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      1 |
      2 |	check FD format
      3 |
      4 |	Written by ITOH Yasufumi
      5 |	This code is in the public domain
      6 |
      7 | $NetBSD: chkfmt.s,v 1.2 2011/02/21 02:31:58 itohy Exp $
      8 
      9 /* FDC address */
     10 #define FDC_STATUS		0xE94001	/* status register */
     11 #define FDC_DATA		0xE94003	/* data register */
     12 
     13 #define INT_STAT		0xE9C001	/* interrupt control */
     14 #define INT_FDC_BIT		2
     15 
     16 /* Status Register */
     17 #define NE7ST_CB_BIT		4		/* FDC busy */
     18 #define NE7ST_DIO_BIT		6		/* data input/output */
     19 #define NE7ST_RQM_BIT		7		/* request for master */
     20 
     21 /* FDC command */
     22 #define NE7CMD_READID		0x4A		/* READ ID */
     23 
     24 |
     25 |	Read ID of all sectors in current track.
     26 |	This routine expects that motor on, drive selection
     27 |	and seek is already done.
     28 |
     29 |	input:	d0.b: 0 0 0 0 0 HD US1 US0 (binary)
     30 |	output:	d0.l: min # sector (N C H R (2hex))
     31 |		d1.l: max # sector (N C H R (2hex))
     32 |	destroy:
     33 |		d0, d1
     34 |
     35 	.text
     36 	.even
     37 	.globl	check_fd_format
     38 check_fd_format:
     39 	moveml	%d2-%d7/%a1-%a3,%sp@-
     40 
     41 	moveb	%d0,%d6			| head, drive
     42 
     43 	lea	FDC_STATUS:l,%a1
     44 	lea	%a1@(FDC_DATA-FDC_STATUS),%a2	| FDC_DATA
     45 	lea	%a2@(INT_STAT-FDC_DATA),%a3	| INT_STAT
     46 
     47 	movew	%sr,%sp@-
     48 	oriw	#0x0700,%sr		| keep out interrupts
     49 	moveq	#INT_FDC_BIT,%d5
     50 	bclr	%d5,%a3@		| disable FDC interrupt
     51 
     52 	jbsr	read_id_sub
     53 	jne	exit_check_format
     54 	movel	%d3,%d2			| first sector
     55 	movel	%d3,%d0			| sector min
     56 sector_is_max:
     57 	movel	%d3,%d1			| sector max
     58 
     59 loop_read_id:
     60 	jbsr	read_id_sub
     61 	jne	exit_check_format
     62 	cmpl	%d0,%d3
     63 	jcc	sector_not_min
     64 	movel	%d3,%d0
     65 sector_not_min:
     66 	cmpl	%d3,%d1
     67 	jcs	sector_is_max
     68 	cmpl	%d2,%d3
     69 	jne	loop_read_id
     70 
     71 exit_check_format:
     72 	bset	%d5,%a3@		| enable FDC interrupt
     73 	movew	%a7@+,%sr
     74 
     75 	tstl	%d7
     76 	moveml	%a7@+,%d2-%d7/%a1-%a3
     77 	jne	_err_read_id
     78 
     79 	rts
     80 
     81 |
     82 |	input:	d6.b: 0 0 0 0 0 HD US1 US0 (binary)
     83 |		a1: FDC status addr
     84 |		a2: FDC data addr
     85 |		interrupt must be disabled
     86 |	output:	d3.l: sector information: N C H R (2hex)
     87 |		d7.l: status (nonzero if error)
     88 |		Z flag: true if no error, false if error
     89 |	destroy:
     90 |		d3-d4, d7
     91 |
     92 read_id_sub:
     93 	| wait for FDC ready
     94 fdc_wait_ready:
     95 	btst	#NE7ST_CB_BIT,%a1@
     96 	jne	fdc_wait_ready
     97 
     98 	| send READ ID command
     99 fdc_send_command1:
    100 	jbsr	fdc_wait_rqm
    101 	jmi	fdc_send_command1
    102 	moveb	#NE7CMD_READID,%a2@
    103 
    104 fdc_send_command2:
    105 	jbsr	fdc_wait_rqm
    106 	jmi	fdc_send_command2
    107 	moveb	%d6,%a2@		| X X X X X HD US1 US0 (binary)
    108 
    109 	| receive data
    110 	moveq	#2,%d4
    111 	jbsr	fdc_read_bytes
    112 	movel	%d3,%d7			| d7: FDC status: X ST0 ST1 ST2 (2hex)
    113 	moveq	#3,%d4
    114 	jbsr	fdc_read_bytes		| d3: sector info: C H R N (2hex)
    115 	rorl	#8,%d3			| d3: sector info: N C H R (2hex)
    116 
    117 	andil	#0x00f8ffff,%d7		| check status (must be zero)
    118 	rts
    119 
    120 |
    121 |	receive d4:w + 1 bytes from FDC
    122 |
    123 fdc_read_bytes:
    124 	asll	#8,%d3
    125 fdc_read_loop:
    126 	jbsr	fdc_wait_rqm
    127 	jpl	fdc_read_loop
    128 	moveb	%a2@,%d3
    129 	dbra	%d4,fdc_read_bytes
    130 	rts
    131 
    132 fdc_wait_rqm:
    133 	moveb	%a1@,%d3
    134 	jpl	fdc_wait_rqm		| NE7ST_RQM_BIT = 7: sign bit
    135 	lslb	#1,%d3			| NE7ST_DIO_BIT = 6 ... move to bit #7
    136 	rts
    137 
    138 |
    139 |	error
    140 |
    141 _err_read_id:
    142 	BOOT_ERROR("READ ID failed")
    143