Extra Tools

Extra tools





Peter Barney,


Letchworth,


Hertfordshire.





Users of Bobby Rao's toolkit machine-code routines for the


Spectrum - page 77, February, Your Computer - may find


these routines useful also. List 3 and 4 are high-resolu-


tion left and right scrolls, but in each case, the byte


listed as 55 or 63 - use only one - will scroll with wrap-


around if 63, or with a white pixel from left or right, as


appropriate, if 55. This same byte poked 0 gives inverse


characters with wrap around.


List 1 and 2 are high-res up or down scrolls, which may


be of interest as they are much shorter - 53 and 55 bytes -


than the 99 and 97 of the published routines.