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1990-02-12
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891 lines
=============================================================================
╠╔╘╘╠┼ ╥┼─ ╥┼┴─┼╥: ═╙-─╧╙ FILE READER FOR THE 128 AND 1571/81 DRIVES.
BY ├RAIG ┬RUCE <CSBRUCE@NEUMANN.UWATERLOO.CA>
1. ╔╬╘╥╧─╒├╘╔╧╬
╘HIS ARTICLE PRESENTS A PROGRAM THAT READS ═╙-─╧╙ FILES AND THE ROOT DIRECTORY
OF ═╙-─╧╙ DISKS. ╘HE PROGRAM COPIES ONLY FROM DRIVE TO DRIVE WITHOUT
BUFFERING FILE DATA INTERNALLY. ╘HIS IS SIMPLER AND IMPOSES NO LIMITS ON THE
SIZE OF THE FILES TRANSFERRED, ALTHOUGH IT REQUIRES THE USE OF TWO DISK DRIVES
(OR A LOGICAL DRIVE). ╘HE USER-INTERFACE CODE IS WRITTEN IN ┬┴╙╔├ AND
PRESENTS A FULL-SCREEN FILE SELECTION MENU. ╘HE GRUNT-WORK CODE IS WRITTEN IN
ASSEMBLY LANGUAGE AND OPERATES AT MAXIMUM VELOSITY.
╘HE ┬URST ├OMMAND ╔NSTRUCTION ╙ET OF THE 1571/81 IS USED TO READ THE ═╙-─╧╙
DISK BLOCKS AND THE STANDARD KERNEL ROUTINES ARE USED FOR OUTPUTTING THE
DATA. (╔ AM AN OPERATING SYSTEMS SPECIALIST, SO ╔ CALL IT A KERN┼L!) ╘HUS,
THE ═╙-─╧╙ FILES MUST BE READ FROM A 1571 OR 1581 DISK DRIVE, BUT THE OUTPUT
DEVICE MAY BE ANY DISK DRIVE TYPE, THE SCREEN OR A PRINTER, OR A VIRTUAL DRIVE
TYPE SUCH AS ╥┴═╠INK, ╥┴═─RIVE, OR ╥┴═─╧╙ (FOR THE ╥┼╒). ╔T IS INTERESTING TO
NOTE THAT THE DATA CAN BE READ IN FROM AN ═╙-─╧╙ DISK FASTER THAN IT CAN BE
WRITTEN OUT TO A 1571, 1581, OR EVEN A ╥┴═─╧╙ FILE. ┴ ╥┴═╠INK CAN SWALLOW THE
DATA ONLY SLIGHTLY FASTER THAN IT CAN BE READ.
╠ITTLE ╥ED ╥EADER (╠╥╥) SUPPORTS DOUBLE DENSITY 3.5" DISKS FORMATTED WITH 80
TRACKS, 9 SECTORS PER TRACK, AND 2 SIDES WITH A 1581 AND 5.25" DOUBLE DENSITY
DISKS FORMATTED WITH 40 TRACKS, 9 SECTORS PER TRACK, AND 2 SIDES WITH A 1571.
┴ LIMIT OF 128 DIRECTORY ENTRIES AND 3 ╞ILE ┴LLOCATION ╘ABLE (╞┴╘) SECTORS IS
IMPOSED. ╘HERE MUST BE 2 COPIES OF THE ╞┴╘ AND THE CLUSTER SIZE MAY BE 1 OR 2
SECTORS. ╘HE SECTOR SIZE MUST BE 512 BYTES.
╧H, ABOUT THE NAME. ╔T IS A PLAY ON THE NAME OF ANOTHER ═╙-─╧╙ FILE COPIER
AVAILABLE FOR THE ├-128. "╠ITTLE" MEANS THAT IT IS SMALLER IN SCOPE THAN THE
OTHER PROGRAM, AND "╥ED" IS A DIFFERENT PRIMARY COLOR TO AVOID ANY LEGAL
COMPLICATIONS. ╔T IS ALSO THE NON-WHITE COLOR OF THE FLAG OF THE COUNTRY OF
ORIGIN OF THIS PROGRAM (NO, ╔ AM NOT ╩APANESE). ┴LSO, THIS PROGRAM IS ╨UBLIC
─OMAIN ╙OFTWARE, AS IS ALL SOFTWARE ╔ DEVELOP FOR 8-BIT ├OMMODORE ├OMPUTERS.
╞EEL FREE TO ┼-MAIL ME IF YOU HAVE QUESTIONS OR COMMENTS ABOUT THIS ARTICLE.
2. ╒╙┼╥ ╟╒╔─┼
╠╧┴─ AND ╥╒╬ THE "LRR.128" ┬┴╙╔├ PROGRAM FILE. ╫HEN THE PROGRAM IS FIRST RUN,
IT WILL DISPLAY AN "INITIALIZING" MESSAGE AND WILL LOAD IN THE BINARY MACHINE
LANGUAGE PACKAGE FROM THE "CURRENT" ├OMMODORE ─╧╙ DRIVE (THE CURRENT DRIVE IS
OBTAINED FROM ╨┼┼╦(186) - THE LAST DEVICE ACCESSED). ╘HE BINARY PACKAGE IS
LOADED ONLY ON THE FIRST RUN AND IS NOT RELOADED ON SUBSEQUENT RUNS IF THE
PACKAGE ╔─ FIELD IS IN PLACE.
2.1. ═┴╔╬ ╙├╥┼┼╬
╘HE MAIN SCREEN OF THE PROGRAM IS THEN DISPLAYED. ╘HE MAIN SCREEN OF THE
PROGRAM WILL LOOK SOMETHING LIKE THIS:
═╙-─┼╓=9 ═╙-╘┘╨┼=1581 ├┬═-─┼╓=8
╬╒═ ╙ ╘╥╬ ╘┘╨ ╞╔╠┼╬┴═┼ ┼╪╘ ╠┼╬╟╘╚
--- - --- --- -------- --- ------
1 * ┴╙├ ╙┼╤ ╚┴├╦4 ╘╪╘ 120732
2 ┬╔╬ ╨╥╟ ╥┴═─╧╙ ╙╞╪ 34923
─=─╔╥┼├╘╧╥┘ ═=═╙-─┼╓ ╞=├┬═-─┼╓ ╤=╤╒╔╘
╘=╘╧╟╟╠┼-├╧╠╒═╬, ├=├╧╨┘-╞╔╠┼╙, +/- ╨┴╟┼
EXCEPT THAT IMMEDIATELY AFTER STARTING UP, "<NO FILES>" WILL BE DISPLAYED
RATHER THAN FILENAMES. ╘HE "═╙-─┼╓" AND "═╙-╘┘╨┼" FIELDS GIVE THE DEVICE
NUMBER AND TYPE OF THE DRIVE CONTAINING THE ═╙-─╧╙ DISK TO COPY FROM, AND THE
"├┬═-─┼╓" GIVES THE DEVICE NUMBER OF THE DRIVE/VIRTUAL DRIVE/CHARACTER DEVICE
TO COPY FILE DATA TO.
╔NFORMATION ABOUT ALL ═╙-─╧╙ FILES IN THE ROOT DIRECTORY OF THE ═╙-─╧╙ DISK IS
DISPLAYED IN COLUMNS BELOW THE DRIVE INFORMATION. "╬╒═" GIVES THE NUMBER OF
THE ═╙-─╧╙ FILE IN THE DIRECTORY LISTING, AND "╙" INDICATES WHETHER THE FILE
IS "SELECTED" OR NOT. ╔F THE FILE IS SELECTED, AN ASTERISK (*) IS DISPLAYED;
OTHERWISE, A BLANK IS DISPLAYED. ╫HEN YOU LATER ENTER ├OPY ═ODE, ONLY THE
FILES THAT HAVE BEEN "SELECTED" ARE COPIED.
╘HE "╘╥╬" FIELD INDICATES THE CHARACTER TRANSLATION SCHEME TO BE USED WHEN THE
FILE IS COPIED. ┴ VALUE OF "┬╔╬" (BINARY) MEANS NO TRANSLATION AND A VALUE OF
"┴╙├" (ASCII) MEANS THE FILE CHARACTERS ARE TO BE TRANSLATED FROM ═╙-─╧╙ ┴╙├╔╔
(OR "┴╙├╔╔-├R╠F") TO ╨┼╘╙├╔╔. ╘HE "╘┘╨" FIELD INDICATES THE TYPE OF
├OMMODORE-─╧╙ FILE TO CREATE FOR WRITING THE ═╙-─╧╙ FILE CONTENTS INTO. ╘HE
POSSIBLE VALUES ARE "╙┼╤" (SEQUENTIAL) AND "╨╥╟" (PROGRAM). ╘HE VALUES OF THE
╘╥╬ AND ╘┘╨ FILEDS ARE SET INDEPENDENTLY, SO YOU CAN COPY BINARY DATA TO ╙┼╤
FILES AND ASCII DATA TO ╨╥╟ FILES IF YOU WISH.
