RELEASE NOTES FOR
=================
SWEDISH PASCAL VERSION 5+
=========================
Originally obtained from John Barr, DECUS Pascal SIG
chairman. He got it from Seved Torstendahl in Stockholm.
Modified, corrected and repackaged by:
Gerry Pelletier
Transport Canada (TARI)
Transport Canada Bldg.
Place de Ville,
Ottawa, Ontario, Canada
K1A 0N8 613-994-2378
CONTENTS
========
1. Introduction................................ 1
2. Files and their contents.................... 2
3. Installing Pascal........................... 6
3.1 Preparing PASLIB......................... 6
3.2 Preparing PAS compiler................... 7
3.3 Preparing PAZ compiler................... 8
4. The Heap and what to do with it.............10
5. Bugs........................................12
6. Incomplete implementation...................12
7. Crosscompiler on DEC-10.....................13
1. Introduction
================
The version 5 Swedish Pascal for PDP-11 as distributed by
DECUS was chosen as an interim compiler for the development
of a large software project at Transport Canada. Upon
encountering severe bugs and limitations of this package, we
embarked on a program of maintaining it ourselves. This was
made easier by the inovation of a method for compiling the
main source module of the compiler on a PDP-11 whereas
previously, this could only be done by cross compiling on a
DEC system 10.
To date, there have been about 53 modifications made to the
compiler and runtime routines. Many of these constitute
corrections for bugs and other deficiencies, but some are
enhancements and extensions. A few of these are worthy of
note here:
- Type CHAR has been redefined to cover the subrange
chr(0) to chr(255) (it was ' '..'_' or
chr(32)..chr(95)). This is more useful in an environment
with modern data terminals where non-printing control
characters are just as common as printing characters.
- Line addresses are displayed instead of line numbers in
PASRUN error messages. This is an easier way of
identifying error locations in programs made up of many
separatly compiled procedures.
- TTY file is the default standard file in a separatly
compiled procedure (see section 2.6 in the user manual).
- Files no longer have to be declared in the main program.
- Bugs were corrected which make possible the use of
string parameters (see section 2.13 of user manual).
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2. Files and their contents
============================
The release tape has all files divided into 4 distinct UICs:
[76,100] - documentation and runtime library PASLIB,
[76,101] - the PAS version of the compiler,
[76,102] - the PAZ version of the compiler, and
[76,103] - utility and sample programs.
The following is a brief outline of the files and their
contents.
[76,100] Documentation
======================
README.TXT This document
USER.FMT User manual (Software Tools formatter format)
USER.TXT User manual (Printable text)
PASERR.HLP Help text for compilation error codes
PASRUN.HLP Help text for runtime error codes
[76,100] Runtime Library
========================
PASLIB.OLB Pascal runtime routines. As distributed, this
is for PDP-11 processors with no EIS, FIS or
FPP running RSX. To upgrade it to your system,
apply appropriate library replacement.
LBR PASLIB/RP = PASEIS for EIS
LBR PASLIB/RP = PASFIS for FIS
LBR PASLIB/RP = PASFPP for FPP
LBR PASLIB/RP = PASIAS for IAS
PASEIS.OBJ Concatenated object modules to do EIS multiply
and divide. These are:
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Module MULI from P11EISMPI.MAC
DIVI from P11EISDVI.MAC
PASFIS.OBJ Contains object module for FIS real aritmetic
operations. This is module P11RAR from source
P11FIS.MAC.
PASFPP.OBJ Concatenated object modules for FPP real
arithmetic operations. These are:
Module P11INI from source P11FPPINI.MAC,
P11RAR from source P11FPP.MAC,
FORTR from source P11FORFPP.MAC.
PASIAS.OBJ Contains object module that has special
difference for tasks run under IAS operating
system. This is module RUNCHK from source
P11IASRNC.MAC.
PASNOX.OBJ Concatenated object modules that can be
applied to a PASLIB.OLB that has been upgraded
from the distributed PASLIB.OLB to restore it
to a state that is useable on a processor with
no extra hardware. It contains the following
modules:
MULI from source P11MPI.MAC
DIVI P11DVI.MAC
P11RAR P11REAL.MAC
P11INI P11INIT.MAC
RUNCHK P11RUNCHK.MAC
FORTR P11FORTR.MAC
PASLIB.PAC Packed source modules for runtime library.
