diff --git a/src/common_throws.cc b/src/common_throws.cc
index 0bb9da2..dc3627a 100644
--- a/src/common_throws.cc
+++ b/src/common_throws.cc
@@ -19,7 +19,7 @@
 #include "base/logging.h"
 #include "class_linker-inl.h"
 #include "dex_file-inl.h"
-#include "dex_instruction.h"
+#include "dex_instruction-inl.h"
 #include "invoke_type.h"
 #include "mirror/abstract_method-inl.h"
 #include "mirror/class-inl.h"
@@ -298,19 +298,24 @@
   uint32_t throw_dex_pc = throw_location.GetDexPc();
   CHECK_LT(throw_dex_pc, code->insns_size_in_code_units_);
   const Instruction* instr = Instruction::At(&code->insns_[throw_dex_pc]);
-  DecodedInstruction dec_insn(instr);
   switch (instr->Opcode()) {
     case Instruction::INVOKE_DIRECT:
+      ThrowNullPointerExceptionForMethodAccess(throw_location, instr->VRegB_35c(), kDirect);
+      break;
     case Instruction::INVOKE_DIRECT_RANGE:
-      ThrowNullPointerExceptionForMethodAccess(throw_location, dec_insn.vB, kDirect);
+      ThrowNullPointerExceptionForMethodAccess(throw_location, instr->VRegB_3rc(), kDirect);
       break;
     case Instruction::INVOKE_VIRTUAL:
+      ThrowNullPointerExceptionForMethodAccess(throw_location, instr->VRegB_35c(), kVirtual);
+      break;
     case Instruction::INVOKE_VIRTUAL_RANGE:
-      ThrowNullPointerExceptionForMethodAccess(throw_location, dec_insn.vB, kVirtual);
+      ThrowNullPointerExceptionForMethodAccess(throw_location, instr->VRegB_3rc(), kVirtual);
       break;
     case Instruction::INVOKE_INTERFACE:
+      ThrowNullPointerExceptionForMethodAccess(throw_location, instr->VRegB_35c(), kInterface);
+      break;
     case Instruction::INVOKE_INTERFACE_RANGE:
-      ThrowNullPointerExceptionForMethodAccess(throw_location, dec_insn.vB, kInterface);
+      ThrowNullPointerExceptionForMethodAccess(throw_location, instr->VRegB_3rc(), kInterface);
       break;
     case Instruction::IGET:
     case Instruction::IGET_WIDE:
@@ -320,7 +325,7 @@
     case Instruction::IGET_CHAR:
     case Instruction::IGET_SHORT: {
       mirror::Field* field =
-          Runtime::Current()->GetClassLinker()->ResolveField(dec_insn.vC,
+          Runtime::Current()->GetClassLinker()->ResolveField(instr->VRegC_22c(),
                                                              throw_location.GetMethod(), false);
       ThrowNullPointerExceptionForFieldAccess(throw_location, field, true /* read */);
       break;
@@ -333,7 +338,7 @@
     case Instruction::IPUT_CHAR:
     case Instruction::IPUT_SHORT: {
       mirror::Field* field =
-          Runtime::Current()->GetClassLinker()->ResolveField(dec_insn.vC,
+          Runtime::Current()->GetClassLinker()->ResolveField(instr->VRegC_22c(),
                                                              throw_location.GetMethod(), false);
       ThrowNullPointerExceptionForFieldAccess(throw_location, field, false /* write */);
       break;
diff --git a/src/dex_instruction.cc b/src/dex_instruction.cc
index 414e78f..1b7d3bb 100644
--- a/src/dex_instruction.cc
+++ b/src/dex_instruction.cc
@@ -262,44 +262,45 @@
 }
 
 std::string Instruction::DumpString(const DexFile* file) const {
-  DecodedInstruction insn(this);
   std::ostringstream os;
-  const char* opcode = kInstructionNames[insn.opcode];
+  const char* opcode = kInstructionNames[Opcode()];
   switch (FormatOf(Opcode())) {
     case k10x:  os << opcode; break;