╘HE "╞╔╠┼╬┴═┼" AND "┼╪╘" FIELDS GIVE THE FILENAME AND EXTENSION TYPE OF THE
═╙-─╧╙ FILES AND "╠┼╬╟╘╚" GIVES THE EXACT LENGTH OF THE FILES IN BYTES. ╬OTE
THAT IF YOU PERFORM "┴╙├" TRANSLATION ON A FILE, ITS ╨┼╘╙├╔╔ VERSION WILL HAVE
A SHORTER LENGTH.
2.2. ╒╙┼╥ ├╧══┴╬─╙
╘HE BOTTOM OF THE SCREEN GIVES THE COMMAND SUMMARY. ┴FTER STARTING THE
PROGRAM, YOU WILL WANT TO SETUP THE ═╙-─╧╙ AND ├┬═-─╧╙ DRIVES WITH THE "═" AND
"╞" COMMANDS. ╙IMPLY PRESS THE (LETTER) KEY CORRESPONDING TO THE COMMAND
NAME TO ACTIVATE THE COMMAND. ╨RESSING ═ WILL PROMPT YOU FOR THE ═╙-─╧╙ ─RIVE
╬UMBER AND THE ═╙-─╧╙ ─RIVE ╘YPE. ╔N BOTH CASES, TYPE THE NUMBER AND PRESS
╥┼╘╒╥╬. (╙ORRY FOR INSULTING ALL NON-NOVICES OUT THERE, BUT ╔ WANT TO BE
COMPLETE). ╘HE ═╙-─╧╙ DRIVE NUMBER CANNOT BE THE SAME AS THE ├┬═-─╧╙ DRIVE
NUMBER (SINCE THE PROGRAM COPIES FROM DRIVE-TO-DRIVE WITHOUT INTERNAL
BUFFERING). ╞OR THE DRIVE TYPE, ENTER AN "8", "81", OR "1581" FOR A 1581
DRIVE OR ANYTHING ELSE FOR A 1571 DRIVE.
╨RESSING ╞ WILL PROMPT YOU FOR THE ├┬═-─╧╙ DEVICE NUMBER. ┘OU MAY ENTER A
NUMBER FROM 0 TO 30, EXCEPT THAT IT MUST NOT BE THE ═╙-─╧╙ DRIVE NUMBER.
┼NTER A "1" FOR ├ASSETTE ─RIVE (╟OD FORBID!), A "3" FOR THE SCREEN, A "4" FOR
THE PRINTER (WITH AN AUTOMATIC SECONDARY ADDRESS OF 7 (LOWERCASE)), ANY NUMBER
ABOVE 7 FOR A ├OMMODORE DISK DRIVE OR SPECIAL VIRTUAL DRIVE, OR A VALUE OF "0"
FOR THE SPECIAL "NULL" DRIVE. ┴ ├┬═-─┼╓ VALUE OF 0 WILL CASE THE PROGRAM TO
READ ═╙-─╧╙ FILES AND DO NOTHING WITH THE OUTPUT. ┘OU CAN USE THIS FEATURE TO
CHECK OUT THE RAW READING SPEED OF THE PROGRAM.
┴FTER SETTING UP THE DRIVES, PRESS ─ TO READ IN THE ROOT DIRECTORY OFF THE
═╙-─╧╙ DISK. ╘HE DATA WILL COME BLAZING IN FROM THE DISK BUT ┬┴╙╔├ WILL TAKE
ITS GOOD OLE TIME SIFTING THROUGH IT. ╞ILENAMES ARE DISPLAYED ON THE SCREEN
AS THEY ARE SCANNED IN. ╘HE PROGRAM WILL (EVENTUALLY) RETURN TO THE MAIN
SCREEN AND DISPLAY THE FORMATTED FILE INFORMATION. ╧NE NOTE: THE PROCESS OF
LOGGING IN A 1581 ═╙-─╧╙ DISK TAKES ABOUT 12 SECONDS (ON MY 1581, ANYWAY), SO
BE PATIENT. ┴N ═╙-─╧╙ DISK WILL HAVE TO BE "LOGGED IN" EVERY TIME YOU CHANGE
═╙-─╧╙ DISKS. (─ISKS ARE LOGGED IN AUTOMATICALLY).
┴ COUPLE OF NOTES ABOUT ACCESSING ═╙-─╧╙ DISKS: DON'T TRY TO ACCESS A DEVICE
THAT IS NOT PRESENT BECAUSE THE MACHINE LANGUAGE ROUTINES CANNOT HANDLE THIS
ERROR FOR SOME REASON AND WILL LOCK UP, REQUIRING A ╙╘╧╨+╥┼╙╘╧╥┼. ┴LSO, MAKE
SURE THAT AN ACTUAL ═╙-─╧╙ DISK IS LOADED INTO THE DRIVE. ╔F YOU ACCIDENTALLY
PLACE ├OMMODORE-─╧╙ DISK INTO THE ═╙-─╧╙ DRIVE, THE 1581 WILL REPORT AN
INVALID BOOT PARAMETERS ERROR (#60), BUT A 1571 WILL LOCK UP (SINCE ╔ DON'T
CHECK THE SECTOR SIZE AND MY BURST ROUTINES ARE EXPECTING 512 BYTES TO COME
OUT OF A SECTOR WHEREAS ├OMMODORE DISKS HAVE ONLY 256 BYTES PER SECTOR).
╬OW YOU ARE READY TO PICK WHAT FILES YOU WANT COPIED AND HOW YOU WANT THEM
COPIED. ┘OU WILL NOTICE THAT A "CURSOR" APPEARS IN THE "╙" COLUMN OF THE
FIRST FILE. ┘OU MAY MOVE THE CURSOR AROUND WITH THE CURSOR KEYS: ╒╨, ─╧╫╬,
╠┼╞╘, ╥╔╟╚╘, ╚╧═┼, AND ├╠╥. ├╠╥ (╙╚╔╞╘-╚╧═┼) WILL MOVE THE CURSOR BACK TO THE
FIRST FILE ON THE FIRST SCREEN. ┘OU CAN MOVE THE CURSOR AMONG THE SELECT,
TRANSLATION, AND FILE-TYPE COLUMNS OF ALL THE FILES. ╨RESSING A ╙╨┴├┼ OR A
╥┼╘╒╥╬ WILL TOGGLE THE VALUE OF THE FIELD THAT THE CURSOR IS ON. ╘O TOGGLE
ALL OF THE VALUES OF THE "CURSOR" COLUMN (INCLUDING FILES ON ALL OTHER
SCREENS), PRESS ╘. ┘OU WILL NOTICE THAT MOVING THE CURSOR AROUND AND TOGGLING
FIELDS IS A BIT SLUGGISH, ESPECIALLY IF YOU ARE IN ╙LOW MODE ON THE 40-COLUMN
SCREEN. ─ID ╔ MENTION THAT THIS PROGRAM WILL RUN ON EITHER THE 40 OR
80-COLUMN SCREEN? ╘OGGLING AN ENTIRE COLUMN CAN TAKE A COUPLE OF SECONDS.
╔F THERE ARE MORE THAN 18 ═╙-─╧╙ FILES, YOU CAN PRESS THE "+" AND "-" KEYS TO
MOVE AMONG ALL OF THE SCREENS OF FILES. ╘HE CURSOR MOVEMENT KEYS WILL WRAP
AROUND ON THE CURRENT SCREEN. "+" IS PAGE FORWARD, AND "-" IS PAGE BACKWARD.
╘HE SCREENS WRAP AROUND TOO.
┴FTER YOU HAVE SELECTED ALL OF THE FILES YOU WANT TO COPY AND THEIR TRANSLATION
AND FILE-TYPE FIELDS HAVE BEEN SET, PRESS THE ├ KEY TO GO INTO ├OPY ═ODE (NEXT
SECTION). ┴FTER COPYING, YOU ARE RETURNED TO THE MAIN SCREEN WITH ALL OF THE
FIELD SETTINGS STILL INTACT. ╘O EXIT FROM THE PROGRAM, PRESS ╤.
2.3. ├╧╨┘ ═╧─┼
╫HEN YOU ENTER COPY MODE, THE SCREEN WILL CLEAR AND THE NAME OF EACH SELECTED
FILE IS DISPLAYED AS IT IS BEING COPIED. ╔F AN ERROR IS ENCOUNTERED ON EITHER
THE ═╙-─╧╙ OR ├┬═-─╧╙ DRIVE DURING COPYING, AN ERROR MESSAGE WILL BE DISPLAYED
AND COPYING WILL CONTINUE (AFTER YOU PRESS A KEY FOR ═╙-─╧╙ ERRORS).
╘O GENERATE A ├┬═-─╧╙ FILENAME FROM AN ═╙-─╧╙ FILENAME, THE EIGHT FILENAME
CHARACTERS ARE TAKEN (INCLUDING SPACES) AND A DOT (.) AND THE THREE CHARACTERS
OF THE EXTENSION ARE APPENDED. ╘HEN, ALL SPACES ARE REMOVED, AND IF THE NAME
ENDS WITH A DOT (.) CHARACTER, THEN THAT DOT CHARACTER IS REMOVED AS WELL. ╔
THINK THIS IS FAIRLY REASONABLE.
