diff --git a/src/Makefile b/src/Makefile
index ca097840..e56dc622 100644
--- a/src/Makefile
+++ b/src/Makefile
@@ -5,7 +5,7 @@ CXXFLAGS=-g -fPIC
 
 LIB_OBJS=args.o obj.o mem.o core.o instruction.o enc.o util.o lex.yy.o
 
-all: harptool libharplib.so libharplib.a qsim-harp.so
+all: harptool libharplib.so libharplib.a libqsim-harp.so
 
 # Use -static so we don't have to install the library in order to just run
 # Harptool.
@@ -29,8 +29,8 @@ core.o : core.cpp include/types.h include/util.h include/mem.h include/archdef.h
 
 QSIM_CXXFLAGS=-DEMU_INSTRUMENTATION
 
-qsim-harp.so: args.cpp enc.cpp instruction.cpp obj.cpp util.cpp mem.cpp core.cpp qsim-harp.cpp include/qsim-harp.h include/types.h include/core.h include/util.h include/enc.h include/archdef.h include/instruction.h include/asm-tokens.h include/mem.h
-	$(CXX) $(CXXFLAGS) $(QSIM_CXXFLAGS) -shared -o $@ args.cpp enc.cpp instruction.cpp obj.cpp util.cpp mem.cpp core.cpp qsim-harp.cpp
+libqsim-harp.so: args.cpp enc.cpp instruction.cpp obj.cpp util.cpp mem.cpp core.cpp qsim-harp.cpp lex.yy.o include/qsim-harp.h include/types.h include/core.h include/util.h include/enc.h include/archdef.h include/instruction.h include/asm-tokens.h include/mem.h
+	$(CXX) $(CXXFLAGS) $(QSIM_CXXFLAGS) -shared -o $@ args.cpp enc.cpp instruction.cpp obj.cpp util.cpp mem.cpp core.cpp qsim-harp.cpp lex.yy.o
 
 
 lex.yy.cc: scanner.lex
diff --git a/src/core.cpp b/src/core.cpp
index dd414556..a0ce92a5 100644
--- a/src/core.cpp
+++ b/src/core.cpp
@@ -30,19 +30,26 @@ void Harp::reg_doWrite(Word cpuId, Word regNum) {
 
 Core::Core(const ArchDef &a, Decoder &d, MemoryUnit &mem, Word id) : 
   a(a), iDec(d), mem(mem), pc(0), interruptEnable(false), supervisorMode(true),
-  activeThreads(1), reg(0), pred(0), shadowReg(a.getNRegs()), shadowPReg(a.getNPRegs()),
-  interruptEntry(0), id(id)
+  activeThreads(1), reg(0), pred(0), shadowReg(a.getNRegs()),
+  shadowPReg(a.getNPRegs()), interruptEntry(0), id(id)
 {
   /* Build the register file. */
   Word regNum(0);
   for (Word j = 0; j < a.getNThds(); ++j) {
+    std::cout << "Pushing back a new register vector.\n";
     reg.push_back(vector<Reg<Word> >(0));
-    for (Word i = 0; i < a.getNRegs(); ++i)
+    for (Word i = 0; i < a.getNRegs(); ++i) {
+      std::cout << "Pushing back a new register in thread " << j << "\n";
       reg[j].push_back(Reg<Word>(id, regNum++));
+    }
 
     pred.push_back(vector<Reg<bool> >(0));
-    for (Word i = 0; i < a.getNPRegs(); ++i)
+    std::cout << "getnpregs returns " << a.getNPRegs() << '\n';
+    for (Word i = 0; i < a.getNPRegs(); ++i) {
+      std::cout << "Pushing back predicate reg " << i << ", thread " << j 
+                << "\n";
       pred[j].push_back(Reg<bool>(id, regNum++));
+    }
   }
 
   /* Set initial register contents. */
@@ -55,6 +62,8 @@ void Core::step() {
 
   if (activeThreads == 0) return;
 
