changeset 79af6cc0384d in /z/repo/gem5
details: http://repo.gem5.org/gem5?cmd=changeset;node=79af6cc0384d
description:
sim: More rigorous clocking comments
The language describing the clockEdge and nextCycle functions were
ambiguous,
and so were prone to misinterpretation/misuse. Clear up the comments to
more
rigorously describe their functionality.
diffstat:
src/sim/clocked_object.hh | 31 +++++++++++++++++++++----------
1 files changed, 21 insertions(+), 10 deletions(-)
diffs (66 lines):
diff -r 0db28826e333 -r 79af6cc0384d src/sim/clocked_object.hh
--- a/src/sim/clocked_object.hh Wed Jun 04 07:48:20 2014 -0700
+++ b/src/sim/clocked_object.hh Mon Jun 09 22:01:16 2014 -0500
@@ -79,7 +79,8 @@
ClockedObject& operator=(ClockedObject&);
/**
- * Align cycle and tick to the next clock edge if not already done.
+ * Align cycle and tick to the next clock edge if not already done. When
+ * complete, tick must be at least curTick().
*/
void update() const
{
@@ -154,13 +155,18 @@
}
/**
- * Determine the tick when a cycle begins, by default the current
- * one, but the argument also enables the caller to determine a
- * future cycle.
+ * Determine the tick when a cycle begins, by default the current one, but
+ * the argument also enables the caller to determine a future cycle. When
+ * curTick() is on a clock edge, the number of cycles in the parameter is
+ * added to curTick() to be returned. When curTick() is not aligned to a
+ * clock edge, the number of cycles in the parameter is added to the next
+ * clock edge.
*
* @param cycles The number of cycles into the future
*
- * @return The tick when the clock edge occurs
+ * @return The start tick when the requested clock edge occurs. Precisely,
+ * this tick can be
+ * curTick() + [0, clockPeriod()) + clockPeriod() * cycles
*/
inline Tick clockEdge(Cycles cycles = Cycles(0)) const
{
@@ -175,7 +181,9 @@
* Determine the current cycle, corresponding to a tick aligned to
* a clock edge.
*
- * @return The current cycle count
+ * @return When curTick() is on a clock edge, return the Cycle
corresponding
+ * to that clock edge. When curTick() is not on a clock edge, return the
+ * Cycle corresponding to the next clock edge.
*/
inline Cycles curCycle() const
{
@@ -186,11 +194,14 @@
}
/**
- * Based on the clock of the object, determine the tick when the next
- * cycle begins, in other words, return the next clock edge.
- * (This can never be the current tick.)
+ * Based on the clock of the object, determine the start tick of the first
+ * cycle that is at least one cycle in the future. When curTick() is at the
+ * current cycle edge, this returns the next clock edge. When calling this
+ * during the middle of a cycle, this returns 2 clock edges in the future.
*
- * @return The tick when the next cycle starts
+ * @return The start tick of the first cycle that is at least one cycle in
+ * the future. Precisely, the returned tick can be in the range
+ * curTick() + [clockPeriod(), 2 * clockPeriod())
*/
Tick nextCycle() const
{ return clockEdge(Cycles(1)); }
_______________________________________________
gem5-dev mailing list
[email protected]
http://m5sim.org/mailman/listinfo/gem5-dev
