Re: sc_pause and sc_get_status() - RESEND

John, Phillip, I would much rather read:

if( sc_get_status() &
( SC_BEFORE_END_OF_ELABORATION |
SC_END_OF_ELABORATION | .
SC_START_OF_SIMULATION ) ) {

// do stuff safe in any stage of elaboration...

}

Users could predefine the bitmask and use that:
#define SC_ELABORATION (SC_BEFORE...) at their peril.

The slight advantage/danger of our defining this for them is that when/if we later decide to divide a stage into a sub stage (prepone...), we can add the new stage into our bitfield, and make their code work automatically (break automatically).

Mac

________________________________
From: owner-systemc-p1666-technical@eda.org <owner-systemc-p1666-technical@eda.org>
To: Philipp A. Hartmann <philipp.hartmann@offis.de>
Cc: systemc-p1666-technical@eda.org <systemc-p1666-technical@eda.org>
Sent: Fri May 21 07:00:05 2010
Subject: Re: sc_pause and sc_get_status() - RESEND

Philipp, All,

Comments inserted below...


From: "Philipp A. Hartmann" <philipp.hartmann@offis.de>
To: john.aynsley@doulos.com
Cc: systemc-p1666-technical@eda.org
Date: 20/05/2010 20:35
Subject: Re: sc_pause and sc_get_status() - RESEND

________________________________



<snip>

If we add this enum directly to the namespace sc_core, shouldn't the enum values have an "SC_" prefix?

[JA] YES, AGREED.

Maybe we could specify the values of the enum in a way, that
SC_ELABORATION and SC_RUNNING cover multiple sub-phases?
This way, a user-query could simply be:

if( sc_get_status() & SC_ELABORATION )
 // either:
 // SC_ELABORATION (e.g. = 0x08)
 // SC_BEFORE_END_OF_ELABORATION = 0x09
 // SC_END_OF_ELABORATION = 0x0A
 // SC_START_OF_SIMULATION = 0x0C

<snip>

[JA] TO QUOTE 1666:
"Whether a particular action is allowed within
a particular callback cannot be inferred from the terms during elaboration and during simulation alone but is
defined in detail in 4.4. For example, a number of actions that are permitted during elaboration are explicitly
forbidden during the end_of_elaboration callback."

[JA] THIS IS JUST MY OPINION, BUT I WOULD PREFER THAT WE REQUIRE USERS EXPLICITLY TO LIST THE VALUES THEY WANT FROM AN ENUM RATHER THAN USING BIT MASKS, BECAUSE I THINK IT IS CLEARER AND MORE FOOL-PROOF.

> - Exactly when should sc_pause take effect?

It should be as similar to sc_stop() as possible, depending on the pause mode (immediate, finish delta).

The original proposal contained a 'finish time step'. This is needed to avoid warping the simulation time to "infinity", as some implementations do on event starvation. Is this behaviour actually defined somewhere?

[JA] I AGREE THE LRM SHOULD EXPLICITLY STATE SOMETHING ABOUT NOT WARPING TIME FOLLOWING AN EXPLICIT CALL TO sc_pause. BUT IF sc_pause IS CALLED IMPLICITLY FROM sc_start(void) DUE TO EVENT STARVATION, THEN time=infinity IS RIGHT-AND-PROPER, SO RESTARTING SIMULATION WOULD NOT SEEM TO MAKE SENSE. HAVE I MISSED SOMETHING?

John A


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