asm {
#define BOOT_ADDRESS	0x040000
#define BLK_SIZE	0x200
#define CD_BLK_SIZE 	2048
#define BOOT_HIGH_LOC	((0xA0000-5*BLK_SIZE)>>4)

#define BOOT_CODE_FLOPPY	1
#define BOOT_CODE_HARDDRIVE	2
#define BOOT_CODE_CDROM		3
#define BOOT_CODE_RAM		4

#define WIN_NOP				0x00
#define WIN_DEV_RESET			0x08
#define WIN_PACKETCMD			0xA0 /* Send a packet cmd. */

#define ERR_STAT		0x01
#define DRQ_STAT		0x08
#define SEEK_STAT		0x10
#define READY_STAT		0x40
#define BUSY_STAT		0x80

#define DRIVE_READY		(READY_STAT  | SEEK_STAT)
#define DATA_READY		(DRQ_STAT)

#define IDE_PRIMARY_BASE	0x1F0
#define IDE_SECONDARY_BASE	0x170

#define IDE_DATA_REG	(0)
#define IDE_FEATURE_REG (1)
#define IDE_NSECTOR_REG (2)
#define IDE_SECTOR_REG	(3)
#define IDE_LCYL_REG	(4)
#define IDE_HCYL_REG	(5)
#define IDE_SELECT_REG	(6)
#define IDE_STATUS	(7)
#define IDE_CMD		(7)
#define IDE_CONTROL_REG (0x3F6-0x1F0)

	USE16
BCD2_START::
	CLD
	MOV	AX,BOOT_HIGH_LOC
	MOV	ES,AX
	MOV	SS,AX
	MOV	SP,5*BLK_SIZE

	CALL	U2 GET_IP
GET_IP:
	POP	BX
	SUB	BX,GET_IP
	SHR	BX,4
	MOV	AX,CS		//COPY HIGH
	ADD	AX,BX
	MOV	DS,AX
	MOV	CX,CD_BLK_SIZE
	XOR	SI,SI
	XOR	DI,DI
	REP_MOVSB

	MOV	AX,SS
	MOV	DS,AX
	MOV	AX,BOOT_ADDRESS/16
	MOV	ES,AX
	XOR	DI,DI		//ES:[DI]=DEST

	MOV	SI,MSG_PS
	CALL	BCD2_PUTS
	XOR	AH,AH
	INT	0x16
	MOV	SI,IDE_SECONDARY_BASE
	CMP	AL,'S'
	JE	@@12
	CMP	AL,'s'
	JE	@@12
	MOV	SI,IDE_PRIMARY_BASE

@@12:
/**********
	PUSH	ES
	XOR	AX,AX
	MOV	ES,AX
	MOV	AL,U1 ES:[0x3EE]
	POP	ES
*******/

	PUSH	SI
	MOV	SI,MSG_UNIT
	CALL	BCD2_PUTS
	XOR	AH,AH
	INT	0x16
	POP	SI

	SHL	AL,4
	OR	AL,0xE0
	MOV	U1 [BCD2_UNIT_VALUE+1],AL

	CLI
	DU1	0xEA;
	DU2	BCD2_MAIN,BOOT_HIGH_LOC;

MSG_PS::
	DU1	"\r\n\r\n\r\n\r\n"
		"\r\nBooting LoseThos Operating System from CD-ROM..."
		"\r\n\r\nPlease specify the location of the CD-ROM"
		"\r\ndrive you are booting from.  (I don't know how"
		"\r\nto detect it.) Typically, CD-ROMs are on the"
		"\r\nsecondary controller, so press 's' if this is the case."
		"\r\n\r\n (p)rimary or (s)econdary IDE controller:",0;
MSG_UNIT::
	DU1	"\r\n\r\nTypically, CD-ROMs are the master unit, so"
		"\r\npress '0' if this is the case."
		"\r\n\r\n Unit (0=Master or 1=Slave):",0;
BCD2_PUTS::
	LODSB
	OR	AL,AL
	JZ	BCD2_RET
	MOV	AH,0x0E
	MOV	BX,0x07
	INT	0x10
	JMP	BCD2_PUTS

