diff --git a/sim/mips/interp.c b/sim/mips/interp.c
index ab20f0799393..951a962f1cc3 100644
--- a/sim/mips/interp.c
+++ b/sim/mips/interp.c
@@ -351,7 +351,8 @@ sim_open (SIM_OPEN_KIND kind, host_callback *cb,
   SIM_ASSERT (STATE_MAGIC (sd) == SIM_MAGIC_NUMBER);
 
   /* The cpu data is kept in a separately allocated chunk of memory.  */
-  if (sim_cpu_alloc_all (sd, 1) != SIM_RC_OK)
+  if (sim_cpu_alloc_all_extra (sd, 1, sizeof (struct mips_sim_cpu))
+      != SIM_RC_OK)
     return 0;
 
   cpu = STATE_CPU (sd, 0); /* FIXME */
@@ -666,19 +667,21 @@ sim_open (SIM_OPEN_KIND kind, host_callback *cb,
     int rn;
     for (rn = 0; (rn < (LAST_EMBED_REGNUM + 1)); rn++)
       {
+	struct mips_sim_cpu *mips_cpu = MIPS_SIM_CPU (cpu);
+
 	if (rn < 32)
-	  cpu->register_widths[rn] = WITH_TARGET_WORD_BITSIZE;
+	  mips_cpu->register_widths[rn] = WITH_TARGET_WORD_BITSIZE;
 	else if ((rn >= FGR_BASE) && (rn < (FGR_BASE + NR_FGR)))
-	  cpu->register_widths[rn] = WITH_TARGET_FLOATING_POINT_BITSIZE;
+	  mips_cpu->register_widths[rn] = WITH_TARGET_FLOATING_POINT_BITSIZE;
 	else if ((rn >= 33) && (rn <= 37))
-	  cpu->register_widths[rn] = WITH_TARGET_WORD_BITSIZE;
+	  mips_cpu->register_widths[rn] = WITH_TARGET_WORD_BITSIZE;
 	else if ((rn == SRIDX)
 		 || (rn == FCR0IDX)
 		 || (rn == FCR31IDX)
 		 || ((rn >= 72) && (rn <= 89)))
-	  cpu->register_widths[rn] = 32;
+	  mips_cpu->register_widths[rn] = 32;
 	else
-	  cpu->register_widths[rn] = 0;
+	  mips_cpu->register_widths[rn] = 0;
       }
 
 
@@ -855,7 +858,9 @@ mips_reg_store (SIM_CPU *cpu, int rn, const void *memory, int length)
      numbering one. We need to know what the width of each logical
      register number is for the architecture being simulated. */
 
-  if (cpu->register_widths[rn] == 0)
+  struct mips_sim_cpu *mips_cpu = MIPS_SIM_CPU (cpu);
+
+  if (mips_cpu->register_widths[rn] == 0)
     {
       sim_io_eprintf (CPU_STATE (cpu), "Invalid register width for %d (register store ignored)\n", rn);
       return 0;
@@ -863,18 +868,18 @@ mips_reg_store (SIM_CPU *cpu, int rn, const void *memory, int length)
 
   if (rn >= FGR_BASE && rn < FGR_BASE + NR_FGR)
     {
-      cpu->fpr_state[rn - FGR_BASE] = fmt_uninterpreted;
-      if (cpu->register_widths[rn] == 32)
+      mips_cpu->fpr_state[rn - FGR_BASE] = fmt_uninterpreted;
+      if (mips_cpu->register_widths[rn] == 32)
 	{
 	  if (length == 8)
 	    {
-	      cpu->fgr[rn - FGR_BASE] =
+	      mips_cpu->fgr[rn - FGR_BASE] =
 		(uint32_t) T2H_8 (*(uint64_t*)memory);
 	      return 8;
 	    }
 	  else
 	    {
-	      cpu->fgr[rn - FGR_BASE] = T2H_4 (*(uint32_t*)memory);
+	      mips_cpu->fgr[rn - FGR_BASE] = T2H_4 (*(uint32_t*)memory);
 	      return 4;
 	    }
 	}
@@ -882,28 +887,28 @@ mips_reg_store (SIM_CPU *cpu, int rn, const void *memory, int length)
 	{
           if (length == 8)
 	    {
-	      cpu->fgr[rn - FGR_BASE] = T2H_8 (*(uint64_t*)memory);
+	      mips_cpu->fgr[rn - FGR_BASE] = T2H_8 (*(uint64_t*)memory);
 	      return 8;
 	    }
 	  else
 	    {
-	      cpu->fgr[rn - FGR_BASE] = T2H_4 (*(uint32_t*)memory);
+	      mips_cpu->fgr[rn - FGR_BASE] = T2H_4 (*(uint32_t*)memory);
 	      return 4;
 	    }
 	}
     }
 
