1 files changed, 88 insertions, 0 deletions
diff --git a/mubios/services/int10.c b/mubios/services/int10.c
new file mode 100644
index 0000000..76a1c1d
--- /dev/null
+++ b/mubios/services/int10.c
@@ -0,0 +1,88 @@
+/*
+ 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 "regs.h"
+
+#define VGA_TEXT_BASE 0x000B8000u
+#define BDA_CURSOR 0x00000450u
+
+static void
+int10_newline (volatile u16 *cursor)
+{
+  u16 row;
+
+  row = (u16)(*cursor / 80u);
+  *cursor = (u16)((row + 1u) * 80u);
+}
+
+void
+int10_service (struct bios_regs *regs)
+{
+  volatile u16 *cursor;
+  volatile u16 *video;
+  u8 function;
+  u8 character;
+  u8 attribute;
+  u16 position;
+
+  function = (u8)(regs->ax >> 8);
+
+  if (function != 0x0Eu)
+    return;
+
+  cursor = (volatile u16 *)BDA_CURSOR;
+  video = (volatile u16 *)VGA_TEXT_BASE;
+
+  character = (u8)regs->ax;
+  attribute = (u8)regs->bx;
+  position = *cursor;
+
+  if (character == 0x0Du)
+    {
+      *cursor = (u16)((position / 80u) * 80u);
+      return;
+    }
+
+  if (character == 0x0Au)
+    {
+      int10_newline (cursor);
+      return;
+    }
+
+  if (character == 0x08u)
+    {
+      if (position != 0u)
+        {
+          position--;
+          video[position] = (u16)(0x20u | ((u16)attribute << 8));
+          *cursor = position;
+        }
+
+      return;
+    }
+
+  if (position >= 2000u)
+    position = 0;
+
+  video[position] = (u16)character | ((u16)attribute << 8);
+  *cursor = (u16)(position + 1u);
+}