1 files changed, 65 insertions, 0 deletions
diff --git a/mubios/drivers/pic.c b/mubios/drivers/pic.c
new file mode 100644
index 0000000..099cee8
--- /dev/null
+++ b/mubios/drivers/pic.c
@@ -0,0 +1,65 @@
+/*
+ RCC-Project
+
+ Copyright (C) 2026 Richard Qin
+
+ This file is part of RCC-Project.
+
+ RCC-Project is free software; you can redistribute it and/or modify it under
+ the terms of the GNU General Public License as published by the Free
+ Software Foundation; either version 3 of the License, or (at your option) any
+ later version.
+
+ RCC-Project is distributed in the hope that it will be useful, but WITHOUT ANY
+ WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
+ A PARTICULAR PURPOSE.  See the GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License along with
+ RCC-Project; see the file COPYING.  If not see
+ <http://www.gnu.org/licenses/>.
+ */
+
+#include "bios.h"
+#include "io.h"
+
+#define PIC1_COMMAND 0x0020u
+#define PIC1_DATA    0x0021u
+#define PIC2_COMMAND 0x00A0u
+#define PIC2_DATA    0x00A1u
+
+#define PIC_ICW1_INIT 0x11u
+#define PIC_ICW4_8086 0x01u
+
+#define PIC1_VECTOR_BASE 0x08u
+#define PIC2_VECTOR_BASE 0x70u
+
+#define PIC1_CASCADE_ID 0x04u
+#define PIC2_CASCADE_ID 0x02u
+
+#define PIC1_MASK_DEFAULT 0xFBu
+#define PIC2_MASK_DEFAULT 0xFFu
+
+void
+pic_init (void)
+{
+  io_out8 (PIC1_COMMAND, PIC_ICW1_INIT);
+  io_out8(PIC2_COMMAND, PIC_ICW1_INIT);
+
+  io_out8(PIC1_DATA, PIC1_VECTOR_BASE);
+  io_out8 (PIC2_DATA, PIC2_VECTOR_BASE);
+
+  io_out8(PIC1_DATA, PIC1_CASCADE_ID);
+  io_out8 (PIC2_DATA, PIC2_CASCADE_ID);
+
+  io_out8(PIC1_DATA, PIC_ICW4_8086);
+  io_out8 (PIC2_DATA, PIC_ICW4_8086);
+
+  /*
+   * Keep the cascade line enabled.
+   * All actual hardware IRQ lines remain masked.
+   */
+  io_out8(PIC1_DATA, PIC1_MASK_DEFAULT);
+  io_out8 (PIC2_DATA, PIC2_MASK_DEFAULT);
+  
+}
+