ftp.barnyard.co.uk/2015.02.ftp.barnyard.co.uk.tar/ftp.barnyard.co.uk/cpm/walnut-creek-CDROM/CPM/DISASM/DCOM8048.LBR/DCOM48.TQT/DCOM48.TXT

Text File | 2000-06-30 | 15KB | 401 lines

                            DCOM8048



       áááááDCOM8048á isá a disassembler for 8048, 8049, and 8041 object
       code.  It allowsá theá userá toá insertá labelsá asá wellá asá DB
       statements.á  This disassembler runs in two passes, the first one
       generating a symbol table, and the second oneá doingá theá actual
       disassembly.  It is coded to run on any CP/M system.

       áááááWhená DCOM8048á signsá on,á it displays a menu of all of the
       commands in it's vocabulary.  This is a interactive disassembler,
       that is it it behaves like a monitor, as well as aá disassembler.
       Allá codeá isá treated in DCOM8048 as though it is located at 00H
       in your machines memory, although it is located elsewhere.á  This
       allowsá the user to move code and look at it the same as it would
       be in a assembly listing.

       áááááWe will nowá goá throughá eachá commandá andá giveá aá brief
       explanationá ofá it as well as a example on how to use it.  Note,
       DCOM8048 doesn't overwriteá theá dataá buffer,á soá itá isá still
       intactá ifá itá isá exited,á thená reentered.á  Listed below is a
       listing of the commands DCOM8048 has:

       ááááááááááááááá[1]  Initialized data buffer
       ááááááááááááááá[2]  Read the Program
       ááááááááááááááá[3]  Move memory image to data buffer
       ááááááááááááááá[4]  Adjust buffer end
       ááááááááááááááá[5]  Set starting and Ending addresses
       ááááááááááááááá[6]  Display data buffer
       ááááááááááááááá[7]  Move data in buffer
       ááááááááááááááá[8]  Change data in buffer
       ááááááááááááááá[9]  Clear symbol table
       ááááááááááááááá[10] Read symbol file (.LBL)
       ááááááááááááááá[11] Display symbol table
       ááááááááááááááá[12] Clear DB table
       ááááááááááááááá[13] Read DB table
       ááááááááááááááá[14] Write buffer to file
       ááááááááááááááá[15] Disassemble Program in buffer
       ááááááááááááááá[16] Set output options
       ááááááááááááááá[17] Hex Math
       ááááááááááááááá[18] Exit, go back to CP/M





















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                                   DCOM8048



                          [1]  Initialized data buffer

       áááááThis command allows you to initialize the data buffer to any
       predetermined HEX value.  You caná useá toá initializeá theá data
       bufferá atá theá start of the disassembly to A known value before
       loading the data.

                             [2]  Read the Program

       áááááUse this command to loadá yourá programá intoá theá internal
       buffer.  You will be prompted first for the filename, you need to
       enterá theá filename.ext,á no ambiguous characters are allowed in
       the filename.  The file can be a binary image file, Hexá fileá in
       either ascii or binary format.  After the filename is entered you
       willá beá askedá forá theá type of file you are loading, then you
       will be prompted as to the offset bias, most of the time itá will
       beá "0".á  Theá fileá willá thená beá readá into the buffer, with
       appropriate error messages, if something goes wrong.  If all went
       OK, the entry point as well as the end of theá dataá loadedá will
       beá displayedá to the user.  The buffer pointers will be adjusted
       according to the length of the file, this is automatic andá needs
       no intervention by the user.

                     [3]  Move memory image to data buffer

       áááááThisá commandá is used to move a memory image from somewhere
       in your machine to the data buffer.  The reason for this isá that
       theá promá programerá mayá haveá read it into a address that DCOM
       doesn't know about.  Currently all memory from 0 to 385BH is used
       by DCOM, with the buffer starting at 385BH.  If the data is below
       this point, it will be overwritten when DCOM is startedá up.á  If
       it is above this point, it will be OK.

