Initial commit

kernel/drivers/ports.c

@@ -0,0 +1,33 @@
+/*
+ * ports.c
+ *
+ *  Created on: Aug 18, 2019
+ *      Author: rick
+ */
+
+
+#include "ports.h"
+
+/**
+ * Read a byte from the specified port
+ */
+unsigned char port_byte_in(unsigned short port) {
+    unsigned char result;
+    __asm__("in %%dx, %%al" : "=a" (result) : "d" (port));
+    return result;
+}
+
+
+void port_byte_out(unsigned short port, unsigned char data) {
+    __asm__("out %%al, %%dx" : : "a" (data), "d" (port));
+}
+
+unsigned short port_word_in(unsigned short port) {
+    unsigned short result;
+    __asm__("in %%dx, %%ax" : "=a" (result) : "d" (port));
+    return result;
+}
+
+void port_wordt_out(unsigned short port, unsigned short data) {
+    __asm__("out %%ax, %%dx" : : "a" (data), "d" (port));
+}