Implement CMOS register access functions

xtoskrnl/hl/x86/firmware.cc

@@ -0,0 +1,56 @@
+/**
+ * PROJECT:         ExectOS
+ * COPYRIGHT:       See COPYING.md in the top level directory
+ * FILE:            xtoskrnl/hl/x86/firmware.cc
+ * DESCRIPTION:     UEFI/BIOS Firmware support
+ * DEVELOPERS:      Aiken Harris <harraiken91@gmail.com>
+ */
+
+#include <xtos.hh>
+
+
+/**
+ * Reads a byte from the specified CMOS register.
+ *
+ * @param Register
+ *        Supplies the CMOS register index to read from.
+ *
+ * @return This routine returns the data read from the register.
+ *
+ * @since XT 1.0
+ */
+XTFASTCALL
+UCHAR
+HL::Firmware::ReadCmosRegister(IN UCHAR Register)
+{
+    /* Select the register (Setting the highest bit disables NMI) */
+    HL::IoPort::WritePort8(CMOS_ADDRESS_PORT, Register | 0x80);
+
+    /* Read value from the data port */
+    return HL::IoPort::ReadPort8(CMOS_DATA_PORT);
+}
+
+/**
+ * Writes a byte to the specified CMOS register.
+ *
+ * @param Register
+ *        Supplies the CMOS register index to write to.
+ *
+ * @param Value
+ *        Supplies the value to write to the register.
+ *
+ * @return This routine does not return any value.
+ *
+ * @since XT 1.0
+ */
+XTFASTCALL
+VOID
+HL::Firmware::WriteCmosRegister(IN UCHAR Register,
+                                IN UCHAR Value)
+{
+    /* Select the register (Setting the highest bit disables NMI) */
+    HL::IoPort::WritePort8(CMOS_ADDRESS_PORT, Register | 0x80);
+
+    /* Write the provided value to the data port */
+    HL::IoPort::WritePort8(CMOS_DATA_PORT, Value);
+}