BBC BASIC for Windows version 6.15a released

Richard_Russell

I have released version 6.15a of BBC BASIC for Windows. This is a maintenance release, primarily to fix a serious bug discovered in version 6.14a. I have also taken the opportunity to improve compatibility with BBC BASIC for SDL 2.0 by introducing a few features supported in that version but not previously in BB4W.

The changes are as follows:

1. Interpreter / Run-Time Engine:
   
   Fixed a nasty memory leak on partially initialising a string array. Oops!
   
   Fixed a bug in VDU 127 (DEL) when in VDU 5 mode, which did not work correctly if the text direction was changed. Also altered its behaviour to match Acorn versions (the background is always plotted opaque, irrespective of the GCOL mode).
   
   Added support for (e.g.) DIM ]^P% 1000, for compatibility with 64-bit editions of BBC BASIC.
   
   Added the SUM (modulo-64-bit addition) operator, for compatibility with BBCSDL.
   
   Added GCOL modes 5-7, for compatibility with BBCSDL and Acorn versions.
   
   Increased the palette size to 256 entries, for compatibility with BBCSDL (although the COLOUR and GCOL statements limit the number of logical colours to 128).
   
   Improved support for odd-value graphics coordinates, especially relative coordinates; errors should no longer accumulate.
   
   
2. Libraries:
   
   Updated the IMGLIB library to support loading and displaying animated GIFs.
   
   
3. Example Programs:
   
   Added the following example programs, virtually identical to those supplied with BBC BASIC for SDL 2.0:
   
   In EXAMPLES\GENERAL: CONWAY.BBC and KERNING.BBC.
   In EXAMPLES\GRAPHICS\: ANIGIF.BBC.
   In EXAMPLES\PHYSICS\: CRADLE.BBC.
   In EXAMPLES\SOUNDS\: METRONOME.BBC.

To upgrade the full (paid-for) version of BBC BASIC for Windows to v6.15a download and install upgrade.exe from the web site; remember that you are allowed to install it on multiple computers so long as only one copy is in use at any given time. To upgrade the trial version (or install it from scratch) download and install bbcwdemo.exe from the same place. It is possible that these executables may trigger security alerts until they have acquired a reputation for safety.