-    case k12x:  os << StringPrintf("%s v%d, v%d", opcode, insn.vA, insn.vB); break;
-    case k11n:  os << StringPrintf("%s v%d, #%+d", opcode, insn.vA, insn.vB); break;
-    case k11x:  os << StringPrintf("%s v%d", opcode, insn.vA); break;
-    case k10t:  os << StringPrintf("%s %+d", opcode, insn.vA); break;
-    case k20t:  os << StringPrintf("%s %+d", opcode, insn.vA); break;
-    case k22x:  os << StringPrintf("%s v%d, v%d", opcode, insn.vA, insn.vB); break;
-    case k21t:  os << StringPrintf("%s v%d, %+d", opcode, insn.vA, insn.vB); break;
-    case k21s:  os << StringPrintf("%s v%d, #%+d", opcode, insn.vA, insn.vB); break;
+    case k12x:  os << StringPrintf("%s v%d, v%d", opcode, VRegA_12x(), VRegB_12x()); break;
+    case k11n:  os << StringPrintf("%s v%d, #%+d", opcode, VRegA_11n(), VRegB_11n()); break;
+    case k11x:  os << StringPrintf("%s v%d", opcode, VRegA_11x()); break;
+    case k10t:  os << StringPrintf("%s %+d", opcode, VRegA_10t()); break;
+    case k20t:  os << StringPrintf("%s %+d", opcode, VRegA_20t()); break;
+    case k22x:  os << StringPrintf("%s v%d, v%d", opcode, VRegA_22x(), VRegB_22x()); break;
+    case k21t:  os << StringPrintf("%s v%d, %+d", opcode, VRegA_21t(), VRegB_21t()); break;
+    case k21s:  os << StringPrintf("%s v%d, #%+d", opcode, VRegA_21s(), VRegB_21s()); break;
     case k21h: {
         // op vAA, #+BBBB0000[00000000]
-        if (insn.opcode == CONST_HIGH16) {
-          uint32_t value = insn.vB << 16;
-          os << StringPrintf("%s v%d, #int %+d // 0x%x", opcode, insn.vA, value, value);
+        if (Opcode() == CONST_HIGH16) {
+          uint32_t value = VRegB_21h() << 16;
+          os << StringPrintf("%s v%d, #int %+d // 0x%x", opcode, VRegA_21h(), value, value);
         } else {
-          uint64_t value = static_cast<uint64_t>(insn.vB) << 48;
-          os << StringPrintf("%s v%d, #long %+lld // 0x%llx", opcode, insn.vA, value, value);
+          uint64_t value = static_cast<uint64_t>(VRegB_21h()) << 48;
+          os << StringPrintf("%s v%d, #long %+lld // 0x%llx", opcode, VRegA_21h(), value, value);
         }
       }
       break;
     case k21c: {
-      switch (insn.opcode) {
+      switch (Opcode()) {
         case CONST_STRING:
           if (file != NULL) {
-            os << StringPrintf("const-string v%d, %s // string@%d", insn.vA,
-                               PrintableString(file->StringDataByIdx(insn.vB)).c_str(), insn.vB);
+            uint32_t string_idx = VRegB_21c();
+            os << StringPrintf("const-string v%d, %s // string@%d", VRegA_21c(),
+                               PrintableString(file->StringDataByIdx(string_idx)).c_str(), string_idx);
             break;
           }  // else fall-through
         case CHECK_CAST:
         case CONST_CLASS:
         case NEW_INSTANCE:
           if (file != NULL) {
-            os << opcode << " v" << insn.vA << ", " << PrettyType(insn.vB, *file)
-               << " // type@" << insn.vB;
+            uint32_t type_idx = VRegB_21c();
+            os << opcode << " v" << VRegA_21c() << ", " << PrettyType(type_idx, *file)
+               << " // type@" << type_idx;
             break;
           }  // else fall-through
         case SGET:
@@ -310,8 +311,9 @@
         case SGET_CHAR:
         case SGET_SHORT:
           if (file != NULL) {
-            os << opcode << "  v" << insn.vA << ", " << PrettyField(insn.vB, *file, true)