╔F THERE ALREADY IS A FILE WITH THE SAME FILENAME ON THE ├┬═-─╧╙ DISK, THEN
YOU WILL BE PROMPTED IF YOU WANT TO OVERWRITE THE FILE OR NOT. ┼NTERING AN
"N" WILL ABORT THE COPYING OF THAT FILE AND GO ON TO THE NEXT FILE, AND
ENTERING A "Y" (OR ANYTHING ELSE) WILL CAUSE THE ├┬═-─╧╙ FILE TO BE
"SCRATCHED" AND THEN RE-WRITTEN.
╘HE PHYSICAL COPYING OF THE FILE IS DONE COMPLETELY IN MACHINE LANGUAGE AND
NOTHING IS DISPLAYED ON THE SCREEN WHILE THIS IS HAPPENING, BUT YOU CAN FOLLOW
THINGS BY LOOKING AT DAS BLINKIN LICHTES AND LISTENING FOR CLICKS AND GRINDS.
┘OU WILL PROBABLY BE SURPRISED BY THE ═╙-─╧╙ FILE READING SPEED (╔ MEAN IN A
GOOD WAY). ╘HE DISK DATA IS READ IN WHOLE TRACKS AND CACHED IN MEMORY AND THE
DIRECTORY INFORMATION AND THE ╞┴╘ ARE RETAINED IN MEMORY AS WELL. ╘HE RESULT
IS THAT MINIMAL TIME IS SPENT READING DISK DATA, AND NO COSTLY SEEKS ARE
REQUIRED FOR OPENING A NEW ═╙-─╧╙ FILE. ┴ RESULT IS THAT SMALL FILES ARE
COPIED ONE AFTER ANOTHER VERY QUICKLY. ┘OU WILL HAVE TO WAIT, HOWEVER, ON THE
RELATIVELY SLOW STANDARD KERNEL/├OMMODORE-─╧╙ FILE WRITING.
┴ FEW CHANGES HAD TO BE MADE TO THE PROGRAM TO ACCOMODATE THE ╥┴═─╧╙ PROGRAM.
╥┴═─╧╙ USES MEMORY FROM $2300 TO $3╞╞╞ OF ╥┴═0, WHICH IS NOT REALLY A GOOD
PLACE FOR A DEVICE DRIVER, AND IT USES SOME OF THE ZERO-PAGE LOCATIONS THAT ╔
WANTED TO USE. ┬UT, DIFFICULTIES WERE OVERCOME. ╘HE IMPORTANCE OF ╥┴═─╧╙
COMPATIBILITY IS THAT IF YOU ONLY HAVE ONE DISK DRIVE BUT YOU HAVE AN ╥┼╒, YOU
CAN USE ╥┴═─╧╙ TO STORE THE ═╙-─╧╙ FILES TEMPORARILY. ╔F YOU ONLY HAVE ONE
DISK DRIVE AND NO ╥┼╒, YOU ARE ╙╧╠ (╧UT OF ╠UCK) UNLESS YOU CAN GET A
╥AM─ISK-TYPE PROGRAM FOR AN UNEXPANDED 128. ╘HE ╥┴═─╧╙ PROGRAM IS AVAILABLE
FROM ╞╘╨ SITE "CCOSUN.CALTECH.EDU" IN FILE "/PUB/RKNOP/UTIL128/RAMDOSII.SFX".
╧NE NOTE ╔ FOUND OUT ABOUT ╥┴═─╧╙: YOU CANNOT USE A
─╧╨┼╬#1,(├╞$),╒(├─),╫
WITH IT LIKE YOU ARE SUPPOSED TO BE ABLE TO; YOU HAVE TO USE A
─╧╨┼╬#1,(├╞$+",╫"),╒(├─)
╚ERE IS A TABLE OF COPYING SPEEDS FOR COPYING FROM 1571S AND 1581S WITH ┴╙├
AND ┬╔╬ TRANSLATION MODES. ┴LL FIGURES ARE IN BYTES/SECOND. ╘HESE RESULTS
WERE OBTAINED FROM COPYING A 127,280 BYTE TEXT FILE (THE TEXT OF ├= ╚ACKING
╔SSUE #3).
╞╥╧═ \ ╘╧: "NULL" ╥┴═╠INK ╥┴═─╧╙ ╩─1581 ╩─1571
-------+ ------ ------- ------ ------ ------
81-BIN ⁿ 5772 3441 2146 N/A 644
81-ASC ⁿ 5772 3434 2164 N/A 661
71-BIN ⁿ 4323 2991 1949 1821 N/A
71-ASC ⁿ 4323 2982 1962 1847 N/A
╘HE "NULL" DEVICE IS THAT "0" ├┬═-─╧╙ DEVICE NUMBER, AND A COUPLE OF ENTRIES
ARE "N/A" SINCE ╔ ONLY HAVE ONE 1571 AND ONE 1581. ╬OTE THAT MY 71 AND 81 ARE
╩IFFY─╧╙-IFIED, SO THE PERFORMANCE OF A STOCK 71/81 WILL BE POORER. ╩IFFY─╧╙
GIVES ABOUT A 2X PERFORMANCE IMPROVEMENT FOR THE STANDARD FILE ACCESSING CALLS
(OPEN, CLOSE, CHRIN, CHROUT). ╥┴═─╧╙ DOESN'T SEEM TO BE AS SNAPPY AS YOU
MIGHT THINK.
╘HE "NULL" FIGURES ARE QUITE IMPRESSIVE, BUT THE RAW SECTOR READING SPEED
WITHOUT THE OVERHEAD OF MUCKING AROUND WITH FILE ORGANIZATION IS 6700
BYTES/SEC FOR A 1581 AND 4600 ┬/S FOR A 71. ╘HE REASON THAT THE 1571 OPERATES
SO QUICKLY IS THAT ╔ USE A SECTOR INTERLEAVE OF 4 (WHICH IS OPTIMAL) FOR
READING THE TRACKS. ╔ THINK THAT OTHER ═╙-─╧╙ FILE COPIER PROGRAM USES AN
INTERLEAVE OF 1 (WHICH IS NOT OPTIMAL). ╔ LOSE SOME OF THE RAW PERFORMANCE
BECAUSE ╔ COPY THE FILE DATA INTERNALLY ONCE BEFORE OUTPUTTING IT (TO SIMPLIFY
SOME OF THE CODE).
╔N A COUPLE OF PLACES YOU WILL NOTICE THAT ┴╙├ TRANSLATION GIVES SLIGHTLY
BETTER OR SLIGHTLY WORSE PERFORMANCE THAN ┬╔╬. ╘HIS IS BECAUSE ALTHOUGH
SLIGHTLY MORE WORK IS REQUIRED TO TRANSLATE THE CHARACTERS, SLIGHTLY FEWER
CHARACTERS WILL HAVE TO BE WRITTEN TO THE ├┬═-─╧╙ FILE, SINCE ╨┼╘╙├╔╔ USES
ONLY ├╥ WHERE ═╙-─╧╙ ┴╙├╔╔ USES ├╥ AND ╠╞ TO REPRESENT END-OF-LINE.
╘RANSLATION IS DONE BY USING A TABLE (THAT YOU CAN CHANGE IF YOU WISH). ═ANY
ENTRIES IN THIS TABLE CONTAIN A VALUE OF ZERO, WHICH MEANS THAT NO CHARACTER
WILL BE OUTPUT ON TRANSLATION. ═OST OF THE CONTROL CHARACTERS AND ALL OF THE
CHARACTERS OF VALUE 128 (0X80) OR GREATER ARE THROWN AWAY ON BEING
TRANSLATED. ╘HE TABLE IS SET UP SO THAT ├╥ CHARACTERS ARE THROWN AWAY AND THE
╠╞ CHARACTER IS TRANSLATED TO A ├┬═-─╧╙ ├╥ CHARACTER. ╘HUS, BOTH ═╙-─╧╙ ┴╙├╔╔
FILES AND ╒╬╔╪ ┴╙├╔╔ FILES CAN BE TRANSLATED CORRECTLY.
2. ┬╒╥╙╘ ├╧══┴╬─╙
╘HREE BURST COMMANDS FROM THE 1571/81 DISK DRIVE ┬URST ├OMMAND ╔NSTRUCTION ╙ET
ARE REQUIRED TO ALLOW THIS PROGRAM TO READ THE ═╙-─╧╙ DISKS: ╤UERY ─ISK
╞ORMAT, ╙ECTOR ╔NTERLEAVE, AND ╥EAD. ╘HE GRUNGY DETAILS ABOUT ISSUING BURST
COMMANDS AND BURST MODE HANDSHAKING ARE COVERED IN ├= ╚ACKING ╔SSUE #3. ╘HE
╤UERY ─ISK ╞ORMAT COMMAND IS USED TO "LOG IN" THE ═╙-─╧╙ DISK. ╘HE ╔NQUIRE
─ISK BURST COMMAND CANNOT BE USED WITH AN ═╙-─╧╙ DISK ON THE 1581 FOR SOME
UNKNOWN REASON. ╔ FOUND THIS OUT THE HARD WAY. ╘HE ╤UERY ─ISK ╞ORMAT COMMAND
HAS THE FOLLOWING FORMAT:
┬┘╘┼ \ BIT: 7 6 5 4 3 2 1 0 ⁿ ╓ALUE
-------+--------+-----+-----+-----+-----+-----+-----+-----+-------
0 ⁿ 0 ⁿ 1 ⁿ 0 ⁿ 1 ⁿ 0 ⁿ 1 ⁿ 0 ⁿ 1 ⁿ "╒"
1 ⁿ 0 ⁿ 0 ⁿ 1 ⁿ 1 ⁿ 0 ⁿ 0 ⁿ 0 ⁿ 0 ⁿ "0"
2 ⁿ ╞ ⁿ ╪ ⁿ ╪ ⁿ ╙ ⁿ 1 ⁿ 0 ⁿ 1 ⁿ ╬ ⁿ 10
-------+--------------------------------------------------+-------
WHERE THE ╞, ╙, AND ╬ BITS HAVE A VALUE OF 0 FOR OUR PURPOSES. ┴ RESPONSE OF
A BURST STATUS BYTE AND SIX OTHER THROW-AWAY BYTES IS GIVEN FROM THE DRIVE.
