Purpose: Restore default channels
Call address: $FFCC (hex) 65484 (decimal)
Registers: none Memory: system map Flags: none Calls: noneResults:
Registers: .A used .X used Memory: DFLTI, DFLTO updated Flags: none
Description: CLRCHN (alias CLRCH) is used to clear all open channels and restore the
system default I/O channels after other channels have been established via CHKIN
and/or CHKOUT. The keyboard is the default input device and the screen is the
default output device. If the input channel was to a serial device, CLRCH first
UNTLKs it. If the output channel was to a serial device, it is UNLSNed first.
The path to CLRCH is through an indirect RAM vector at $322. Applications may therefore provide their own CLRCH procedures or supplement the system's by redirecting this vector to their own routine.
JSR $FFCC ;restore default I/O