Annotation of sys/arch/mac68k/mac68k/pramasm.s, Revision 1.1
1.1 ! nbrk 1: /* $OpenBSD: pramasm.s,v 1.7 2007/04/10 17:14:42 miod Exp $ */
! 2: /* $NetBSD: pramasm.s,v 1.4 1995/09/28 03:15:54 briggs Exp $ */
! 3:
! 4: /*
! 5: * RTC toolkit version 1.08b, copyright 1995, erik vogan
! 6: *
! 7: * All rights and privileges to this code hereby donated
! 8: * to the ALICE group for use in NetBSD. see the copyright
! 9: * below for more info...
! 10: */
! 11: /*
! 12: * Copyright (c) 1995 Erik Vogan
! 13: * All rights reserved.
! 14: *
! 15: * This code is derived from software contributed to the Alice Group
! 16: * by Erik Vogan.
! 17: *
! 18: * Redistribution and use in source and binary forms, with or without
! 19: * modification, are permitted provided that the following conditions
! 20: * are met:
! 21: * 1. Redistributions of source code must retain the above copyright
! 22: * notice, this list of conditions and the following disclaimer.
! 23: * 2. Redistributions in binary form must reproduce the above copyright
! 24: * notice, this list of conditions and the following disclaimer in the
! 25: * documentation and/or other materials provided with the distribution.
! 26: * 3. All advertising materials mentioning features or use of this software
! 27: * must display the following acknowledgement:
! 28: * This product includes software developed by the Alice Group.
! 29: * 4. The names of the Alice Group or any of its members may not be used
! 30: * to endorse or promote products derived from this software without
! 31: * specific prior written permission.
! 32: *
! 33: * THIS SOFTWARE IS PROVIDED BY THE ALICE GROUP ``AS IS'' AND ANY EXPRESS OR
! 34: * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
! 35: * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
! 36: * IN NO EVENT SHALL THE ALICE GROUP BE LIABLE FOR ANY DIRECT, INDIRECT,
! 37: * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
! 38: * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
! 39: * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
! 40: * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
! 41: * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
! 42: * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
! 43: */
! 44:
! 45: /*
! 46: * The following are the C interface functions to RTC access functions
! 47: * that are defined later in this file.
! 48: */
! 49:
! 50: /* The following routines are the hardware
! 51: * specific routines for the machines that
! 52: * use the II-like method to access the PRAM. */
! 53:
! 54: /*
! 55: * The following are the C interface functions to RTC access functions
! 56: * that are defined later in this file.
! 57: */
! 58:
! 59: .text
! 60:
! 61: .even
! 62:
! 63: .globl _getPramTimeII
! 64: _getPramTimeII:
! 65: link a6,#-4 | create a little home for ourselves
! 66: jbsr _readClock | call the routine to read the time
! 67: unlk a6 | clean up after ourselves
! 68: rts | and return to caller
! 69:
! 70: .globl _setPramTimeII
! 71: _setPramTimeII:
! 72: link a6,#-4 | create a little home for ourselves
! 73: movel a6@(8),d0 | get the passed in long (seconds since 1904)
! 74: jbsr _writeClock | call the routine to write the time
! 75: unlk a6 | clean up after ourselves
! 76: rts | and return to caller
! 77:
! 78: /*
! 79: * The following are the RTC access functions used by the interface
! 80: * routines, above.
! 81: */
! 82:
! 83: _readClock:
! 84: moveml #0x7cc0, sp@- | store off the regs we need
! 85: moveq #00,d0 | zero out our result reg
! 86: readagan:
! 87: moveq #00,d5 | and our temp result reg
! 88: moveq #03,d4 | set our count down reg to 4
! 89: movel #0x00000081,d1 | read sec byte 0 first
! 90: getSecb:
! 91: bsr _Transfer | get that byte
! 92: rorl #8,d5 | shift our time to the right
! 93: swap d1 | we want to access our new data
! 94: moveb d1,d5 | move that byte to the spot we vacated
! 95: swap d1 | return our PRAM command to orig. config
! 96: addqb #4,d1 | increment to the next sec byte
! 97: dbf d4,getSecb | any more bytes to get ?
! 98: cmpl d5,d0 | same secs value we as we just got ?
! 99: beq gotTime | we got a good time value
! 100: movel d5,d0 | copy our current time to the compare reg
! 101: bra readagan | read the time again
! 102: gotTime:
! 103: rorl #8,d0 | make that last shift to correctly order
! 104: | time bytes!!!
! 105: movel #0x00d50035,d1 | we have to set the write protect bit
! 106: | so the clock doesn't run down !
! 107: bsr _Transfer | (so says Apple...)
