Return to pramasm.s CVS log

Up to [local] / sys / arch / mac68k / mac68k

Initial revision

/*	$OpenBSD: pramasm.s,v 1.7 2007/04/10 17:14:42 miod Exp $	*/
/*	$NetBSD: pramasm.s,v 1.4 1995/09/28 03:15:54 briggs Exp $	*/

/*
 * RTC toolkit version 1.08b, copyright 1995, erik vogan
 *
 * All rights and privileges to this code hereby donated
 * to the ALICE group for use in NetBSD.  see the copyright
 * below for more info...
 */
/*
 * Copyright (c) 1995 Erik Vogan
 * All rights reserved.
 *
 * This code is derived from software contributed to the Alice Group
 * by Erik Vogan.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the Alice Group.
 * 4. The names of the Alice Group or any of its members may not be used
 *    to endorse or promote products derived from this software without
 *    specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE ALICE GROUP ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE ALICE GROUP BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

/*
 *  The following are the C interface functions to RTC access functions
 * that are defined later in this file.
 */

				/* The following routines are the hardware
				 * specific routines for the machines that
				 * use the II-like method to access the PRAM. */

/*
 *  The following are the C interface functions to RTC access functions
 * that are defined later in this file.
 */

	.text

	.even

.globl _getPramTimeII
_getPramTimeII:
	link	a6,#-4		|  create a little home for ourselves
	jbsr	_readClock	|  call the routine to read the time
	unlk	a6		|  clean up after ourselves
	rts			|  and return to caller

.globl _setPramTimeII
_setPramTimeII:
	link	a6,#-4		|  create a little home for ourselves
	movel	a6@(8),d0	|  get the passed in long (seconds since 1904)
	jbsr	_writeClock	|  call the routine to write the time
	unlk	a6		|  clean up after ourselves
	rts			|  and return to caller

/*
 *  The following are the RTC access functions used by the interface
 * routines, above.
 */

_readClock:
	moveml	#0x7cc0, sp@-	| store off the regs we need
	moveq	#00,d0		| zero out our result reg
readagan:
	moveq	#00,d5		| and our temp result reg
	moveq	#03,d4		| set our count down reg to 4
	movel	#0x00000081,d1	| read sec byte 0 first
getSecb:
	bsr	_Transfer	| get that byte
	rorl	#8,d5		| shift our time to the right
	swap	d1		| we want to access our new data
	moveb	d1,d5		| move that byte to the spot we vacated
	swap	d1		| return our PRAM command to orig. config
	addqb	#4,d1		| increment to the next sec byte
	dbf	d4,getSecb	| any more bytes to get ?
	cmpl	d5,d0		| same secs value we as we just got ?
	beq	gotTime		| we got a good time value
	movel	d5,d0		| copy our current time to the compare reg
	bra	readagan	| read the time again
gotTime:
	rorl	#8,d0		| make that last shift to correctly order
				|  time bytes!!!
	movel	#0x00d50035,d1	| we have to set the write protect bit
				| so the clock doesn't run down !
	bsr	_Transfer	| (so says Apple...)
	moveml	sp@+, #0x033e	| restore our regs
	rts			| and return to caller

_writeClock:
	moveml	#0x78c0, sp@-	| store off the regs we need
	moveq	#03,d4		| set our count down reg to 4
	movel	#0x00550035,d1	| de-write-protect the PRAM
	bsr	_Transfer	| so we can set our value
	moveq	#1,d1		| write sec byte 0 first
putSecb:
	swap	d1		| we want access to data byte of command
	moveb	d0,d1		| set our first secs byte
	swap	d1		| and return command to orig. config
	bsr	_Transfer	| write that byte
	rorl	#8,d0		| shift our time to the right 
	addqb	#4,d1		| increment to the next sec byte
	dbf	d4,putSecb	| any more bytes to put ?
	movel	#0x00d50035,d1	| we have to set the write protect bit
				| so the clock doesn't run down !
	bsr	_Transfer	| (so says Apple...)
	moveml	sp@+, #0x031e	| restore our regs
	rts			| and return to caller

_Transfer:
	movew	sr,sp@-		| store the SR (we'll change it!)
	oriw	#0x0700,sr	| disable all interrupts
	moveal	_Via1Base,a1	| move VIA1 addr in reference reg
	moveq	#0,d2		| zero out d2 (it'll hold VIA1 reg B contents)
	moveb	a1@,d2		| and get VIA1 reg B contents
	andib	#0xF8,d2	| don't touch any but RTC bits
				| (and zero all those)
	movew	d1,d3		| we want to manipulate our command
	andiw	#0xFF00,d3	| zero the LSB
	beq	oldPRAMc	| do an old PRAM style command
xPRAMc:
	rorw	#8,d1		| swap the command bytes (1st byte of 2)
	bsr	writebyte	| and write the command byte
	rorw	#8,d1		| swap the command bytes again (2nd byte of 2)
	bsr	writebyte	| write that byte to RTC too
	moveq	#0x1F,d3	| r/w bit is $F for an extended command
				| (but command is swapped to MSW!! so add $10)
	bra	Rwbrnch		| go figure out if it's a read or a write cmd
oldPRAMc:
	bsr	writebyte	| only one byte for an old PRAM command
	moveq	#0x17,d3	| r/w bit is $7 for and old PRAM command
				| ( command is swapped to MSW, add $10)
Rwbrnch:
	swap	d1		| better get that (data/dummy) byte ready
	btst	d3,d1		| test bit no. d3 of reg d1 (read or write ?)
	beq	Wtrue		| 0 = write, 1 = read (branch on write)
Rtrue:
	bsr	readbyte	| read a byte from the RTC
	bra	Cleanup		| and call mom to clean up after us
Wtrue:
	bsr	writebyte	| write the data to the RTC
Cleanup:
	swap	d1		| move command to LSW again
	bset	#2,a1@		| bring the RTC enable line high (end of xfer)
	movew	sp@+,sr		| restore prior interrupt status
	rts			| and return to caller

writebyte:
	moveq	#7,d3		| set our bit counter to 8
wagain:	
	lsrb	#1,d2		| ditch the old data channel value
	roxlb	#1,d1		| and move a new value to X
	roxlb	#1,d2		| now move value from X to data channel
	moveb	d2,a1@		| set our VIA1 reg B contents to match
	bset	#1,a1@		| and finish strobing the clock line
	dbf	d3,wagain	| do this until we've sent a whole byte
	lsrb	#1,d2		| ditch the data channel value one last time
	roxlb	#1,d1		| get rid of the extra X bit we've carried
	lslb	#1,d2		| and restore d2 to prior status
	rts			| return to caller

readbyte:
	moveq	#7,d3		| set our bit counter to 8
	bclr	#0,a1@(0x0400)	| set VIA1 reg B data line to input
ragain:
	bclr	#1,a1@		| strobe the clock line to make
	bset	#1,a1@		| the data valid
	moveb	a1@,d2		| and get out data byte	
	lsrb	#1,d2		| get the data channel value to X
	roxlb	#1,d1		| and move X to data byte
	dbf	d3,ragain	| do this until we've received a whole byte
	bset	#0,a1@(0x0400)	| and return RTC data line to output
	rts			| return to caller