Initial support for CPU switching. New SamplingCPU object encompasses a set

of CPUs that get switched round-robin (though currently we're only shooting for
two CPUs and one switch event, and even that doesn't quite work yet).  Registration
of ExecContexts with System/Process object factored out so we can create two CPUs
but only register one of them at a time.  Also worked at making behavior and naming
in System and Process objects more consistent.

arch/alpha/ev5.cc:
    Rename ipr_init to initIPRs and get rid of unused mem arg.
arch/alpha/fake_syscall.cc:
    Process:numCpus is now a function (not a data member).
base/remote_gdb.hh:
    Support for ExecContext switching.
cpu/base_cpu.cc:
cpu/base_cpu.hh:
cpu/exec_context.cc:
cpu/exec_context.hh:
cpu/simple_cpu/simple_cpu.hh:
    Support for ExecContext switching.
    Renamed contexts array to execContexts to be consistent with Process.
    CPU ID now auto-assigned by system object.
cpu/simple_cpu/simple_cpu.cc:
    Support for ExecContext switching.
    Renamed contexts array to execContexts to be consistent with Process.
    CPU ID now auto-assigned by system object.
    Cleaned up MP full-system initialization a bit.
dev/alpha_console.cc:
    Renamed xcvec array to execContexts to be consistent with Process.
kern/tru64/tru64_system.cc:
kern/tru64/tru64_system.hh:
    Support for ExecContext switching.
    CPU ID now auto-assigned by system object.
sim/prog.cc:
sim/prog.hh:
    Support for ExecContext switching.
    Process:numCpus is now a function (not a data member).
sim/system.cc:
sim/system.hh:
    Support for ExecContext switching.
    Renamed xcvec array to execContexts to be consistent with Process.

--HG--
extra : convert_revision : 79649cffad5bf3e83de8df44236941907926d791

1 files changed, 23 insertions, 13 deletions

diff --git a/sim/prog.cc b/sim/prog.cc
index 275e1551b..599a0ca9a 100644
--- a/sim/prog.cc
+++ b/sim/prog.cc
@@ -85,8 +85,6 @@ Process::Process(const string &name,
         fd_map[i] = -1;
     }
 
-    numCpus = 0;
-
     num_syscalls = 0;
 
     // other parameters will be initialized when the program is loaded
@@ -136,30 +134,42 @@ Process::openOutputFile(const string &filename)
 }
 
 
-void
-Process::registerExecContext(ExecContext *ec)
+int
+Process::registerExecContext(ExecContext *xc)
 {
-    if (execContexts.empty()) {
+    // add to list
+    int myIndex = execContexts.size();
+    execContexts.push_back(xc);
+
+    if (myIndex == 0) {
         // first exec context for this process... initialize & enable
 
         // copy process's initial regs struct
-        ec->regs = *init_regs;
+        xc->regs = *init_regs;
 
         // mark this context as active
-        ec->setStatus(ExecContext::Active);
+        xc->initStatus(ExecContext::Active);
     }
     else {
-        ec->setStatus(ExecContext::Unallocated);
+        xc->initStatus(ExecContext::Unallocated);
     }
 
-    // add to list
-    execContexts.push_back(ec);
-
-    // increment available CPU count
-    ++numCpus;
+    // return CPU number to caller and increment available CPU count
+    return myIndex;
 }
 
 
+void
+Process::replaceExecContext(int xcIndex, ExecContext *xc)
+{
+    if (xcIndex >= execContexts.size()) {
+        panic("replaceExecContext: bad xcIndex, %d >= %d\n",
+              xcIndex, execContexts.size());
+    }
+
+    execContexts[xcIndex] = xc;
+}
+
 // map simulator fd sim_fd to target fd tgt_fd
 void
 Process::dup_fd(int sim_fd, int tgt_fd)