╘HIS COMMAND TAKES QUITE A LONG TIME TO EXECUTE ON MY 1581 BUT WORKS QUITE
QUICKLY ON MY 1571. ┘OU ONLY HAVE TO LOG IN A DISK WHENEVER YOU CHANGE
DISKS.
╘HE ╙ECTOR ╔NTERLEAVE COMMAND IS USED TO SET A SOFT INTERLEAVE FOR THE ╥EAD
COMMAND. ╔ USE AN INTERLEAVE OF 1 FOR THE 1581 AND AN INTERLEAVE OF 4 FOR THE
1571. ╘HIS MEANS THAT THE ═╙-─╧╙ SECTORS WILL COME FROM 1571 TO THE COMPUTER
IN THE FOLLOWING ORDER: 1, 5, 9, 4, 8, 3, 7, 2, 6 (THERE ARE 9 SECTORS PER
TRACK ON AN ═╙-─╧╙ DISK (BOTH 3.5" AND 5.25"), NUMBERED FROM 1 TO 9). ╠╥╥
HANDLES THE DATA COMING IN IN THIS ORDER, AND IN STRAIGHT ORDER FROM THE
1581. ╘HE ╙ECTOR ╔NTERLEAVE COMMAND HAS THE FOLLOWING FORMAT, WHERE THE ╫ AND
╬ BITS ARE 0 FOR US:
┬┘╘┼ \ BIT: 7 6 5 4 3 2 1 0 ⁿ ╓ALUE
-------+--------+-----+-----+-----+-----+-----+-----+-----+-------
0 ⁿ 0 ⁿ 1 ⁿ 0 ⁿ 1 ⁿ 0 ⁿ 1 ⁿ 0 ⁿ 1 ⁿ "╒"
1 ⁿ 0 ⁿ 0 ⁿ 1 ⁿ 1 ⁿ 0 ⁿ 0 ⁿ 0 ⁿ 0 ⁿ "0"
2 ⁿ ╫ ⁿ ╪ ⁿ ╪ ⁿ 0 ⁿ 1 ⁿ 0 ⁿ 0 ⁿ ╬ ⁿ 8
3 ⁿ <INTERLEAVE> ⁿ 1 OR 4
-------+--------------------------------------------------+-------
╘HE ╥EAD COMMAND IS USED TO TRANSFER THE NINE SECTORS OF A TRACK TO THE
COMPUTER IN THE ORDER SPECIFIED BY THE INTERLEAVE. ╘HE FORMAT IS:
┬┘╘┼ \ BIT: 7 6 5 4 3 2 1 0 ⁿ ╓ALUE
-------+--------+-----+-----+-----+-----+-----+-----+-----+-------
0 ⁿ 0 ⁿ 1 ⁿ 0 ⁿ 1 ⁿ 0 ⁿ 1 ⁿ 0 ⁿ 1 ⁿ "╒"
1 ⁿ 0 ⁿ 0 ⁿ 1 ⁿ 1 ⁿ 0 ⁿ 0 ⁿ 0 ⁿ 0 ⁿ "0"
2 ⁿ ╘/╠ ⁿ ┼ ⁿ ┬/╪ ⁿ ╙ ⁿ 0 ⁿ 0 ⁿ 0 ⁿ ╬ ⁿ 0 OR 16
3 ⁿ <TRACK> ⁿ ???
4 ⁿ <SECTOR> ⁿ 1
5 ⁿ <NUMBER OF SECTORS> ⁿ 9
-------+--------------------------------------------------+-------
╘HERE ARE A COUPLE OF DIFFERENCES BETWEEN THE 1571 AND 1581 VERSIONS OF THIS
COMMAND. ═OST IMPORTANT, THE ╙ BIT (╙IDE OF DISK TO USE) HAS THE OPPOSITE
MEANING ON THE TWO DRIVES. ╘HERE'S NO GOOD REASON THAT ╔ KNOW OF FOR THIS
INCONSISTENCY. ╘HIS IS THE REASON THAT ╠╥╥ NEEDS TO KNOW WHAT TYPE OF ═╙-─╧╙
DRIVE IT IS DEALING WITH (PLUS INTERLEAVING).
╘HE READ COMMAND RETURNS THE FOLLOWING DATA USING BURST MODE HANDSHAKING:
+-------------------+
0 ⁿ ┬URST ╙TATUS ┬YTE ⁿ
+-------------------+
1 ⁿ ⁿ
... + 512 ─ATA ┬YTES ⁿ
512 ⁿ ⁿ
+-------------------+
FOR EACH SECTOR TRANSFERRED. ╔F THE ┬URST ╙TATUS ┬YTE INDICATES AN ERROR,
THEN THE DATA IS NOT TRANSFERRED AND NONE OF THE FOLLOWING SECTORS ARE
EITHER. ╔F THE STATUS BYTE GIVES A "─ISK ├HANGED" ERROR, THEN YOU HAVE TO LOG
IN THE DISK WITH THE ╤UERY ─ISK ╞ORMAT COMMAND BEFORE READ WILL WORK
PROPERLY. ╘HIS IS ACTUALLY A GOOD FEATURE SINCE IT LETS YOU KNOW ABOUT A DISK
CHANGE SO YOU CAN UPDATE ANY DATA STRUCTURES YOU MAY HAVE. ╠╥╥ SIMPLY RE-LOGS
IN THE DISK WITHOUT UPDATING ANY DATA STRUCTURES AND RE-TRIES THE FAILED READ
OPERATION.
3. ═╙-─╧╙ ─╔╙╦ ╞╧╥═┴╘
┴N ═╙-─╧╙ DISK IS SEPARATED INTO 4 DIFFERENT PARTS: THE ┬OOT ╙ECTOR, THE
╞┴╘(S), THE ╥OOT ─IRECTORY, AND THE ╞ILE ─ATA ╙ECTORS. ╘HE LOGICAL SECTORS
(BLOCKS) OF A DISK ARE NUMBERED FROM 0 TO SOME MAXIMUM NUMBER (1439 FOR A
3.5", 719 FOR A 5.25" ── DISK). ╘HE PHYSICAL LAYOUT AND THE LOGICAL SECTOR
NUMBERS TYPICALLY USED BY A 3.5" DISK ARE SHOWN HERE:
+-------------------+
0 ⁿ ┬OOT ╙ECTOR ⁿ
+-------------------+
1..3 ⁿ ╞┴╘ COPY #1 ⁿ
+-------------------+
4..6 ⁿ ╞┴╘ COPY #2 ⁿ
+-------------------+
7..14 ⁿ ╥OOT ─IRECTORY ⁿ
+-------------------+
15 ⁿ ⁿ
... ⁿ ╞ILE ─ATA ╙ECTORS ⁿ
1439 ⁿ ⁿ
+-------------------+
3.1. ╘╚┼ ┬╧╧╘ ╙┼├╘╧╥
╘HE ┬OOT ╙ECTOR IS ALWAYS AT LOGICAL SECTOR NUMBER 0. ╔T CONTAINS SOME
IMPORTANT INFORMATION ABOUT THE FORMAT OF THE DISK AND IT ALSO CONTAINS CODE
TO BOOT AN ═╙-─╧╙ MACHINE FROM. ╫E AREN'T CONCERNED WITH THE BOOTSTRAPPING
CODE, BUT THE IMPORTANT VALUES WE NEED TO OBTAIN FROM THE BOOT SECTOR ARE:
┴┬┬╥ ╧╞╞╙┼╘ 1571 1581 ─┼╙├╥╔╨╘╔╧╬
---- ------ ---- ---- -----------
├╙ 13 2 2 ├LUSTER SIZE IN SECTORS
╬┬ 14 1 1 ╬UMBER OF BOOT SECTORS
╬╞ 16 2 2 ╬UMBER OF ╞┴╘S
╞╠ 23 2 3 ╞┴╘ SIZE IN SECTORS
─┼ 17 112 112 ╬UMBER OF ROOT DIRECTORY ENTRIES
╘╙ 19,20 720 1440 ╘OTAL ╬UMBER OF SECTORS
╬╙ 24 9 9 ╬UMBER OF SECTORS PER TRACK
╬╚ 26 2 2 ╬UMBER OF SIDES
╘HE 1571 AND 1581 COLUMNS GIVE THE TYPICAL VALUES OF THESE PARAMETERS FOR
5.25" AND 3.5" DISKS. ╘HE ╧╞╞╙┼╘ IS THE ADDRESS OF THE PARAMETER WITHIN THE
BOOT SECTOR. ╘HE TOTAL NUMBER OF SECTORS IS GIVEN IN LOW-BYTE, HIGH-BYTE
ORDER (SINCE THE 80X86 FAMILY IS LITTLE-ENDIAN LIKE THE 6502 FAMILY). ╞ROM
THE ABOVE PARAMETERS, WE CAN DERIVE THE FOLLOWING IMPORTANT PARAMETERS:
┴┬┬╥ ╞╧╥═╒╠┴ 1571 1581 ─┼╙├╥╔╨╘╔╧╬
---- ------- ---- ---- -----------
╞1 ╬┬+╬╞*╞╠ 5 7 ╞IRST ROOT DIRECTORY SECTOR
╞╙ ╬┬+╬╞*╞╠+─┼ 12 14 ╞IRST FILE DATA SECTOR NUMBER
╬├ (╘╙-╞╙)/├╙ 354 713 ╘OTAL NUMBER OF FILE CLUSTERS
╠╥╥ IMPOSES A NUMBER OF LIMITS ON THESE PARAMETERS AND WILL ERROR-OUT IF YOU
TRY TO USE A DISK THAT IS OUTSIDE OF ╠╥╥'S LIMITS.
