diff --git a/sim/ppc/.Sanitize b/sim/ppc/.Sanitize
index 625fd3695d4..e99ca8a0fb5 100644
--- a/sim/ppc/.Sanitize
+++ b/sim/ppc/.Sanitize
@@ -31,6 +31,7 @@ README.psim
 basics.h
 bits.c
 bits.h
+config.in
 configure
 configure.in
 core.c
diff --git a/sim/ppc/ChangeLog b/sim/ppc/ChangeLog
index 6ba9a81f620..fdc580e152b 100644
--- a/sim/ppc/ChangeLog
+++ b/sim/ppc/ChangeLog
@@ -1,3 +1,27 @@
+	* configure.in: Call AC_CONFIG_HEADER.  Don't try to use
+	bfd/hosts/*.h file or bfd/config/*.mh file.  Call AC_PROG_CC and
+	AC_PROG_RANLIB.  Substitute in values for CFLAGS, HDEFINES, AR,
+	and CC_FOR_BUILD.  Call AC_CHECK_HEADERS for various header files.
+	Touch stamp.h if creating config.h.
+	* configure: Rebuild.
+	* config.in: New file, created by autoheader.
+	* Makefile.in (AR): Define as @AR@.
+	(CC): New variable, defined as @CC@.
+	(CFLAGS): Define as @CFLAGS@.
+	(CC_FOR_BUILD): New variable, defined as @CC_FOR_BUILD@.
+	(RANLIB): Define as @RANLIB@.
+	(HDEFINES, TDEFINES): New variables.
+	(@host_makefile_frag@): Remove.
+	(mostlyclean): Make the same as clean, not distclean.
+	(clean): Remove config.log.
+	(distclean): Remove config.h and stamp-h.
+	(Makefile): Don't depend upon @frags@.  Just rebuild Makefile when
+	invoking config.status.
+	(config.h, stamp-h): New targets.
+	(gen, gen.o): Build with CC_FOR_BUILD, not CC.
+	(ppc-config.h): Rename from old config.h build.
+	* (basics.h,gen.c,ppc-endian.c,psim.c): Include ppc-config.h.
+	
 Fri Sep  8 09:51:03 1995  Michael Meissner  <meissner@tiktok.cygnus.com>
 
 	* configure{,.in}: Don't include sysdep.h from bfd, since bfd no
diff --git a/sim/ppc/Makefile.in b/sim/ppc/Makefile.in
index c4b1b5fe349..2756751cc0b 100644
--- a/sim/ppc/Makefile.in
+++ b/sim/ppc/Makefile.in
@@ -49,19 +49,23 @@ docdir = $(datadir)/doc
 
 SHELL = /bin/sh
 
-# FIXME: use autoconf's AC_PROG_INSTALL
 INSTALL = $(srcroot)/install.sh -c
 INSTALL_PROGRAM = $(INSTALL)
 INSTALL_DATA = $(INSTALL)
 INSTALL_XFORM = $(INSTALL) -t='$(program_transform_name)'
 INSTALL_XFORM1= $(INSTALL_XFORM) -b=.1
 
-AR = ar
+AR = @AR@
 AR_FLAGS = rc
-CFLAGS = -g
+CC = @CC@
+CFLAGS = @CFLAGS@
+CC_FOR_BUILD = @CC_FOR_BUILD@
 BISON = bison
 MAKEINFO = makeinfo
-RANLIB = ranlib
+RANLIB = @RANLIB@
+
+HDEFINES = @HDEFINES@
+TDEFINES =
 
 .NOEXPORT:
 MAKEOVERRIDES=
@@ -76,10 +80,6 @@ CONFIG_FILE	= std-config.h
 LIBIBERTY_LIB	= ../../libiberty/libiberty.a
 BFD_LIB		= ../../bfd/libbfd.a
 
-#### Makefile fragments come in here.
-# @host_makefile_frag@
-###
-
 TARGETLIB = libsim.a
 
 all:	run libsim.a $(GDB_OBJ)
@@ -91,6 +91,7 @@ all:	run libsim.a $(GDB_OBJ)
 
 BASICS_H = \
 	config.h \
+	ppc-config.h \
 	words.h \
 	ppc-endian.h \
 	debug.h \
@@ -136,7 +137,8 @@ BUILT_SRC = \
 	idecode.h idecode.c \
 	semantics.h semantics.c \
 	spreg.h spreg.c \
-	config.h
+	config.h \
+	ppc-config.h
 
