ACTION! BUG SHEET #3 - part 2

-------------------------------------

   BUGS IN THE ACTION! CARTRIDGES

The following is a list of all bugs
we currently know exist in the
ACTION! cartridge.  We list these
bugs separately from those in the
RunTime library and/or the PAD disk
or ToolKit, which occur in following
pages.  Each bug is described in
detail and, when possible, bug fixes
are given.  Many of these bugs deal
only with specific versions of
ACTION!.  To find out which version
of ACTION! you own, type the
following from the ACTION! monitor:

  ?$B000 [RETURN]

Below is an actual copy of what
printed following that command for
one of our cartridges.

  45055,$B000 = 0 $0730 48 1840
              ^

To find out the version number, look
at the character to the right of the
equals sign (here printed with a
caret under it).  The "0" in this
case implies that the cartridge is
version 3.0.  If yours has a "6", you
own version 3.6, etc.  As of the date
of this bug sheet, the current
cartridge version is 3.6.

1.  OFFSETS -- Using a TYPE
    declaration will generate a
    spurious error whenever the code
    offset (contents of location $B5)
    is non-zero.

    Affects:  All versions of the
    cartridge to date.  (Presumably
    only noticed if using RunTime
    disk, though.)

    Fix:  Make all TYPE declarations
    before changing the code offset.

    Example:
        ; Beginning of program --
        ; First, declare TYPEs
        TYPE IOCB =
         [
          BYTE Id, Devnum,
               Command, Status
         ]

        ; Then, if desired,
        ; change offset
        SET $B5 = $1000
        ; example: offset=4096

2.  OFFSETS -- Using a code offset
    greater than $7FFF (i.e., a
    negative offset, if you consider
    it to be of type INT) causes the
    compiler to generate improper
    code.

    Affects:  All versions,
    especially when used with the
    RunTime disk.

    Fix:  No direct fix, but you may
    use the relocator program
    described later in this document
    (which is also usable with
    assembly language).

3.  ATARI DOS -- Exiting to Atari DOS
    from ACTION! can cause a system
    crash if DUP.SYS is not present
    on the disk in drive 1.

    Affects:  All versions, but only
    when used with Atari DOS.

    Fix:  Use DOS XL (or be careful
    when exiting to DOS).

4.  ARRAYS AND ELSEIF -- We have just
    learned that there is a
    relatively obscure bug in ACTION!
    related to the use of ELSEIF.  In
    particular, statements similar to
    the form
      ELSEIF a(i) = 0 THEN ...
    (where a is an ARRAY and i is a
    CARD OR INT), or statements like
      ELSEIF p^ = 0 THEN
    (where p is a POINTER) produce
    incorrect code.  

    Affects:  All versions

    Fix:  There is no direct fix at
    this time.  The best way around
    the problem seems to be to code
    something like this:
      t = a(i) ; t is an INTEGER
         ...
      ELSEIF t=0 THEN ...
    This works properly.

5.  WRITING OBJECT FILES -- If a
    monitor Write command fails
    because of a disk error (e.g.,
    disk full, 162, or device done,
    144), the IOCB is not properly
    closed.  If the disk is changed
    before another disk operation is
    performed, the new disk can have
    invalid data written to it.

    Affects:  All versions

    Fix:  If you get an error when
    writing an ACTION! object file,
    type the following command to the
    monitor:
      X Close( 1 ) [RETURN]
    You can then erase the file which
    caused the error.

6.  HEX ARRAY SIZES -- Hexadecimal
    values as array dimensions cause
    incorrect code to be generated.

    Affects:  All versions

    Fix:  Use decimal array
    dimensions.

7.  TYPE POINTER ARGUMENTS --
    PROC/FUNC declarations with
    record pointer arguments other
    than the first don't compile
    correctly.  For example, the
    following code generates an error
    7 (invalid argument list):
      TYPE REC=[...]
         ...
      PROC Test( BYTE x, REC POINTER
    p )

    Affects:  All versions

    Fix:  Omit the comma in the
    argument list for the PROC/FUNC,
    as in:
      PROC Test( BYTE x
              REC POINTER p )

    As this is just a temporary fix,
    it may not work in future
    versions, but the correct
    declaration (with the comma)
    will.

8.  MONITOR LOCKUP -- Typing the
    following command from the
    monitor will lock up the system:
      R* [RETURN]

    Affects:  All versions

    Fix:  Don't do it!  If you do
    type that command, hit [RESET]

9.  PADDLE FUNCTION -- The Paddle
    function does not work properly
    in all versions of the ACTION!
    cartridge.

    Affects:  Versions 3.0 to 3.5

    Fix:  Make the following
    declaration in your program:
      BYTE ARRAY Paddle(4) = 624

10. SOUND ON CHANNELS 3 AND 4 -- If
    you use a Sound() procedure call
    after having done any disk I/O,
    sound channels 3 and 4 will
    remain silent.  This is because
    Atari's OS does not reset some of
    the serial control registers
    completely.