(Use P11DEF.MAC module as prefix for
assembling all MAC modules in this package.)
[76,101] Compiler (PAS)
========================
P11PAS.PAS Pascal source of general part of compiler.
P11FIL.PAS PDP-11-specific part of compiler.
P11CRS.PAS DEC-10-specific part of compiler.
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SPECAL.PAC Packed source for special runtime routines
required by the compiler itself.
PAS.BLD
PAS.ODL TKB files to build compiler
PAS.OLB Library of object modules of compiler. These
are the objects obtained from compiling
P11PAS.PAS, P11FIL.PAS and all the modules in
SPECAL.PAC.
PAS.TSK Task image of compiler. This version is to run
under RSX-11M in 32K on processor with no
extra hardware (ie. no EIS, FIS or FPP).
TRICK, ACOMPI, ADEC1, ADEC2
AINI2, AFCS (.MAC and .OBJ)
These routines are used to accomplish some
convoluted overlaying which is required to
reduce the task size to give reasonable com-
piler capacity.
[76,102] Big Compiler (PAZ)
============================
This version of the compiler is esentially the same as the
PAS task. It is built with considerably heavier overlaying
and as a result uses memory resident overlays to maintain
good speed performance. It needs about 67K words to run.
The main application of this compiler is to compile the
compiler itself since the PAS compiler does'nt have enough
capacity to compile P11PAS.PAS. PAZ can compile P11PAS.PAS
(about 8300 lines) in about 13 minutes (PDP-11/40 - RK06).
PAZ.BLD
PAZ.ODL TKB files to build PAZ
PAZ.TSK PAZ compiler task to run under RSX-11M on
processors with no extra hardware.
OVTRIK.PAC Packed source for routines that are needed for
doing extra overlaying.
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ABOD1, ABOD2, ACALLN, ACALLS, ACOMPI, ADEC1, ADEC2,
ADEC3, AEXPR, ASTMN1, ASTMN2, ASTMN3, HEAP, TRICK (.OBJ)
These are the objects of routines in OVTRIK.PAC
[76,103] Pascal Utilities
=========================
UNPACK Asks for the name of a packed file and splits
it into its constituent files.
LISTPACK Lists the names of files in a packed file.
PACK Packs arbitrary source files into a new packed
file. When it asks for name of source file,
you can also enter "@file" where "file" itself
contains the names of files to be packed.
SELECT Can extract a particular file from a packed
file.
CROSS Program for formatting and crossreferencing a
Pascal program. Eg.:
>RUN CROSS
FILE: <filename><cr> device and directory not
allowed, .PAS default type. Gives new
source and cross reference listing in
<filename>.CRL.
PASREF Another Pascal crossreferencer.
FLIST Lists a source file on terminal with line
numbers.
Task images (for RSX-11M v3) for some of these these
utilities are provided. (No optional hardware required.)
29-NOV-79 - 5 -
3. Installing Pascal
=====================
Use FLX to read the files from tape to disk. The files do
not have to go into directories with the same UICs as used
on the tape, but they should not be combined into one
directory. Each directory of files on tape must be in a
separate directory on disk. The remainder of the discussion
will assume that the files are on disk in the same
directories they were in on tape (use FLX /UI switch).
3.1 Preparing PASLIB
=====================
In uic [76,100] apply the appropriate library replacements
to PASLIB.OLB.
LBR PASLIB/RP = PASEIS if processor has EIS
LBR PASLIB/RP = PASFIS if processor has FIS
LBR PASLIB/RP = PASFPP if processor has FPP
LBR PASLIB/RP = PASIAS if operating system is IAS
Note that on many PDP-11 models (eg. 34,45,55) the EIS
(Extended Instruction Set) is built into the processor and
is not refered to as an option. Treat these models as if
they have EIS.
The EIS and FPP replacements should be done if Fortran IV
Plus (F4P) routines will be called from Pascal.
After these replacements, the Pascal runtime library will be
ready as a separate OLB file.
If you want to install PASLIB into the system library,
SYSLIB, then do a library extraction and insertion.
