diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/boot.asm | 55 |
1 files changed, 55 insertions, 0 deletions
diff --git a/src/boot.asm b/src/boot.asm new file mode 100644 index 0000000..fda8b0c --- /dev/null +++ b/src/boot.asm @@ -0,0 +1,55 @@ +[BITS 32] +global start +start: + mov esp, _sys_stack ; Points stack to stack area + jmp stublet + +; Align with 4 Bytes +ALIGN 4 +mboot: + ; Multiboot macros + MULTIBOOT_PAGE_ALIGN equ 1<<0 + MULTIBOOT_MEMORY_INFO equ 1<<1 + MULTIBOOT_AOUT_KLUDGE equ 1<<16 + MULTIBOOT_HEADER_MAGIC equ 0x1BADB002 + MULTIBOOT_HEADER_FLAGS equ MULTIBOOT_PAGE_ALIGN | MULTIBOOT_MEMORY_INFO | MULTIBOOT_AOUT_KLUDGE + MULTIBOOT_CHECKSUM equ -(MULTIBOOT_HEADER_MAGIC + MULTIBOOT_HEADER_FLAGS) + EXTERN code, bss, end + + ; GRUB Multiboot header + dd MULTIBOOT_HEADER_MAGIC + dd MULTIBOOT_HEADER_FLAGS + dd MULTIBOOT_CHECKSUM + + ; AOUT kludge + dd mboot + dd code + dd bss + dd end + dd start + +; Endless loop +stublet: + extern kernel_main + call kernel_main + jmp $ + +global gdt_flush +extern gp +gdt_flush: + lgdt [gp] + mov ax, 0x10 ; Data segment offset of GDT + mov ds, ax + mov es, ax + mov fs, ax + mov gs, ax + mov ss, ax + jmp 0x08:flush2 ; Code segment offset +flush2: + ret ; Returns to C code + +; TODO: ISR + +SECTION .bss + resb 8192 ; Reserve 8KiB +_sys_stack:
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