-  if (cpu->register_widths[rn] == 32)
+  if (mips_cpu->register_widths[rn] == 32)
     {
       if (length == 8)
 	{
-	  cpu->registers[rn] =
+	  mips_cpu->registers[rn] =
 	    (uint32_t) T2H_8 (*(uint64_t*)memory);
 	  return 8;
 	}
       else
 	{
-	  cpu->registers[rn] = T2H_4 (*(uint32_t*)memory);
+	  mips_cpu->registers[rn] = T2H_4 (*(uint32_t*)memory);
 	  return 4;
 	}
     }
@@ -911,12 +916,12 @@ mips_reg_store (SIM_CPU *cpu, int rn, const void *memory, int length)
     {
       if (length == 8)
 	{
-	  cpu->registers[rn] = T2H_8 (*(uint64_t*)memory);
+	  mips_cpu->registers[rn] = T2H_8 (*(uint64_t*)memory);
 	  return 8;
 	}
       else
 	{
-	  cpu->registers[rn] = (int32_t) T2H_4(*(uint32_t*)memory);
+	  mips_cpu->registers[rn] = (int32_t) T2H_4(*(uint32_t*)memory);
 	  return 4;
 	}
     }
@@ -930,7 +935,9 @@ mips_reg_fetch (SIM_CPU *cpu, int rn, void *memory, int length)
   /* NOTE: gdb (the client) stores registers in target byte order
      while the simulator uses host byte order */
 
-  if (cpu->register_widths[rn] == 0)
+  struct mips_sim_cpu *mips_cpu = MIPS_SIM_CPU (cpu);
+
+  if (mips_cpu->register_widths[rn] == 0)
     {
       sim_io_eprintf (CPU_STATE (cpu), "Invalid register width for %d (register fetch ignored)\n", rn);
       return 0;
@@ -939,17 +946,17 @@ mips_reg_fetch (SIM_CPU *cpu, int rn, void *memory, int length)
   /* Any floating point register */
   if (rn >= FGR_BASE && rn < FGR_BASE + NR_FGR)
     {
-      if (cpu->register_widths[rn] == 32)
+      if (mips_cpu->register_widths[rn] == 32)
 	{
 	  if (length == 8)
 	    {
 	      *(uint64_t*)memory =
-		H2T_8 ((uint32_t) (cpu->fgr[rn - FGR_BASE]));
+		H2T_8 ((uint32_t) (mips_cpu->fgr[rn - FGR_BASE]));
 	      return 8;
 	    }
 	  else
 	    {
-	      *(uint32_t*)memory = H2T_4 (cpu->fgr[rn - FGR_BASE]);
+	      *(uint32_t*)memory = H2T_4 (mips_cpu->fgr[rn - FGR_BASE]);
 	      return 4;
 	    }
 	}
@@ -957,28 +964,28 @@ mips_reg_fetch (SIM_CPU *cpu, int rn, void *memory, int length)
 	{
 	  if (length == 8)
 	    {
-	      *(uint64_t*)memory = H2T_8 (cpu->fgr[rn - FGR_BASE]);
+	      *(uint64_t*)memory = H2T_8 (mips_cpu->fgr[rn - FGR_BASE]);
 	      return 8;
 	    }
 	  else
 	    {
-	      *(uint32_t*)memory = H2T_4 ((uint32_t)(cpu->fgr[rn - FGR_BASE]));
+	      *(uint32_t*)memory = H2T_4 ((uint32_t)(mips_cpu->fgr[rn - FGR_BASE]));
 	      return 4;
 	    }
 	}
     }
 