Eg. >LBR PASLIB = PASLIB/EX ! Creates PASLIB.OBJ
>SET /UIC=[1,1]
>PIP /NV = SYSLIB.OLB ! Keep copy of old SYSLIB
>LBR SYSLIB = [76,100]PASLIB ! Insert PASLIB routines
29-NOV-79 - 6 -
3.2 Preparing PAS compiler
===========================
The distributed compiler task image in [76,101] is built to
run under RSX-11 with no requirement for optional hardware
and only has to be INStalled to run on any RSX system. If
you want an upgraded compiler that takes advantage of
arithmetic hardware then there are two levels to which this
can be done: re-building only or re-compiling and
re-building. (IAS users will have to at least re-build).
Re-building the compiler with the upgraded PASLIB will mean
that the software-only arithmetic routines will be replaced
by routines that use your hardware instead.
Re-compiling the compiler Pascal source will result in a
task that is even more closely matched to the hardware. For
example, if your processor has EIS then the compiler, if
compiled accordingly, will have MUL instructions in-line
rather than calling the MULI routine.
To re-compile the compiler source:
- intall the PAZ compiler from [76,102] (it will only
run on mapped systems with a partition of at least
67K)
- in uic [76,101] compile the two source modules:
>PAZ P11PAS{switches} = P11PAS
>PAZ P11FIL{switches} = P11FIL
where switches ::=
/E for processors with EIS
/E/G for processors with EIS/FIS
/E/F for processors with EIS/FPP
- replace the object in PAS.OLB:
>LBR PAS/RP = P11PAS, P11FIL
>;
>; Compress and purge to recover space
>LBR PAS/CO = PAS
>PIP PAS.OLB/PU
To build the PAS compiler:
- edit the PAS.BLD file to set the new default switches
29-NOV-79 - 7 -
for the compiler (see comments in PAS.BLD) and to set
the /FP switch if FPP is being used.
- if the compiler source was recompiled with /E switch
as shown above then edit the PAS.ODL file to remove
the MULI routine from the root (see comments in
PAS.ODL).
- arrange access to PASLIB.OLB in [76,100]:
>PIP /EN = [76,100]PASLIB.OLB
- invoke the task builder (eg. >TKB @PAS.BLD) and
disregard the multiply define diagnostic messages from
TKB.
- install the compiler and try it out.
If the resulting task image is larger than 32K words, it
will not install without using the /INC switch to change the
task extention. In this case, the EXTTSK option in the
PAS.BLD file should be adjusted to result in a 32K task
image. Remember that the compiler's workspace is greatest
when the task image is exactly 32K.
3.3 Preparing PAZ compiler
===========================
The considerations for arithmetic hardware for the PAS
compiler apply equally to the PAZ compiler. It can be
re-built from your new PASLIB.OLB (and PAS.OLB if you
re-compiled) as follows:
- set uic to [76,102]
- edit the PAZ.BLD file to set the new default switches
for the compiler (see comments in PAZ.BLD) and to set
the /FP switch if FPP is being used.
- if the compiler source was re-compiled with the /E
switch as shown above then edit the PAZ.ODL file to
remove the MULI routine from the root (see comments in
PAZ.ODL).
- arrange access to PASLIB.OLB and PAS.OLB:
29-NOV-79 - 8 -
>PIP /EN = [76,100]PASLIB.OLB, [76,101]PAS.OLB
- invoke the task builder (eg. >TKB @PAZ.BLD) and
disregard the multiply define diagnostic messages from
TKB.
- install PAZ and try it out.
The EXTSCT option statement in PAZ.BLD controls the size of
the compiler's workspace. For maximum workspace, this
extention should be adjusted to make the root segment 160000
octal bytes long.
29-NOV-79 - 9 -
4. The Heap and what to do with it
===================================
Pascal programs (tasks) contain a heap section which is a
contiguous area of memory that is used for dynamic variables
(heap) at the low end and for static variables and
parameters (stack) at the high end. The compiler creates a
heap section in the object code of every main program.
(Seperatly compiled procedures do not get a heap of their
own.) The size of this section is enough to accomodate the
static variables (not considering recursion) plus a fixed
amount. If this "default" heap is not big enough for your
program then you can extend it at task build time or when
installing.
The heap psect is called 999999. This name causes the task
builder to, in general, place the section at the end of the
task image. This position is essential because the Pascal
runtime initialization assumes that the space that can be
used for heap extends from the begining of the heap section
to the end of the task partition.
