
                                                            
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
              PASCAL FOR PDP 11 UNDER RSX/IAS
              ===============================




This document is intended as a supplement to the book Pascal
User  Manual and Report by Jensen and Wirth (Second Edition,
Springer Verlag, 1975). It describes the "Swedish" implemen-
tation of Pascal under the PDP-11 operating systems  RSX-11M
and IAS.
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
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                          Contents
                          --------

    1       Usage of the PASCAL compiler
      1.1     How to compile
      1.2     How to link
      1.3     How to run a PASCAL program
    2       Extensions
      2.1     Character set and special symbols
      2.2     Identifiers
      2.3     The PROGRAM statement
      2.4     Standard constants
      2.5     Standard types
      2.6     Standard files
      2.7     The extended CASE statement
      2.8     The LOOP statement
      2.9     Standard procedures
      2.10    Standard functions
      2.11    Procedures and functions as parameters
      2.12    Separate compilation
      2.13    String parameters
      2.14    Structured function results
      2.15    Boundless array parameters
    3       Restrictions
    4       Compiler options
    5       Representation
    
    
    Appendices
    
    A       Character set
    B       Special symbols
    C       Reserved words
    D       Standard procedures
    E       Standard functions
    F       Error codes
    G       Options and switches
    H       Additional procedures and functions
 
 
 
 
 
 
 
 
 
 
 
 
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1 USAGE OF THE PASCAL COMPILER

Usage under RSX-11M is described. The author is not familiar
with IAS, and therefore IAS procedures are left out.
 
 
1.1 How to compile

The compiler is activated in the standard way:
 
        >PAS <object>,<list>,<gencode> = <source>
 
The   file   specifications   follow   RSX   standard,  i.e.
dev:[p,pn]file.ext/sw. Default values are
 
        dev: SY0:
        [p,pn] fetched from user terminal table
        .ext .OBJ, .LST, .CXP or .PAS respectively

        The default dev: and [p,pn] for the LST and CXP
        files are implied from the specifications on the
        preceeding file specifications.
 
Switches corresponding to  most  so  called  options  (  see
chapter 4 ) can be given. Only one letter is significant, /E
is  equivalent to /EIS. Switches can be negated through - or
NO, ex. /-R or /NORR.

Most switches apply to the object file, only /U (spool)  /LW
(line  width),  /PW (page width) and /W (warnings) should be
placed on the list file specification.

Default values may differ from installation to  installation
since they are chosen at compiler generation time.

Four  switches not corresponding to options exist. /U on the
list file tells whether the file  should  be  spooled  after
compilation or not; default: /-U (no spool). /PW:n and /LW:n
on  the list file can redefine the page and line widths. De-
faults selected at compiler generation time.  /AA:n  defines
which level of predefined identifiers to use (See ch. 4.).
 
        Eg.     PAS  EX,EX/U=EX
                PAS  EX, EX, EX = EX
                PAS  T.OBJ,L=DK1:[200,200]EX2.PAS
                PAS  EX3/AA:1,L=EX3
 
Object and list files are optional.
 
 
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        Eg.     PAS  EX2=EX2
                PAS  ,EX3=EX3
 
 
Four error signals can be generated at this point. All cause
immediate exit from the compiler:
 
        -  FILE NOT FOUND  if there is no file with
           the given name
        -  FILE SPECIFICATION ERROR  if  '=' is not 
           found or if no source filename is given
        -  SWITCH ERROR if an illegal switch is given
        -  ERROR OPENING OUTPUT FILE if an I/O error is
           encountered in creating any of the output files
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
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1.2 How to link Pascal programs

Pascal  programs  are  linked  by the normal linker: TKB (or
FTB). It is used as for all object modules
 
        >TKB <task>,<map>,<symtab>=<object>

The file names are given  as  above,  and  only  the  object
file(s)  are mandatory. Dynamic memory is reserved according
to the compilation report of the main program. If more  sto-
rage is needed, the size of the task can be extended.
 
  Eg.   >TKB
        TKB>EX4,EX4=EX4
        TKB>/
        ENTER OPTIONS:
        TKB>EXTTSK=4000         ; add 4000 words (decimal)
        TKB>//
 
TKB  option  TSKVEC=$P.VEC can be specified. In that case, a
fatal error will also give an octal dump  of  the  heap  and
stacks  of  the task. The dump is done with the PMD facility
if installed.
 
 
 
 
1.3 How to execute a Pascal program
 
The program is activated the ordinary  way:  >RUN  EX4.  The
worskspace  can  be  increased  by  INStall through the /INC
switch.
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
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2 EXTENSIONS

2.1 Character set and special symbols

Many installations have character sets with the bracket sym-
bols replaced with national characters. In order to make  it
easy  to write readable programs it was necessary to allow a
special symbol combination as well. New special symbols are:
 
        (. left bracket
        .) right bracket
        (* start of comment
        *) end of comment
        # <> (* not equal *)
        & and
        ! or
 
 
 
 
2.2 Identifiers
 
Identifiers of up to 10 characters in length are  recognized
distinctively.  Any  characters beyond 10 are ignored. Lower
case characters are treated as upper case.
 
 
 
 
2.3 The PROGRAM statement

A Pascal program must as a first statement have:
 
        PROGRAM <name> <program parameter list>;
 
The first six characters in the program name may be the same
as the first six of a procedure or function.  The  parameter
list  may be empty, or give one or more of INPUT, OUTPUT and
TTY. When a file is mentioned it is equivalent to a declara-
tion of a textfile of the same name. For files not mentioned
no space will be reserved. The file TTY is treated in a spe-
cial way, and is  bound  to  the  user's  terminal  (TI:  in
RSX/IAS).  The  initial state of TTY is eoln(TTY) = true and
no characters automatically input.
 
 
 
 
 
 
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    Eg.
        PROGRAM COPY ( INPUT, OUTPUT );
        PROGRAM DIALOG ( TTY );
        PROGRAM INTROVERT;
 
 
 
 
2.4 Standard constants

For deflevel (/AA) >= 2 some standard constants  are  prede-
clared. The integer constants are defined as
 
        CONST   MAXINT = 077777B (*  32767 *);
                MININT = 100000B (* -32768 *);
                ALFALENG = 10;
 
The real constants are defined as:
 
        CONST   MAXREAL   = 1.7014111E+38;
                MINREAL   = 1.5224277E-39;
                SMALLREAL = 1.1983428E-7;
 
They  represent  the absolutely greatest and smallest reals,
and SMALLREAL is the smallest value that makes 1.0+SMALLREAL
<> 1.0 .
 
