.set SEL_SDATA,0x8
	.set SEL_RDATA,0x10
	.set SEL_SCODE,0x18
	.set SEL_SCODE16,0x20

	.set SERIAL_BASE,0x3f8
	.set UART_LSR,0x5
	.set UART_TX,0x0
	.set UART_LSR_TXRDY,0x20

	.code16
	.globl start
	.org 0x0, 0x0

start:
	cld
	xorw %ax,%ax
	movw %ax,%ss
	movw $start,%sp
	movw %ax,%ds
	movw %ax,%es

	lgdt gdtdesc
	cli
	movl %cr0,%eax
	orb $1,%al
	movl %eax,%cr0
	ljmp $SEL_SCODE,$pm

	.code32
pm:
	movw $SEL_SDATA,%ax
	movw %ax,%ds
	movw %ax,%es
	call main
#if 0
	ljmp $SEL_SCODE16,$pm16

	.code16
pm16:
	movw $SEL_RDATA,%ax
	movw %ax,%ds
	movw %ax,%es
	movl %cr0,%eax
	andb $~1,%al
	movl %eax,%cr0
	ljmp $0,$pm_out

pm_out:
	sti
#endif
	movw $5,%cx
1:
	movw $msg,%si
	call putstr
	loop 1b
	cli
	hlt

putstr:
	lodsb
	testb %al,%al
	jnz putc
	ret
putc:
#if 0
	movw $7,%bx
	movb $0xe,%ah
	int $0x10
	jmp putstr
#else
	movb %al,%bl
1:
	movw $SERIAL_BASE+UART_LSR,%dx
	inb %dx,%al
	andb $UART_LSR_TXRDY,%al
	jz 1b
	movb %bl,%al
	movw $SERIAL_BASE+UART_TX,%dx
	outb %al,%dx
	jmp putstr
#endif

	.code16
	.p2align 4

gdt:	.word 0x0,0x0,0x0,0x0
	.word 0xffff,0x0,0x9200,0xcf	# SEL_SDATA
	.word 0xffff,0x0,0x9200,0x0 	# SEL_RDATA
	.word 0xffff,0x0,0x9a00,0xcf	# SEL_SCODE (32-bit)
	.word 0xffff,0x0,0x9a00,0x8f	# SEL_SCODE16
gdt.1:

gdtdesc: .word gdt.1 - gdt - 1		# limit
	 .long gdt			# base

msg:	.asciz "woo\r\n"