-               << " // field@" << insn.vB;
+            uint32_t field_idx = VRegB_21c();
+            os << opcode << "  v" << VRegA_21c() << ", " << PrettyField(field_idx, *file, true)
+               << " // field@" << field_idx;
             break;
           }  // else fall-through
         case SPUT:
@@ -322,22 +324,23 @@
         case SPUT_CHAR:
         case SPUT_SHORT:
           if (file != NULL) {
-            os << opcode << " v" << insn.vA << ", " << PrettyField(insn.vB, *file, true)
-               << " // field@" << insn.vB;
+            uint32_t field_idx = VRegB_21c();
+            os << opcode << " v" << VRegA_21c() << ", " << PrettyField(field_idx, *file, true)
+               << " // field@" << field_idx;
             break;
           }  // else fall-through
         default:
-          os << StringPrintf("%s v%d, thing@%d", opcode, insn.vA, insn.vB);
+          os << StringPrintf("%s v%d, thing@%d", opcode, VRegA_21c(), VRegB_21c());
           break;
       }
       break;
     }
-    case k23x:  os << StringPrintf("%s v%d, v%d, v%d", opcode, insn.vA, insn.vB, insn.vC); break;
-    case k22b:  os << StringPrintf("%s v%d, v%d, #%+d", opcode, insn.vA, insn.vB, insn.vC); break;
-    case k22t:  os << StringPrintf("%s v%d, v%d, %+d", opcode, insn.vA, insn.vB, insn.vC); break;
-    case k22s:  os << StringPrintf("%s v%d, v%d, #%+d", opcode, insn.vA, insn.vB, insn.vC); break;
+    case k23x:  os << StringPrintf("%s v%d, v%d, v%d", opcode, VRegA_23x(), VRegB_23x(), VRegC_23x()); break;
+    case k22b:  os << StringPrintf("%s v%d, v%d, #%+d", opcode, VRegA_22b(), VRegB_22b(), VRegC_22b()); break;
+    case k22t:  os << StringPrintf("%s v%d, v%d, %+d", opcode, VRegA_22t(), VRegB_22t(), VRegC_22t()); break;
+    case k22s:  os << StringPrintf("%s v%d, v%d, #%+d", opcode, VRegA_22s(), VRegB_22s(), VRegC_22s()); break;
     case k22c: {
-      switch (insn.opcode) {
+      switch (Opcode()) {
         case IGET:
         case IGET_WIDE:
         case IGET_OBJECT:
@@ -346,8 +349,9 @@
         case IGET_CHAR:
         case IGET_SHORT:
           if (file != NULL) {
-            os << opcode << " v" << insn.vA << ", v" << insn.vB << ", "
-               << PrettyField(insn.vC, *file, true) << " // field@" << insn.vC;
+            uint32_t field_idx = VRegC_22c();
+            os << opcode << " v" << VRegA_22c() << ", v" << VRegB_22c() << ", "
+               << PrettyField(field_idx, *file, true) << " // field@" << field_idx;
             break;
           }  // else fall-through
         case IPUT:
@@ -358,35 +362,40 @@
         case IPUT_CHAR:
         case IPUT_SHORT:
           if (file != NULL) {
-            os << opcode << " v" << insn.vA << ", v" << insn.vB << ", "
-               << PrettyField(insn.vC, *file, true) << " // field@" << insn.vC;
+            uint32_t field_idx = VRegC_22c();
+            os << opcode << " v" << VRegA_22c() << ", v" << VRegB_22c() << ", "
+               << PrettyField(field_idx, *file, true) << " // field@" << field_idx;
             break;
           }  // else fall-through
         case INSTANCE_OF:
           if (file != NULL) {
-            os << opcode << " v" << insn.vA << ", v" << insn.vB << ", "
-               << PrettyType(insn.vC, *file) << " // type@" << insn.vC;
+            uint32_t type_idx = VRegC_22c();
