bootsect.S

.code16

.global _bootstart

.equ BOOTSEG, 0x07c0
.equ INITSEG, 0x9000
.equ DEMOSEG, 0x1000

.text

#16-real mode
# SEG:OFFSET e.g 0x07c0:0x0000 -> SEG<<4 OFFSET -0x7c00

ljmp $BOOTSEG, $_bootstart

_bootstart:
# Get cursor position
	mov $0x03, %ah
	int $0x10

	mov $BOOTSEG, %ax
	mov %ax, %es
	mov $_string, %bp
	mov $0x1301, %ax
	mov $0x000b, %bx
	mov $20, %cx
	int $0x10

_load_demo:
	mov $0x0000, %dx
	mov $0x0002, %cx
	mov $DEMOSEG, %ax
	mov %ax, %es
	mov $0x0200, %bx
	mov $0x02, %ah
	mov $4, %al
	int $0x13
	jnc demo_load_ok
	jmp _load_demo

demo_load_ok:
	# Jump to the demo program
	mov $DEMOSEG, %ax
	mov %ax, %ds

	# mov %ax, %cs
	ljmp $0x1020, $0

_string:
	.ascii "Hello from Bootloader!"
	.byte 13, 10, 13, 10

.= 510



signature:
	.word 0xaa55