3.2. ├╚┼╫╔╬╟ ╘╚┼ ╞┴╘
═╙-─╧╙ DISKS USE A DATA STRUCTURE CALLED A ╞ILE ┴LLOCATION ╘ABLE (╞┴╘) TO
RECORD WHICH CLUSTERS BELONG TO WHICH FILE IN WHAT ORDER AND WHICH BLOCKS ARE
FREE. ┴ CLUSTER IS A SET OF CONTIGUOUS SECTORS WHICH ARE ALLOCATED TO FILES
AS A GROUP. ╠╥╥ HANDLES CLUSTER SIZES OF 1 AND 2 SECTORS, GIVING A LOGICAL
FILE BLOCK SIZE OF 512 OR 1024 BYTES. ╘YPICALLY, A CLUSTER SIZE OF 2 SECTORS
IS USED.
╘HE ╞┴╘ IS AN ARRAY OF 12-BIT NUMBERS, WITH AN ENTRY CORRESPONDING TO EACH
CLUSTER THAT CAN BE ALLOCATED TO FILES. ╞┴╘ ENTRIES 0 AND 1 ARE RESERVED. ╔F
A ╞┴╘ ENTRY CONTAINS A VALUE OF $000, THEN THE CORRESPONDING CLUSTER IS FREE
AND CAN BE ALLOCATED TO A FILE; OTHERWISE, THE CLUSTER IS ALLOCATED AND THE
╞┴╘ ENTRY CONTAINS THE NUMBER OF THE ╬┼╪╘ ╞┴╘ ENTRY THAT BELONGS TO THE FILE.
╘HUS, ═╙-─╧╙ FILES ARE STORED IN A SINGLY-LINKED LIST OF CLUSTERS LIKE
├OMMODORE-─╧╙ FILES ARE, EXCEPT THAT THE LINKS ARE NOT IN THE DATA SECTORS BUT
RATHER ARE IN THE ╞┴╘. ╘HE POINTER TO THE FIRST ╞┴╘ ENTRY FOR A FILE IS GIVEN
IN THE FILE'S DIRECTORY ENTRY.
┴ SPECIAL ╬╒╠╠/╬╔╠ POINTER VALUE OF $╞╞╞ IS USED TO INDICATE THE END OF THE
CHAIN OF CLUSTERS ALLOCATED TO A FILE. ╘HIS VALUE IS STORED IN THE ╞┴╘ ENTRY
OF THE LAST CLUSTER ALLOCATED TO A FILE (OF COURSE). ├ONSIDER THE FOLLOWING
EXAMPLE ╞┴╘:
┼╬╘╥┘ ╓┴╠╒┼
----- -----
$000 $╞╞╞
$001 $╞╞╞
$002 ⁿ----$003 <------─IRECTORY ┼NTRY
$003 +--> $005----+
$004 $000 ⁿ
$005 $╞╞╞ <--+
┼NTRIES 0 AND 1 ARE INSIGNIFICANT SINCE THEY ARE RESERVED. ╙AY THAT A FILE
STARTS AT ╞┴╘ ENTRY #2. ╘HEN, IT CONSISTS OF THE FOLLOWING CHAIN OF CLUSTERS:
2, 3, AND 5. ├LUSTER #4 IS FREE. ├LUSTERS CAN BE ALLOCATED TO A FILE IN
RANDOM ORDER, BUT IF THEY ARE ALLOCATED CONTIGUOUSLY IN FORWARD ORDER, THEN
THE FILE WILL BE ABLE TO BE READ FASTER. ╘HE ╞┴╘ IS SUCH AN IMPORTANT DATA
STRUCTURE THAT TYPICALLY TWO COPIES ARE KEPT ON THE DISK INCASE ONE OF THEM
SHOULD BECOME CORRUPTED.
╘HE ═╙-─╧╙ DESIGNERS WERE A LITTLE SNEAKY IN STORING THE 12-BIT ╞┴╘ ENTRIES -
THEY USED ONLY 12 REAL BITS PER ENTRY. ╔E., THEY STORE TWO ╞┴╘ ENTRIES IN
THREE BYTES, WHERE THE TWO ENTRIES SHARE THE TWO NYBBLES OF THE MIDDLE BYTE.
╘HE FOLLOWING DIAGRAM SHOWS HOW THE NYBBLES 1 (HIGH), 2 (MID), AND 3 (LOW) ARE
STORED INTO ╞┴╘ ENTRIES ┴ AND ┬:
┬┘╘┼: 0 1 2
+---+---+ +---+---+ +---+---+
┼╬╘╥┘: ⁿ ┴ ⁿ ┴ ⁿ ⁿ ┬ ⁿ ┴ ⁿ ⁿ ┬ ⁿ ┬ ⁿ
╬┘┬┬╠┼: ⁿ 2 ⁿ 3 ⁿ ⁿ 3 ⁿ 1 ⁿ ⁿ 1 ⁿ 2 ⁿ
+---+---+ +---+---+ +---+---+
┴NYWAY, LET'S JUST SAY IT'S A BIT TRICKY TO EXTRACT THE 12-BIT VALUES FROM
THIS COMPRESSED DATA STRUCTURE. ╧N TOP OF THAT, ╔ DON'T THINK THERE IS ANY
SAVING IN DISK SPACE RESULTING FROM COMPRESSING THIS STRUCTURE; THEY MIGHT AS
WELL HAVE JUST USED A 16-BIT ╞┴╘ (LIKE THEY DO NOWADAYS ON LARGER DISKS).
3.3. ╘╚┼ ╥╧╧╘ ─╔╥┼├╘╧╥┘
╘HE ROOT DIRECTORY HAS A FIXED SIZE, ALTHOUGH ╔ DON'T THINK THAT
SUBDIRECTORIES DO. ╠╥╥ CANNOT ACCESS SUBDIRECTORIES. ┼ACH 512-BYTE SECTOR OF
THE ROOT DIRECTORY CONTAINS SIXTEEN 32-BYTE DIRECTORY ENTRIES. ╧NE DIRECTORY
ENTRY IS REQUIRED FOR EACH FILE STORED ON THE DISK. ┴ DIRECTORY ENTRY HAS THE
FOLLOWING STRUCTURE:
╧╞╞╙┼╘ ╠┼╬ ─┼╙├╥╔╨╘╔╧╬
------ --- -----------
0..7 8 ╞ILENAME
8..10 3 ┼XTENSION
11 1 <UNUSED?>
12 1 ┴TTRIBUTES: $10=─IRECTORY, $08=╓OLUME╔D
13..21 9 <UNUSED>
22..25 4 ─ATE
26..27 2 ╙TARTING ╞┴╘ ENTRY NUMBER
28..31 4 ╞ILE LENGTH IN BYTES
╘HE FILENAME AND EXTENSION ARE STORED WITH TRAILING PADDING SPACES. ╔F A
DIRECTORY ENTRY IS UNUSED OR DELETED, THEN THE FIRST CHARACTER OF THE FILENAME
IS EITHER A $00 OR A $┼5 (229). ╘HIS IS WHY YOU HAVE TO PROVIDE THE FIRST
CHARACTER OF A FILENAME IF YOU ARE UNDELETING A FILE ON AN ═╙-─╧╙ MACHINE.
╬OTE THAT THERE IS ENOUGH UNUSED SPACE THAT ═ICROSOFT OR ╔┬═ COULD HAVE
DITCHED THE ANNOYING 8+3 CHARACTER FILENAME FORMAT.
