[mubios] Write mubios reset entry point

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

1 files changed, 61 insertions, 0 deletions

diff --git a/mubios/arch/reset.S b/mubios/arch/reset.S
new file mode 100644
index 0000000..b3dbde2
--- /dev/null
+++ b/mubios/arch/reset.S
@@ -0,0 +1,61 @@
+# 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, "ax"
+
+	.global reset_entry
+	.type reset_entry, @function
+
+reset_entry:
+	cli
+	cld
+
+	xor ax, ax
+	mov ds, ax
+	mov es, ax
+	mov ss, ax
+	mov sp, 0x8000
+
+reset_halt:
+	hlt
+	jmp reset_halt
+
+	.section .reset, "ax"
+	
+	.global reset_vector
+
+reset_vector:
+	cli
+
+	/*
+        * The linker places .text16 at physical address 0xF0000.
+        * F000:0000 therefore reaches the first 16-bit entry.
+        */
+	.byte 0xEA
+	.word 0x0000
+	.word 0xF000
+
+	.fill 16 - (. - reset_vector), 1, 0x90
+	
+	
+	
+