 LIB_SRC = \
 	psim.c \
@@ -201,7 +203,7 @@ bits.o: bits.c bits.h
 debug.o: debug.c $(BASICS_H)
 
 ppc-endian.o: ppc-endian.c ppc-endian.h \
-	config.h words.h sim_callbacks.h
+	config.h ppc-config.h words.h sim_callbacks.h
 
 system.o: system.c system.h $(CPU_H) $(IDECODE_H)
 
@@ -243,8 +245,8 @@ semantics.o: semantics.c semantics.h $(CPU_H) $(IDECODE_H)
 # Rules to create the built c source code files
 #
 
-config.h: $(CONFIG_FILE)
-	cp $(srcdir)/$(CONFIG_FILE) config.h
+ppc-config.h: $(CONFIG_FILE)
+	cp $(srcdir)/$(CONFIG_FILE) ppc-config.h
 
 
 tmp-gencode: gen ppc-instructions ppc-spr-table $(srcdir)/../../move-if-change
@@ -268,26 +270,31 @@ tmp-gencode: gen ppc-instructions ppc-spr-table $(srcdir)/../../move-if-change
 
 icache.h idecode.h idecode.c semantics.h semantics.c spreg.h spreg.c: tmp-gencode
 
-gen.o: gen.c config.h
+gen.o: gen.c config.h ppc-config.h
+	$(CC_FOR_BUILD) -c $(CFLAGS) $(HDEFINES) $(CSEARCH) $(CSWITCHES) $(srcdir)/gen.c
 
-gen: gen.o config.h $(LIBIBERTY_LIB) $(LIBS)
-	$(CC) $(CFLAGS) $(LDFLAGS) -o gen gen.o $(LIBIBERTY_LIB) $(LIBS)
+gen: gen.o config.h ppc-config.h $(LIBIBERTY_LIB) $(LIBS)
+	$(CC_FOR_BUILD) $(CFLAGS) $(LDFLAGS) -o gen gen.o $(LIBIBERTY_LIB) $(LIBS)
 		
 #
 
 tags etags: TAGS
 
-TAGS: tmp-gencode config.h
+TAGS: tmp-gencode config.h ppc-config.h
 	etags $(srcdir)/*.h $(srcdir)/*.c $(BUILT_SRC)
 
-clean:
-	rm -f tmp-* *.[oas] core psim run gen
+clean mostlyclean:
+	rm -f tmp-* *.[oas] core psim run gen config.log
 
-distclean mostlyclean realclean: clean
-	rm -f TAGS $(BUILT_SRC) Makefile config.cache config.log config.status
+distclean realclean: clean
+	rm -f TAGS $(BUILT_SRC) Makefile config.cache config.status config.h stamp-h
 
-Makefile: Makefile.in config.status @frags@
-	$(SHELL) ./config.status
+Makefile: Makefile.in config.status
+	CONFIG_FILES=Makefile CONFIG_HEADERS= $(SHELL) ./config.status
+
+config.h: stamp-h ; @true
+stamp-h: config.in config.status
+	CONFIG_FILES= CONFIG_HEADERS=config.h:config.in $(SHELL) ./config.status
 
 config.status: configure
 	$(SHELL) ./config.status --recheck
diff --git a/sim/ppc/configure.in b/sim/ppc/configure.in
index 19c46485bca..b964ece066a 100644
--- a/sim/ppc/configure.in
+++ b/sim/ppc/configure.in
@@ -2,23 +2,31 @@ dnl Process this file with autoconf to produce a configure script.
 AC_PREREQ(2.3)dnl
 AC_INIT(Makefile.in)
 
+AC_CONFIG_HEADER(config.h:config.in)
+
 AC_CONFIG_AUX_DIR(`cd $srcdir;pwd`/../..)
 AC_CANONICAL_SYSTEM
 AC_ARG_PROGRAM
 
 . ${srcdir}/../../bfd/configure.host
 
-if test -f ${srcdir}/../../bfd/config/${my_host}.mh; then
-	host_makefile_frag=../../bfd/config/${my_host}.mh
+AC_PROG_CC
+AC_SUBST(CFLAGS)
+AC_SUBST(HDEFINES)
+AR=${AR-ar}
+AC_SUBST(AR)
+AC_PROG_RANLIB
+
+# Put a plausible default for CC_FOR_BUILD in Makefile.
+AC_C_CROSS
+if test "x$cross_compiling" = "xno"; then
+  CC_FOR_BUILD='$(CC)'
 else
-	host_makefile_frag=/dev/null
+  CC_FOR_BUILD=gcc
 fi
+AC_SUBST(CC_FOR_BUILD)
 
