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UDG.BAS by John P Stevenson

UDG.BAS is a 1987 program by John P Stevenson which allows the PCW character set to be redefined: a forerunner of LetaEdit. It is supplied with 10 example fonts. Some of these are raw 2048-byte font files (with the file type .UDG); others are .COM files that install the font when run.

Before UDG.BAS can be used, UDG.COM must be run. This copies a number of machine-code helper functions into memory, which are then called by UDG.BAS. UDG.BAS does not check that its machine-code helper routines are present before trying to call them, so it's left up to the user to get this right.

Both UDG.BAS and the .COM files are specific to the PCW, and don't check that they are running on the PCW before attempting to use PCW features.

A number of the fonts contain "icons" in the range 127-142 — that is, two 32x16 graphics each composed of eight character tiles. At the PCW aspect ratio, they look like this:

There appears to have been a bug in the process used to generate the icons, in that the first line of the following character (number 143) has also been blanked.

In the supplied .PSF files, characters used in icons have been mapped to the Unicode Private Use Area.



The self-loading .COM files have been rebuilt to support operation on the CPC, Spectrum +3 and PcW16.

The fonts define only characters 0-249, leaving 250-255 either containing random data or a placeholder bitmap.

  • BOLD.COM: Self-loading font for PCW, CPC, Spectrum +3 and PcW16
  • BOLD.UDG: Font in raw .UDG format
  • BOLD.PSF: Font in PSF format
Charset 1
Charset 2 Identical to the standard PCW character set, except for the copyright sign and the undefined characters 250-255.
Charset 3
Fatty FATTY.COM only defines the first 128 characters, hence the abbreviated preview image.
Fenice 2
Fenice  B
Tidy mk2
UDGFin Almost identical to Tidy Mk2, except for a few differences in the digits and the icons.

Other files

John Elliott 2021-01-09