Campbell CR9000, Instruction Manual

Page: 192 / 218

Section 9. Program Control Instructions
9-6
Call
The Call statement is used to transfer program control from the main program
to a subroutine.
Syntax
Call
Name ( List of Variables )
Remarks
Use of the Call keyword when calling a subroutine is optional.
The Call statement has these parts:
Part Description
Call
Call is an optional keyword used to transfer
program control to a subroutine..
name The Name parameter is the name of the
subroutine to call.
List of Variables or Constants The list may contain variables, constants, or
expressions that evaluate to a constant (i.e., do
not contain variable) that should be passed into
the variables declared in the subroutine.
Values of variables passed can be altered by
the subroutine. If the subroutine changes the
value of the subroutine declared variable, it
changes the value in the variable that was
passed in. If a constant is passed to one of the
subroutine declared “variables”, that “variable”
becomes a constant and its value cannot be
changed by the subroutine.
You are never required to use the Call keyword when calling a subroutine. If
you use the Call keyword to call a procedure that requires arguments , the
arguments list must be enclosed in parentheses. If you omit the Call keyword,
you also must omit the parentheses around the arguments list.
You can pass arguments to a procedure by reference or by value. Values of
arguments passed by reference can be altered by the procedure when the
arguments are returned; CRBasic supplies the actual address of the argument .
Call Statement Example
See Sub description in Section 5.
Call Table
Used to call a data table.
Syntax
CallTable
Name
Remarks
Calls DataTable that has been declared above BeginProg. When the DataTable
is called, it will process data as programmed and check the output condition.
CallTable Example
This example uses CallTable to transfer program control to the ACCEL table.
CallTable ACCEL