Table of Contents
Advertisement
I/O Handling
159
UTILITY:
Mm read xfer
General Procedure: The MSTID is used to retrieve the record from the device buffer. The
record is stored into a location set aside for the purpose.
Special Requirements:
The MSTID must be available from a previous call to
Mm read start. A location of 128 consecutive words must be set aside to hold the contents of
-
-
the record when they are returned by the utility.
Calling Procedure:
1. Load register A with the contents of the MSTID.
2. Load register B with the address of the storage location for the data.
3. Call the utility. The transfer may not be completed on the first or subsequent calls (see
exit conditions). In that case, to successfully complete the transfer, all three steps must
be repeated.
Exit Conditions:
RET 1
Occurs when the transfer is not completed.
It
is up to y~ur routine at this point to
decide whether another attempt should be made immediately, or whether some-
thing else should be executed (and to come back later).
RET 2
Occurs when the transfer is complete. The location specified contains the data. If
register A contains a non-zero value, an error occurred and A is the error number. In
addition to mass storage errors (80 through 99), error 19 is returned if the MSTID
parameter is invalid.
CAUTION
Pressing RESET (
(CONnll
STOP
I)
during execution of either of the
above utiities may cause a SCRATCH A to occur.
Advertisement
Table of Contents