BCD2_STAT::
	MOV	DX,SI
	ADD	DX,IDE_STATUS
	IN	AL,DX
BCD2_RET:
	RET
BCD2_SELECT_UNIT::
	MOV	DX,SI
	ADD	DX,IDE_SELECT_REG
BCD2_UNIT_VALUE::
	MOV	AL,0xF0	//Gets patched
	OUT	DX,AL
	RET
BCD2_CMD::
	MOV	AH,AL
	XOR	AL,AL
	MOV	DX,SI
	ADD	DX,IDE_FEATURE_REG
	OUT	DX,AL
	MOV	AL,AH
	MOV	DX,SI
	ADD	DX,IDE_CMD
	OUT	DX,AL
	RET
BCD2_WAIT_NOT_BUSY::
	CALL	BCD2_STAT
	AND	AL,BUSY_STAT
	JNZ	BCD2_WAIT_NOT_BUSY
	RET
BCD2_WAIT_DRQ::
	CALL	BCD2_STAT
	AND	AL,DRQ_STAT
	JZ	BCD2_WAIT_DRQ
	RET
BCD2_PKT::
	PUSH	AX
	CALL	BCD2_WAIT_DRQ
	POP	BX
	MOV	AL,BH
	MOV	AH,BL
	MOV	DX,SI
	ADD	DX,IDE_DATA_REG
	OUT	DX,AX
	RET
BCD2_RESET::
	CALL	BCD2_SELECT_UNIT
	MOV	AL,WIN_DEV_RESET
	CALL	BCD2_CMD
	CALL	BCD2_WAIT_NOT_BUSY
	RET

BCD2_MAIN::
	CALL	BCD2_RESET
BCD2_WAIT_READY::
	MOV	ECX,100000	//Busy wait
	MOV	DX,0x379	//Par Port
@@1:	IN	AL,DX
	DEC	ECX
	JNZ	@@1
BCD2_WAIT_READY2::
	CALL	BCD2_SELECT_UNIT
	MOV	AL,WIN_NOP
	CALL	BCD2_CMD
	CALL	BCD2_WAIT_NOT_BUSY
	CALL	BCD2_STAT
	AND	AL,READY_STAT
	JNZ	@@1
	CALL	BCD2_RESET
	JMP	BCD2_WAIT_READY

@@1:	CALL	BCD2_SELECT_UNIT
	MOV	AL,WIN_PACKETCMD
	CALL	BCD2_CMD
	MOV	AX,0x1B00
	CALL	BCD2_PKT
	XOR	AX,AX
	CALL	BCD2_PKT
	MOV	AX,0x0100
	CALL	BCD2_PKT
	XOR	AX,AX
	CALL	BCD2_PKT
	XOR	AX,AX
	CALL	BCD2_PKT
	XOR	AX,AX
	CALL	BCD2_PKT
	CALL	BCD2_WAIT_NOT_BUSY

	MOV	DX,SI
	ADD	DX,IDE_FEATURE_REG
	IN	AL,DX
	OR	AL,AL
	JNZ	BCD2_WAIT_READY

BCD2_SEND_READ::
	MOV	AL,8
	MOV	DX,SI
	ADD	DX,IDE_CONTROL_REG
	OUT	DX,AL
	CALL	BCD2_SELECT_UNIT
	MOV	AL,0
	MOV	DX,SI
	ADD	DX,IDE_LCYL_REG
	OUT	DX,AL
	MOV	AL,8
	INC	DX	//IDE_HCYL_REG
	OUT	DX,AL
	MOV	AL,WIN_PACKETCMD
	CALL	BCD2_CMD
	MOV	AX,0xA800
	CALL	BCD2_PKT
BCD2_BLK_HI::
	MOV	AX,512
	CALL	BCD2_PKT
BCD2_BLK_LO::
	MOV	AX,512
	CALL	BCD2_PKT
	XOR	AX,AX	//cnt_hi
	CALL	BCD2_PKT
BCD2_BLK_CNT::
	MOV	AX,512
	PUSH	AX
	CALL	BCD2_PKT
	XOR	EAX,EAX
	CALL	BCD2_PKT

	POP	AX	//cnt
	SHL	EAX,10
	MOV	EBX,EAX

@@10:	CALL	BCD2_WAIT_DRQ

	XOR	ECX,ECX
	MOV	DX,SI
	ADD	DX,IDE_HCYL_REG
	IN	AL,DX
	MOV	CH,AL
	MOV	DX,SI
	ADD	DX,IDE_LCYL_REG
	IN	AL,DX
	MOV	CL,AL
	SHR1	CX
	JZ	@@10
	CMP	CX,0x7F00
	JB	@@20
	MOV	CX,0x7F00
@@20:	PUSH	CX
	MOV	DX,SI
	ADD	DX,IDE_DATA_REG
	REP_INSW

	MOV	AX,DI
	SHR	AX,4
	MOV	DX,AX
	MOV	AX,ES
	ADD	AX,DX
	MOV	ES,AX
	AND	DI,0xF

	POP	CX
	SUB	EBX,ECX
	JZ	@@100	//TODO look-up branch
	JNC	@@10

@@100:	CALL	BCD2_WAIT_NOT_BUSY

	MOV	AX,SI
	SHL	EAX,16
	MOV	AH,U1 [BCD2_UNIT_VALUE+1]
	MOV	AL,BOOT_CODE_CDROM
	MOV	EBX,EAX

	DU1	0xEA;
BCD2_JMP_START::
	DU2	0,BOOT_ADDRESS/16;
BCD2_END::
	END
}