-frags=
-if test $host_makefile_frag != /dev/null; then
-	frags="$frags $host_makefile_frag"
-fi
-AC_SUBST_FILE(host_makefile_frag)
-AC_SUBST(frags)
+AC_CHECK_HEADERS(string.h strings.h stdlib.h time.h sys/times.h)
 
-AC_OUTPUT(Makefile)
+AC_OUTPUT(Makefile,
+[case x$CONFIG_HEADERS in xconfig.h:config.in) echo > stamp-h ;; esac])
diff --git a/sim/ppc/gen.c b/sim/ppc/gen.c
index e6e5c161e10..9341cd81486 100644
--- a/sim/ppc/gen.c
+++ b/sim/ppc/gen.c
@@ -42,6 +42,7 @@
 #include <string.h>
 
 #include "config.h"
+#include "ppc-config.h"
 
 #undef WITH_ASSERT
 #define WITH_ASSERT 1
diff --git a/sim/ppc/ppc-endian.c b/sim/ppc/ppc-endian.c
index 0158116eb41..734ea213e52 100644
--- a/sim/ppc/ppc-endian.c
+++ b/sim/ppc/ppc-endian.c
@@ -28,6 +28,7 @@
 
 
 #include "config.h"
+#include "ppc-config.h"
 #include "words.h"
 #include "ppc-endian.h"
 #include "sim_callbacks.h"
diff --git a/sim/ppc/psim.c b/sim/ppc/psim.c
new file mode 100644
index 00000000000..45fb821bcaf
--- /dev/null
+++ b/sim/ppc/psim.c
@@ -0,0 +1,904 @@
+/*  This file is part of the program psim.
+
+    Copyright (C) 1994-1995, Andrew Cagney <cagney@highland.com.au>
+
+    This program is free software; you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation; either version 2 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+ 
+    You should have received a copy of the GNU General Public License
+    along with this program; if not, write to the Free Software
+    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ 
+    */
+
+
+#ifndef _PSIM_C_
+#define _PSIM_C_
+
+#include "config.h"
+#include "ppc-config.h"
+#include "inline.h"
+
+#ifndef STATIC_INLINE_PSIM
+#define STATIC_INLINE_PSIM STATIC_INLINE
+#endif
+
+#include <string.h>
+#include <setjmp.h>
+
+#include "cpu.h" /* includes psim.h */
+#include "idecode.h"
+
+#include "inline.c"
+
+
+/* system structure, actual size of processor array determined at
+   runtime */
+
+struct _psim {
+  event_queue *events;
+  device_node *devices;
+  core *memory;
+  /* escape routine for inner functions */
+  void *path_to_halt;
+  void *path_to_restart;
+  /* status from last halt */
+  psim_status halt_status;
+  /* the processes proper */
+  int nr_cpus;
+  int last_cpu; /* CPU that last (tried to) execute an instruction */
+  cpu *processors[0];
+};
+
+
+int current_target_byte_order;
+int current_host_byte_order;
+int current_environment;
+int current_alignment;
+
+INLINE_PSIM psim *
+psim_create(const char *file_name,
+	    int nr_processors)
+{
+  int cpu_nr;
+  psim *system;
+
+  /* sanity check */
+  if (nr_processors <= 0
+      || (!WITH_SMP && nr_processors != 1))
+    error("psim_create() invalid number of cpus\n");
+
+  /* create things */
+  system = (psim*)zalloc(sizeof(psim)
+			 + sizeof(cpu*) * (nr_processors + 1));
+  system->nr_cpus = nr_processors;
+  system->events = event_queue_create();
+  system->devices = device_tree_create(file_name);
+  system->memory = core_create(system->devices, 0);
+  for (cpu_nr = 0; cpu_nr < nr_processors; cpu_nr++) {
+    system->processors[cpu_nr] = cpu_create(system,
+					    system->memory,
+					    system->events,
+					    cpu_nr);
+  }
+
+  /* fill in the missing endian information */
+  current_target_byte_order
+    = (device_tree_find_boolean(system->devices, "/options/little-endian?")
+       ? LITTLE_ENDIAN
+       : BIG_ENDIAN);
+  if (WITH_TARGET_BYTE_ORDER