╘HE ATTRIBUTES BITS TELL WHETHER THE DIRECTORY ENTRY IS FOR A REGULAR FILE, A
SUBDIRECTORY, A DISK VOLUME NAME (IN WHICH CASE THERE IS NO FILE DATA), AND A
COUPLE OF OTHER THINGS ╔ CAN'T REMEMBER. ╔'M NOT SURE ABOUT THE EXACT
POSITION OR FORMAT OF THE DATE, BUT ╠╥╥ DOESN'T USE IT ANYWAY. ╘HE STARTING
╞┴╘ ENTRY NUMBER AND THE FILE LENGTH ARE STORED IN LOWER-BYTE-FIRST ORDER.
3.4. ╘╚┼ ╞╔╠┼ ─┴╘┴ ╙╨┴├┼
╘HE RAMAINDER OF THE DISK SPACE IS USED FOR STORING FILE DATA IN CLUSTERS OF 1
OR 2 SECTORS EACH. ╟IVEN A CLUSTER NUMBER (WHICH IS ALSO THE ╞┴╘ ENTRY
NUMBER), THE FOLLOWING FORMULA IS USED TO CALCULATE THE STARTING LOGICAL
SECTOR NUMBER OF THE CLUSTER:
(├LUSTER╬UMBER - 2) * ├LUSTER╙IZE╔N┬LOCKS + ╞IRST╞ILE─ATA╠OGICAL╙ECTOR╬UMBER
WHERE "╞IRST╞ILE─ATA╠OGICAL╙ECTOR╬UMBER" IS THE "╞╙" PARAMETER DERIVED
EARLIER. ╘HE FOLLOWING CONSECUTIVE LOGICAL SECTOR NUMBERS UP TO THE NUMBER OF
SECTORS PER CLUSTER FORM THE REST OF THE CLUSTER. ╬OTE THAT A SINGLE CLUSTER
CAN SPAN SECTORS FROM ONE SIDE OF THE DISK TO ANOTHER OR FROM ONE TRACK TO
ANOTHER. ╫E PERFORM THE "(├LUSTER╬UMBER - 2)" PORTION OF THE CALCULATION
SINCE THE FIRST TWO ╞┴╘ ENTRIES ARE RESERVED.
╙INCE THE ╥EAD BURST COMMAND OF THE 1571/81 WANTS THE SIDE, TRACK, AND SECTOR
NUMBER OF A SECTOR RATHER THAN ITS LOGICAL NUMBER, WE ALSO NEED FORMULAE FOR
THESE CONVERSIONS:
╘RACK = ╠OGICAL╙ECTOR╬UMBER / 18
╙ECTOR = ╠OGICAL╙ECTOR╬UMBER % 9 + 1
╙IDE = (╠OGICAL╙ECTOR╬UMBER / 9) % 2
╘HESE FORMULAE ARE MORE PROBLEMATIC THAN THE PREVIOUS ONE SINCE THEY REQUIRE
DIVISION BY 9 AND 18. ╠╥╥ USES THE METHOD OF REPEATED SUBTRACTION TO PERFROM
THE NECESSARY DIVISION (ONLY ONE DIVISION IS NECESSARY). ╘HE ABOVE FORMULAE
IMPLY THAT SEQUENTIAL LOGICAL SECTORS ARE STORED ON THE TOP OF THE DISK
FIRST AND THEN THE BOTTOM OF THE DISK OF THE SAME TRACK, AND THEN ON THE TOP
OF THE NEXT TRACK, ETC. ╘HIS IS A GOOD SECTOR NUMBERING SCHEME (UNLIKE THE
├┬═-─╧╙ SCHEME FOR 1571 SECTORS) SINCE IT IS FASTER TO SWITCH SIDES OF THE
DISK THAN IT IS TO SWITCH TRACKS, SO YOU CAN READ THE DISK FASTER.
╧H YEAH, THE WAY THAT YOU KNOW HOW MANY FILE DATA BYTES ARE IN THE LAST
CLUSTER OF A FILE CHAIN (THE CLUSTER WITH THE ╬╒╠╠ ╞┴╘ ENTRY) IS TO TAKE THE
FILE LENGTH FROM THE DIRECTORY ENTRY AND "MOD" (THE ├ LANGUAGE % OPERATOR) IT
WITH THE CLUSTER SIZE. ╧NE SPECIAL CASE IS IF THIS CALCULATION RESULTS IN A
ZERO, THEN THE LAST CLUSTER IS COMPLETELY FULL (RATHER THAN COMPLETELY EMPTY
AS THE CALCULATION WOULD SUGGEST). ╘HIS CALCULATION IS EASILY DONE IN
MACHINE LANGUAGE WITH AN ┴╬─ OPERATION SINCE THE CLUSTER SIZE IS ALWAYS A
POWER OF TWO.
4. ╞╔╠┼ ├╧╨┘╔╬╟ ╨┴├╦┴╟┼
╘HIS SECTION DISCUSSES THE INTERFACE TO AND IMPLEMENTATION OF THE ═╙-─╧╙ FILE
COPYING PACKAGE. ╔T IS WRITTEN IN ASSEMBLY LANGUAGE AND IS LOADED INTO MEMORY
AT ADDRESS $8000 ON BANK 0 AND REQUIRES ABOUT 13╦ OF MEMORY. ╘HE PACKAGE IS
LOADED AT THIS HIGH ADDRESS TO BE OUT OF THE WAY OF THE MAIN ┬┴╙╔├ PROGRAM,
EVEN IF ╥┴═─╧╙ IS INSTALLED.
4.1. ╔╬╘┼╥╞┴├┼
╘HE SUBROUTINE CALL AND PARAMETER PASSING INTERFACE TO THE FILE COPYING
PACKAGE IS SUMMARIZED AS FOLLOWS:
┴──╥┼╙╙ ─┼╙├╥╔╨╘╔╧╬
------- -----------
╨╦ ╔NIT╨ACKAGE SUBROUTINE
╨╦+3 ╠OAD─IRECTORY SUBROUTINE
╨╦+6 ├OPY╞ILE SUBROUTINE
╨╦+9 TWO-BYTE PACKAGE IDENTIFICATION NUMBER
╨╦+15 ERRNO : ERROR CODE RETURNED
╨╦+16 ═╙-─╧╙ DEVICE NUMBER (8 TO 30)
╨╦+17 ═╙-─╧╙ DEVICE TYPE ($00=1571, $╞╞=1581)
╨╦+18 TWO-BYTE STARTING CLUSTER NUMBER FOR FILE COPYING
╨╦+20 LOW AND MID BYTES OF FILE LENGTH FOR COPYING
WHERE "╨╦" IS THE LOAD ADDRESS OF THE PACKAGE. ┴DDITIONAL SUBROUTINE
PARAMETERS ARE PASSED IN THE PROCESSOR REGISTERS.
╘HE "╔NIT╨ACKAGE" SUBROUTINE SHOULD BE CALLED WHEN THE PACKAGE IS FIRST
INSTALLED, WHENEVER THE ═╙-─╧╙ DEVICE NUMBER IS CHANGED, AND WHENEVER A NEW
DISK IS MOUNTED TO INVALIDATE THE INTERNAL TRACK CACHE. ╔T REQUIRES NO
PARAMETERS.
╘HE "╠OAD─IRECTORY" SUBROUTINE WILL LOAD THE DIRECTORY, ╞┴╘, AND THE ┬OOT
╙ECTOR PARAMETERS INTO THE INTERNAL MEMORY OF THE PACKAGE FROM THE CURRENT
═╙-─╧╙ DEVICE NUMBER. ╬O (OTHER) INPUT PARAMETERS ARE NEEDED AND THE
SUBROUTINE RETURNS A POINTER TO THE DIRECTORY SPACE IN THE .┴┘ REGISTERS AND
THE NUMBER OF DIRECTORY ENTRIES IN THE .╪ REGISTER. ╔F AN ERROR OCCURS, THEN
THE SUBROUTINE RETURNS WITH THE ├ARRY FLAG SET AND THE ERROR CODE IS AVAILABLE
IN THE "ERRNO" INTERFACE VARIABLE. ╘HE DIRECTORY ENTRY DATA IS IN THE
DIRECTORY SPACE AS IT WAS READ IN RAW FROM THE DIRECTORY SECTORS ON THE ═╙-─╧╙
DISK.
╘HE "├OPY╞ILE" SUBROUTINE WILL COPY A SINGLE FILE FROM THE ═╙-─╧╙ DISK TO A
SPECIFIED ├┬═-╦ERNAL LOGICAL FILE NUMBER (THE ├┬═ FILE MUST ALREADY BE
OPENED). ╔F THE ├┬═ LOGICAL FILE NUMBER IS ZERO, THEN THE FILE DATA IS SIMPLY
DISCARDED AFTER IT IS READ FROM THE ═╙-─╧╙ FILE. ╘HE STARTING CLUSTER NUMBER
OF THE FILE TO COPY AND THE LOW AND MID BYTES OF THE FILE LENGTH ARE PASSED IN
THE ╨╦+18 AND ╨╦+20 INTERFACE WORDS. ╘HE TRANSLATION MODE TO USE IS PASSED IN
THE .┴ REGISTER ($00=BINARY, $╞╞=ASCII) AND THE ├┬═ LOGICAL FILE NUMBER TO
OUTPUT TO IS PASSED IN THE .╪ REGISTER. ╔F AN ERROR OCCURS, THE ROUTINE
RETURNS WITH THE ├ARRY FLAG SET AND THE ERROR CODE IN THE "ERRNO" INTERFACE
VARIABLE. ╘HERE ARE NO OTHER OUTPUT PARAMETERS.
