7. Boot disk sector (t0s0):

Conditions d'entree:
	BC= 0x4200
	A= Dernier octet du secteur soit 0x11

7.1 Listing a partir d'un dump de disk

4200	CP	11
	DI
	LD	HL,372c
	LD	(HL),fe	-- ??
	LD	(HL),d0	-- Immediate interrupt
	INC	HL	-- HL = track
	LD	(HL),0
	INC	HL	-- HL = sector
	LD	(HL),0
4210	LD	DE,0005
	EXX
	LD	SP,41e0
	LD	HL,51ff
	CALL	4252
	CP	20
	LD	B,A
4220	JR	NC,$29
	LD	D,A
	CALL	4252
	LD	C,A
	CALL	4252
	LD	E,A
	DJNZ	$12
	CALL	4252
4230	LD	D,A
	DEC	C
	DEC	C
	INC	L
	CALL	Z,4255
:0
	LD	A,(HL)
	LD	(DE),A
	INC	DE
:1
	DEC	C
	JR	NZ,:0
	JR	$DB

	DJNZ	:1
4241	CALL	4252
	LD	D,A
	LD	A,(DE)
	CP	a5
	INC	DE
	PUSH	DE
	RET	Z
	LD	HL,42e5	-- Print NO SYS message
	JP	42c3

	INC	L
4252	LD	A,(HL)
	RET	NZ
	EXX
4255	LD	B,0a
	LD	HL	37e1	-- Select drive 1
	PUSH	DE
	PUSH	BC
	LD	A,E
	SUB	0a
4261	JR	C,:2
	LD	E,A
	LD	(HL),9	-- ?
:2
	LD	HL,37ec	-- command
	CALL	42ce
	LD	(37ee),DE	-- update both data (D) and sector (E)
4270	LD	(HL),1b	-- SEEK, no verify, 20ms/step
	CALL	42ce
	LD	(HL),88	-- READ One sector
	LD	DE,37ef	-- data
	LD	BC,5100
	CALL	42d7
4280	LD	A,(HL)
:3
	AND	83
	JP	PO,:3	-- Boucle sans fin (?)
:4
	LD	A,(DE)
4287	LD	(BC),A
	INC	BC
	BIT	1,(HL)	-- DRQ?
	JP	NZ,4287	-- <??> devrait etre 4286
	BIT	1,(HL)	-- DRQ? <??> pourquoi recommencer?
4290	JP	NZ,4287	-- <?>
	BIT	1,(HL)	--
	JR	NZ,:4
	BIT	0,(HL)	-- Busy?
	JR	Z,$08	-- Not busy
	BIT	1,(HL)	-- <??> Encore!!!????
	JR	NZ,:4
	BIT	7,(HL)	-- Not Ready?
42a1	JR	Z,$e6
	LD	A,(HL)
	LD	(HL),d0	-- FORCEINTERRUPT
	POP	BC
	POP	DE
	AND	fc	-- Any error pending?
	JR	NZ,:6	-- YES!
	INC	E
	LD	A,E
	SUB	0a
42b0	JR	NZ,:5
	INC	D
	LD	E,0
:5
	EXX
	LD	A,(HL)
	RET
:6
	CALL	42d7
	LD	(HL),0b	-- RESTORE, no verify, 20 ms/step
	DJNZ	$98
	LD	HL,42dd	-- Print ERROR message
:7
42c2	LD	A,(HL)
	CP	03
	JR	Z,:7	-- End of text
	INC	HL
	CALL	0033	-- Print ASCII character
	JR	:7

	CALL	42d7
:8
42d0	BIT	0,(HL)	-- Busy?
	JR	NZ,:8	-- Yes
	LD	A,(HL)
	RET

42d6	LD	(HL),6	-- RESTORE <?> |
:9                                     | 42d7	LD	B,3d
42d8	DEC	A                       | 
	JR	NZ,:9
	RET
42dc	HEX	1c1f
	DFM	'ERROR',03
42e4	HEX	1c1f
	DFM	'NO SYS',03
