Printing on the Bottom Line

According to Sinclair’s programming manual, you cannot PRINT on the bottom two screen lines. This is not quite true. Here are two different ways to PRINT where you aren’t supposed to.

1. One way:

  10 LET L=USR 2591
  20 PRINT "THE BOTTOM LINE"
  30 PAUSE 1000

USR 2591 is a routine in the 8K ROM that clears the bottom part of the screen and is then effectively PRINT AT 23,0;. This method is crash-proof, but AT and TAB still won’t work at the bottom.

2. Another way:

  10 POKE 16418,0
  20 PRINT AT 23,7;"THE BOTTOM LINE"
  30 FOR N=0 TO 23
  40 PRINT AT N,0;N
  50 NEXT N
  60 POKE 16418,12
  70 PAUSE 1000

You can now PRINT to the entire screen, even using AT and TAB. Be careful–if you INPUT while address 16418 (DF SZ) is less than 2, the computer crashes. PLOT still starts two lines above the bottom.