From 1eecad21db3a9f4ae91c6c32504c1c6e3b74461a Mon Sep 17 00:00:00 2001
From: belliash <belliash@codingworkshop.eu.org>
Date: Mon, 20 Nov 2023 15:26:03 +0100
Subject: [PATCH] Implement HlReadApicRegister() and HlWriteApicRegister()
 routines for basic APIC support

---
 xtoskrnl/CMakeLists.txt |  1 +
 xtoskrnl/hl/apic.c      | 48 +++++++++++++++++++++++++++++++++++++++++
 xtoskrnl/includes/hl.h  |  9 ++++++++
 3 files changed, 58 insertions(+)
 create mode 100644 xtoskrnl/hl/apic.c

diff --git a/xtoskrnl/CMakeLists.txt b/xtoskrnl/CMakeLists.txt
index 730f302..8cb0c0e 100644
--- a/xtoskrnl/CMakeLists.txt
+++ b/xtoskrnl/CMakeLists.txt
@@ -13,6 +13,7 @@ list(APPEND XTOSKRNL_SOURCE
     ${XTOSKRNL_SOURCE_DIR}/ar/${ARCH}/procsup.c
     ${XTOSKRNL_SOURCE_DIR}/ar/${ARCH}/traps.c
     ${XTOSKRNL_SOURCE_DIR}/ex/rundown.c
+    ${XTOSKRNL_SOURCE_DIR}/hl/apic.c
     ${XTOSKRNL_SOURCE_DIR}/hl/cport.c
     ${XTOSKRNL_SOURCE_DIR}/hl/efifb.c
     ${XTOSKRNL_SOURCE_DIR}/hl/globals.c
diff --git a/xtoskrnl/hl/apic.c b/xtoskrnl/hl/apic.c
new file mode 100644
index 0000000..59a5566
--- /dev/null
+++ b/xtoskrnl/hl/apic.c
@@ -0,0 +1,48 @@
+/**
+ * PROJECT:         ExectOS
+ * COPYRIGHT:       See COPYING.md in the top level directory
+ * FILE:            xtoskrnl/hl/apic.c
+ * DESCRIPTION:     Advanced Programmable Interrupt Controller (APIC) support
+ * DEVELOPERS:      Rafal Kupiec <belliash@codingworkshop.eu.org>
+ */
+
+#include <xtos.h>
+
+
+/**
+ * Reads from the local APIC register.
+ *
+ * @param Register
+ *        Supplies the APIC register to read from.
+ *
+ * @return This routine returns the value read from the APIC register.
+ *
+ * @since XT 1.0
+ */
+XTFASTCALL
+ULONG
+HlReadApicRegister(IN APIC_REGISTER Register)
+{
+    return RtlReadRegisterLong((PULONG)APIC_BASE + (Register << 4));
+}
+
+/**
+ * Writes to the local APIC register.
+ *
+ * @param Register
+ *        Supplies the APIC register to write to.
+ *
+ * @param Value
+ *        Supplies the value to write to the APIC register.
+ *
+ * @return This routine does not return any value.
+ *
+ * @since XT 1.0
+ */
+XTFASTCALL
+VOID
+HlWriteApicRegister(IN APIC_REGISTER Register,
+                    IN ULONG Value)
+{
+    RtlWriteRegisterLong((PULONG)APIC_BASE + (Register << 4), Value);
+}
diff --git a/xtoskrnl/includes/hl.h b/xtoskrnl/includes/hl.h
index 918e9e5..4d976fc 100644
--- a/xtoskrnl/includes/hl.h
+++ b/xtoskrnl/includes/hl.h
@@ -51,4 +51,13 @@ XTAPI
 XTSTATUS
 HlInitializeDisplay(VOID);
 
+XTFASTCALL
+ULONG
+HlReadApicRegister(IN APIC_REGISTER Register);
+
+XTFASTCALL
+VOID
+HlWriteApicRegister(IN APIC_REGISTER Register,
+                    IN ULONG Value);
+
 #endif /* __XTOSKRNL_HL_H */