T7TplFix ======== Summary ------Bugfix Patch for Turbo/Borland Pascal "Run Time Error 200" bug in the delay initialisation that occurs on fast PC's (Pentium II with approx. 233 MHz and above). Patch program for run time library files (TURBO.TPL and TPP.TPL) of Turbo Pascal and Borland Pascal versions 7.0 and 7.01. License ------This program is free to use but comes without warranty of any kind, use it on your own risk. Please send me an e-mail if you used this as motivation to spend time in helping others again. Donations are of course welcome. Use --1. Make a backup copy of your files TURBO.TPL and optionally TPP.TPL 2. Run the patch program T7TplFix in the directory that contains the original run time library file TURBO.TPL and/or TPP.TPP of Turbo Pascal 7.0 or 7.01. 3. Recompile your programs to include the new Run Time Library in them. Notes: - Turbo Pascal and Borland Pascal version 7.01 report themselves as version 7.0, but the time of all files is 07:01 - the file TPP.TPL is only included in Borland Pascal, not Turbo Pascal - the difference between Borland Pascal and Turbo Pascal is that Borland Pascal can compile for protected mode and windows and includes additional things, for example the source of the run time library, the assembler, the profiler and an external debugger. Advantages ---------Advantages of this patch program - ONLY the single modifications described below is applied, all other contents of the Run Time Library remain completely unchanged. Most other patch programs for this problem do lot's of undocumented changes to the SYSTEM.TPU. Maybe that's just a strange effect of recompilation, but I'm not sure about that because changing only CRT does not require any thanges in SYSTEM and the number of changes seems to be far bigger than can be explained just by new date stamps. - Patches also version 7.01 unlike the original TPL distributed by c't,

that was based on 7.0 only. That old version has several bugs that are reintroduced by using that patched TPL. - Does not require the run time library source that is only available if you have purchased the more expensive Borland Pascal instead of the smaller Turbo Pascal. Details ------The delay count variable is changed from 16 to 32 bits. This prevents it from overrunning on fast PC's. The patch being applied is the one as distributed by German c't magazine. The differences are listed in the included file CRT.DIF FAQ --Frequently asked questions (and answers). Please read these *before* asking me any questions! - Where can I find more informations? See the web pages on http://www.brain.uni-freiburg.de/~klaus/pascal/runerr200/ - Is an official fix for this bug available from Borland / Inprise? Unfortunately not! If you think they should provide one, please send an email to customer-service@inprise.com and tell them so. - Is a fix available for compiled programs of which I don't have source? Yes if that program does not require precise timing, otherwise probably not. See the web page mentioned at question 'more informations'. - Why do you not simply distribute the patched file CRT.TPU or TURBO.TPL ? It is copyrighted, distributing that file may be illegal. I asked Inprise for permission but they sent an inappropriate canned reply without having read my mail. I tried again and didn't get any reply at all. - The patch program does not list any of the patches as applicable Either none of the files TURBO.TPL, TURBO.TPP, CRT.TPU, and CRT.TPP is in the current directory or they are not original (they may already be patched or they contain other changes). Make sure that you run the program in the same directory where the file TURBO.TPL (and optionally TURBO.TPP) is stored.

If that doesn't help, restore the file(s) from your original disks. If you have applied custom changes to the Run Time Library, then read the section about custom changes below. - The patch program lists only part of the patches as applicable This is normal. If you have Turbo Pascal, then usually only one of the two Run Time Library patches for real mode (file TURBO.TPL) can be applied. If you have Borland Pascal, then additionally one of the two Run Time Library patches for protected mode (file TPP.TPL). The files CRT.TPU and CRT.TPP are normally hidden inside the Run Time Library. These two patches are only included separately for special purposes. Most users won't need them. - Is a patch also required for Run Time Library for Windows ? I didn't ever compile for Sindows, but as far as I have seen there's no CRT unit for Windows, so there's also nothing to patch. - How can I find out if I have Turbo Pascal version 7.0 or 7.01 Look at the time stamp of the files in your Turbo Pascal directory or on the original disks. If the time is 07:00, then you have version 7.0 If it's 07:01, then you have version 7.01. - What is the difference between Turbo Pascal 7.0 and 7.01 Version 7.01 contains several bug fixes. - Should I try to obtain version 7.01 if I only have 7.0 Definitely yes, contact Borland but note that many people there don't know about a version 7.01. I have been told that it's possible to request replacement disks. They automatically contain the latest version. However this has been reported to be expensive outside the US. - What exactly does this program change in the run time library? See the section Details above and check the included file CRT.DIF - How comes that an overrun results in a "Division by Zero" error ? Borland didn't distinguish between these two errors in that case. - What does the delay initialization do, how does the delay procedure work? PC's have a hardware timer that ticks 1193180 times per second. This is divided in hardware by 65536 to get the Bios timer ticks. The delay initialization waits for a timer tick, then runs in a tiny loop

until the next timer tick and counts how often it can loop during that time. These timer ticks occur about 18.2 times per second, i.e. one about every 55 milliseconds. The initialization then divides the number of loops per tick by 55 to get the number of loops per millisecond. The delay procedure multiplies the number of loops per millisecond found in the initialization with the number of requested milliseconds for the delay. Then it runs the loop that number of times. - Why does the new code multiply with 1193 where the original divides by 55? It does not only multiply with 1193, it additionally then dumps the lowest order word of the result of that multiplication, so it effectively also divides by 65536. Both combined results effectively in a division by 54.934. This is done because 55 is not exactly the correct number. 54.934 is also still not exact, but nearer the real thing (about 54.925). - What has happened to the additional patch that disables interrupts during delay initialisation to make the timing more reliable? This was included in an earlier version of this patch program, but I decided to remove it for compatibility reasons. This would disable all interrupts each time a program starts that includes that code. This could for example cause data loss if a serial transmission is running at that time. I was never told about this actually happening, but it may happen, so I removed it. - Is the source of the patch program available so I can tell myself what exactly it changes? I can send you the source if you really want, but it won't tell you much because it's a general purpose patch program that reads a data file to know what exactly to patch and how. All information is in the data file. To see what this does simply compare your TURBO.TPL before and after patching. - How comes that I find a big number of changes in my TURBO.TPL after applying the patch? Take into account that several bytes are *inserted*, so the rest of the contents is moved to make space inbetween. For a thorough comparison, extract the TPU files from the TPL and compare them separately. You will find all files except CRT.TPU being completely unchanged. Now look at CRT.TPU. Ignore the changed link and debug informations at the beginning and the end of the file and look for changed and a few inserted bytes in two places (delay initialization and delay call) about in the middle. Behind that you'll find all other bytes moved and only few more single bytes changed, probably because they contain jump addresses and those have changed due to the move. - My copy of TURBO.TPL does contain custom changes and I want to keep them If your changes are not in the CRT unit, then use TPUMOVER to extract

CRT.TPU from your TURBO.TPL (and optionally CRT.TPP from TPP.TPL) and let the program patch them. Then move them back into the Run Time Library files. If your changes are in the CRT unit, you must either apply the Runtime Error 200 patch manually in addition to your patches, or reinstall the original CRT unit, let the program patch it and then apply your changes again. Revision History 1.0 first release 2.0 chg: easier to use add: patch crt.tpu add: patch turbo.tpl and tpp.tpl of version 7.0 2.01 fix: strings, windos and winapi were erased from tpp.tpl - end -