0,0 +1,5 @@
+unsigned char port_byte_in();
+void port_byte_out();
+
+unsigned short port_word_in();
+void port_word_out();