Clock: Add a Cycles wrapper class and use where applicable

This patch addresses the comments and feedback on the preceding patch
that reworks the clocks and now more clearly shows where cycles
(relative cycle counts) are used to express time.

Instead of bumping the existing patch I chose to make this a separate
patch, merely to try and focus the discussion around a smaller set of
changes. The two patches will be pushed together though.

This changes done as part of this patch are mostly following directly
from the introduction of the wrapper class, and change enough code to
make things compile and run again. There are definitely more places
where int/uint/Tick is still used to represent cycles, and it will
take some time to chase them all down. Similarly, a lot of parameters
should be changed from Param.Tick and Param.Unsigned to
Param.Cycles.

In addition, the use of curTick is questionable as there should not be
an absolute cycle. Potential solutions can be built on top of this
patch. There is a similar situation in the o3 CPU where
lastRunningCycle is currently counting in Cycles, and is still an
absolute time. More discussion to be had in other words.

An additional change that would be appropriate in the future is to
perform a similar wrapping of Tick and probably also introduce a
Ticks class along with suitable operators for all these classes.

1 files changed, 20 insertions, 17 deletions

diff --git a/src/cpu/inorder/resource_pool.cc b/src/cpu/inorder/resource_pool.cc
index 31511314e..c09f6c31d 100644
--- a/src/cpu/inorder/resource_pool.cc
+++ b/src/cpu/inorder/resource_pool.cc
@@ -64,54 +64,57 @@ ResourcePool::ResourcePool(InOrderCPU *_cpu, ThePipeline::Params *params)
     // name - id - bandwidth - latency - CPU - Parameters
     // --------------------------------------------------
     resources.push_back(new FetchSeqUnit("fetch_seq_unit", FetchSeq,
-                                         stage_width * 2, 0, _cpu, params));
+                                         stage_width * 2, Cycles(0),
+                                         _cpu, params));
 
     // Keep track of the instruction fetch unit so we can easily
     // provide a pointer to it in the CPU.
     instUnit = new FetchUnit("icache_port", ICache,
-                             stage_width * 2 + MaxThreads, 0, _cpu,
+                             stage_width * 2 + MaxThreads, Cycles(0), _cpu,
                              params);
     resources.push_back(instUnit);
 
     resources.push_back(new DecodeUnit("decode_unit", Decode,
-                                       stage_width, 0, _cpu, params));
+                                       stage_width, Cycles(0), _cpu,
+                                       params));
 
     resources.push_back(new BranchPredictor("branch_predictor", BPred,
-                                            stage_width, 0, _cpu, params));
+                                            stage_width, Cycles(0),
+                                            _cpu, params));
 
     resources.push_back(new InstBuffer("fetch_buffer_t0", FetchBuff, 4,
-                                       0, _cpu, params));
+                                       Cycles(0), _cpu, params));
 
     resources.push_back(new UseDefUnit("regfile_manager", RegManager,
-                                       stage_width * 3, 0, _cpu,
+                                       stage_width * 3, Cycles(0), _cpu,
                                        params));
 
     resources.push_back(new AGENUnit("agen_unit", AGEN,
-                                     stage_width, 0, _cpu, params));
+                                     stage_width, Cycles(0), _cpu,
+                                     params));
 
     resources.push_back(new ExecutionUnit("execution_unit", ExecUnit,
-                                          stage_width, 0, _cpu, params));
+                                          stage_width, Cycles(0), _cpu,
+                                          params));
 
     resources.push_back(new MultDivUnit("mult_div_unit", MDU,
-                                        stage_width * 2,
-                                        0,
-                                        _cpu,
-                                        params));
+                                        stage_width * 2, Cycles(0),
+                                        _cpu, params));
 
     // Keep track of the data load/store unit so we can easily provide
     // a pointer to it in the CPU.
     dataUnit = new CacheUnit("dcache_port", DCache,
-                             stage_width * 2 + MaxThreads, 0, _cpu,
+                             stage_width * 2 + MaxThreads, Cycles(0), _cpu,
                              params);
     resources.push_back(dataUnit);
 
     gradObjects.push_back(BPred);
     resources.push_back(new GraduationUnit("graduation_unit", Grad,
-                                           stage_width, 0, _cpu,
+                                           stage_width, Cycles(0), _cpu,
                                            params));
 
     resources.push_back(new InstBuffer("fetch_buffer_t1", FetchBuff2, 4,
-                                       0, _cpu, params));
+                                       Cycles(0), _cpu, params));
 
 }
 
@@ -234,7 +237,7 @@ ResourcePool::slotsInUse(int res_idx)
 //       to the event construction
 void
 ResourcePool::scheduleEvent(InOrderCPU::CPUEventType e_type, DynInstPtr inst,
-                            int delay,  int res_idx, ThreadID tid)
+                            Cycles delay,  int res_idx, ThreadID tid)
 {
     assert(delay >= 0);
 
@@ -456,7 +459,7 @@ ResourcePool::ResPoolEvent::description() const
 
 /** Schedule resource event, regardless of its current state. */
 void
-ResourcePool::ResPoolEvent::scheduleEvent(int delay)
+ResourcePool::ResPoolEvent::scheduleEvent(Cycles delay)
 {
     InOrderCPU *cpu = resPool->cpu;
     assert(!scheduled() || squashed());