╬OTE THAT SINCE THE STARTING CLUSTER NUMBER AND LOW-FILE LENGTH OF THE FILE TO
BE COPIED ARE REQUIRED RATHER THAN THE FILENAME, IT IS THE RESPONSIBILITY OF
THE FRONT-END APPLICATION PROGRAM TO DIG THROUGH THE RAW DIRECTORY SECTOR DATA
TO GET THIS INFORMATION. ╘HE APPLICATION MUST ALSO OPEN THE ├OMMODORE-─╧╙
FILE OF WHATEVER FILETYPE ON WHATEVER DEVICE IS REQUIRED; THE PACKAGE DOES NOT
NEED TO KNOW THE ├OMMODORE-─╧╙ DEVICE NUMBER.
╘HE ═╙-─╧╙ DEVICE NUMBER AND DEVICE TYPE INTERFACE VARIABLES ALLOW YOU TO SET
THE ═╙-─╧╙ DRIVE AND THE PACKAGE IDENTIFICATION NUMBER ALLOWS THE APPLICATION
PROGRAM TO CHECK IF THE PACKAGE IS ALREADY LOADED INTO MEMORY SO THAT IT ONLY
HAS TO LOAD THE PACKAGE THE FIRST TIME THE APPLICATION IS RUN AND NOT ON
RE-RUNS. ╘HE IDENTIFICATION SEQUENCE IS A VALUE OF $├┬ FOLLOWED BY A VALUE
OF 131.
4.2. ╔═╨╠┼═┼╬╘┴╘╔╧╬
╘HIS SECTION PRESENTS THE CODE THAT IMPLEMENTS THE ═╙-─╧╙ FILE READING
PACKAGE. ╔T IS HERE IN A SPECIAL FORM; EACH CODE LINE IS PRECEDED BY A FEW
SPECIAL CHARACTERS AND THE LINE NUMBER. ╘HE SPECIAL CHARACTERS ARE THERE TO
ALLOW YOU TO EASILY EXTRACT THE ASSEMBLER CODE FROM THE REST OF THIS MAGAZINE
(AND ALL OF MY UGLY COMMENTS). ╧N A ╒NIX SYSTEM, ALL YOU HAVE TO DO IS
EXECUTE THE FOLLOWING COMMAND LINE (SUBSTITUTE FILENAMES AS APPROPRIATE):
GREP '^\.%...\!' ╚ACK4 ⁿ SED 'S/^.%...\!..//' ⁿ SED 'S/.%...\!//' >LRR.S
┘OU'LL NOTICE THAT THE INITIAL COMMENT LINES HERE WERE AN AFTERTHOUGHT.
.%000! ;╠ITTLE ╥ED ╥EADER ═╙-─╧╙ FILE COPIER PROGRAM
.%000! ;WRITTEN 92/10/03 BY ├RAIG ┬RUCE FOR ├= ╚ACKING ╬ET ═AGAZINE
.%000!
╘HE CODE IS WRITTEN FOR THE ┬UDDY ASSEMBLER AND HERE ARE A COUPLE SETUP
DIRECTIVES. ╬OTE THAT MY COMMENTS COME BEFORE THE SECTION OF CODE.
.%001! .ORG $8000
.%002! .OBJ "@:LRR.BIN"
.%003!
.%004! ;====JUMP TABLE AND PARAMETERS INTERFACE ====
.%005!
.%006! JMP INIT╨ACKAGE
.%007! JMP LOAD─IRECTORY
.%008! JMP COPY╞ILE
.%009!
.%010! .BYTE $CB,131 ;IDENTIFICATION
.%011! .BYTE 0,0,0,0
.%012!
╘HESE VARIABLES ARE INCLUDED IN THE PACKAGE PROGRAM SPACE TO MINIMIZE UNWANTED
INTERACTION WITH OTHER PROGRAMS LOADED AT THE SAME TIME, SUCH AS THE ╥┴═─╧╙
DEVICE DRIVER.
.%013! ERRNO .BUF 1 ;(LOCATION PK+15)
.%014! SOURCE─EVICE .BUF 1
.%015! SOURCE╘YPE .BUF 1 ;$00=1571, $FF=1581
.%016! START├LUSTER .BUF 2
.%017! LEN═╠ .BUF 2 ;LENGTH MEDIUM AND LOW BYTES
.%018!
.%019! ;====GLOBAL DECLARAIONS====
.%020!
.%021! KERNEL╠ISTEN = $FFB1
.%022! KERNEL╙ECOND = $FF93
.%023! KERNEL╒NLSN = $FFAE
.%024! KERNEL┴CPTR = $FFA2
.%025! KERNEL├IOUT = $FFA8
.%026! KERNEL╙PINP = $FF47
.%027! KERNEL├HKOUT = $FFC9
.%028! KERNEL├LRCHN = $FFCC
.%029! KERNEL├HROUT = $FFD2
.%030!
.%031! ST = $D0
.%032! CIA├LOCK = $DD00
.%033! CIA╞LAGS = $DC0D
.%034! CIA─ATA = $DC0C
.%035!
╘HESE ARE THE PARAMETERS AND DERIVED PARAMETERS FROM THE BOOT SECTOR. ╘HEY
ARE KEPT IN THE PROGRAM SPACE TO AVOID INTERACTIONS.
.%036! CLUSTER┬LOCK├OUNT .BUF 1 ;1 OR 2
.%037! FAT┬LOCKS .BUF 1 ;UP TO 3
.%038! ROOT─IR┬LOCKS .BUF 1 ;UP TO 8
.%039! ROOT─IR┼NTRIES .BUF 1 ;UP TO 128
.%040! TOTAL╙ECTORS .BUF 2 ;UP TO 1440
.%041! FIRST╞ILE┬LOCK .BUF 1
.%042! FIRST╥OOT─IR┬LOCK .BUF 1
.%043! FILE├LUSTER├OUNT .BUF 2
.%044!
╘HE CYLINDER (TRACK) AND SIDE THAT IS CURRENTLY STORED IN THE TRACH CACHE.
.%045! BUF├YLINDER .BUF 1
.%046! BUF╙IDE .BUF 1
.%047! FORMAT╨ARMS .BUF 6
.%048!
╘HIS PACKAGE IS SPLIT INTO A NUMBER OF LEVELS. ╘HIS LEVEL INTERFACES WITH THE
╦ERNAL SERIAL BUS ROUTINES AND THE BURST COMMAND PROTOCOL OF THE DISK DRIVES.
.%049! ;====HARDWARE LEVEL====
.%050!
├ONNECT TO THE ═╙-─╧╙ DEVICE AND SEND THE "╒0" BURST COMMAND PREFIX AND THE
BURST COMMAND BYTE.
.%051! SEND╒0 = * ;( .┴=BURST├OMMAND├ODE ) : .├╙=ERR
.%052! PHA
.%053! LDA #0
.%054! STA ST
.%055! LDA SOURCE─EVICE
.%056! JSR KERNEL╠ISTEN
.%057! LDA #$6F
.%058! JSR KERNEL╙ECOND
.%059! LDA #"U"
.%060! JSR KERNEL├IOUT
.%061! BIT ST
.%062! BMI SEND╒0┼RROR
.%063! LDA #"0"
.%064! JSR KERNEL├IOUT
.%065! PLA
.%066! JSR KERNEL├IOUT
.%067! BIT ST
.%068! BMI SEND╒0┼RROR
.%069! CLC
.%070! RTS
.%071!
.%072! SEND╒0┼RROR = *
.%073! LDA #5
.%074! STA ERRNO
.%075! SEC
.%076! RTS
.%077!
╘OGGLE THE "─ATA ┴CCEPTED / ╥EADY ╞OR ═ORE" CLOCK SIGNAL FOR THE BURST
TRANSFER PROTOCOL.
.%078! TOGGLE├LOCK = *
.%079! LDA CIA├LOCK
.%080! EOR #$10
.%081! STA CIA├LOCK
.%082! RTS
.%083!
╫AIT FOR A BURST BYTE TO ARRIVE IN THE SERIAL DATA REGISTER OF ├╔┴#1 FROM THE
FAST SERIAL BUS.
.%084! SERIAL╫AIT = *
.%085! LDA #$08
.%086! - BIT CIA╞LAGS
.%087! BEQ -
.%088! RTS
.%089!
╫AIT FOR AND GET A BURST BYTE FROM THE FAST SERIAL BUS, AND SEND THE "─ATA
┴CCEPTED" SIGNAL.
.%090! GET┬URST┬YTE = *
.%091! JSR SERIAL╫AIT
.%092! LDX CIA─ATA
.%093! JSR TOGGLE├LOCK
.%094! TXA
.%095! RTS
.%096!
╙END THE BURST COMMANDS TO "LOG IN" THE ═╙-─╧╙ DISK AND SET THE ╥EAD SECTOR
INTERLEAVE FACTOR.
