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Text File | 1987-01-14 | 7.6 KB | 240 lines

IBM Pascal Compiler Version 2.00 Carrington Dixon North Texas IBM Personal Computer User Group My upgrade of the IBM Pascal Compiler arrived a few days ago. Most, if not all, of the bugs in Version 1.00 have been fixed and a number of significant new capabilities have been added. The first thing one notices is that the documentation has nearly doubled! Where the original version required only one binder to hold its four hundred odd pages, the new version requires two binders: "Pascal Compiler Fundamentals" and "Pascal Compiler Language Reference". Each is the size of the original document. The latter supplies an alphabetically arranged discussion of all the reserved words, functions and metacommands for IBM Pascal. The former supplies a topical discussion of many features, much as the original did, and gives instructions for executing the compiler, linker and the library manager. New with this version is support for the 8087 chip, double precision arithmetic and long integers (32 bit). Programs now can address up to 640KB of memory via the long heap management routines. Single level code overlays are supported as are DOS 2.x pathnames (both at compile time and at runtime). Data structures now can be as large as 64KB. The internal floating point format has been changed for reasons of 8087 compatibility. Because of the many different options that may be required, Pascal no longer comes with a ready-to-use object library. IBM supplies a SETUP procedure that makes installing Pascal relatively painless. There are two choices of DOS interface routines: DOS 1.1 and DOS 2.0. The former will produce files that can run under DOS 1.1 or DOS 2.x but will not support pathnames under 2.x. The latter supports pathnames but will not run under DOS 1.1 at all. There are three choices of math routines: 8087ONLY, REGMATH, and EMULATOR. As the names imply, the first choice will produce files that require the 8087 chip for execution; the second will produce results in a precision that is comparable to the old Pascal; and EMULATOR is for the undecided. These math routines will use the 8087, if available, and will produce the largest EXE files of the three choices and run slower than the REGMATH routines on machines without an 8087 chip (the higher precision costs). Note that this configuration is made once at installation time and need not be repeated every time the linker is run. All of this is made possible by the Library Manager, a program that has been available from Microsoft for nearly a year but is making its first appearance in an official IBM version. This utility can create object libraries and update existing ones. Object modules can be added, deleted or replaced on existing libraries. A cross-reference listing of a library can be generated¼ anΣ aε objec⌠ modulσ can be extracted from the library and placed into its own .OBJ file. This capability is extremely welcome as it was awkward to build a program from a number of separately compiled modules without it. A new version of the linker program, 2.20, is included on the library diskette. This version supports single level overlays and program sizes of up to 1 megabyte. There is no new linker directive to support overlays. Instead object modules to be placed in overlay are pre-processed with the MKOVL.COM program. The overlay loader PLOADER.OBJ is then included before the main program in the LINK command line. Each overlay is brought in explicitly by calls to the LOADER function from the main program. The Reference Manual has a rather lengthy example of this for those who may need the capability. This feature works only for programs that run under DOS 2.x; it will not work under DOS 1.1. Several bugs and short-comings of the original Pascal Compiler have been fixed in this release. The bug where the sine function returned incorrect values for negative angles has been fixed. It is no longer necessary to run CHKDSK to recover disk space after the compiler has terminated because of some error in the source code. The compiler and linker now set ERRORLEVEL so that batch files can check for compile errors. (You can even set ERRORLEVEL from your Pascal program, if you happen to stumble pAacross the documentation on how to do it, hint: see page 4-7). The default for the DEBUG compiler metacommand has been changed from ON to OFF. I have not had a chance to recompile any major programs, yet. I dug out my old sine test program (which demonstrated the old SIN error) and ran it through both compilers. I used the REGMATH library and set DEBUG to OFF in the source file to produce something like apples-to-apples comparisons. This program does little more than print out the values for SIN and COS for every 0.5 radian between -10 and 10 radians. The results are: Version 1.00 Version 2.00 Compile time 40 sec 44 sec Link time 1 min 4 sec 1 min 24 sec OBJ size 938 bytes 994 bytes EXE size 32384 bytes 31046 bytes Run time 22 sec 7 sec This is more a measure of the speed of the new math routines than of the generated code. Still, this kind of speed up is very impressive. The BYTE 'Sieve of Eratsthenes' test from the January 1983 issue gives a slightly different picture of the two compilers: Version 1.0 Version 2.0 Compile time 40 sec 44 sec Link time 50 sec 51 sec OBJ size 816 bytes 867 bytes EXE size 32512 bytes 26966 bytes Run time 17 sec 16 sec pò All these times are from the Norton TIMEMARK utility and thus include the load time from a floppy disk. The difference in the link and run times are within the variation that one might expect from one run to another; that is, no measurable speed difference. The significant improvement here is in the EXE file size. The new documentation for Pascal is not only larger, it is better; IBM has added a number of examples. There is even an explanation of how to use the DOSXQQ function; that was left as an exercise to the user last time. There are still a few oversights and omissions (like the setting of ERRORLEVEL mentioned above) but your chances of finding the information you want and of understanding it once you have found it are very much improved. Although the compiler can produce code that will execute on any supported configuration of PC, the compiler itself will only run under DOS 2.x, and it requires at least 192KB of memory. The manual suggests that object modules created by the version 1.00 compiler should not be linked with those created by the new compiler. They include the FILKQQ and FILUQQ modules. The INC module has been replaced by FINK.INT and FINU.INT; so, modules that included them will have to be changed before they will compile. The internal representation of floating point numbers has changed; so, binary data files that contain floating point numbers cannot be passed between programs compiled under the different versions. Documentation on the Unit U function calls and the detailed FCB are no longer included as IBM recommends that these interfaces not be used. The list price for the new compiler is $350. For a limited time, owners of version 1.00 can order the upgrade from IBM for $100; your Authorized Dealer has the forms for that right now. [Editor's note: A complete product announcement of the new Pascal version 2.0 appeared in the April aissue of Exchange.]