+            os << opcode << " v" << VRegA_22c() << ", v" << VRegB_22c() << ", "
+               << PrettyType(type_idx, *file) << " // type@" << type_idx;
             break;
           }
         case NEW_ARRAY:
           if (file != NULL) {
-            os << opcode << " v" << insn.vA << ", v" << insn.vB << ", "
-               << PrettyType(insn.vC, *file) << " // type@" << insn.vC;
+            uint32_t type_idx = VRegC_22c();
+            os << opcode << " v" << VRegA_22c() << ", v" << VRegB_22c() << ", "
+               << PrettyType(type_idx, *file) << " // type@" << type_idx;
             break;
           }  // else fall-through
         default:
-          os << StringPrintf("%s v%d, v%d, thing@%d", opcode, insn.vA, insn.vB, insn.vC);
+          os << StringPrintf("%s v%d, v%d, thing@%d", opcode, VRegA_22c(), VRegB_22c(), VRegC_22c());
           break;
       }
       break;
     }
-    case k32x:  os << StringPrintf("%s v%d, v%d", opcode, insn.vA, insn.vB); break;
-    case k30t:  os << StringPrintf("%s %+d", opcode, insn.vA); break;
-    case k31t:  os << StringPrintf("%s v%d, %+d", opcode, insn.vA, insn.vB); break;
-    case k31i:  os << StringPrintf("%s v%d, #%+d", opcode, insn.vA, insn.vB); break;
-    case k31c:  os << StringPrintf("%s v%d, thing@%d", opcode, insn.vA, insn.vB); break;
+    case k32x:  os << StringPrintf("%s v%d, v%d", opcode, VRegA_32x(), VRegB_32x()); break;
+    case k30t:  os << StringPrintf("%s %+d", opcode, VRegA_30t()); break;
+    case k31t:  os << StringPrintf("%s v%d, %+d", opcode, VRegA_31t(), VRegB_31t()); break;
+    case k31i:  os << StringPrintf("%s v%d, #%+d", opcode, VRegA_31i(), VRegB_31i()); break;
+    case k31c:  os << StringPrintf("%s v%d, thing@%d", opcode, VRegA_31c(), VRegB_31c()); break;
     case k35c: {
-      switch (insn.opcode) {
+      uint32_t arg[5];
+      GetArgs(arg);
+      switch (Opcode()) {
         case INVOKE_VIRTUAL:
         case INVOKE_SUPER:
         case INVOKE_DIRECT:
@@ -394,42 +403,44 @@
         case INVOKE_INTERFACE:
           if (file != NULL) {
             os << opcode << " {";
-            for (size_t i = 0; i < insn.vA; ++i) {
+            uint32_t method_idx = VRegB_35c();
+            for (size_t i = 0; i < VRegA_35c(); ++i) {
               if (i != 0) {
                 os << ", ";
               }
-              os << "v" << insn.arg[i];
+              os << "v" << arg[i];
             }
-            os << "}, " << PrettyMethod(insn.vB, *file) << " // method@" << insn.vB;
+            os << "}, " << PrettyMethod(method_idx, *file) << " // method@" << method_idx;
             break;
           }  // else fall-through
         default:
-          os << opcode << " {v" << insn.arg[0] << ", v" << insn.arg[1] << ", v" << insn.arg[2]
-                       << ", v" << insn.arg[3] << ", v" << insn.arg[4] << "}, thing@" << insn.vB;
+          os << opcode << " {v" << arg[0] << ", v" << arg[1] << ", v" << arg[2]
+                       << ", v" << arg[3] << ", v" << arg[4] << "}, thing@" << VRegB_35c();
           break;
       }
       break;
     }
     case k3rc: {
-      switch (insn.opcode) {
+      switch (Opcode()) {
         case INVOKE_VIRTUAL_RANGE:
         case INVOKE_SUPER_RANGE:
         case INVOKE_DIRECT_RANGE:
         case INVOKE_STATIC_RANGE:
         case INVOKE_INTERFACE_RANGE:
           if (file != NULL) {
