G007 ROM: 0x2800 to 0x2FFF

Dec. Hex. Bytes System Calls: G007
10566 2946   Plot N routine, with N in register A
11737 2DD9   Delete high-res display file.
Temporarily sets fast mode, so CALL 519 afterwards.
11807 2E1F   Check and set up hi-res display file if not already there.
Also checks that system variables have been initialised.
11858 2E1F   Clear the screen
This is equivalent to CLS n in BASIC.
The routine should be called with the value of n in the accumulator.
      Setting the high/low resolution mode
There is no easily accessible routine for setting display mode. This can be done by loading the Z80 register I with 30 (1EH) for low-res display, or 31 (1FH) for hi-res display.