systemc: Get rid of an unused private member in sc_clock.

It's not useful, and having it makes clang upset.

Change-Id: I51366fd18a287e186c88f08af5c6ba8692779003
Reviewed-on: https://gem5-review.googlesource.com/c/13876
Reviewed-by: Gabe Black <gabeblack@google.com>
Maintainer: Gabe Black <gabeblack@google.com>

systemc: Switch to using predefined messages for channels.

Create and use predefined messages for channels which match the ones
Accellera uses.

Change-Id: I179214838bbd83604e50225926cdc6b5b1b16923
Reviewed-on: https://gem5-review.googlesource.com/c/13330
Reviewed-by: Gabe Black <gabeblack@google.com>
Maintainer: Gabe Black <gabeblack@google.com>

systemc: Add some error checks to sc_clock.

The Accellera version reports an error if the period, high or low
portions of the clock are zero.

Change-Id: I2cbb7c3a1b6abe4d969ef875ebf8754d2d1c489a
Reviewed-on: https://gem5-review.googlesource.com/c/13303
Reviewed-by: Gabe Black <gabeblack@google.com>
Maintainer: Gabe Black <gabeblack@google.com>

systemc: Implement the sc_clock::time_stamp function.

This is just a non-standard static alias for the sc_time_stamp
function.

Change-Id: Ibcd0559e7dab8232528628259abb8d1bfaee16e0
Reviewed-on: https://gem5-review.googlesource.com/c/12619
Reviewed-by: Gabe Black <gabeblack@google.com>
Maintainer: Gabe Black <gabeblack@google.com>

systemc: Keep all pre-init processes on a single list.

We were keeping track of processes which should be initialized and
those which shouldn't on two different lists, and then processing
each list one after the other. This could reorder processes from the
order they were created, and so cause spurious differences which cause
the Accellera tests to fail.

This does make the scheduler slightly simpler, so it's not all bad.

Change-Id: I63306a41ce7bea91fa9ff2f6774ce9150134ce48
Reviewed-on: https://gem5-review.googlesource.com/c/12613
Reviewed-by: Gabe Black <gabeblack@google.com>
Maintainer: Gabe Black <gabeblack@google.com>

systemc: Change how sc_clock creates processes to match the tests.

Accellera sets up the mechanism which toggles sc_clock differently
than it's set up in gem5. This change moves things around a little to
more closely match the order things are done by Accellera so that the
test output matches.

Change-Id: Ia6d327f4cd5d689f6969398f02a66278a3dc010c
Reviewed-on: https://gem5-review.googlesource.com/c/12609
Reviewed-by: Gabe Black <gabeblack@google.com>
Maintainer: Gabe Black <gabeblack@google.com>

systemc: Warn if a process is dont_initialize with no static sensitivieis.

Change-Id: I4db64f42872a6fb459faa401abdad3f168297347
Reviewed-on: https://gem5-review.googlesource.com/c/12599
Reviewed-by: Gabe Black <gabeblack@google.com>
Maintainer: Gabe Black <gabeblack@google.com>

systemc: Raise an error when SC_METHOD, etc. is used after starting.

Those mechanisms for creating processes are only allowed before the
end of elaboration, or in other words before sc_start is called.
Technically the check in Accellera's implementation won't trigger if
the simulation is stopped, and we immitate that behavior.

Change-Id: I9b8b5bd32f876781b6e0d5c0ee0e09de19bdabc1
Reviewed-on: https://gem5-review.googlesource.com/c/12447
Reviewed-by: Gabe Black <gabeblack@google.com>
Maintainer: Gabe Black <gabeblack@google.com>

systemc: Implement a significant portion of sc_clock.

Change-Id: Ic195f46ac13b46a02c86a5fc8d90ba66a415a9c8
Reviewed-on: https://gem5-review.googlesource.com/12215
Reviewed-by: Gabe Black <gabeblack@google.com>
Maintainer: Gabe Black <gabeblack@google.com>

systemc: Add the nonstandard time_stamp function.

Change-Id: I608c390b125611e5b62483c7e8567bb5479df553
Reviewed-on: https://gem5-review.googlesource.com/11281
Reviewed-by: Gabe Black <gabeblack@google.com>
Maintainer: Gabe Black <gabeblack@google.com>

systemc: Add some deprecated features to sc_clock.*.

Add in two deprecated typedefs, and a deprecated constructor. These
are necessary to get the regressions to build.

Change-Id: Id8320a67c680acbca0abaee9898158ffd2678d67
Reviewed-on: https://gem5-review.googlesource.com/11183
Reviewed-by: Gabe Black <gabeblack@google.com>
Maintainer: Gabe Black <gabeblack@google.com>

systemc: Stub out the predefined channels.

Change-Id: Ie030aad26875bd49e54981ec1e9076b7b5af6630
Reviewed-on: https://gem5-review.googlesource.com/10839
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
Maintainer: Gabe Black <gabeblack@google.com>