-            os << StringPrintf("%s, {v%d .. v%d}, ", opcode, insn.vC, (insn.vC + insn.vA - 1))
-               << PrettyMethod(insn.vB, *file) << " // method@" << insn.vB;
+            uint32_t method_idx = VRegB_3rc();
+            os << StringPrintf("%s, {v%d .. v%d}, ", opcode, VRegC_3rc(), (VRegC_3rc() + VRegA_3rc() - 1))
+               << PrettyMethod(method_idx, *file) << " // method@" << method_idx;
             break;
           }  // else fall-through
         default:
-          os << StringPrintf("%s, {v%d .. v%d}, thing@%d", opcode, insn.vC, (insn.vC + insn.vA - 1),
-                             insn.vB);
+          os << StringPrintf("%s, {v%d .. v%d}, thing@%d", opcode, VRegC_3rc(),
+                             (VRegC_3rc() + VRegA_3rc() - 1), VRegB_3rc());
           break;
       }
       break;
     }
-    case k51l: os << StringPrintf("%s v%d, #%+d", opcode, insn.vA, insn.vB); break;
+    case k51l: os << StringPrintf("%s v%d, #%+lld", opcode, VRegA_51l(), VRegB_51l()); break;
     default: os << " unknown format (" << DumpHex(5) << ")"; break;
   }
   return os.str();
diff --git a/src/oat/runtime/support_invoke.cc b/src/oat/runtime/support_invoke.cc
index 369858e..a96555d 100644
--- a/src/oat/runtime/support_invoke.cc
+++ b/src/oat/runtime/support_invoke.cc
@@ -15,7 +15,7 @@
  */
 
 #include "callee_save_frame.h"
-#include "dex_instruction.h"
+#include "dex_instruction-inl.h"
 #include "mirror/class-inl.h"
 #include "mirror/abstract_method-inl.h"
 #include "mirror/object-inl.h"
@@ -110,10 +110,15 @@
     CHECK(instr_code == Instruction::INVOKE_INTERFACE ||
           instr_code == Instruction::INVOKE_INTERFACE_RANGE)
         << "Unexpected call into interface trampoline: " << instr->DumpString(NULL);
-    DecodedInstruction dec_insn(instr);
-    uint32_t dex_method_idx = dec_insn.vB;
+    uint32_t dex_method_idx;
+    if (instr_code == Instruction::INVOKE_INTERFACE) {
+      dex_method_idx = instr->VRegB_35c();
+    } else {
+      DCHECK_EQ(instr_code, Instruction::INVOKE_INTERFACE_RANGE);
+      dex_method_idx = instr->VRegB_3rc();
+    }
     method = FindMethodFromCode(dex_method_idx, this_object, caller_method, self,
-                                                false, kInterface);
+                                false, kInterface);
     if (UNLIKELY(method == NULL)) {
       CHECK(self->IsExceptionPending());
       return 0;  // Failure.
diff --git a/src/oat/runtime/support_stubs.cc b/src/oat/runtime/support_stubs.cc
index 161a7b2..df2dda2 100644
--- a/src/oat/runtime/support_stubs.cc
+++ b/src/oat/runtime/support_stubs.cc
@@ -17,7 +17,7 @@
 #include "callee_save_frame.h"
 #include "class_linker-inl.h"
 #include "dex_file-inl.h"
-#include "dex_instruction.h"
+#include "dex_instruction-inl.h"
 #include "mirror/class-inl.h"
 #include "mirror/abstract_method-inl.h"
 #include "mirror/object_array-inl.h"
@@ -40,35 +40,52 @@
 
   ClassLinker* linker = Runtime::Current()->GetClassLinker();
   InvokeType invoke_type;
-  uint32_t dex_method_idx;
+  bool is_range;
   if (called->IsRuntimeMethod()) {
     const DexFile::CodeItem* code = MethodHelper(caller).GetCodeItem();
     CHECK_LT(dex_pc, code->insns_size_in_code_units_);
     const Instruction* instr = Instruction::At(&code->insns_[dex_pc]);
     Instruction::Code instr_code = instr->Opcode();
     switch (instr_code) {
-      case Instruction::INVOKE_DIRECT:  // Fall-through.
