Used by several routines to blank out the address of the controlling routine held in
bytes 9 and 10 of the character's buffer. This has the effect of making the routine
at 25296 consider the address held in bytes 3 and 4
of the character's buffer as the next candidate for controlling routine.
25488
2E0A
LD L,10
Byte 10 of the buffer contains the MSB of the address of the routine which has
just surrendered control of the character