 
 
 
2.5 Standard types

For deflevel (/AA) >= 2 the standard  type  TEXT  is  prede-
clared as
 
        TYPE  TEXT = FILE OF CHAR;
 
To  allow  characters  of full ASCII or eightbit code, ASCII
and BYTE are defined as
 
        TYPE ASCII = CHR(0) .. CHR(177B) ;
        TYPE BYTE  = CHR(0) .. CHR(377B) ;
 
For deflevel >= 3 a standard type for RSX/IAS file  handling
is predeclared as
 
        TYPE IOSPEC = (RANDOM,UPDATE,APPEND,TEMPORARY,INSERT,
                        SHARED,SPOOL,BLOCK);
 
 
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It is used in reset/rewrite, see 2.9.4 below.
 
 
 
 
2.6 Standard files

In  addition  to the standard textfiles INPUT and OUTPUT the
standard textfile TTY is available. This  file  is  used  to
communicate  with the user's terminal (TI: of RSX/IAS). This
file can be opened only through the program statement.
 
The specification of TTY in the program  statement  actually
causes  the  declaration  of two textfile variables, TTY and
TTYIN, for terminal output and input respectively.  However,
for  I/O  procedures and functions related to input, the use
of TTY as the file variable will be automatically interpret-
ed as a reference to TTYIN. For example, READ(TTY,X) is  the
same as READ(TTYIN,X).
 
When the file variable is omitted from the parameter list of
standard I/O procedures such as read and write, the standard
files  will be assumed in the following way. For output pro-
cedures, OUTPUT is assumed if present in the program  state-
ment,  otherwise TTY if present; for input procedures, INPUT
is assumed if present in the  program  statement,  otherwise
TTY if present.
 
In  separatly compiled procedures, standard file TTY is ava-
ilable as the default file. Note  that  external  procedures
that  use  TTY  for  I/O can only be used with main programs
that have TTY specified in the program statement.
 
 
 
 
2.7 The extended CASE statement

The CASE statement may be extended with the case OTHERS. The
statement associated with OTHERS will be executed if the ex-
pression of the CASE statement does not evaluate to  one  of
the explicitly given case labels. Syntax:

 
 
 
 
 
 
 
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        <case statement> ::= CASE <expression> OF
             <case element>  { ;<case element> }  END
        <case element> ::= <case label list> : <statement> !
                           <empty>
        <case label list> ::= <case label>  { ,<case label> }  !
                              OTHERS

        Example:
                VAR X: CHAR;
                  ...
                CASE X OF
                  'A':  P(X);
                  'B':  Q(X);
                  ...
                  OTHERS:       Z(X)
                  END;
 
 
 
 
2.8 The LOOP statement

The  LOOP statement is an additional control statement which
combines the effects of WHILE and REPEAT statements. Syntax:

        <loop statement> ::= LOOP
                              <statement part>
                             EXIT IF <expression>;
                              <statement part>
                               END
        <statement part> ::= <statement>  { ;<statement>  }

The expression must result in a Boolean value.
 
 
 
 
2.9 Standard procedures

2.9.1 DATE and TIME

The procedure DATE( <alfa variable> )  assigns  the  current
date  in the format '19yy-mm-dd' to the parameter which must
be of type PACKED ARRAY [1..10] OF CHAR.
 
The procedure TIME( <alfa variable> ) assigns the daytime in
the format 'hh:mm:ss.t' to the parameter which  must  be  of
type PACKED ARRAY [1..10] OF CHAR.
 
 
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2.9.2 MARK and RELEASE

There  is no procedure DISPOSE but the pair MARK and RELEASE
takes care of deallocation when a nested structure is  used.
MARK  puts  a mark in the heap and RELEASE releases all sto-
rage above the topmost mark in the heap. They have no param-
eters, but for compatibility with  the  PASREL  compiler  on
DEC10 they may be called with one (unused) parameter.
 
 
 
 
2.9.3 HALT

The  procedure  HALT  can  be used to help debug Pascal pro-
grams. A call of HALT gives a dump of the  stack  and  heap,
and  exit from the program. The dump is done through the PMD
(Post Mortem Dump) facility if installed.
 
 
 
 
2.9.4 RESET and REWRITE

The standard procedures RESET(f) and  REWRITE(f)  have  been
extended with up to 5 new parameters. These make it possible
to  use  almost all of the RSX/IAS file system, but two pro-
perties are fixed:
   - all files are accessed in locate mode,
   - textfiles ( files of char, ascii or byte ) use  records
     of  variable length with one line per record, all other
     files use records of fixed length.
 
The new call format is:
 
        RESET(f,filename,dir,dev,ioselect) and
        REWRITE(f,filename,dir,dev,ioselect)
 
Only as many parameters as necessary need be  present.  They
must be declared as:
 
   f:      FILE OF <type>;
   
   filename: ARRAY OF CHAR or string constant to give
           an external file name. Examples:
           'SOURCE.PAS','TEXT;3' or  a string
           variable containing 'FILE2.EX     '.
           The length is insignificant. If the name is
 
 
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           shorter than the string, the string must be
           filled with trailing blanks.
 
   dir:    ARRAY OF CHAR or string constant to give
           a file directory. Example:
           '(40,13)','[200,200]'. The parentheses are
           automaticaly translated to brackets. The length
           is insignificant. If the directory name is
           shorter than the string, the string must be
           filled with trailing blanks.
   
   dev:    ARRAY OF CHAR or string constant to give
           device name. Example:  'SY:','LP0:'. The length
           is insignificant. If the device name is
           shorter than the string, the string must be
           filled with trailing blanks.
   
   ioselect: SET OF IOSPEC;
                   IOSPEC is predeclared if DEFLEVEL >= 3.
                   Otherwise it can be declared as
                   TYPE IOSPEC = (RANDOM,UPDATE,APPEND
                   TEMPORARY,INSERT,SHARED,SPOOL,BLOCK);
 
                   The keywords mean (cf RSX/IAS):
 
       RANDOM      the records of the file may be fetched
                   in random order,
       UPDATE      an existing file shall be changed.
       APPEND      an existing file shall be appended,
       TEMPORARY   a temporary file shall be used,
       INSERT      together with UPDATE this condition
                   gives that the file shall not be
                   truncated if written into,
       SHARED      the file is opened  in such a way that
                   other tasks may open it too,
       SPOOL       this textfile shall, when closed,
                   be handed over to the print spooler
                   for printing on the line printer,
       BLOCK       enables blockwise read and write. Only
                   one file element is read or written,
                   even if more than one can be contained
                   in one block. QIO is used directly, so
                   this is not exactly as READ and WRITE
                   of RSX/IAS.
 
