Utility1

Utility 1 - UDG Editor and Font Editor 28-MAR-1998 Geoff Wearmouth.

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This is the first in a series of screen-resident utilities for the

ZX Spectrum range and emulators. These programs are different because

the loading screen is the program. They are called using INPUT USR

16384. All three are self-deleting and have to be reloaded every

time they are required.



The file is saved to a tapfile with a demo basic program that explains

most features and contains some imperfect characters and udg's to

experiment with.

All you really need is the SCREEN$. Resave it to your tools tapfile

or microdrive. A snapshot is no good but a .scr file can be handy.



The advantage of screen-resident utilities is that they are easy to load,

easy to delete and can be used regardless of the size of your program

and without altering RAMTOP.



I developed 'u1' so that I could work directly with characters in

my programs without merging in a Basic editor ar leaving room above

RAMTOP for a machine-code one. My first attempt was 255 bytes long

and lived in the printer buffer.



The Program

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The program can best be examined by using it against one of your

own programs. In the example program the font can be found by using

the left arrow in the Character Set Menu. This will scan down

through memory and any graphics stored as successive bytes will

reveal themselves.

On the 16K Spectrum, the top 32K of memory is ignored.

On the 128K Spectrum there are 19 UDG's instead of the 21 of the

48K Spectrum.

There is no facility to save characters from within the program.

The idea is that you resave your entire program after modifying

the characters.

The address of the start of the character set is given on the

respective Help page available from the Menu and the length is just

the number of characters multiplied by eight.



History

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Mar 89 v1.1 published on Outlet magazine, Issue19.



Mar 98 bar changed from green to cyan.

Basic demo written.

Obsolete Outlet address removed from help screens.

v1.2 uploaded to ftp incoming directories.



Limitations and Features

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The program uses only Screen memory and the system

variables associated with the screen. Apart from resetting CHARS

to normal and CAPS LOCK off, the program does not affect your

Spectrum in any other way apart from altering the characters

of course.



The program uses ROM routines so is unlikely to work on standard TS2068.



Send bugs to gwearmouth@hotmail.com