User guide

19-35

Using the VCS / SystemC Cosimulation Interface

The return keyword is only allowed once for each task. It becomes

an output argument on the Verilog side to a return value on the

SystemC side. This feature is required because blocking functions in

SystemC may return values, while Verilog tasks do not have a return

value.

There is one special case here. If the methods of the SystemC

interface class use reference parameters, for example

my_method(int& par), then you need to mark this parameter as

inout& parameter in the interface definition file. Note that the &

appendix is only allowed for inout parameters. For input

parameters this special marker is not needed and not supported. Pure

output parameters that should be passed as reference must be

defined as inout in the interface definition file.

Example interface definition file for the simple_bus blocking

interface:

interface simple_bus_blocking_if

direction sv_calls_sc

verilog_adapter simple_bus_blocking_if_adapter

systemc_adapter simple_bus_blocking_if_adapter

#include "simple_bus_blocking_if.h"

task burst_read

input int unsigned priority_

inout int data[32]

input int unsigned start_address

input int unsigned length

input int unsigned lock