1. Example of subroutine call

Below is a simple example of calling a subroutine using its parameters and local variables.

Implement a program that adds two single characters and returns a double character result.

The subroutine 'addition' implements this logic.

图1 Subroutine parameter filling

Implement an input bit parameter as an execution enable.

Implement two input single character parameters as operands for addition.

Implement a dual word parameter output as the result.

图2 logic realise

The ladder diagram below implements the call logic.

When M0=ON, D2=D0+D1. When M10=ON, D12=D10+D11.

图3 External call

The parameters for two CALL instructions are filled in as follows.

图4 Parameter filling for the first CALL instruction

图5 Parameter filling for the second CALL instruction