Commodore Amiga A500 Technical Reference Manual page 134

READ SHlFT STATUS (AH
=
02H)
INPUT: DS
=
ROM data segment (0040h)
OUTPUT: AL
=
SHlFT STATUS BYTE
CASSEITE INT 1 SH DSR
OUTPUT: AH
=
8 6 h , Error code, Carry set.
Interrupts off
KYBDSR ENTRY POINT
READ KEYBOARD INPUT (AH
=
OOH)
VIA S / W INT
16H
INPUT: DS
=
ROM data segment (0040h)
OUTPUT: AL
=
ASCll CHARACTER
AH =SCAN CODE
READ KEYBOARD STATUS (AH
=
01 H)
INPUT: DS
=
ROM data segment (0040h)
OUTPUT: AL
=
ASCll CHARACTER
AH =SCAN CODE
Z FLAG
=
1 if no character available
Z FLAG
=
0 if character available
READ SHlFT STATUS (AH
=
02H)
INPUT: DS
=
ROM data segment (0040h)
OUTPUT: AL
=
SHlFT STATUS BYTE
PRINTER ENTRY POINT
PRINT CHARACTER (AH
=
OOH)
VIA S/W INT 17H
INPUT: AL
=
Character to output
DX
=
Index to Printer k b l e port
+
1
(the Status port)
CX
=
Timeout value
OUTPUT: AH
=
Printer Status