+  cout << "in step pc=0x" << hex << pc << '\n';
+
   /* Fetch and decode. */
   if (wordSize < sizeof(pc)) pc &= ((1ll<<(wordSize*8))-1);
   Instruction *inst;
@@ -78,7 +87,9 @@ void Core::step() {
       interrupt(pf.notFound?1:2);
     }
   } while (fetchMore);
+  cout << "Fetched at 0x" << hex << pc << '\n';
   //cout << "0x" << hex << pc << ": " << *inst << '\n';
+  cout << "sizeof(core)=" << dec << sizeof(*this) << '\n';
 
 #ifdef EMU_INSTRUMENTATION
   { Addr pcPhys(mem.virtToPhys(pc));
diff --git a/src/enc.cpp b/src/enc.cpp
index 4b44fc32..49a3e28d 100644
--- a/src/enc.cpp
+++ b/src/enc.cpp
@@ -344,7 +344,7 @@ Instruction *WordDecoder::decode(const std::vector<Byte> &v, Size &idx) {
     inst.setImmRef(*r);
   }
 
-  //cout << "Decoded 0x" << hex << code << " into: " << inst << '\n';
+  cout << "Decoded 0x" << hex << code << " into: " << inst << '\n';
 
   return &inst;
 }
diff --git a/src/include/archdef.h b/src/include/archdef.h
index b7cf97e7..0d897f57 100644
--- a/src/include/archdef.h
+++ b/src/include/archdef.h
@@ -4,6 +4,7 @@
 #ifndef __ARCHDEF_H
 #define __ARCHDEF_H
 
+#include <iostream>
 #include <string>
 #include <sstream>
 
@@ -15,6 +16,7 @@ namespace Harp {
     struct Undefined {};
 
     ArchDef(const std::string &s) {
+      std::cout << "New archdef for \"" << s << "\"\n";
       std::istringstream iss(s.c_str());
       
       iss >> wordSize;
@@ -29,6 +31,8 @@ namespace Harp {
       iss >> sep >> nThds;
       if (!iss || sep != '/') { extent = EXT_PREGS; return; }
       extent = EXT_THDS;
+
+      std::cout << nRegs << " regs, " << nPRegs << " pred regs.\n";
     }
 
     operator std::string () const {
diff --git a/src/include/core.h b/src/include/core.h
index c4d26ff8..4ec87d34 100644
--- a/src/include/core.h
+++ b/src/include/core.h
@@ -50,7 +50,7 @@ namespace Harp {
     bool getSupervisorMode() const { return supervisorMode; }
 #endif
 
-  private:
+//  private:
     const ArchDef a;
     Decoder &iDec;
     MemoryUnit &mem;
diff --git a/src/include/qsim-harp.h b/src/include/qsim-harp.h
index 02c79b7a..589a42e0 100644
--- a/src/include/qsim-harp.h
+++ b/src/include/qsim-harp.h
@@ -1,6 +1,10 @@
 /*******************************************************************************
  HARPtools by Chad D. Kersey, Summer 2011
 *******************************************************************************/
+#ifndef EMU_INSTRUMENTATION
+#define EMU_INSTRUMENTATION
+#endif
+
 #ifndef __QSIM_HARP_H
 #define __QSIM_HARP_H
 
@@ -131,7 +135,8 @@ namespace Harp {
     class Cpu {
     public:
       Cpu(Harp::OSDomain &osd);
-      ~Cpu() { delete dec; delete core; }
+      Cpu(): dec(NULL), core(NULL) {}
+      ~Cpu() { if (dec) delete dec; if (core) delete core; }
 
       bool idle() const { return false; }
       int get_tid() const { return 0; }
@@ -140,9 +145,9 @@ namespace Harp {
       void interrupt(int vec) { core->interrupt(vec); }
       bool booted() const { return core->running(); }
 
