1 files changed, 118 insertions, 0 deletions
diff --git a/src/bootloader/hdd1.asm b/src/bootloader/hdd1.asm
new file mode 100644
index 0000000..c347625
--- /dev/null
+++ b/src/bootloader/hdd1.asm
@@ -0,0 +1,118 @@
+BITS 16
+ORG 0x7C00
+
+%define INODE_ADDRESS 0xF000
+%define INODE_NBLOCKS 20
+%define INODE_DBP0 24
+
+; Save the boot drive id
+mov [bootDriveID], dl
+
+jmp start
+
+print:
+    mov ah, 0x0E
+    xor bh, bh
+    .print_L:
+        lodsb
+        test al, al
+        jz .print_end
+        int 0x10
+        jmp .print_L
+    .print_end:
+    ret
+
+bootDriveID: db 0
+
+dapack:
+    dapack_size: db 0x10
+    dapack_null: db 0x00
+    dapack_blkcount: dw 0x0001
+    dapack_boffset: dw 0x8000
+    dapack_bsegment: dw 0x0000
+    dapack_start: dd 0x00000000
+    dapack_upper_lba_bits: dd 0x00000000
+
+readsector:
+    mov dword [dapack_start], eax
+    mov ah, 0x42
+    mov dl, [bootDriveID]
+    xor bx, bx
+    mov ds, bx
+    mov si, dapack
+    int 0x13
+    ret
+
+; 5K max
+readwholefile:
+    mov bx, word [dapack_boffset]
+    push bx
+    mov bx, INODE_ADDRESS
+    mov word [dapack_boffset], bx
+    call readsector
+    pop bx
+    mov word [dapack_boffset], bx
+
+    mov edx, [INODE_ADDRESS+INODE_NBLOCKS]
+
+    xor ecx, ecx
+    .readwholefile_L:
+        lea bx, [INODE_ADDRESS + INODE_DBP0 + (ecx*4)]
+        mov eax, dword [bx]
+
+        push dx
+        call readsector
+        pop dx
+
+        add dword [dapack_boffset], 512
+
+        inc cx
+        cmp cx, dx
+        jl .readwholefile_L
+    ret
+
+welcome db "Melvix", 0x0A, 0x0D, 0x00
+nolba db "BIOS lacks support for LBA addressing.", 0x00
+signaturebad db "Bad disk signature.", 0x00
+
+start:
+    mov ax, 0x0003
+    int 0x10
+
+    mov si, welcome
+    call print
+
+    mov ah, 0x41
+    mov bx, 0x55AA
+    int 0x13
+    jc lba_not_supported
+    cmp bx, 0xAA55
+    jnz lba_not_supported
+
+    mov eax, 1
+    call readsector
+
+    mov eax, [0x8000+0]
+    cmp eax, 0x34B59645
+    jnz signature_BAD
+    mov eax, [0x8000+4]
+    cmp eax, 0x1083B99F
+    jnz signature_BAD
+
+    mov eax, 2
+    call readwholefile
+
+    jmp 0x8000
+
+lba_not_supported:
+    mov si, nolba
+    call print
+    jmp $
+
+signature_BAD:
+    mov si, signaturebad
+    call print
+    jmp $
+
+times 510-($-$$) db 0
+dw 0xAA55
+\ No newline at end of file