Code stub

BIOS/boot.asm

@@ -0,0 +1,65 @@
+[ORG 0x7C00]
+[BITS 16]
+
+start:
+    jmp	0x0000:Boot
+    nop
+
+times 8-($-$$) db 0
+PrimaryVolumeDescriptor dd 0
+BootFileLocation dd 0
+BootFileLength dd 0
+Checksum dd 0
+Reserved times 40 db 0
+times 90-($-$$) db 0
+
+%include "print.inc"
+
+Boot:
+	cli
+    mov [BOOT_DISK], dl
+	xor ax, ax
+    mov ds, ax
+    mov ss, ax
+    mov sp, 0x9C00
+
+    mov si, ErrorText
+    call Print
+    hlt
+    jmp $
+
+    mov si, BootloaderText
+    call Print
+    call ReadDisk
+    jmp EX_ADDRESS
+    jmp $
+
+ReadDisk:
+    sti
+    mov ah, 0x02
+    mov bx, EX_ADDRESS
+    mov al, 20 ; max 65
+    mov dl, [BOOT_DISK]
+    mov ch, 0x00
+    mov dh, 0x00
+    mov cl, 0x02
+    int 0x13
+    jc DiskError
+    cli
+    ret
+
+DiskError:
+    cli
+    mov si, DiskReadingErrorMessage
+    call Print
+    jmp $
+
+ErrorText db 'BIOS boot not implemented', 0
+BootloaderText db 'Lynx Bootloader', 0
+DiskReadingErrorMessage: db ' Disk Error', 0
+EX_ADDRESS equ 0x8000
+BOOT_DISK: db 0
+
+times 510-($-$$) db 0
+db 0x55
+db 0xAA