.%097! MOUNT─ISK = * ;() : .├╙=ERR
.%098! LDA #%00011010
.%099! JSR SEND╒0
.%100! BCC +
.%101! RTS
.%102! + JSR KERNEL╒NLSN
.%103! BIT ST
.%104! BMI SEND╒0┼RROR
.%105! CLC
.%106! JSR KERNEL╙PINP
.%107! BIT CIA╞LAGS
.%108! JSR TOGGLE├LOCK
.%109! JSR GET┬URST┬YTE
.%110! STA ERRNO
.%111! AND #$0F
.%112! CMP #2
.%113! BCS MOUNT┼XIT
╟RAB THE THROW-AWAY PARAMETERS FROM THE MOUNT OPERATION.
.%114! LDY #0
.%115! - JSR GET┬URST┬YTE
.%116! STA FORMAT╨ARMS,Y
.%117! INY
.%118! CPY #6
.%119! BCC -
.%120! CLC
╙ET THE SECTOR INTERLEAVE TO 1 FOR A 1581 OR 4 FOR A 1571.
.%121! ;** SET INTERLEAVE
.%122! LDA #%00001000
.%123! JSR SEND╒0
.%124! BCC +
--
- ├RAIG ╘AYLOR ⁿⁿ ╙TANDARD ─ISCLAIMER ┴PPLIES (OF COURSE!)
DUCK@PEMBVAX1.PEMBROKE.EDU (╨EMBROKE ╙TATE ╒NIVERSITY)
╧REGON, N.:
┼IGHTY BILLION GALLONS OF WATER WITH NO PLACE TO GO ON ╙ATURDAY
NIGHT.
┼ND OF ╞ILE, ╨RESS ╥┼╘╒╥╬ TO QUIT
┴RTICLE #10125 (10178 IS LAST):
╞ROM: DUCK@PEMBVAX1.PEMBROKE.EDU
╬EWSGROUPS: COMP.SYS.CBM
╙UBJECT: ├OMMODORE ╚ACKING ╔SSUE #4 5/5
─ATE: ═ON ╧CT 5 10:03:18 1992
.%708! CLUSTER┬UF = TRACKBUF+4608
.%709! FATBUF = CLUSTER┬UF+1024
.%710! DIRBUF = FATBUF+1536
.%711! END = DIRBUF+4096
5. ╒╙┼╥-╔╬╘┼╥╞┴├┼ ╨╥╧╟╥┴═
╘HIS SECTION PRESENTS THE LISTING OF THE USER-INTERFACE ┬┴╙╔├ PROGRAM. ┘OU
SHOULD BE AWARE THAT YOU CAN EASILY CHANGE SOME OF THE DEFAULTS TO YOUR OWN
PREFERENCES IF YOU WISH. ╘HIS PROGRAM IS NOT LISTED IN THE ".%NNN!" FORMAT
THAT THE ASSEMBLER LISTING IS SINCE YOU CAN RECOVER THIS LISTING FROM THE
UUENCODED BINARY PROGRAM FILE. ╘HIS PROGRAM SHOULD BE A LITTLE EASIER TO
FOLLOW THAN THE ASSEMBLER LISTING SINCE ┬┴╙╔├ IS A SELF-COMMENTING LANGUAGE. :-)
10 REM LITTLE RED READER, BY CRAIG BRUCE, 30-SEP-92, FOR C= HACKING NETMAG
11 :
╘HESE LINES SET UP THE DEFAULT ├┬═-─╧╙ AND ═╙-─╧╙ DEVICE NUMBERS, TAKING CARE
TO DISALLOW THEM TO BE THE SAME DEVICE. ┘OU CAN CHANGE THIS TO YOUR OWN DRIVE
CONFIGURATION.
20 CD=PEEK(186) : REM ** DEFAULT CBM-DOS DRIVE **
25 DV=9:DT=0 : REM ** MS-DOS DRIVE, TYPE (0=1571,255=1581)
26 IF DV=CD THEN DV=8:DT=0 : REM ** ALTERNATE MS-DOS DRIVE
27 :
30 PRINT CHR$(147);"INITIALIZING..." : PRINT
40 BANK0 : PK=DEC("8000")
50 IF PEEK(PK+9)=DEC("CB") AND PEEK(PK+10)=131 THEN 60
55 PRINT"LOADING MACHINE LANGUAGE ROUTINES..." : BLOAD"LRR.BIN",U(CD)
60 POKE PK+16,DV : POKE PK+17,DT : SYS PK
╔ "DIM" THE FOLLOWING VARIABLES BEFORE THE ARRAYS TO AVOID THE OVERHEAD OF
PUSHING THE ARRAYS AROUND WHEN CREATING NEW SCALAR VARIABLES.
70 DIM T,R,B,I,A$,C,DT$,FL$,IL$,X,X$
80 DIM DI$(128),CL(128),SZ(128)
90 IF DT=255 THEN DT$="1581" :ELSE DT$="1571"
100 FL$=CHR$(19)+CHR$(17)+CHR$(17)+CHR$(17)+CHR$(17)
110 IL$=FL$:FORI=1TO19:IL$=IL$+CHR$(17):NEXT
120 GOTO 500
130 :
131 REM ** LOAD MS-DOS DIRECTORY **
140 PRINT"LOADING DIRECTORY..." : PRINT
150 SYS PK : SYS PK+3
160 DL=0
╘HE "RREG" INSTRUCTION RETURNS THE RETURN VALUES OF THE .┴, .╪, .┘, AND .╙
REGISTERS FROM THE LAST "SYS" CALL. ╔ CHECK THE 1-BIT OF THE .╙ REGISTER
(THE ├ARRY FLAG) FOR ERROR RETURNS.
170 RREG BL,DC,BH,S : E=PEEK(PK+15)
180 IF (S AND 1) THEN GOSUB 380 : RETURN
190 PRINT"SCANNING DIRECTORY..." : PRINT
200 DB=BL+256*BH
210 IF DC=0 THEN 360
220 FOR DP=DB TO DB+32*(DC-1) STEP 32
230 IF PEEK(DP)=0 OR PEEK(DP)=229 THEN 350
240 IF PEEK(DP+12) AND 24 THEN 350
250 DL=DL+1
╘HIS NEXT LINE IS WHERE ╔ SET THE DEFAULT SELECTION STATUS, TRANSLATION TYPE,
AND ├┬═ FILE TYPE FOR THE ═╙-─╧╙ FILES. ┘OU CAN CHANGE THESE DEFAULTS SIMPLY
BY OVERTYPING THE STRING IN ( ⁿ ⁿⁿⁿ ⁿⁿⁿ ) THE "╓" LOCATIONS.
╓ ╓╓╓ ╓╓╓
260 D$=RIGHT$(" "+STR$(DL),3)+" ASC SEQ " : REM ** DEFAULT SEL/TR/FT **
270 A$="" : FORI=0TO10 : A$=A$+CHR$(PEEK(DP+I)) : NEXT
280 A$=LEFT$(A$,8)+" "+RIGHT$(A$,3)
290 PRINT DL; A$
300 D$=D$+A$+" "
310 CL(DL)=PEEK(DP+26)+256*PEEK(DP+27)
320 SZ=PEEK(DP+28)+256*PEEK(DP+29)+65536*PEEK(DP+30)
330 DI$(DL)=D$+RIGHT$(" "+STR$(SZ),6)
340 SZ(DL)=SZ
350 NEXT DP
360 RETURN
370 :
371 REM ** REPORT MS-DOS DISK ERROR **
380 PRINT CHR$(18);"MS-DOS DISK ERROR #";MID$(STR$(E),2);
390 PRINT " ($";MID$(HEX$(E),3);"), PRESS KEY.";CHR$(146)
400 GETKEY A$ : RETURN
410 :
411 REM ** SCREEN HEADING **
420 PRINTCHR$(147);"MS-DEV=";MID$(STR$(DV),2);" MS-TYPE=";DT$;
430 PRINT" CBM-DEV=";MID$(STR$(CD),2):PRINT
440 RETURN
450 :
451 REM ** SCREEN FOOTING **
460 PRINT IL$;"D=DIRECTORY M=MS-DEV F=CBM-DEV Q=QUIT"
470 PRINT"T=TOGGLE-COLUMN, C=COPY-FILES, +/- PAGE";
480 RETURN
490 :
491 REM ** MAIN ROUTINE **
500 T=1 : C=0
510 R=0
520 GOSUB 420
530 PRINT "NUM S TRN TYP FILENAME EXT LENGTH"
540 PRINT "--- - --- --- -------- --- ------"
550 GOSUB 460
560 B=T+17 : IF B>DL THEN B=DL
570 PRINT FL$;: IF T>DL THEN 590
580 FOR I=T TO B : PRINT DI$(I) : NEXT
590 IF DL=0 THEN PRINT CHR$(18);"<NO FILES>";CHR$(146)
600 IF DL=0 THEN 660
610 PRINT LEFT$(IL$,R+5);CHR$(18);
620 ON C+1 GOTO 630,640,650
630 PRINT SPC(4);MID$(DI$(T+R),5,3) : GOTO 660
640 PRINT SPC(7);MID$(DI$(T+R),8,5) : GOTO 660
650 PRINT SPC(12);MID$(DI$(T+R),13,5) : GOTO 660
660 GETKEY A$