Texas Instruments 990 User Manual page 113

Applications Programming
4.6.2 Subroutine Calls
The following paragraphs describe the calls, which are similiar
for FORTRAN and Pascal, to the previous assembly language
subroutine. Unless stated otherwise, all parameters passed in
the call statements must be 16-bit integer variables (INTEGER*2
in FORTRAN and INTEGER in Pascal). In the syntax definition for
each call statement, the parameters are enclosed in angle
brackets « » , . indicating that they are to be replaced by your
assigned variables.
Note that available network IDs are always expressed as' BCD
numbers in the range 0100 through 9999. However, they must be
supplied in applications programs in hexadecimal format. For
example, a network ID of 0431 would be entered in the program as
>0431. The characters A through F are invalid for all network
IDs. The IDs 0000 to 0099 are reserved for the communications
package software.
The subroutine calls
activation services
paragraphs.
for read
(WKUP4D)
4.6.2.1 READ4D Subroutine Call.
(READ4D), write
are described in
(WRIT4D) , and
the following
Subroutine READ4D builds an SVC block and executes an SVC with
I/O opcode 3. A call to this subroutine causes one block of data
addressed to the calling program to be transferred from a
communications input buffer to the
program~s
data buffer. A
program can either execute a call to READ4D and test the status
code to determine if any input data was found, or request
activation services with subroutine WKUP4D and then retrieve the
data with subroutine READ4D after it has been reactivated. One
call to subroutine READ4D retrieves one block of data; retrieving
multiple blocks of data requires multiple calls. The syntax for
the call statement is as follows:
FORTRAN:
CALL READ4D«buffer>,<buf lng>,<char cnt>,<did>,<sid>,<st code»
Pascal:
READ4D«buffer>,<buf Ing>,<char cnt>,<did>,<sid>,<st code»
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