-  if (cpu->register_widths[rn] == 32)
+  if (mips_cpu->register_widths[rn] == 32)
     {
       if (length == 8)
 	{
 	  *(uint64_t*)memory =
-	    H2T_8 ((uint32_t) (cpu->registers[rn]));
+	    H2T_8 ((uint32_t) (mips_cpu->registers[rn]));
 	  return 8;
 	}
       else
 	{
-	  *(uint32_t*)memory = H2T_4 ((uint32_t)(cpu->registers[rn]));
+	  *(uint32_t*)memory = H2T_4 ((uint32_t)(mips_cpu->registers[rn]));
 	  return 4;
 	}
     }
@@ -987,12 +994,12 @@ mips_reg_fetch (SIM_CPU *cpu, int rn, void *memory, int length)
       if (length == 8)
 	{
 	  *(uint64_t*)memory =
-	    H2T_8 ((uint64_t) (cpu->registers[rn]));
+	    H2T_8 ((uint64_t) (mips_cpu->registers[rn]));
 	  return 8;
 	}
       else
 	{
-	  *(uint32_t*)memory = H2T_4 ((uint32_t)(cpu->registers[rn]));
+	  *(uint32_t*)memory = H2T_4 ((uint32_t)(mips_cpu->registers[rn]));
 	  return 4;
 	}
     }
@@ -2532,55 +2539,66 @@ mips_core_signal (SIM_DESC sd,
 void
 mips_cpu_exception_trigger(SIM_DESC sd, sim_cpu* cpu, address_word cia)
 {
+  struct mips_sim_cpu *mips_cpu = MIPS_SIM_CPU (cpu);
+
   ASSERT(cpu != NULL);
 
-  if (cpu->exc_suspended > 0)
-    sim_io_eprintf(sd, "Warning, nested exception triggered (%d)\n", cpu->exc_suspended);
+  if (mips_cpu->exc_suspended > 0)
+    sim_io_eprintf (sd, "Warning, nested exception triggered (%d)\n",
+		    mips_cpu->exc_suspended);
 
   PC = cia;
-  memcpy(cpu->exc_trigger_registers, cpu->registers, sizeof(cpu->exc_trigger_registers));
-  cpu->exc_suspended = 0;
+  memcpy (mips_cpu->exc_trigger_registers, mips_cpu->registers,
+	  sizeof (mips_cpu->exc_trigger_registers));
+  mips_cpu->exc_suspended = 0;
 }
 
 void
 mips_cpu_exception_suspend(SIM_DESC sd, sim_cpu* cpu, int exception)
 {
+  struct mips_sim_cpu *mips_cpu = MIPS_SIM_CPU (cpu);
+
   ASSERT(cpu != NULL);
 
-  if (cpu->exc_suspended > 0)
+  if (mips_cpu->exc_suspended > 0)
     sim_io_eprintf(sd, "Warning, nested exception signal (%d then %d)\n",
-		   cpu->exc_suspended, exception);
+		   mips_cpu->exc_suspended, exception);
 
-  memcpy(cpu->exc_suspend_registers, cpu->registers, sizeof(cpu->exc_suspend_registers));
-  memcpy(cpu->registers, cpu->exc_trigger_registers, sizeof(cpu->registers));
-  cpu->exc_suspended = exception;
+  memcpy (mips_cpu->exc_suspend_registers, mips_cpu->registers,
+	  sizeof (mips_cpu->exc_suspend_registers));
+  memcpy (mips_cpu->registers, mips_cpu->exc_trigger_registers,
+	  sizeof (mips_cpu->registers));
+  mips_cpu->exc_suspended = exception;
 }
 
 void
 mips_cpu_exception_resume(SIM_DESC sd, sim_cpu* cpu, int exception)
 {
+  struct mips_sim_cpu *mips_cpu = MIPS_SIM_CPU (cpu);
+
   ASSERT(cpu != NULL);
 
-  if (exception == 0 && cpu->exc_suspended > 0)
+  if (exception == 0 && mips_cpu->exc_suspended > 0)
     {
       /* warn not for breakpoints */
-      if (cpu->exc_suspended != sim_signal_to_host(sd, SIM_SIGTRAP))
+      if (mips_cpu->exc_suspended != sim_signal_to_host(sd, SIM_SIGTRAP))
 	sim_io_eprintf(sd, "Warning, resuming but ignoring pending exception signal (%d)\n",
-		       cpu->exc_suspended);
+		       mips_cpu->exc_suspended);
     }
-  else if (exception != 0 && cpu->exc_suspended > 0)
+  else if (exception != 0 && mips_cpu->exc_suspended > 0)
     {
-      if (exception != cpu->exc_suspended)
+      if (exception != mips_cpu->exc_suspended)
 	sim_io_eprintf(sd, "Warning, resuming with mismatched exception signal (%d vs %d)\n",
-		       cpu->exc_suspended, exception);
+		       mips_cpu->exc_suspended, exception);
 
