COPY FUNCTION (16K ZX-81)
by A Tugwell, Walton-on-Thames, Surrey
from Your Computer, April 1984, pages 188 and 191

Using the COPY command on the ZX-81 is a simple and effective way of dumping
the contents of the screen to the ZX Printer but it does have one drawback -
it copies the whole of the screen even though the bottom half or more is
blank.

The routine that I wrote to solve this problem is 51 bytes in length and,
for a change, is slower than the equivalent Basic. It will also only work
with a fully expanded display file.

If you study lines 330 to 380 you will see that the routine will only copy
down to the line where the last "printing" has occurred.
