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39 lines
2.1 KiB
Plaintext
39 lines
2.1 KiB
Plaintext
head 1.1;
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branch 1.1.1;
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access ;
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symbols start:1.1.1.1 Xerox:1.1.1;
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locks ; strict;
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comment @# @;
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1.1
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date 2001.08.12.22.22.22; author freier; state Exp;
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branches 1.1.1.1;
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next ;
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1.1.1.1
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date 2001.08.12.22.22.22; author freier; state Exp;
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branches ;
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next ;
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desc
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@@
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1.1
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log
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@Initial revision
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@
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text
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@{File name: FloppyInitial.mc
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Copyright (C) 1981, 1982, 1984, 1987 by Xerox Corporation. All rights reserved.
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Description: Initial microcode for the floppy disk booting sequence,
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Author: PXJ ,
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Created: November 7, 1980,
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last edited by:
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RDH 22-Apr-87 10:21:35 Add last edit line to reflect MDS relief.
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Last Edited: AHL, 1-Feb-87 12:13:17 - MDS relieve. See comment at label GFT. (This line added by RDH to satisfy my need for order.).
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Last Edited: Dennis DEG , 1-Sep-84 22:05:14 - add copyright notice.
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Last Edited: ETN , January 13, 1982 3:14 PM - deleted at miscRet
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Last Edited: PXJ , March 23, 1981 10:46 AM}
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SetTask[0],
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DoneOnceOnlyInit:
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{clear bank 0, 0-FFFF, takes 27 msec (411-9 secs per click) (only the first two pages are of interest)}
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Noop, {miscRet used to be here. Not needed} c1;
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rE¬ 0, c2; {source of 0}
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rD¬ 0, rDrh¬ 0, c3;
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clearBank0: MAR¬ [rDrh, rD+0], c1;
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MDR¬ rE, rD¬ rD+1, ZeroBr, c2;
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BRANCH[clearBank0, $], c3;
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{ The germ is in memory, but the map is wrong. The first page of the germ is its GFT. We move it from virtual page 1 to virtual page 200. Then shift virtual pages down by 1. The Remap loop stops at page FE, but I dont think the germ will ever get bigger. AHL }
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GFT: rBrh ¬ 1, rB ¬ 1, c1;
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Noop, c2;
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rCrh ¬ 2, rC ¬ 0, c3;
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MAR ¬ [rBrh, rB], { read page 1 map } c1;
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rB ¬ 0FE, CANCELBR[$,2], c2;
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rS ¬ MD, c3;
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Map ¬ [rCrh, rC], { page 200 ¬ old page 1 } c1;
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MDR ¬ rS, c2;
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rS ¬ MD, c3;
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Remap: MAR ¬ [rBrh, rB], { FE ¬ 200, FD ¬ FE, 1 ¬ 2 } c1;
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MDR ¬ rS, rB ¬ rB - 1, CANCELBR[$,2], ZeroBr, WriteOK, c2;
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rS ¬ MD, BRANCH[Remap, DoneRemap], c3;
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DoneRemap:
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{ end AHL }
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Noop, c1;
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Noop, c2;
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GOTO[exitToEmulator], c3;
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@
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1.1.1.1
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log
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@first add
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@
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text
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@@
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