 
For  both RESET and REWRITE, f is the only mandatory parame-
ter. The other parameters have default values if left out in
 
 
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a call:
 
       filename: the internal name of the file variable
       dir:    default uic from RSX-11M
       dev:    'SY0:'  ( Selectable at compiler generation )
       iospec: []   the empty set
 
       Example: RESET(F) is equivalent to
                RESET(F,'F',,'SY0:',[])
 
 
 
 
2.9.5 BREAK and PAGE

The procedure PAGE( <textfile> ) inserts a form feed in  the
given file. It may be called without parameter in which case
it  is  assumed to be the standard file OUTPUT if present in
the PROGRAM statement, otherwise TTY if present.

The procedure BREAK can be called  without  a  parameter  or
with  one  textfile  parameter. If no parameter is specified
and TTY is present in the program statement, or if the  file
parameter  is  TTY  then  the current line buffer is written
without carriage return added. Thereby, a later  input  from
TTY  can  be given on the same line. If the file is not TTY,
break is equivalent to writeln.
 
 
 
 
2.9.6 GET and PUT

The standard procedures GET and PUT can take a second param-
eter of type integer. This parameter has effect only if RAN-
DOM or BLOCK was specified when opening the file. In case of
RANDOM, it is the number of the record to be input from  the
file  (GET)  or  written  to the file (PUT). If the file was
opened with BLOCK in ioselect, one file  element  is  trans-
ferred  to  or  from the block with the given number. Notice
that since locate mode is used why it is necessary to locate
a random record with GET before PUT can be used.
 
 
 
 
 
 
 
 
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2.9.7 READ and WRITE

The standard procedures READ and WRITE  are  generalized  to
allow all types of files.
 
READ  is  extended to allow direct read of an array of char-
acters. The array is filled from the current line buffer. If
enough characters are not left in the buffer, spaces are in-
serted.
 
When reading integers or reals, spaces preceding the  number
are  skipped. Trailing spaces are also skipped (but see also
option $H below) until eof or not space, but  for  TTY  only
until eoln or not space.
 
The procedures WRITE and WRITELN have been extended to allow
output of integers in octal representation. The format is:
 
        WRITE (..., I:m:O, K:m,...)
 
where I will be written in octal, K will be written in deci-
mal and m is the minimum field width expression as described
in the user manual.
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
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2.9.8 NEW (on variant records)

When  a NEW is performed to allocate a record that has vari-
ants and if one or more variant selectors  are  supplied  as
parameters  to  NEW  then the corresponding tag field(s), if
any, will be assigned the given selector value(s).
 
 
  Eg.
    type
        Ttyp = (V1,V2,V3);
        smallrectyp = record
            i: integer;
            case b: boolean of
                FALSE: ( j: ... );
                TRUE:  ( k: ... )
            end;
        bigrectyp = record
            a: sometype;
            case t: Ttyp of
                V1: ( ... );
                V2: ( ... );
                V3: ( a3: integer;
                      b3: smallrectyp );
            end;

    var
        p: ^bigrectyp;

    begin
      :
    new ( p );          { Allocates space for largest
                          variant of bigrectyp        }
      :
    new ( p, V2 );      { Allocates just enough space for
                          V2 variant.  p^.t = V2         }
      :
    new ( p, V3, TRUE ); { p^.t = V3  and  p^.b3.b = TRUE }
 
 
 
 
 
 
 
 
 
 
 
 
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2.9.9 NEW (on arrays)
 
When a NEW is performed to allocate an array, space is  nor-
mally  provided  to accomodate the entire array as declared.
An optional parameter can, however, be specified in the  NEW
to allocate only a portion of the array.
 
    Eg.
        type
            atyp = array [0..10] of anytype;

        var
            a: ^atyp;

        begin

        new ( a: i );
 
 
In  this example, only enough space for i+1 elements will be
allocated. The expression i must be  of  a  type  compatible
with  the index type of the array and represents the maximum
index useable in the allocated array.
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
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2.10 Standard functions

2.10.1 RUNTIME

The function RUNTIME returns an integer giving  the  daytime
in  seconds  modulo  8  hours  (RSX/IAS  doesn't measure CPU
time).
 
 
 
 
2.10.2 TWOPOW and SPLITREAL

The function TWOPOW(<integer expression>):REAL gives as  re-
sult the real 2**<integer expression>.

The    function    SPLITREAL(<real   expression>,   <integer
variable>):REAL returns the binary exponent of the real  ex-
pression  in the integer variable and gives as result a real
with binary exponent zero but the same mantissa as  the  ex-
pression.
 
 
 
 
2.10.3 IORESULT

The function IORESULT(<file>):INTEGER returns an integer va-
lue indicating the result of the last operation on the given
file. Result = +1 if OK and <0 if error. The error codes are
those returned from RSX/IAS. For further details see RSX/IAS
manuals. A few error codes are added, see appendix F.
 
 
 
 
2.10.4 ORD
 
The  ORD  function can also take a pointer or a set (16 ele-
ments or less) as an argument. The integer  result  will  be
the 16 bit representation of the argument.
 
 
 
 
 
 
 
 
 
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2.11 Procedures and functions as parameters

In  this implementation of Pascal it is necessary to declare
the formal parameters of a formal procedure or function.  At
the  declaration  of a formal procedure or function no iden-
tifier is required  for  its  formal  parameters,  only  the
type(s) of the argument(s) must be specified.
 
The  declaration  of "formal formal parameters" is necessary
for  the  compiler  to  check  the  actual  procedure-   and
function-parameters  with  respect  to  their parameters and
types. This avoids a considerable overhead of parameter- and
type-checking at runtime of a Pascal program.
 
    Example:
        PROGRAM INTEGRATION;
        FUNCTION INTEGRATE ( FUNCTION F (REAL):REAL;
                LOWBOUND, HIGHBOUND, DELTA: REAL ): REAL;
                (* BODY *) ...
        FUNCTION SINUS ( ARG: REAL ): REAL;
          BEGIN   SINUS := SIN( ARG );
          END;
        
        BEGIN
          WRITELN( INTEGRATE( SINUS, 0, 3.14, 0.01 );
        END.
 

Note that external procedures and functions not  written  in
Pascal  and  standard  procedures  and functions must not be
used as actual parameters to formal procedures or  functions
since they obey different parameter conventions.
 