-      memcpy(cpu->registers, cpu->exc_suspend_registers, sizeof(cpu->registers));
+      memcpy (mips_cpu->registers, mips_cpu->exc_suspend_registers,
+	      sizeof (mips_cpu->registers));
     }
-  else if (exception != 0 && cpu->exc_suspended == 0)
+  else if (exception != 0 && mips_cpu->exc_suspended == 0)
     {
       sim_io_eprintf(sd, "Warning, ignoring spontanous exception signal (%d)\n", exception);
     }
-  cpu->exc_suspended = 0;
+  mips_cpu->exc_suspended = 0;
 }
 
 
diff --git a/sim/mips/sim-main.h b/sim/mips/sim-main.h
index 418c65991189..d4e6a2f4a547 100644
--- a/sim/mips/sim-main.h
+++ b/sim/mips/sim-main.h
@@ -20,6 +20,8 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
 #ifndef SIM_MAIN_H
 #define SIM_MAIN_H
 
+#define SIM_HAVE_COMMON_SIM_CPU
+
 #define SIM_CORE_SIGNAL(SD,CPU,CIA,MAP,NR_BYTES,ADDR,TRANSFER,ERROR) \
 mips_core_signal ((SD), (CPU), (CIA), (MAP), (NR_BYTES), (ADDR), (TRANSFER), (ERROR))
 
@@ -171,20 +173,20 @@ typedef struct _pending_write_queue {
 #ifndef PENDING_TRACE
 #define PENDING_TRACE 0
 #endif
-#define PENDING_IN ((CPU)->pending.in)
-#define PENDING_OUT ((CPU)->pending.out)
-#define PENDING_TOTAL ((CPU)->pending.total)
-#define PENDING_SLOT_SIZE ((CPU)->pending.slot_size)
-#define PENDING_SLOT_BIT ((CPU)->pending.slot_bit)
-#define PENDING_SLOT_DELAY ((CPU)->pending.slot_delay)
-#define PENDING_SLOT_DEST ((CPU)->pending.slot_dest)
-#define PENDING_SLOT_VALUE ((CPU)->pending.slot_value)
+#define PENDING_IN (MIPS_SIM_CPU (CPU)->pending.in)
+#define PENDING_OUT (MIPS_SIM_CPU (CPU)->pending.out)
+#define PENDING_TOTAL (MIPS_SIM_CPU (CPU)->pending.total)
+#define PENDING_SLOT_SIZE (MIPS_SIM_CPU (CPU)->pending.slot_size)
+#define PENDING_SLOT_BIT (MIPS_SIM_CPU (CPU)->pending.slot_bit)
+#define PENDING_SLOT_DELAY (MIPS_SIM_CPU (CPU)->pending.slot_delay)
+#define PENDING_SLOT_DEST (MIPS_SIM_CPU (CPU)->pending.slot_dest)
+#define PENDING_SLOT_VALUE (MIPS_SIM_CPU (CPU)->pending.slot_value)
 
 /* Invalidate the pending write queue, all pending writes are
    discarded. */
 
 #define PENDING_INVALIDATE() \
-memset (&(CPU)->pending, 0, sizeof ((CPU)->pending))
+memset (&MIPS_SIM_CPU (CPU)->pending, 0, sizeof (MIPS_SIM_CPU (CPU)->pending))
 
 /* Schedule a write to DEST for N cycles time.  For 64 bit
    destinations, schedule two writes.  For floating point registers,
@@ -258,12 +260,11 @@ typedef union {
 #define SIM_STATE  sim_cpu *cpu, address_word cia
 #define SIM_ARGS   CPU, cia
 
-struct _sim_cpu {
-
+struct mips_sim_cpu {
 
   /* The following are internal simulator state variables: */
   address_word dspc;  /* delay-slot PC */
-#define DSPC ((CPU)->dspc)
+#define DSPC (MIPS_SIM_CPU (CPU)->dspc)
 