       áááááWhená the command is entered, the absolute starting point of
       the buffer is displayed (actual address in your machine), withá a
       promptá forá theá starting address (actual memory address in your
       machine) where the code is located.  The last prompt will beá for
       theá absoluteá ending address of the code in your machine.  Note,
       the ending address must be greaterá thená theá startingá address,
       andá youá areá notá allowedá toá moveá dataá fromá theá buffer to
       elsewhere in your machine.  If you need to do this, exit DCOM and
       you will find the data at the buffer starting address.

                             [4]  Adjust buffer end

       áááááUse this command to move the buffer ending addressá iná your
       machine.á  Normally you will not have to use this command, but it
       is included as a convenience.

       áááááWhen this command is invoked, you will be givená theá buffer
       startingá and ending addresses, as well as the maximum address it
       can be set to.  Please note, this is actual memoryá addressesá in
       yourá machine, not addresses referenced by the code that is to be
       disassembled.





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                                   DCOM8048



                     [5]  Set starting and Ending addresses

       áááááThis allows you to set the starting andá endingá addressá of
       theá buffer.á  Theseá addressesá areá relative to the code in the
       buffer, NOT machine addresses.á  Normallyá theá startingá address
       willá beá 00Há and the ending address will be the end of the code
       loaded.  If no code was loaded, the default is 100H

                            [6]  Display data buffer

       áááááUsing this command allowsá youá toá viewá theá dataá iná the
       bufferá iná bothá HEXá andá ASCII formats.  This is useful to see
       ascii data as well as to examine the data iná theá buffer.á  This
       commandá dumpsá theá wholeá buffer,á withá Sá andá Q stopping and
       starting the display.

                            [7]  Move data in buffer

       áááááIf for any reason you need or want to moveá dataá aroundá in
       theá buffer,á thisá isá theá commandá toá use.á  It automatically
       determines which way to move the data, so itá doesn'tá trashá the
       dataá iná theá buffer.á  Ifá you ask it to move the data form the
       wrong place, to the wrong place, or incorrect amount, it willá do
       it, as it does what you said, not what you meant.

       áááááYouá will be prompted for the starting and ending address of
       the data you want to move, thená theá destinationá addressá where
       theá dataá is to be moved to.  This command will not let you move
       data out of the buffer, or move more data then is in theá buffer.

                           [8]  Change data in buffer

       áááááIná orderá toá patch the data in the buffer, you need to use
       this command.  You will be promptedá forá theá startingá address,
       whichá is the address of the data you want to alter.  The address
       will be shown along with the data followedá withá aá dash,á enter
       the new data, then a space to advance to the next location.  If a
       spaceá is entered after the dash, with no data being entered, the
       data in the buffer will remain unchanged.  When you areá finished
       changingá theá data,á enterá aá carriageá return to terminate the
       command.  If you make a mistake in entering the data, reenter the
       data, as only the last 8 bits are used, the rest being discarded.
       This command will not allow you toá alterá dataá outsideá ofá the
       buffer.


                            [9]  Clear symbol table

       áááááThisá commandá isá usedá to clear the internal symbol table,
       that is generated with theá disassemblerá orá readá iná fromá the
       (.LBL) file.








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                                   DCOM8048



                          [10] Read symbol file (.LBL)

       áááááAsá youá progressá withá yourá disassembly, or have a source
       listing, you can enter the labels into a fileá withá yourá editor
       iná theá formatá "Label=XXXX"á where label is the label name, and
       XXXX is the hex value of the address or data value.  Pleaseá note
       theá disassemblerá willá use the first label it encounters in the
       table.  Several labels can be entered on each line of text.á  The
       labelsá theá disassembler generates will be in the form of ABXXXX
       where A will be a "C" for a call reference and a "J" will beá for
       a jmp reference to that label.  The first letter will always be a
       "C"á orá "J",á butá theá secondá will be a "X" unless there was a
       second reference to that labelá thatá isá notá theá sameá asá the
       first.á  What this means it the label will start with "CX", "JX",
       "CJ", or "JC".  The XXXX will be the address thatá theá labelá is
       located at.

       áááááExperiment with your editor and generate several label files
       to get comfortable with this feature.  This file is loaded at the
       time the command is given.

