diff --git a/src/include/core.h b/src/include/core.h
index ce719bc1..d447b7d3 100644
--- a/src/include/core.h
+++ b/src/include/core.h
@@ -6,6 +6,7 @@
 
 #include <string>
 #include <vector>
+#include <stack>
 
 #include "types.h"
 #include "archdef.h"
@@ -47,6 +48,12 @@ namespace Harp {
 #endif
   };
 
+  // Entry in the IPDOM Stack
+  struct DomStackEntry {
+    std::vector<bool> tmask;
+    Word pc;
+  };
+
   class Core {
   public:
     Core(const ArchDef &a, Decoder &d, MemoryUnit &mem, Word id=0);
@@ -67,6 +74,9 @@ namespace Harp {
     std::vector<std::vector<Reg<Word> > > reg;
     std::vector<std::vector<Reg<bool> > > pred;
 
+    std::vector<bool> tmask;
+    std::stack<DomStackEntry> domStack;
+
     std::vector<Word> shadowReg;
     std::vector<bool> shadowPReg;
 
diff --git a/src/include/instruction.h b/src/include/instruction.h
index ed24eeab..d421cd6a 100644
--- a/src/include/instruction.h
+++ b/src/include/instruction.h
@@ -30,7 +30,8 @@ namespace Harp {
                   JALI, JALR, JMPI, JMPR, CLONE, JALIS, JALRS, 
                   JMPRT, LD, ST, LDI, RTOP, ANDP, ORP, XORP, NOTP, ISNEG, 
                   ISZERO, HALT, TRAP, JMPRU, SKEP, RETI, TLBRM,
-                  ITOF, FTOI, FADD, FSUB, FMUL, FDIV, FNEG, WSPAWN };
+                  ITOF, FTOI, FADD, FSUB, FMUL, FDIV, FNEG, WSPAWN,
+                  SPLIT, JOIN };
     enum ArgClass {
       AC_NONE, AC_2REG, AC_2IMM, AC_3REG, AC_3PREG, AC_3IMM, AC_3REGSRC, 
       AC_1IMM, AC_1REG, AC_3IMMSRC, AC_PREG_REG, AC_2PREG, AC_2REGSRC
diff --git a/src/instruction.cpp b/src/instruction.cpp
index 61ec008e..bf7f0c1a 100644
--- a/src/instruction.cpp
+++ b/src/instruction.cpp
@@ -81,6 +81,8 @@ Instruction::InstTableEntry Instruction::instTable[] = {
   {"fdiv",     false, false, false, false, AC_3REG,     ITYPE_FPDIV   },
   {"fneg",     false, false, false, false, AC_2REG,     ITYPE_FPBASIC },
   {"wspawn",   false, false, true,  false, AC_2REGSRC,  ITYPE_NULL    },
+  {"split",    false, false, true,  false, AC_NONE,     ITYPE_NULL    },
+  {"join",     false, false, true,  false, AC_NONE,     ITYPE_NULL    },
   {NULL,false,false,false,false,AC_NONE,ITYPE_NULL}/////// End of table.
 };