 
 
 
2.12 Separate compilation

It  is  possible to compile one or more procedures without a
main program. In that case, no program statement is  allowed
and  the source file must begin with an option comment stat-
ing M-. For further details see paragraph 4.9 below.
 
Separately compiled procedures and functions can be accessed
if they are declared with the procedure body replaced by EX-
TERN. Fortran and assembler-written routines can also be ac-
cessed if their parameter transport follows Pascal  standard
or  Fortran. In the latter case the procedure body should be
 
 
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replaced by EXTERN( FORTRAN ). If the external name contains
'$' or '.' it can be given as a string constant.
 
    Eg.
        EXTERN( FORTRAN, '$TEST' )
 
 
Global variables can be shared between the main program  and
separately compiled procedure/functions. This is done in the
procedure  by declaring the shared variables before the par-
ameter statement. Because there can be  no  checking  across
separate compilations, it is the programmer's responsibility
for  ensuring  that  these variables are declared in exactly
the same way in both the main  program  and  the  procedure.
Good use can be made here of the compiler's include facility
or of a separate inlcude preprocessor.
 
   Example:
        Main program                    Separate Procedure
        ------------                    ------------------

   program main;                        {$m-}

   type                                 type
       atyp = ...                           atyp = ...
       ctyp = ...
                                        var { global }
   var                                      a: atyp;
       a: atyp;                             b: integer;
       b: integer;
       c: ctyp;
                                        procedure proc;
   procedure proc; extern;
                                        var { local }
   begin { main }                           x: ...
     :                                      y: ...
     :
                                        begin { proc }
                                          :
                                          :
 
 
 
 
 
 
 
 
 
 
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2.13    String parameters
 
Arbitrary  length character strings can be passed as parame-
ters to procedures and functions. These "string  paramaters"
are declared using the word STRING.
 
    Eg.  PROCEDURE PA (...; STRING A,B,...; ...);
 
Both character arrays and string constants of any length can
be  supplied  as  arguments for string parameters and can be
modified by the procedure. Use caution here because  a  con-
stant can be modified.
 
Within  a  procedure  that is using string parameters, these
will always be treated as  arrays  of  characters  with  the
first  character  at subscript 0. The standard function SIZE
can be used to  obtain  the  actual  length  of  the  passed
string.
 
    Eg.
        CONST
            C = 'NAMED CONSTANT';

        VAR
            V = ARRAY [1..8] OF CHAR;

        PROCEDURE  P ( STRING S );
            BEGIN
            IF SIZE(S) >= 5 THEN CH := S[4]
            END;

        BEGIN
        P(C);
        P('STRING');
        V := 'VARIABLE';
        P(V)
        END.
 
 
Note that there are only two ways in which string paramaters
can   be   used:   as   an   actual   parameter  to  another
procedure/function or to access a single  character  in  the
string.  Currently, the compiler will not give errors when a
string parameter is used in other ways.
 
A substring specification can be used as an actual parameter
for a paramater that has been declared  as  a  string  para-
mater. A substring specification has the form:
 
 
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        A [ n..m ]
 
where A is an array of characters or a formal string parame-
ter and n and m are expressions of a type that is compatible
with  the  subscript type of A. The values of n and m define
the bounds of the substring of A.
 
Substrings can also be used as parameters  to  the  standard
procedures WRITE, WRITELN, READ, REWRITE and RESET.
 
 
 
 
2.14 Structured function results
 
The  result of a function is not limited to scalar, subrange
or pointer types. The result can be of any  structured  type
also.
 
 
 
 
2.15 Boundless array parameters
 
The  declaration of the type of a formal array parameter can
be made so that the dimensions of the actual  parameter  are
passed at run time.
 
   Eg.
     procedure P ( var a: array [integer,integer] of atyp );
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
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3 RESTRICTIONS

3.1 Reserved words

The following words are also reserved:
 
        LOOP EXIT OTHERS EXTERN FORWARD
 
 
 
 
3.2 Packed structures

Packed  data  structures  are only implemented for character
arrays (always packed, two char's per word) and for  Boolean
arrays  (packing  optional, one Boolean per bit). The proce-
dures PACK and UNPACK are not implemented.
 
 
 
 
3.3 GOTO statement

The GOTO statement is restricted to allow only local GOTO's.
 
 
 
 
3.4 SET size

The representation of sets is chosen so that a set may  have
at most 64 members.
 
 
 
 
3.5 File declarations

A  file  that  is declared in a procedure must be explicitly
closed (if it is open) within that procedure. See  procedure
CLOSEF in appendix H.
 
 
 
 
 
 
 
 
 
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3.6 Parameter transmission

Standard  procedures  or  functions or external Fortran rou-
tines may not be passed as actual parameters.
 
 
 
 
3.7 Definition level 0 and 1

The compiler can be generated with a predeclaration level of
0, 1, 2 or 3. The level can also be chosen at  compile  time
through  the  switch /AA:n on the object file specification,
see point 4.1 below. Level 1  is  exactly  standard  Pascal,
level  0  is  restricted to give the compiler more workspace
(no arithmetic functions).
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
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4 COMPILER OPTIONS AND SWITCHES

When compiling a Pascal program it  is  possible  to  select
some  special  features  called options. All option switches
have default values. Some can  be  changed  dynamically  and
some  may  be  set  only  before the first statement. Option
switches are turned on and off  through  comments  beginning
with  '$' ( =chr(44B)) followed by one or more option selec-
tors, separated by commas. Each option selector consists  of
one  letter  followed by '+' or '-'. Example: (*$L+,C-,M+*).
The default values listed below may be changed  at  compiler
generation time.

Most  option  switches  can  also  be  set with command line
switches. These override all selecting of the same option in
the source code. The switches follow  RSX/IAS  standard  but
only one character is significant.
 
        Eg. /EI/-CC/MM .
 
 
 
 
4.1 Predeclaration level: A

The  compiler  always  has  some names predeclared, i.e. IN-
TEGER, TRUE etc. All names occupy data space when  the  com-
piler is run. For large programs, and for compatibility rea-
sons  it  can  be of interest to reduce the number of prede-
clared types, functions etc. to a  minimum  or  to  standard
Pascal.  The  predeclaration  level  is selected at compiler
generation time, but can be reset for a  single  compilation
through  the  command line switch /A followed by an unsigned
integer. Examples: /AA:1, /A0 .
 