                           [11] Display symbol table

       áááááUseá thisá command to display all the symbols in the buffer.

                              [12] Clear DB table

       áááááUsing your editor set up a file that tells theá disassembler
       to use DB statements in disassembling the file.  Please note that
       theá DBá addressá have to be in ascending order.  This file isn't
       read until the disassembly takes place.  The format for theá file
       isá "XXX-YYY" where XXX is the address that the DB statements are
       to start, and YYY is the ending addressá ofá theá DBá statements.
       You can use as many statements in your file as you like, but keep
       them in ascending order.  You can place each statement on a line,
       or you can place multiple statements on each line.

                               [13] Read DB table

       áááááThisá commandá allows you to specify the filename.ext of the
       DB table information.  All this does is set up theá fileá control
       block, it doesn't do any checking to see if there is a valid file
       oná the disk.  If you enter a invalid file specification, a error
       will be displayed at disassembly time.

                           [14] Write buffer to file

       áááááWhen you finish patching your code, or want toá saveá itá on
       disk,á use this command.  When this command is given, you will be
       prompted for the name of the file you want data to beá savedá in.
       Note:á noá ambiguousá charactersá areá allowed in the filename or
       extension.  After the file is specified, youá willá beá askedá if
       thisá isá aá binaryá image file, if so, the data will be saved in
       binary format.  If it isn't a binary file, you will beá askedá if
       itá isá toá beá writtená in ascii, if the answer is yes, the data
       will




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                                   DCOM8048



       Γe saved in ascii intel hex format, if the answerá isá no,á   the
       dataá willá beá savedá iná a binary hex format (not ascii).  DCOM
       will ask you if a filename exists withá theá sameá name,á doá you
       wantá to erase it?  The choice is yours, but note no backup files
       areá generated.á  Whená theá fileá isá writtená toáá andáá closed
       successfully or if there is a error, you will be notified.

                       [15] Disassemble Program in buffer

       áááááThisá commandá is the core of the program, and automatically
       disassembles all of the data in the buffer.  Itá isá aá twoá pass
       disassembler,á usingá theá symbol and db files you told it to do.
       Ifá youá didn'tá specifyá aá symbolá thatá itá needs,áá itáá will
       automaticallyá generateá one for you, and show it on the listing.

       áááááThis command generatesá 3á differentá outputs,á oneá toá the
       console, one to the printer, and one to the disk.  Each output if
       formattedá forá itsá destination,á withá theá console showing the
       information in a general format, the printer will looká likeá the
       outputá ofá aá assembler,á andá the disk file will be ready for a
       assembler.

                            [16] Set output options

       áááááThis command directs the output toá theá devicesá youá want.
       Youá willá beá askedá if it is to go to the list device, and to a
       disk file.  If a disk file is specified, you willá beá askedá for
       theá nameá ofá theá file, no ambiguous characters please.  If the
       file is already open, you will be asked to close it or flushá it,
       the choice is yours.

                                 [17] Hex Math

       áááááThisá commandá is useful for calculating address offsets and
       jump values.  You will be asked for "value one" and "valueá two",
       DCOMá willá thená display the sum and difference of value one and
       two.  After the calculation, you will be asked if you want toá do
       another calculation, the choice is yours.

                           [18] Exit, go back to CP/M

       áááááThisá is the proper way to exit DCOM and go back to the CP/M
       operating system.

                                     Enjoy

                                   Gil Shultz

       P.S.

       áááááIf any problems occur, you can leaveá meá aá messageá oná my
       BBS.  In order to do this, enter "CHAT D", and this will take you
       to the message handler.  If some enhancements are wanted, you can
       alsoá leaveá aá message.á  I wrote this program in 1982, and have
       decided to put it in the public domain, butá itá cannotá beá used
       for




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                                   DCOM8048



       ßnyá commercialá reason,á norá caná it be sold or used as a sales
       tool.  (C) 4/29/86 By Gil Shultz
                                   The Realm
                                 [phone]
                                 Novi, Michigan






















































       4-26-86                     Page -6-                By Gil Shultz


                                   DCOM8048