Commodore Plus 4 - Page 322

Bit
0
1
2
3.
4
5
6
7
Tape I/O
—
short block
long block
read error
checksum error
end of file
end of tape
Serial I/O
timeout write
timeout read
—
—
—
—
end or identify
device not present
RS232I/O
parity error
framing error
receiver buffer overrun
receiver buffer empty
clear to send missing
—
data set ready missing
break detected
For the 1541 disk drive, the end or identify bit set usually means the end of file
has been reached. Also, for a LOADSP ($FFD5) with the verify flag set, bit 4 set
means that a verify error was found.
$FFBA SETLFS
Registers Altered: none
Prepares for a call to OPEN ($FFC0), LOADSP ($FFD5), or SAVESP
($FFD8). Before calling the routine, set .A to the logical file number to be
associated with the file (needed for OPEN only), .X to the device number, and. Y
to the secondary address to be sent to the device for OPEN; for LOADSP, a zero
for this secondary address causes a relocated load. If no secondary address is
needed, set ,Y to $FF.
SFFBD SETNAM
Registers Altered: none
Prepares for a call to OPEN ($FFC0), LOADSP ($FFD5), or SAVESP
($FFD8). Before calling this routine, set .A to the length of the file name, .X to the
low byte of the address of the file name, and .Y to the high byte of the address of
the file name. If no file name is needed, set .A to $00.
SFFCO OPEN
Registers Altered: .A, .X, .Y
This routine is vectored through $0318-$0319. It opens the logical file specified
in calls to SETLFS ($FFBA) and SETNAM ($FFBD).
If an error occurs, the message flag (see SETMSG, $FF90) is consulted to
determine what message (if any) to output. The carry is returned set, and .A
contains the error number. Possible errors are as follows:
$01 = The logical file table is full.