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| author | Richard Qin <richard.qin.x@gmail.com> | 2026-11-08 06:48:12 +0800 |
|---|---|---|
| committer | Richard Qin <richard.qin.x@gmail.com> | 2026-11-08 06:48:12 +0800 |
| commit | 58e9f8a9c7f63e500a20c7ee15ee7c67a3f90abc (patch) | |
| tree | 9a10e8e2a5a32d9ae7ca5e87dcec6c45572bd464 /mubios | |
| parent | e3598eddc3ec9a3deb321a2c04803246db4abb84 (diff) | |
| download | rcc-project-58e9f8a9c7f63e500a20c7ee15ee7c67a3f90abc.tar.gz rcc-project-58e9f8a9c7f63e500a20c7ee15ee7c67a3f90abc.tar.xz | |
[mubios] Transfer control from the BIOS to the MBR, which has been loaded at 0x7C00.
Signed-off-by: Richard Qin <richard.qin.x@gmail.com>
Diffstat (limited to 'mubios')
| -rw-r--r-- | mubios/arch/reset.S | 18 |
1 files changed, 18 insertions, 0 deletions
diff --git a/mubios/arch/reset.S b/mubios/arch/reset.S index 0be8a05..9654a0f 100644 --- a/mubios/arch/reset.S +++ b/mubios/arch/reset.S @@ -20,6 +20,10 @@ .intel_syntax noprefix .code16 + .equ MBR_LOAD_SEGMENT, 0x0000 + .equ MBR_LOAD_OFFSET, 0x7C00 + .equ BOOT_DRIVE_SLOT, 0x7FFC + .extern enter_protected_mode .section .text16.entry, "ax" @@ -36,9 +40,23 @@ reset_entry: mov es, ax mov ss, ax mov sp, 0x8000 + mov byte ptr [BOOT_DRIVE_SLOT], dl call enter_protected_mode + cli + mov dl, byte ptr [BOOT_DRIVE_SLOT] + xor ax, ax + mov ds, ax + mov es, ax + mov ss, ax + mov sp, MBR_LOAD_OFFSET + cld + + .byte 0xEA + .word MBR_LOAD_OFFSET + .word MBR_LOAD_SEGMENT + reset_halt: sti |