    Affects:  Versions 3.0 to 3.5

    Fix:  Type in and use the
    following procedure.  You should
    call this before doing any
    Sound() calls and/or in place of
    any SndRst() calls:

      ; Contributed by Michael Ross
        PROC SoundOff()
            BYTE AudCtl = $D208,
                 SSKCtl = $232,
                 SKCtl  = $D20F

            SSKCtl = 3
            SKCtl  = 3
            AudCtl = 0
            SndRst()
        RETURN

11. TYPE FIELDS AS PARAMETERS --
    Using fields of TYPEs as
    parameters to PROCs or FUNCs
    generates incorrect code.  For
    example,
      MoveBlock( rec.addr1,
    rec.addr2, length )

    Affects:  Versions 3.0 to 3.5

    Fix:  Assign the TYPE field to a
    temporary variable and pass that
    as a parameter:
      temp1 = rec.addr1
      temp2 = rec.addr2
      MoveBlock(temp1,temp2,length)

12. SASSIGN PROBLEMS -- SAssign does
    not work properly when the source
    string has a length of zero.

    Affects:  Versions 3.0 to 3.5

    Fix:  No fix available at this
    time.

13. CARD FIELDS IN TYPES -- Accessing
    CARD fields of TYPEs generates
    incorrect code.

    Affects:  Versions 3.0 to 3.2

    Fix:  No fix available at this
    time.

14. MOVEBLOCK PROBLEMS -- MoveBlock
    does not move more than 256 bytes
    of data.

    Affects:  Versions 3.0 to 3.2

    Fix:  No fix at this time.  You
    could write an ACTION! routine to
    do the equivalent.

15. CONTROL-SHIFT RETURN -- Using
    [CS] RETURN to split a line into
    two lines generates garbage in
    the second line.

    Affects:  Versions 3.0 and 3.1

    Fix:  No fix available, but not a
    disastrous problem.

16. DIVISION ERRORS -- On old
    cartridges, neither the "/"
    operator nor the "MOD" operator
    works properly under certain
    conditions.

    Affects:  Versions 3.0 and 3.1

    Fix:  Insert the following code
    into your program before any of
    your own PROCedure or FUNCtion
    declarations (this can be done
    easily using INCLUDE):

    ; Copyright (c) 1983 by
    ; Action Computer Services
    ;
    ; Permission is granted to
    ; duplicate and/or distribute
    ; the contents of this file
    ; to ACTION! users.  Copies of
    ; this file may not be sold or
    ; used for monetary gain.

    PROC DivI=*()
    [$20 $A06C $85 $86 $A2 $10
     $26 $82 $26 $83 $26 $86 $26
     $87 $38 $A5 $86 $E5 $84 $A8
     $A5 $87 $E5 $85 $90 $04 $85
     $87 $84 $86 $CA $D0 $E5 $A5
     $82 $2A $26 $83 $A6 $83
     $4C $A032]

    PROC RemI=*()
    [$20 DivI $86A5 $87A6 $60]

    SET $4EA=DivI
    SET $4EC=RemI

17. ERROR ROUTINE NOT INITIALIZED --
    The address of the Error
    PROCedure is not restored by
    ACTION! if a user program has
    changed it.

    Affects:  Versions 3.0 and 3.1

    Fix:  Make sure to restore the
    original Error vector upon
    exiting a program, if you changed
    it.

18. COMPLEX EXPRESSIONS IN UNTIL --
    Complex relational expressions in
    an UNTIL statement generate
    incorrect code.  For example,
      DO
        ...
        UNTIL a>0 AND b=3
      OD

    Affects:  Versions 3.0 and 3.1

    Fix:  Assign the expression to a
    temporary variable and test that
    variable, instead:
      DO
        ...
        temp = a>0 AND b=3
        UNTIL temp
      OD

19. BANK SWITCH BUG -- When loading
    and running compiled ACTION!
    object files from DOS, the system
    can crash when using older
    cartridges.  This is because the
    ACTION! library is not
    accessible.

    Affects:  Version 3.0 only

    Fix:  Put the following program
    lines at the VERY BEGINNING of
    your main procedure (i.e., the
    last procedure in your program):

        BYTE bank = $D500
        ; This declares the variable
        ; 'bank' to reside at $D500.

        bank = 0 ; This must be the
        ; first executable statement.

20. .COM PROGRAMS -- Running compiled
    ACTION! programs as .COM files
    under OS/A+ causes those programs
    to execute twice.

    Affects:  All versions, but only
    when using a version of OS/A+.
    DOS XL is not affected.

    Fix:  Insert the following as the
    first global variable you
    declare:

        BYTE RTS=[$60]
        ; This MUST be the first
        ; line in your program,
        ; aside from comments and
        ; SET commands.

21. PROC ADDRESSING -- Under certain
    conditions, specifying the
    address of a procedure (e.g., to
    interface to a machine code
    routine) causes ACTION! to
    generate incorrect code which
    could cause your program to
    "hang".

    Affects:  Versions 3.1 and 3.4

    Fix:  Insert an empty code block
    after the declaration of a
    procedure whose address is
    specified.  For example:

        PROC CIO = $E456() []
        ; An empty code block!

22. ERROR #3 -- If you get an ERROR 3
    during a compile, the system
    hangs when you return to the
    editor.

    Affects:  All versions

    Fix:  Do not go to the editor
    until you type the following line
    to the monitor.  This command
    resets the ACTION! memory
    pointer.

        SET $E=$491^

23. STRING INPUT -- When using the
    string input library functions
    (InputS, InputSD, and InputMD),
    there must be room in the string
    for the termination EOL, even
    though the resulting string
    length will not include it.

    Affects:  All versions

    Fix:  Adjust your declaration
    appropriately.