! 108: moveml sp@+, #0x033e | restore our regs
! 109: rts | and return to caller
! 110:
! 111: _writeClock:
! 112: moveml #0x78c0, sp@- | store off the regs we need
! 113: moveq #03,d4 | set our count down reg to 4
! 114: movel #0x00550035,d1 | de-write-protect the PRAM
! 115: bsr _Transfer | so we can set our value
! 116: moveq #1,d1 | write sec byte 0 first
! 117: putSecb:
! 118: swap d1 | we want access to data byte of command
! 119: moveb d0,d1 | set our first secs byte
! 120: swap d1 | and return command to orig. config
! 121: bsr _Transfer | write that byte
! 122: rorl #8,d0 | shift our time to the right
! 123: addqb #4,d1 | increment to the next sec byte
! 124: dbf d4,putSecb | any more bytes to put ?
! 125: movel #0x00d50035,d1 | we have to set the write protect bit
! 126: | so the clock doesn't run down !
! 127: bsr _Transfer | (so says Apple...)
! 128: moveml sp@+, #0x031e | restore our regs
! 129: rts | and return to caller
! 130:
! 131: _Transfer:
! 132: movew sr,sp@- | store the SR (we'll change it!)
! 133: oriw #0x0700,sr | disable all interrupts
! 134: moveal _Via1Base,a1 | move VIA1 addr in reference reg
! 135: moveq #0,d2 | zero out d2 (it'll hold VIA1 reg B contents)
! 136: moveb a1@,d2 | and get VIA1 reg B contents
! 137: andib #0xF8,d2 | don't touch any but RTC bits
! 138: | (and zero all those)
! 139: movew d1,d3 | we want to manipulate our command
! 140: andiw #0xFF00,d3 | zero the LSB
! 141: beq oldPRAMc | do an old PRAM style command
! 142: xPRAMc:
! 143: rorw #8,d1 | swap the command bytes (1st byte of 2)
! 144: bsr writebyte | and write the command byte
! 145: rorw #8,d1 | swap the command bytes again (2nd byte of 2)
! 146: bsr writebyte | write that byte to RTC too
! 147: moveq #0x1F,d3 | r/w bit is $F for an extended command
! 148: | (but command is swapped to MSW!! so add $10)
! 149: bra Rwbrnch | go figure out if it's a read or a write cmd
! 150: oldPRAMc:
! 151: bsr writebyte | only one byte for an old PRAM command
! 152: moveq #0x17,d3 | r/w bit is $7 for and old PRAM command
! 153: | ( command is swapped to MSW, add $10)
! 154: Rwbrnch:
! 155: swap d1 | better get that (data/dummy) byte ready
! 156: btst d3,d1 | test bit no. d3 of reg d1 (read or write ?)
! 157: beq Wtrue | 0 = write, 1 = read (branch on write)
! 158: Rtrue:
! 159: bsr readbyte | read a byte from the RTC
! 160: bra Cleanup | and call mom to clean up after us
! 161: Wtrue:
! 162: bsr writebyte | write the data to the RTC
! 163: Cleanup:
! 164: swap d1 | move command to LSW again
! 165: bset #2,a1@ | bring the RTC enable line high (end of xfer)
! 166: movew sp@+,sr | restore prior interrupt status
! 167: rts | and return to caller
! 168:
! 169: writebyte:
! 170: moveq #7,d3 | set our bit counter to 8
! 171: wagain:
! 172: lsrb #1,d2 | ditch the old data channel value
! 173: roxlb #1,d1 | and move a new value to X
! 174: roxlb #1,d2 | now move value from X to data channel
! 175: moveb d2,a1@ | set our VIA1 reg B contents to match
! 176: bset #1,a1@ | and finish strobing the clock line
! 177: dbf d3,wagain | do this until we've sent a whole byte
! 178: lsrb #1,d2 | ditch the data channel value one last time
! 179: roxlb #1,d1 | get rid of the extra X bit we've carried
! 180: lslb #1,d2 | and restore d2 to prior status
! 181: rts | return to caller
! 182:
! 183: readbyte:
! 184: moveq #7,d3 | set our bit counter to 8
! 185: bclr #0,a1@(0x0400) | set VIA1 reg B data line to input
! 186: ragain:
! 187: bclr #1,a1@ | strobe the clock line to make
! 188: bset #1,a1@ | the data valid
! 189: moveb a1@,d2 | and get out data byte
! 190: lsrb #1,d2 | get the data channel value to X
! 191: roxlb #1,d1 | and move X to data byte
! 192: dbf d3,ragain | do this until we've received a whole byte
! 193: bset #0,a1@(0x0400) | and return RTC data line to output
! 194: rts | return to caller
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