Level   Restriction (-) or extension (+)
  0     - arithmetic functions ( sin, cos etc. )
  1     standard Pascal
  2     + maxint,minint,maxreal,minreal,smallreal
        + text,ascii,byte,alfaleng
  3     + ( 2 ),   + iospec
 
 
 
 
 
 
 
 
 
7-DEC-79                  - 23 -                            

                                                            
 
 
4.2 Listing of generated code: C

This switch can be changed dynamically. When C+  is  in  ef-
fect,  statement  addresses  (octal) will be included on the
program listing and the symbolic generated code will be out-
put to the CXP file (ie. 3rd output  file  spec  on  command
line) if any was specified.
Default: C-.
 
 
 
 
4.3 Extended instruction set, EIS: E

The compiler generates MUL and DIV instructions if option E+
is   selected,  otherwise  these  operations  are  performed
through subroutines. (E+ is implied by F+ or G+)
 
 
 
 
4.4 Floating point processor, FPP: F

The floating point hardware for PDP 11 model 45 and  up  can
be used if option F is selected.
 
 
 
 
4.5 Floating instruction set, FIS: G

The  PDP 11/35 and 40 floating point hardware can be used if
option G is selected.
 
 
 
 
4.6 Error handling and conversion selection: H

When a Pascal program is executed certain errors can  occur,
i.e.  index  out  of  bounds.  See appendix F for a complete
list. They are  grouped  into  three  categories:  messages,
warnings and fatal errors. Message and warning printouts can
be  suppressed,  and  it  is  possible to continue execution
after warnings and even after errors. It is also possible to
choose to skip spaces after reading integers  and  reals  in
addition to just before. The choices are made through an in-
teger  following H+. The value is the sum of any of the fol-
 
 
7-DEC-79                  - 24 -                            

                                                            
 
 
lowing selections:
 
        Value   Meaning
          1     print warnings
          2     continue after warning
          4     continue after fatal error
          8     print messages
         16     skip spaces after read integer/real
 
        Example:   (*$H+19*).
 
Default 3 = print warnings and continue after warnings. H is
not selectable through a command line switch.
 
 
 
 
4.7 Program listing: L

Listing of the source program may be  switched  on  and  off
during  compilation.  Default:  L+.  If no listing at all is
wanted, the listfile specification can be omitted  from  the
command line. There is no corresponding command line switch.
 
 
 
 
4.8 Line width: L

The maximum number of characters printed per line is select-
able  in the same way as the page width (P). The line split-
ting can occur in the middle of a Pascal symbol.
Example: /LW:72, /L132.
Default: /L132.
 
 
 
 
4.9 Main program: M

It is possible to compile a set of procedures and  functions
separately.  In  this case, no PROGRAM statement and no main
program may be given, and the source text must begin with an
option selection of  M-.  The  last  procedure  or  function
should  end  with  a  period (.) instead of a semicolon (;).
Default: M+.
 
 
 
 
7-DEC-79                  - 25 -                            

                                                            
 
 
4.10 Page width: P

It is possible to select the maximum number of lines printed
per page through a switch on the  list  file  specification.
Normally  a suitable page width is selected at compiler gen-
eration time
Example: /PW:50, /P29
 
 
 
 
4.11 Page eject: P

There are two ways to force the compiler to start on  a  new
page after the current line. The character form feed and the
option P+ both give this effect. P+ is reset afterwards.
 
 
 
 
4.12 Frequency measurement: Q

It is possible to get the compiler to insert instructions in
the  generated  code that count the number of times the code
is executed. The measuring points are  inserted  before  the
first  beginning  of  a statement in each line of the source
code.
 
Example, (**) = measuring point:
        (**)    for i:=1 to 5 do
        (**)    a[i]:=0;
        (**)    if i=3
                then    (**)    x:=2.0
                else    (**)    x:=0.0;
 
This option must be selected before the  program  statement,
but may be switched on and off after the program statement.

After  execution of a program compiled with Q+ or /Q, a file
of name <source file name>.FQV is produced. It contains  the
measuring information in a form ready for printing (i.e. PIP
EX.FQV/SP).
 
If  R-  is  selected  only  the beginnings of procedures and
functions are measured, and if both R- and T- are in  effect
no  measuring at all is performed. It is also necessary that
the program statement include OUTPUT.
 
 
 
7-DEC-79                  - 26 -                            

                                                            
 
 
Note that the storage for the execution  counts  is  in-line
with  the  code being executed. As such, frequency measuring
destroys the read-only nature of the generated code.
 
 
 
 
4.13 Runtime checks: R and T

The compiler can generate  checks  of  dynamic  storage  and
stack  allocation  at procedure and function entry and calls
of NEW. Default: T+.
 
Checks of assignment to subrange variables and of array  in-
dices  are  not generated if option R- is selected. Default:
R+.
 
 
 
 
4.14 Trace: S
 
The compiler will generate calls to a runtime  routine  that
will display the current statement address on the TI: termi-
nal. The trace points are at each source line where a state-
ment  begins. The option may be switched on/off at any point
in the program or selected on the command line.
Default: S-.
 
 
 
 
4.15 Spool listfile: U

The listfile is normally not spooled. It will  automatically
be printed if the switch /U is given on the listfile specif-
ication in the command line.
 
 
 
 
4.16 Object module version: V

The object modules that are generated can get version infor-
mation,  which the linker will print on the map. The version
identifier consists of  up  to  six  alfanumeric  characters
after  V+.  Example: (*$V+PAS500*). There is no /V switch in
the command line.
 
 
7-DEC-79                  - 27 -                            

                                                            
 
 
4.17 Warning suppression: W

Error messages classified as warnings may be  suppressed  by
selecting option W-. Warning error numbers are > 900.
Default: W+.
 
 
 
 
4.18 Conditional compilation: X and Z

It  is possible to write test statements which generate code
only if option X+ is selected.
Default: X-.

The conditional parts of the code must be enclosed in a spe-
cial option  parenthesis,  (*$Z+*)  <conditionally  compiled
code> (*$Z-*).
 
 
 
 
4.19 Object module splitting: Y

The  generated  object code can be split into several object
modules (in one file) through insertion of option Y+ in  the
source  text.  All  procedure bodies whose compilation start
with Y+ in effect will become separate object modules in the
object file. This option is implemented to allow large  pro-
grams to be overlaid in PDP 11.
Default: Y-.
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
7-DEC-79                  - 28 -                            

                                                            
 
 
5 REPRESENTATION

5.1 Scalars

Integers,  booleans  and  characters  occupy  one word each.
Reals occupy two words with one sign bit, one exponent  sign
bit,  seven exponent bits and a mantissa of 23 bits plus one
bit hidden. Sets of up to 16 members  occupy  one  word  and
sets of up to 64 members occupy four words.
 
