diff --git a/src/core/sal/CPU.cc b/src/core/sal/CPU.cc
index e701e062..2315fa92 100644
--- a/src/core/sal/CPU.cc
+++ b/src/core/sal/CPU.cc
@@ -1,15 +1,19 @@
+#include <algorithm>
 #include "CPU.hpp"
 
 namespace fail {
 
-void CPUArchitecture::m_addRegister(Register* reg)
+void CPUArchitecture::m_addRegister(Register* reg, RegisterType type)
 {
-	assert(!reg->isAssigned() && "FATAL ERROR: The register is already assigned!");
-	m_Registers.push_back(reg);
+	// We may be called multiple times with the same register, if it needs to
+	// reside in multiple subsets.
+	if (std::find(m_Registers.begin(), m_Registers.end(), reg) == m_Registers.end()) {
+		m_Registers.push_back(reg);
+	}
 
-	UniformRegisterSet* urs = getRegisterSetOfType(reg->getType());
-	if (urs == NULL) {
-		urs = new UniformRegisterSet(reg->getType());
+	UniformRegisterSet* urs = getRegisterSetOfType(type);
+	if (!urs) {
+		urs = new UniformRegisterSet(type);
 		m_RegisterSubsets.push_back(urs);
 	}
 	urs->m_add(reg);
@@ -34,7 +38,7 @@ UniformRegisterSet* CPUArchitecture::getRegisterSetOfType(RegisterType t) const
 		if ((*it)->getType() == t)
 			return *it;
 	}
-	return NULL;
+	return 0;
 }
 
 } // end-of-namespace: fail
diff --git a/src/core/sal/CPU.hpp b/src/core/sal/CPU.hpp
index 27a14135..65ff9d3e 100644
--- a/src/core/sal/CPU.hpp
+++ b/src/core/sal/CPU.hpp
@@ -73,7 +73,7 @@ protected:
 	 * @param reg a pointer to the register object to be added
 	 * @see getType()
 	 */
-	void m_addRegister(Register* reg);
+	void m_addRegister(Register* reg, RegisterType type = RT_NONE);
 };
 
 } // end-of-namespace: fail
diff --git a/src/core/sal/Register.cc b/src/core/sal/Register.cc
index 2e1bfac2..bf9f4e36 100644
--- a/src/core/sal/Register.cc
+++ b/src/core/sal/Register.cc
@@ -10,11 +10,8 @@ Register* UniformRegisterSet::getRegister(size_t i) const
 
 void UniformRegisterSet::m_add(Register* preg)
 {
-	assert(!preg->m_Assigned &&
-		"FATAL ERROR: The register has already been assigned.");
+	assert(std::find(m_Regs.begin(), m_Regs.end(), preg) == m_Regs.end());
 	m_Regs.push_back(preg);
-	preg->m_Assigned = true;
-	preg->m_Index = m_Regs.size()-1; // the index within the vector (set)
 }
 
 } // end-of-namespace: fail
diff --git a/src/core/sal/Register.hpp b/src/core/sal/Register.hpp
index f349237e..96ff6505 100644
--- a/src/core/sal/Register.hpp
+++ b/src/core/sal/Register.hpp
@@ -19,10 +19,11 @@ namespace fail {
  * specific to a simulator/architecture.
  */
 enum RegisterType {
-	RT_GP, //!< general purpose
-	RT_FP, //!< floating point register
-	RT_IP, //!< program counter / instruction pointer
-	RT_ST  //!< status register
+	RT_NONE, //!< no classification
+	RT_GP,   //!< general purpose
+	RT_FP,   //!< floating point register
+	RT_IP,   //!< program counter / instruction pointer
+	RT_ST    //!< status register
 };
 
