Texas Instruments 990 User Manual page 108

Applications Programming
4.6 FORTRAN AND PASCAL PROGRAMMING EXAMPLES
Applications programs written in FORTRAN or Pascal can interface
with the communications package by calling assembly language
subroutines. These subroutines build the SVC blocks, using the
parameters passed to the subroutine, and then execute the SVCs.
The following paragraphs provide an example of the assembly
language subroutines required, describe calls to the subroutines,
and provide examples of programs that use the subroutine calls.
The examples given are for FORTRAN programs, but are similar to
those for Pascal programs. For Pascal programs, the subroutines
WRIT4D, READ4D, and WKUP4D must be declared as EXTERNAL FORTRAN.
All Pascal parameters must be defined as variable parameters
(VAR).
4.6.1 Assembly Language Subroutine for FORTRAN Interface
Figure 4-7 shows an example of the assembly language code that is
required for the FORTRAN interface with the communications
package. This code builds the SVC blocks that allow FORTRAN
programs to execute read (READ4D), write/send (WRIT4D), and
request activation services (WKUP4D). The object code for this
routine is on file .INDSCOMM.OBJ.SUB4D. This· file contains a
module that has been partially linked with a module (F$RGMY) from
the FORTRAN run-time library. Thus, Pascal users do not need the
FORTRAN libraries when linking.
4-22
227 05 26 - 9 70 I