GRIPE CURE
Julian Vincent, Reading, Berkshire.
from Your Computer, December 1982

I HAVE JUST solved a problem which has been plaguing me on my Spectrum. It
occurred after editing lines which ended in the inverted video mode.
Occasionally I would edit such a line only to find that the Spectrum
belched as if it were full and refused to list any more of the program.
Also the cursor was very sluggish.

The answer seems to be due to the way Inv Video and True Video act. Inv
Video puts 20,1 into two memory locations in the line, although of course
there is nothing on the screen to show this. If you press either key
several times you fill up that program line two locations at a time.

If you happen to end an inverse video line with two presses of the True
Video control, that is, 20,0,20,0 in RAM and make a hash of editing it
later, you can end up with 20,0,0, at the end of the line, which the
Spectrum does not like.

It is easily corrected but caused me some problems until I sorted it out.

   1 REM
   2 LET a=PEEK 23635+256*PEEK 23636
   3 PRINT a;" ";PEEK a: LET a=a+1: GO TO 3

23755 0         -----           23755 0
23756 1           |             23756 1
23757 12          |             23757 12
23758 0           |             23758 0
23759 234         |             23759 234
23760 20          |             23760 20
23761 0           |             23761 0
23762 20     This is all        23762 20
23763 0         line 1          23763 0
23764 20          |             23764 20
23765 0           |             23765 0
23766 20 --.      |         .-- 23766 20
23767 0    | Swap last two  |   23767 20  --.
23768 20   |   to give      |   23768 0     |This jams the computer
23769 0  --.      |         .-- 23769 0   --.
23770 13        -----           23770 13
23771 0                         23771 0
23772 2                         23772 2
23773 39                        23773 39
23774 0                         23774 0
23775 241                       23775 241
23776 97                        23776 97
.....

If you POKE 23767,0 everything works. You must have 20,0,0.