 /**
@@ -33,13 +34,8 @@ enum RegisterType {
  */
 class Register {
 protected:
-	RegisterType m_Type; //!< the type of this register
 	regwidth_t m_Width; //!< the register width
 	unsigned int m_Id; //!< the unique id of this register
-	//! \c true if register has already been assigned, \c false otherwise
-	bool m_Assigned;
-	//! The index in it's register set if assigned (\c -1 otherwise)
-	size_t m_Index;
 	std::string m_Name; //!< The (optional) name, maybe empty
 	friend class UniformRegisterSet;
 public:
@@ -49,14 +45,8 @@ public:
 	 * @param t the type of the register to be constructed
 	 * @param w the width of the register in bits
 	 */
-	Register(unsigned int id, RegisterType t, regwidth_t w)
-		: m_Type(t), m_Width(w), m_Id(id), m_Assigned(false),
-		  m_Index(static_cast<size_t>(-1)) { }
-	/**
-	 * Returns the (fixed) type of this register.
-	 * @return the type of this register
-	 */
-	RegisterType getType() const { return m_Type; }
+	Register(unsigned int id, regwidth_t w)
+		: m_Width(w), m_Id(id) { }
 	/**
 	 * Returns the (fixed) width of this register.
 	 * @return the width in bits
@@ -72,20 +62,6 @@ public:
 	 * @return the textual register description
 	 */
 	const std::string& getName() const { return m_Name; }
-	/**
-	 * Retrieves the unique index within it's assigned register set.
-	 * If the register has not been assigned, \c (size_t)-1 will be
-	 * returned.
-	 * @return the register index or -1 if not assigned
-	 * @see isAssigned()
-	 */
-	size_t getIndex() const { return m_Index; }
-	/**
-	 * Checks whether this register has already been assigned. On
-	 * creation the register isn't initially assigned.
-	 * @return \c true if assigned, \c false otherwise
-	 */
-	bool isAssigned() const { return m_Assigned; }
 	/**
 	 * Returns the unique id of this register.
 	 * @return the unique id
diff --git a/src/core/sal/arm/ArmArchitecture.cc b/src/core/sal/arm/ArmArchitecture.cc
index 4121ef8a..a17f28a4 100644
--- a/src/core/sal/arm/ArmArchitecture.cc
+++ b/src/core/sal/arm/ArmArchitecture.cc
@@ -10,19 +10,19 @@ ArmArchitecture::ArmArchitecture()
 	// 16x 32-Bit GP Registers
 	for (int i = 0; i < 16; i++) {
 		if (i != RI_IP) { // IP will be added separately (see below)
-			Register *reg = new Register(i, RT_GP, 32);
+			Register *reg = new Register(i, 32);
 			// Build and set the register name:
 			std::stringstream sstr;
 			sstr << "R" << i+1;
 			reg->setName(sstr.str().c_str());
-			m_addRegister(reg);
+			m_addRegister(reg, RT_GP);
 		}
 	}
 
 	// Instruction Pointer:
-	Register *reg = new Register(RI_IP, RT_IP, 32);
+	Register *reg = new Register(RI_IP, 32);
 	reg->setName("IP");
-	m_addRegister(reg);
+	m_addRegister(reg, RT_IP);
 }
 
 ArmArchitecture::~ArmArchitecture()
diff --git a/src/core/sal/x86/X86Architecture.cc b/src/core/sal/x86/X86Architecture.cc
index e8587e69..97ff6e2d 100644
--- a/src/core/sal/x86/X86Architecture.cc
+++ b/src/core/sal/x86/X86Architecture.cc
@@ -13,34 +13,34 @@ X86Architecture::X86Architecture()
   	const  std::string names[] = { "RAX", "RCX", "RDX", "RBX", "RSP", "RBP", "RSI", "RDI", "R8",
   	                               "R9", "R10", "R11", "R12", "R13", "R14", "R15" };
 	for (unsigned short i = 0; i < 16; i++) {
-		Register* pReg = new Register(i, RT_GP, 64);
+		Register* pReg = new Register(i, 64);
 		pReg->setName(names[i]);
-		m_addRegister(pReg);
+		m_addRegister(pReg, RT_GP);
 	}
   #else
   	// -- 32 bit register --
   	const std::string names[] = { "EAX", "ECX", "EDX", "EBX", "ESP", "EBP", "ESI", "EDI" };
 	for (unsigned short i = 0; i < 8; i++) {
-		Register* pReg = new Register(i, RT_GP, 32);
+		Register* pReg = new Register(i, 32);
 		pReg->setName(names[i]);
-		m_addRegister(pReg);
+		m_addRegister(pReg, RT_GP);
 	}
   #endif // SIM_SUPPORT_64
 	// -------------------------------------
 	// Add the program counter (PC) register:
   #ifdef SIM_SUPPORT_64
-	Register* pPCReg = new Register(RID_PC, RT_IP, 64);
+	Register* pPCReg = new Register(RID_PC, 64);
 	pPCReg->setName("RIP");
   #else
-    Register* pPCReg = new Register(RID_PC, RT_IP, 32);
+    Register* pPCReg = new Register(RID_PC, 32);
 	pPCReg->setName("EIP");
   #endif // SIM_SUPPORT_64
-	m_addRegister(pPCReg);
+	m_addRegister(pPCReg, RT_IP);
     // -------------------------------------
 	// Add the status register (EFLAGS):
-	Register* pFlagReg = new Register(RID_FLAGS, RT_ST, 32);
+	Register* pFlagReg = new Register(RID_FLAGS, 32);
 	pFlagReg->setName("EFLAGS");
-	m_addRegister(pFlagReg);
+	m_addRegister(pFlagReg, RT_ST);
 }
 
 X86Architecture::~X86Architecture()