Texas Instruments 990 User Manual page 95

Applications Programming
5. The applications program executes a read call (I/O
opcode
3)
to re tr ieve the da ta add ressed to it. If a
time delay has been requested, an error on the read
call could indicate that activation services did not
activate the program, but that the operating system did
a t the expira tion of the time delay. -
To request activation services,
execute the appropriate SVC.
contain the opcode >40. The I/O
block specifies the operation
perform. The I/O opcodes for
range from 4 through 7.
the applications program must
Byte
0
of the call block must
opcode in byte 2 of the call
that activation services is to
requesting activation services
After the activation services request is made, the applications
program should make the appropriate inactive state request by
executing one of the following SVCs':
*
Time Delay SVC, if the request for activation services
is to be activated from a time delay. A delay request
of 5 to 15 seconds (depending on the number of attached
secondary stations and the amount of traffic flow in the
network) should be made.
*
Suspend SVC, if the request for activation services
to be unsu spend ed •
is
*
Terminate SVC, if the request for activation services is
to be bid.
4.2.2.1 Activation Services Call Block.
For activation services calls, the SVC block consists only of
bytes 0 through 3; the remainder of the call block is not
required for these calls. The format for the call block is shown
in Figure 4-2. The data contained in the call block originates
as follows:
*
Data supplied by the applications program:
SVC >40
I/O opcode
*
Data returned by the SVC processor:
Status/error code
2270526-9701
4-9