first steps towards (optional) serial mouse support

1 files changed, 59 insertions, 0 deletions

diff --git a/pic.h b/pic.h
new file mode 100644
index 0000000..0d87369
--- /dev/null
+++ b/pic.h
@@ -0,0 +1,59 @@
+/*
+ * VBMouse - Programmable Interrupt Controller routines
+ * Copyright (C) 2022 Javier S. Pedro
+ *
+ * This program 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 2
+ * of the License, or (at your option) any later version.
+
+ * This program 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 this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ */
+
+#ifndef PIC_H
+#define PIC_H
+
+#include <conio.h>
+
+// TODO Currently do not support secondary PIC
+
+enum {
+	PIC1_CMD_IOPORT = 0x20,
+	PIC1_DATA_IOPORT = PIC1_CMD_IOPORT+1,
+	PIC2_CMD_IOPORT = 0xA0,
+	PIC2_DATA_IOPORT = PIC2_CMD_IOPORT+1,
+};
+
+enum PIC_CMDS {
+	/** End-Of-Interrupt command. */
+	PIC_CMD_EOI = 0x20
+};
+
+static void pic_mask_irq(unsigned irq)
+{
+	uint8_t mask = inp(PIC1_DATA_IOPORT);
+	mask |=  (1 << irq);
+	outp(PIC1_DATA_IOPORT, mask);
+}
+
+static void pic_unmask_irq(unsigned irq)
+{
+	uint8_t mask = inp(PIC1_DATA_IOPORT);
+	mask &= ~(1 << irq);
+	outp(PIC1_DATA_IOPORT, mask);
+}
+
+static void pic_eoi_irq(unsigned irq)
+{
+	(void) irq;
+	outp(PIC1_CMD_IOPORT, PIC_CMD_EOI);
+}
+
+#endif // PIC_H