+      Harp::OSDomain *osd;
       Harp::Decoder *dec;
       Harp::Core *core;
-      Harp::OSDomain *osd;
     };
 
     Harp::ArchDef arch;
diff --git a/src/qsim-harp.cpp b/src/qsim-harp.cpp
index 9b11a383..d25ad9ec 100644
--- a/src/qsim-harp.cpp
+++ b/src/qsim-harp.cpp
@@ -7,15 +7,16 @@
 #include <string>
 
 using namespace Harp;
+using namespace Qsim;
 using namespace std;
 
 Harp::OSDomain* Harp::OSDomain::osDomain(NULL);
 
-Harp::OSDomain::OSDomain(ArchDef &arch, string imgFile) :
+Harp::OSDomain::OSDomain(ArchDef &archref, string imgFile) :
   /* TODO: Move the mu to the Cpu. They're sharing a TLB now! */
-  arch(arch), mu(4096, arch.getWordSize()), 
+  arch(archref), mu(4096, arch.getWordSize()), 
   ram(imgFile.c_str(), arch.getWordSize()),
-  cpus()
+  cpus(0)
 {
   if (osDomain != NULL) {
     cout << "Error: OSDomain is a singleton.";
@@ -23,6 +24,9 @@ Harp::OSDomain::OSDomain(ArchDef &arch, string imgFile) :
   }
   osDomain = this;
 
+  std::cout << "Constructing an OSDomain with archref, " << archref.getNPRegs() << '\n';
+
+  std::cout << "Pushing back a Cpu in OSDomain constructor.\n";
   cpus.push_back(Cpu(*this));
 
   console = new ConsoleMemDevice(arch.getWordSize(), cout, *cpus[0].core);
@@ -33,6 +37,7 @@ Harp::OSDomain::OSDomain(ArchDef &arch, string imgFile) :
 
 void Harp::OSDomain::connect_console(std::ostream &s) {
   /* For now this does nothing. ConsoleMemDevice is not redirectable. */
+  std::cout << "in connect_console\n";
 }
 
 Harp::OSDomain::Cpu::Cpu(Harp::OSDomain &o) :
@@ -40,10 +45,13 @@ Harp::OSDomain::Cpu::Cpu(Harp::OSDomain &o) :
   osd(&o), dec(new WordDecoder(osd->arch)),
   core(new Core(osd->arch, *dec, osd->mu))
 {
+  std::cout << "Constructing a new Cpu.\n";
 }
 
 uint64_t Harp::OSDomain::Cpu::run(uint64_t n) {
   uint64_t i;
+  std::cout << "pc=0x" << std::hex << core->pc << ", " << std::dec << sizeof(*core) << '\n';
+  //osd->console->poll();
   for (i = 0; i < n; ++i) core->step();
   return i;
 }
diff --git a/src/unit_test/qsim_test.cpp b/src/unit_test/qsim_test.cpp
new file mode 100644
index 00000000..2130ecd0
--- /dev/null
+++ b/src/unit_test/qsim_test.cpp
@@ -0,0 +1,25 @@
+#include <iostream>
+#include <iomanip>
+#include "include/qsim-harp.h"
+
+class CallbackAdaptor {
+public:
+  void inst_cb(int c, uint64_t v, uint64_t p, uint8_t l, const uint8_t *b,
+               enum inst_type t)
+  {
+    std::cout << "Inst @ 0x" << std::hex << v << "(0x" << p << ")\n";
+  }
+} cba;
+
+int main(int argc, char** argv) {
+  Harp::ArchDef arch("8w32/32/8");
+  Harp::OSDomain osd(arch, std::string("../test/sieve.bin"));
+
+  osd.set_inst_cb(&cba, &CallbackAdaptor::inst_cb);
+
+  for (unsigned i = 0; i < 1000; ++i) {
+    osd.run(0, 1);
+  }
+
+  return 0;
+}