 
 
 
5.2 Arrays
 
Character  arrays are always packed two characters per word.
Booleans, in unpacked  arrays,  occupy  one  word  each,  in
packed arrays, one bit each, that is, 16 per word.
 
 
 
 
5.3 Files

See  also RSX/IAS I/O Operations Reference Manual. Files are
represented as fixed length record  files  except  textfiles
which  have  variable  length  records, one line per record.
They are used in locate mode. File descriptor blocks are al-
located in the stack and a file  declaration  thus  reserves
108  bytes  plus  the  size  of  one record of the file. For
textfiles, the maximum line length  is  132  characters  for
which a buffer is reserved.
 
 
 
 
5.4 Stack and heap

The  stack and heap are given a contiguous area in which the
stack grows from one end and the heap from the other. Dynam-
ic storage is allocated on the heap while  static  variables
and parameters are placed on the stack. This area is a psec-
tion  named  999999  and which is thus normally allocated at
the end of the task image. Runtime errors will occur  if  it
is not placed there.
 
There are two ways of extending the heap/stack space:
 
 
 
7-DEC-79                  - 29 -                            

                                                            
 
 
  1. with the EXTSCT option at build time, or
  2.  by  task extension, specified at build, install or run
     time.
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
7-DEC-79                  - 30 -                            

                                                            
 
 
5.5 Parameter transmission

A Pascal program has a special stack for allocation of  data
and for parameter transmission. The Pascal stack is accessed
through register R5. The first parameter is pushed first and
the  last  item  pushed is a special link word. This link is
used for accessing variables at intermediate levels  and  is
of no value to assembler routines. An assembler routine, de-
clared in a Pascal program as:
 
        function A ( i, j: integer;
                     c: char;
                     var x: xtyp;
                     string s ); extern;
 
will receive a stack as follows:
 
        R5+14:  reserved for result (functions only)
        R5+12:  value of i
        R5+10:  value of j
        R5+8:   value of c
        R5+6:   address of x
        R5+4:   address of first character of s
        R5+2:   length of s in bytes
        R5:     link
 
Each parameter occupies an area large enough to hold its va-
lue,  ie. entire arrays and records are copied to the stack.
However, for parameters declared with the VAR attribute, on-
ly the address of the actual parameter is  transmitted.  For
arrays,  the  address given is the address of a hypothetical
zeroth element of the array (this can be odd  for  character
arrays).
 
The  link  and all parameters must be removed from the stack
before return (by RTS PC). For functions, an  area  for  the
result  is  reserved  on the stack before the parameters are
pushed. At return, R5 will thus point to this area.
 
Assembler routines called from Pascal can alter registers 0,
1 and 2 but must preserve registers 3, 4 and 5.
 
 
 
 
 
 
 
 
 
7-DEC-79                  - 31 -                            

                                                            
 
 
                         APPENDICES
                         ==========
 
 
 
A. Character set

The compiler accepts all ASCII characters in the source  in-
put.  Lower  case characters will be listed as such but will
be treated as uppercase except in strings. Two control char-
acters are recognized, HT (tab) and FF (formfeed); all  oth-
ers  are  converted  to  SP  (space). The formfeed character
forces the listing to a new page. Comments can  be  enclosed
in braces: {...}.
 
For  historical reasons, comments may be enclosed in percent
and backslash characters ( eg. %Comment\) as well as (*...*)
and {...}.
 
In Pascal programs, character variables can take on any  va-
lue from chr(0) to chr(377B). However, since sets are limit-
ed to 64 elements, only a limited range of characters can be
elements  of a set of characters. This range is encircled in
the following table.
 
 
            0   1   2   3   4   5   6   7

        00  NUL SOH STX ETX EOT ENQ ACK BEL
        01  BS  HT  LF  VT  FF  CR  SO  SI
        02  DLE DC1 DC2 DC3 DC4 NAK SYN ETB
        03  CAN EM  SUB ESC FS  GS  RS  US
   --------------------------------------------
   I    04  SP  !   "   #   $   %   &   '     I
   I    05  (   )   *   +   ,   -   .   /     I
   I    06  0   1   2   3   4   5   6   7     I
   I    07  8   9   :   ;   <   =   >   ?     I
   I    10  @   A   B   C   D   E   F   G     I
   I    11  H   I   J   K   L   M   N   O     I
   I    12  P   Q   R   S   T   U   V   W     I
   I    13  X   Y   Z   [   \   ]   ^   _     I
   --------------------------------------------
        14  `   a   b   c   d   e   f   g    
        15  h   i   j   k   l   m   n   o    
        16  p   q   r   s   t   u   v   w    
        17  x   y   z   {   |   }   ~   DEL 
 
 
 
 
7-DEC-79                  - 32 -                            

                                                            
 
 
B. Special symbols

Table of special symbols with their meaning.
 
    Stand-  Altern- Meaning
    ard     ative
    
    :=              assignment
    +               with one operand: identity
    -               with one operand: negation
    +               with two operands: addition
    -               with two operands: subtraction
    *               multiplication
    /               real division
    div             integer division
    mod             remainder
    =               equal
    <>      #       not equal
    <               less
    >               greater
    <=              less or equal, set inclusion
    >=              greater or equal, set inclusion
    in              set membership
    not             negation
    or      !       disjunction
    and     &       conjunction
    or      !       set union
    -               set difference
    and     &       set intersection
    (*      % {     start of comment
    *)      \ }     end of comment
     .              end of program
    ,               comma
    :               colon
    ;               statement separator
    '               string delimiter
    (               left parenthesis
    )               right parenthesis
    [       (.      left bracket
                    set constructor
    ]       .)      right bracket
                    set constructor
    ^               pointer constructor
    $               option constructor
 
 
 
 
 
 
7-DEC-79                  - 33 -                            

                                                            
 
 
C. Reserved words


The following words are reserved:
 
        if      do      of      to      in
        or      end     for     var     div
        mod     set     and     not     then
        else    with    goto    loop    case
        type    file    exit    begin   until
        while   array   label   const   others
        repeat  record  downto  packed  extern
        forward function        procedure
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
7-DEC-79                  - 34 -                            

                                                            
 
 
D. Standard procedures

This is a list of standard procedures, with an indication of
parameter types.

