
July 1985 - published in Popular Computing Weekly, May 1986

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UDG Editor on Spectrum

by Geoffrey Wearmouth

UDG Editors - you've got plenty - but this one is so tiny it will fit
in the printer buffer. That means you don't have to alter RAMTOP
before loading and you won't corrupt the program you wish to modify.

Such a program should not define characters in DATA statements, but
start by loading the character codes. Similarly it should have a
routine that saves the character codes after the BASIC program.

To add this utility to your toolkit, just type in the listing and
run. If you get the 'OK' message, save the contents of the printer
buffer with

	SAVE "UDG" CODE 23296,256

To use the editor enter

	RANDOMIZE USR 23296.

The control keys are shown in the listing.

If you have a rubber keyboard then the following pokes remove the
need to press SHIFT with the cursor keys and use '0' for plotting.

	POKE 23543,53
	POKE 23545,56
	POKE 23547,54
	POKE 23549,55
	POKE 23541,48

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