At build time the heap can be extended with a TKB option
statement such as EXTSCT=999999:n, where n is the number of
bytes of extention (octal) or EXTTSK=m where m is the number
of words of extention (decimal).
At install or run time, the heap can be effectively extended
by extending the task size with the /INC=n switch, where n
is the number of words of extention.
For tasks using overlays, a special procedure must be
followed to position the heap section at the end of the task
image. If memory resident overlays are being used, the heap
section must be placed at the end of the virtual address
block accessed by the first mapping window. In both cases,
the heap section generated by the compiler, must be made
available as a separate object module so that it can be
positioned in the overlay structure. The way this is done is
to select module splitting when compiling the main program
at a point just before the final end statement. So, just
before the last end, code {$y+}. The generated object file
will then contain a separate module for psect 999999 called
$HEAP. The whole object file must then be placed in an
object library so that this module can be explicitly refered
to in the overlay description (ODL).
With a separatly accessible heap module, the overlay
29-NOV-79 - 10 -
description can be written to position it at the end of the
task. This is done by creating a separate co-tree of one
segment.
eg. .ROOT SOMLIB/LB:MAIN-*(OV1,OV2,OV3),HEAP
HEAP: .FCTR SOMLIB/LB:$HEAP
When memory resident overlays are used, there is a severe
problem introduced that makes it difficult to position the
heap section. This is caused by the task builder's
segregation of read-only and read-write psects and the
introduction of two read-only psects as part of the overlay
management software. One way of surmounting this problem is
to use a hand coded heap module which is given the RO
attribute so that the task builder will place it after the
other RO psects. You will find such a module in
[76,102]OVTRIK.PAC and its object is available in
[76,102]HEAP.OBJ. For more details, see the comments in
HEAP.MAC in OVTRIK.PAC.
29-NOV-79 - 11 -
5. Bugs
========
This Pascal performs comparisons on all structured types as
a word compare loop. Since, for odd length character array
variables, the last byte is undefined, comparisons of these
will, in general, be unpredictable. The correction of this
problem is quite involved and has not yet been attempted. To
avoid any problems, never declare odd length character
arrays.
There are certain unusual circumstances of bad source code
syntax that will cause the compiler to hang in an endless
loop. If you suspect the compiler is hung, abort it and
restart the compilation specifying your terminal as the
listing device. The listing will stop at the line just
before the line with the bad syntax.
There is a problem in calling Fortran subroutines that
themselves do Fortran I/O. Some F4P users have reported
success in circumventing this problem by removing one
instruction from PASLIB routine FORTR. The source for this
routine is in PASLIB.PAC, module P11FORFPP.MAC. The
instruction to be removed is:
MOV DAPADDR(GP),$OTSV
To incorporate the change in PASLIB:
MAC P11FORFPP = P11DEF, P11FORFPP
LBR PASLIB/RP = P11FORFPP
This fix apparantly does not work for Fortran IV (Version
01C at least).
6. Incomplete implementation
=============================
The beginings of a symbolic debug facility are evident in
this compiler. It may be complete in a future release.
29-NOV-79 - 12 -
7. Crosscompiler on DEC-10
===========================
To generate a cross compiler on a DEC-10, proceed as
follows:
- transfer the files P11PAS.PAS and P11CRS.PAS to DEC-10,
- compile them with the PASREL compiler from Hamburg,
- load the produced modules and save the core image:
.LOAD P11PAS,P11CRS
.SAVE P11PAS 64
(64 is enough but maybe less will suffice.)
When run, the compiler will ask for the filename of the
source. A full name including volume and p,pn is allowed.
Filename extention is not necessary if it is .PAS. Two new
files are produced: a list file with extension .LST and an
object file with extention .OBJ.
Example:
.RUN P11PAS
*PROG
will produce the files PROG.LST and PROG.OBJ
from PROG.PAS .
The object file contains one PDP-11 byte per DEC-10 word and
is in PDP-11 DOS format. It can be transfered to a PDP-11 on
DECtape or other suitable medium.
Example:
.MOUNT DTA:DT/V:DTNAME/WE
.R FILEX
*DT:/V/Q/I=PROG.OBJ
*^C
This object module can then be retrieved on a PDP-11 with
RSX-11M by:
>FLX SY:/RS=DT:*.*/DO/FB
29-NOV-79 - 13 -