    Input/output:
    
      RESET(FILE, STRING, STRING, STRING, SET)
      REWRITE(FILE, STRING, STRING, STRING, SET)
      GET(FILE)
      GET(FILE,INTEGER)
      PUT(FILE)
      PUT(FILE,INTEGER)
      PAGE([FILE])
      READ([FILE,] INTEGER or REAL or CHAR or STRING, ... )
      READLN([FILE,] INTEGER or REAL or CHAR or STRING, ... )
      WRITE([FILE,] INTEGER or REAL or CHAR 
                            or BOOLEAN or STRING, ... )
      WRITELN([FILE,] INTEGER or REAL or CHAR 
                            or BOOLEAN or STRING, ... )
      BREAK
        Where FILE is optional, the standard text file INPUT
        or OUTPUT will be implied by default if it has  been
        declared  (ie. in the program statement). Otherwise,
        the text file TTY will be assumed if it has been de-
        clared. If none of these have been declared then  an
        error will be flagged.
 
    Execution control:
    
      HALT
    
    Administration of dynamic storage:
    
      NEW(POINTER,variant selector, ... )
      MARK
      RELEASE
    
    Miscellaneous:
    
      DATE(STRING)          ( array [1..10] of char )
      TIME(STRING)          ( array [1..10] of char )
 
 
 
 
 
 
 
 
7-DEC-79                  - 35 -                            

                                                            
 
 
E. Standard functions

This  is  a list of standard functions with an indication of
parameter types.
 
      Mathematical functions:
      
        ABS(INTEGER or REAL):INTEGER or REAL
        COS(INTEGER or REAL):REAL
        EXP(INTEGER or REAL):REAL
        LN(INTEGER or REAL):REAL
        SIN(INTEGER or REAL):REAL
        SQR(INTEGER or REAL):INTEGER or REAL
        SQRT(INTEGER or REAL):REAL
      
      Conversion routines:
      
        ROUND(REAL):INTEGER
        TRUNC(REAL):INTEGER
        CHR(INTEGER):CHAR
        ORD(any type occupying one word): integer;
      
      Miscellaneous:
      
        ODD(INTEGER):BOOLEAN
        EOF([FILE]):BOOLEAN
        EOLN([FILE]):BOOLEAN
        IORESULT([FILE]):INTEGER
        PRED(any scalar except REAL):same as argument
        SUCC(any scalar except REAL):same as argument
        RUNTIME:INTEGER
        SPLITREAL(REAL,INTEGER):REAL
        TWOPOW(INTEGER):REAL
        SIZE (STRINGPARM):INTEGER
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
7-DEC-79                  - 36 -                            

                                                            
 
 
F. Error codes


F.1 Compile-time errors

       1      error in simple type
       2      identifier expected
       3      error in value part
       4      ')' expected
       5      ':' expected
       6      illegal symbol
       7      error in parameter list
       8      'of' expected
       9      '(' expected
      
      10      error in type
      11      '[' expected
      12      ']' expected
      13      'end' expected
      14      ';' expected
      15      integer expected
      16      '=' expected
      17      'begin' expected
      18      error in declaration part
      19      error in field list
      
      20      ',' expected
      21      constant expected
      22      'program' expected
      23      standard files only 'input', 'output', 'tty'
      
      50      error in constant
      51      ':=' expected
      52      'then' expected
      53      'until' expected
      54      'do' expected
      55      'to'/'downto' expected
      56      'if' expected
      57      'exit' expected
      58      error in factor
      59      error in variable
      
      101     identifier declared twice
      102     low bound must not be greater than high round
      103     identifier is not of appropriate class
      104     identifier not declared
      105     sign not allowed
      106     number expected
 
 
7-DEC-79                  - 37 -                            

                                                            
 
 
      107     incompatible subrange type
      108     file not allowed here
      109     type must not be real
 
      110     tag field must be scalar or subrange
      111     incompatible with tag field type
      112     index type must not be real
      113     index type must be scalar or subrange
      114     base type must not be real
      115     base type must be scalar or subrange
      116     error in type of standard procedure parameter
      117     unsatisfied forward reference
      118     forward referenced type identifier in variable
              declaration
      119     forward declared: repetition of parameter list
              not allowed
      
      120     function result type must not be files
      121     file value parameter not allowed
      122     forward declared function:
              repetition of result type not allowed
      123     missing result type in function declaration
      124     fixed format for real only
      125     error in type of standard function parameter
      126     number of parameters does not agree with
              declaration
      127     illegal parameter substitution
      128     result type of parameter function does not
              agree with declaration
      129     type conflict of operands
      
      130     left operand of set membership test is not scalar or
              right operand is not of set type
      131     tests on equality allowed only
      132     strict inclusion not allowed
      133     file comparison not allowed
      134     illegal type of operand(s)
      135     type of operand must be boolean
      136     set element type must be scalar or subrange
      137     set element types not compatible
      138     type of variable is not array
      139     index type is not compatible with declaration
      
      140     type of variable is not record
      141     type of variable must be file or pointer
      142     illegal parameter substitution
      143     illegal type of loop control variable
      144     illegal type of expression
 
 
7-DEC-79                  - 38 -                            

                                                            
 
 
      145     type conflict
      146     assignment of files not allowed
      147     label type incompatible with selecting 
              expression
      148     subrange bounds must be scalar
      149     index type must not be integer
 
      150     assignment to standard function not allowed
      151     assignment to formal function is not allowed
      152     no such field in this record
      153     type error in read
      154     actual parameter must be a variable
      155     control variable must not be formal
      156     multiply defined case label
      157     too many cases in case statement
      158     missing corresponding variant declaration
      159     real and string tag fields not implemented
      
      160     previous declaration was not forward
      161     again forward declared
      162     slice variant separator is colon
      163     missing variant in declaration
      164     missing slice variant in declaration
      165     multiply defined label
      166     multiply declared label
      167     undeclared label
      168     undefined label
      169     error in tag field
      
      170     variant must have the same type as tag field
      
      180     standard file not in program statement
      181     'input', 'output' or 'tty' missing in program
              statement
      182     parameters to external Fortran routines must be
              var parameters
      183     body not allowed when not main
      184     assignment to function only in its body
      
      201     error in real constant: digit expected
      202     string constant contains 'eol'
      203     integer constant exceeds range
      204     8 or 9 in octal number
      205     real constant exceeds range
      206     octal output format for integers only
      
      250     too many nested scopes of identifiers
      251     too many nested procedures and/or functions
 
 
7-DEC-79                  - 39 -                            

                                                            
 