 #define DELAY_SLOT(TARGET) NIA = delayslot32 (SD_, (TARGET))
 #define FORBIDDEN_SLOT() { NIA = forbiddenslot32 (SD_); }
@@ -273,8 +274,8 @@ struct _sim_cpu {
   /* State of the simulator */
   unsigned int state;
   unsigned int dsstate;
-#define STATE ((CPU)->state)
-#define DSSTATE ((CPU)->dsstate)
+#define STATE (MIPS_SIM_CPU (CPU)->state)
+#define DSSTATE (MIPS_SIM_CPU (CPU)->dsstate)
 
 /* Flags in the "state" variable: */
 #define simHALTEX        (1 << 2)  /* 0 = run; 1 = halt on exception */
@@ -331,7 +332,7 @@ struct _sim_cpu {
   unsigned_word registers[LAST_EMBED_REGNUM + 1];
 
   int register_widths[NUM_REGS];
-#define REGISTERS       ((CPU)->registers)
+#define REGISTERS       (MIPS_SIM_CPU (CPU)->registers)
 
 #define GPR     (&REGISTERS[0])
 #define GPR_SET(N,VAL) (REGISTERS[(N)] = (VAL))
@@ -409,7 +410,7 @@ struct _sim_cpu {
 #define SIM_CPU_EXCEPTION_RESUME(SD,CPU,EXC) mips_cpu_exception_resume(SD,CPU,EXC)
 
   unsigned_word c0_config_reg;
-#define C0_CONFIG ((CPU)->c0_config_reg)
+#define C0_CONFIG (MIPS_SIM_CPU (CPU)->c0_config_reg)
 
 /* The following are pseudonyms for standard registers */
 #define ZERO    (REGISTERS[0])
@@ -431,7 +432,7 @@ struct _sim_cpu {
 
 #define NR_COP0_GPR	32
   unsigned_word cop0_gpr[NR_COP0_GPR];
-#define COP0_GPR	((CPU)->cop0_gpr)
+#define COP0_GPR	(MIPS_SIM_CPU (CPU)->cop0_gpr)
 #define COP0_BADVADDR	(COP0_GPR[8])
 
   /* While space is allocated for the floating point registers in the
@@ -441,17 +442,17 @@ struct _sim_cpu {
 #define NR_FGR    (32)
 #define FGR_BASE  FP0_REGNUM
   fp_word fgr[NR_FGR];
-#define FGR       ((CPU)->fgr)
+#define FGR       (MIPS_SIM_CPU (CPU)->fgr)
 
   /* Keep the current format state for each register: */
   FP_formats fpr_state[32];
-#define FPR_STATE ((CPU)->fpr_state)
+#define FPR_STATE (MIPS_SIM_CPU (CPU)->fpr_state)
 
   pending_write_queue pending;
 
   /* The MDMX accumulator (used only for MDMX ASE).  */
   MDMX_accumulator acc;
-#define ACC             ((CPU)->acc)
+#define ACC             (MIPS_SIM_CPU (CPU)->acc)
 
   /* LLBIT = Load-Linked bit. A bit of "virtual" state used by atomic
      read-write instructions. It is set when a linked load occurs. It
@@ -460,7 +461,7 @@ struct _sim_cpu {
      no longer be atomic. In particular, it is cleared by exception
      return instructions. */
   int llbit;
-#define LLBIT ((CPU)->llbit)
+#define LLBIT (MIPS_SIM_CPU (CPU)->llbit)
 
 
 /* The HIHISTORY and LOHISTORY timestamps are used to ensure that
@@ -468,13 +469,11 @@ struct _sim_cpu {
    following operation is spotted. See mips.igen for more details. */
 
   hilo_history hi_history;
-#define HIHISTORY (&(CPU)->hi_history)
+#define HIHISTORY (&MIPS_SIM_CPU (CPU)->hi_history)
   hilo_history lo_history;
-#define LOHISTORY (&(CPU)->lo_history)
-
-
-  sim_cpu_base base;
+#define LOHISTORY (&MIPS_SIM_CPU (CPU)->lo_history)
 };
+#define MIPS_SIM_CPU(cpu) ((struct mips_sim_cpu *) CPU_ARCH_DATA (cpu))
 
 extern void mips_sim_close (SIM_DESC sd, int quitting);
 #define SIM_CLOSE_HOOK(...) mips_sim_close (__VA_ARGS__)
