Commodore 128 Programmer's Reference Manual page 443

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THE COMMODORE 128 OPERATING SYSTEM 433
1 e. Keyboard data is input by turning on the cursor, reading characters from the
keyboard buffer, and echoing them on the screen until a carriage return is
Pj encountered. Characters are then returned one at a time from the screen until
I \ all characters input have been passed, including the carriage return. Any calls
after the EOL will start the process over again.
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I | The path to BASIN is through an indirect RAM vector at $324. Applications
may therefore provide their own BASIN procedures or supplement the system's by
^ redirecting this vector to their own routine.
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28. $FFD2 BSOUT ;output to channel
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PREPARATION:
Registers:
Memory:
Flags:
Calls:
RESULTS:
Registers:
Memory:
Flags:
EXAMPLE:
LDA #character
JSR $FFD2
.A = character
system map
none
CKOUT (if necessary)
.A = error code (if any)
STATUS, RSSTAT updated
.C = 1 if error
;output a character
BSOUT (alias CHROUT) writes the character in .A to the current output
device (DFLTO $9A). Output to devices other than the screen (the default output
device) must be OPENed and CKOUTed. The character is written to the output
buffer associated with the current output channel:
a. Cassette data is put a character at a time into the cassette buffer at $B00, with
tape blocks being written when necessary.
b. RS-232 data is put a character at a time into the RS-232 output buffer at $D00,
waiting until there is room if necessary.
c. Serial data is passed to CIOUT, which buffers one character and sends the
previous character.
d. Screen data is put into screen RAM at the current cursor position.
e. Keyboard output is illegal.
The path to BSOUT is through an indirect RAM vector at $326. Applications
j i may therefore provide their own BSOUT procedures or supplement the system's by
' redirecting this vector to their own routine.