+      case Instruction::INVOKE_DIRECT:
+        invoke_type = kDirect;
+        is_range = false;
+        break;
       case Instruction::INVOKE_DIRECT_RANGE:
         invoke_type = kDirect;
+        is_range = true;
         break;
-      case Instruction::INVOKE_STATIC:  // Fall-through.
+      case Instruction::INVOKE_STATIC:
+        invoke_type = kStatic;
+        is_range = false;
+        break;
       case Instruction::INVOKE_STATIC_RANGE:
         invoke_type = kStatic;
+        is_range = true;
         break;
-      case Instruction::INVOKE_SUPER:  // Fall-through.
+      case Instruction::INVOKE_SUPER:
+        invoke_type = kSuper;
+        is_range = false;
+        break;
       case Instruction::INVOKE_SUPER_RANGE:
         invoke_type = kSuper;
+        is_range = true;
         break;
-      case Instruction::INVOKE_VIRTUAL:  // Fall-through.
+      case Instruction::INVOKE_VIRTUAL:
+        invoke_type = kVirtual;
+        is_range = false;
+        break;
       case Instruction::INVOKE_VIRTUAL_RANGE:
         invoke_type = kVirtual;
+        is_range = true;
         break;
       default:
         LOG(FATAL) << "Unexpected call into trampoline: " << instr->DumpString(NULL);
-        invoke_type = kDirect;  // Avoid used uninitialized warnings.
+        // Avoid used uninitialized warnings.
+        invoke_type = kDirect;
+        is_range = true;
     }
-    DecodedInstruction dec_insn(instr);
-    dex_method_idx = dec_insn.vB;
+    uint32_t dex_method_idx = (is_range) ? instr->VRegB_3rc() : instr->VRegB_35c();
     called = linker->ResolveMethod(dex_method_idx, caller, invoke_type);
   } else {
     CHECK(called->IsStatic()) << PrettyMethod(called);
@@ -210,29 +227,47 @@
     CHECK_LT(dex_pc, code->insns_size_in_code_units_);
     const Instruction* instr = Instruction::At(&code->insns_[dex_pc]);
     Instruction::Code instr_code = instr->Opcode();
+    bool is_range;
     switch (instr_code) {
-      case Instruction::INVOKE_DIRECT:  // Fall-through.
+      case Instruction::INVOKE_DIRECT:
+        invoke_type = kDirect;
+        is_range = false;
+        break;
       case Instruction::INVOKE_DIRECT_RANGE:
         invoke_type = kDirect;
+        is_range = true;
         break;
-      case Instruction::INVOKE_STATIC:  // Fall-through.
+      case Instruction::INVOKE_STATIC:
+        invoke_type = kStatic;
+        is_range = false;
+        break;
       case Instruction::INVOKE_STATIC_RANGE:
         invoke_type = kStatic;
+        is_range = true;
         break;
-      case Instruction::INVOKE_SUPER:  // Fall-through.
+      case Instruction::INVOKE_SUPER:
+        invoke_type = kSuper;
+        is_range = false;
+        break;
       case Instruction::INVOKE_SUPER_RANGE:
         invoke_type = kSuper;
+        is_range = true;
         break;
-      case Instruction::INVOKE_VIRTUAL:  // Fall-through.
+      case Instruction::INVOKE_VIRTUAL:
+        invoke_type = kVirtual;
+        is_range = false;
+        break;
       case Instruction::INVOKE_VIRTUAL_RANGE:
         invoke_type = kVirtual;
+        is_range = true;
         break;
       default:
         LOG(FATAL) << "Unexpected call into trampoline: " << instr->DumpString(NULL);
-        invoke_type = kDirect;  // Avoid used uninitialized warnings.
+        // Avoid used uninitialized warnings.
+        invoke_type = kDirect;
+        is_range = false;
     }
-    DecodedInstruction dec_insn(instr);
-    dex_method_idx = dec_insn.vB;
+    dex_method_idx = (is_range) ? instr->VRegB_3rc() : instr->VRegB_35c();
 #if !defined(__i386__)
     shorty = linker->MethodShorty(dex_method_idx, caller, &shorty_len);
 #endif