 
      253     too much code produced
      254     too many string/set/real constants in this
              procedure
      255     too many errors in this source line
      
      399     not implemented
      
      400     compiler error
 
      600     indextype of boundless array must be of scalar
              type (but not of type real)
      601     colon in parameter list must be followed by
              identifier or array symbol
      602     boundless arrays must be var specified
      603     standard functions/procedures are not allowed as
              actual procedure parameters
      604     ordinal numbers of setelements must lie in the
              range 0..63, or ' '..'_' for characters
      605     the set variables in an expression do not have
              the same base type
      606     base types of sets are incompatible
      607     colon is missing in the specification of
              parameters of a formal procedure/function
              (warning only)
      608     error in parameter specification
      609     fortran routines are not allowed as actual
              procedure parameters
      
      610     integer constants required as actual parameters
      612     parameter list structure of formal and actual
              procedure are not the same
      617     parameter must have stringparm form
      
      626     only string parameters allowed as parameter to
              size function
      
      
      900-999 warnings only
      
      900     undeclared label
      901     unused declared label
      902     undefined option switch
      
      920     program statement missing ('input' and 'output'
              assumed)
      
      930     OUTPUT must be present to allow frequency
              measurement
 
 
7-DEC-79                  - 40 -                            

                                                            
 
 
      931     too many procedures with the first 6 characters
              in their names equal
      
      940     source code "include" nesting > 3 not allowed
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
7-DEC-79                  - 41 -                            

                                                            
 
 
F.2 Runtime errors

Runtime error messages are written on the terminal, and  ap-
pear in the form

        PASRUN -- ERROR  nn. (mmmmmm) vvvvv.

        where   nn = error number, see list below
                mmmmmm = line address where error occured (octal).
                vvvvv = offending value ( error 12 only ).
 
The  line  address  is not correct if the error appears in a
part of the program where the  runtime  check  option  R  is
switched  off  (R-).  In such a case, the displayed line ad-
dress will be that of the last executed statement  where  R+
was  in  effect or the address of the last entered procedure
where T+ was in effect.
 
Only a short error message with no numbers will  be  written
if there is insuficient R6 stack space to build the complete
message.

It  is  possible  to redefine the error handling at compiler
generation time, or in the source code through the option  H
(see  4.6).  Normal  actions  for the three classes of error
are:
 
  F:    Fatal errors.
        Continuation of the program is normally not
        possible or useful, and the program is
        therefore terminated.

  W:    Warnings.
        After having printed the error message, the
        program will continue execution.
        See the comments.

  M:    Messages.
        Conversion errors are normally only signalled
        through IORESULT, but messages can be printed.
        Execution continues afterwards.
 
 
 
 
 
 
 
 
 
7-DEC-79                  - 42 -                            

                                                            
 
 
                       RUNTIME ERROR SUMMARY
                       ---------------------

Number  Kind of operation       Comments
------  -----------------       --------
    Class
    -----

10  F   Procedure entry or      Stack overruns heap
        dynamic allocation      or heap overruns stack
                                Too much code + data,
                                or error(s) in program
                                (40 words left)

11  F   Same as 10              Hardware stack overflow
                                (20 words left)

12  F   Assignment or           Subrange overflow
        indexing in array       Index out of bounds
 
20  F   Integer division        An attempt was made
        or modulo               to divide by 0

21  F   Integer division        Divisor was -32768
        or modulo               (most negative number)

23  F   Integer multiplication  First operand = -32768

30  W   All real operations     Exponent overflow
                                MAXREAL assumed

31  W   All real operations     Exponent underflow
                                Floating zero taken

33  F   Trunc or round          Floating number too
                                large

34  F   Real division           Attempt to divide by 0

40  M   Read integer            No digits after sign,
                                zero taken

41  M   Read integer            Number too large,
                                77777B taken

42  M   Read real or integer    Too many digits
 
 
 
 
7-DEC-79                  - 43 -                            

                                                            
 
 
44  M   Read real               No char's read,
                                floating zero taken

50  W   Exponentiation          Exponent overflow
                                MAXREAL taken

51  F   Square root             Square root of negative

60  F   Substring parameter     Substring range
                                out of bounds

61  F   Indexing in substring   Index out of bounds

66  F   Read or get             Attempt to read beyond
                                end of file
 
 
 
 
F.3 Result codes after I/O operations

The result codes received by IORESULT are the RSX/IAS codes.
Six new codes are added:
 
-101    too many files (RESET/REWRITE)
-102    file not opened (GET/PUT)
-103    too many digits (read integer or real exponent,
        MAXINT taken)
-104    no digits read (read integer or real exponent,
        zero taken)
-105    integer overflow (read integer: MAXINT taken,
        read exponent: MAXREAL taken)
-106    no digits read and "." or "E" not found
        (read real, 0.0 taken)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
7-DEC-79                  - 44 -                            

                                                            
 
 
G. Options and switches


All default values can be changed  at  compiler  generation.
The values listed are from the distribution set.


Name    Default Option/switch used for

A       3       Predeclaration level (switch only)
B
C       -       Printing of octal relative addresses
D       -       Debug ( not implemented yet )
E       -       EIS
F       -       FPP
G       -       FIS
H       3       Runtime error handling (option only)
I
J
K
L       +       Listing on/off (option only)
        132     Line width ( switch only )
M       +       Main program
N
O
P       -       Page eject ( option only )
        55      Page width ( switch only )
Q       -       Frequency measurements
R       +       Runtime checks of indexbounds etc.
S       -       Trace
T       +       Runtime checks of stack/heap overflow
U       -       Spool listfile ( switch only )
V               Object module version
W       +       Print compiler warning messages
X       -       Conditional compilation
Y       -       Object module splitting
Z               Conditional compilation
 
 
 
 
 
 
 
 
 
 
 
 
 
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H. ADDITIONAL PROCEDURES AND FUNCTIONS


The  following  procedures  and  functions  are available in
SYSLIB/PASLIB and can be used if declared as:

      procedure GCML ( var s: line; var len: integer );
        extern;
        (* type line = array [1..80] of char .
           Returns the MCR command line in s and its
           length in len. *)
      
      procedure closef ( var f: <filetype> );   extern;
        (* closes the external file associated with
           the file parameter *)
      
      procedure attach ( var f: <filetype> );   extern;
        (* issues a QIO with IO.ATT to the file *)
      
      procedure detach ( var f: <filetype> );   extern;
        (* issues a QIO with IO.DET to the file *)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
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