[mubios] Create 16-bit entry points for IRQ0/IRQ1 and install the IVT vectors.

Signed-off-by: Richard Qin <richard.qin.x@gmail.com>

1 files changed, 51 insertions, 0 deletions

diff --git a/mubios/arch/irq.S b/mubios/arch/irq.S
new file mode 100644
index 0000000..6eea350
--- /dev/null
+++ b/mubios/arch/irq.S
@@ -0,0 +1,51 @@
+# 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/>.
+
+	.intel_syntax noprefix
+	.code16
+
+	.section .text16.irq, "ax"
+
+	.global irq0_entry
+	.type irq0_entry, @function
+
+irq0_entry:
+	push ax
+
+	# Acknowledge IRQ0 on the master PIC.
+	mov al, 0x20
+	out 0x20, al
+
+	pop ax
+	iret
+
+	.global irq1_entry
+	.type irq1_entry, @function
+
+irq1_entry:
+	push ax
+
+	# Read the PS/2 scan code before sending EOI.
+	in al, 0x60
+
+	mov al, 0x20
+	out 0x20, al
+
+	pop ax
+	iret