+      && WITH_TARGET_BYTE_ORDER != current_target_byte_order)
+    error("target byte order conflict\n");
+
+  current_host_byte_order = 1;
+  current_host_byte_order = (*(char*)(&current_host_byte_order)
+			     ? LITTLE_ENDIAN
+			     : BIG_ENDIAN);
+  if (WITH_HOST_BYTE_ORDER
+      && WITH_HOST_BYTE_ORDER != current_host_byte_order)
+    error("host byte order conflict\n");
+
+  /* fill in the missing OEA/VEA information */
+  current_environment = (device_tree_find_boolean(system->devices,
+						  "/options/vea?")
+			 ? VIRTUAL_ENVIRONMENT
+			 : OPERATING_ENVIRONMENT);
+
+  /* fill in the missing ALLIGNMENT information */
+  current_alignment = (device_tree_find_boolean(system->devices,
+						"/options/aligned?")
+		       ? STRICT_ALIGNMENT
+		       : NONSTRICT_ALIGNMENT);
+  if (WITH_ALIGNMENT
+      && CURRENT_ALIGNMENT != WITH_ALIGNMENT)
+    error("target alignment support conflict\n");
+
+  return system;
+}
+
+
+/* allow the simulation to stop/restart abnormaly */
+
+STATIC_INLINE_PSIM void
+psim_set_halt_and_restart(psim *system,
+			  void *halt_jmp_buf,
+			  void *restart_jmp_buf)
+{
+  system->path_to_halt = halt_jmp_buf;
+  system->path_to_restart = restart_jmp_buf;
+}
+
+STATIC_INLINE_PSIM void
+psim_clear_halt_and_restart(psim *system)
+{
+  system->path_to_halt = NULL;
+  system->path_to_restart = NULL;
+}
+
+INLINE_PSIM void
+psim_restart(psim *system,
+	     int current_cpu)
+{
+  system->last_cpu = current_cpu;
+  longjmp(*(jmp_buf*)(system->path_to_restart), current_cpu + 1);
+}
+
+
+INLINE_PSIM void
+psim_halt(psim *system,
+	  int current_cpu,
+	  unsigned_word cia,
+	  stop_reason reason,
+	  int signal)
+{
+  system->last_cpu = current_cpu;
+  system->halt_status.cpu_nr = current_cpu;
+  system->halt_status.reason = reason;
+  system->halt_status.signal = signal;
+  system->halt_status.program_counter = cia;
+  longjmp(*(jmp_buf*)(system->path_to_halt), current_cpu + 1);
+}
+
+INLINE_PSIM psim_status
+psim_get_status(psim *system)
+{
+  return system->halt_status;
+}
+
+
+cpu *
+psim_cpu(psim *system,
+	 int cpu_nr)
+{
+  if (cpu_nr < 0 || cpu_nr >= system->nr_cpus)
+    return NULL;
+  else
+    return system->processors[cpu_nr];
+}
+
+
+
+STATIC_INLINE_PSIM int
+sizeof_argument_strings(char **arg)
+{
+  int sizeof_strings = 0;
+
+  /* robust */
+  if (arg == NULL)
+    return 0;
+
+  /* add up all the string sizes (padding as we go) */
+  for (; *arg != NULL; arg++) {
+    int len = strlen(*arg) + 1;
+    sizeof_strings += ALIGN_8(len);
+  }
+
+  return sizeof_strings;
+}
+
+STATIC_INLINE_PSIM int
+number_of_arguments(char **arg)
+{
+  int nr;
+  if (arg == NULL)
+    return 0;
+  for (nr = 0; *arg != NULL; arg++, nr++);
+  return nr;
+}
+
+STATIC_INLINE_PSIM int
+sizeof_arguments(char **arg)
+{
+  return ALIGN_8((number_of_arguments(arg) + 1) * sizeof(unsigned_word));
+}
+
+STATIC_INLINE_PSIM void
+write_stack_arguments(psim *system,
+		      char **arg,
+		      unsigned_word start_block,
+		      unsigned_word start_arg)
+{
+  TRACE(trace_create_stack,
+	("write_stack_arguments() - %s=0x%x %s=0x%x %s=0x%x %s=0x%x\n",
+	 "system", system, "arg", arg,
+	 "start_block", start_block, "start_arg", start_arg));
+  if (arg == NULL)
+    error("write_arguments: character array NULL\n");
+  /* only copy in arguments, memory is already zero */
+  for (; *arg != NULL; arg++) {
+    int len = strlen(*arg)+1;
+    TRACE(trace_create_stack,
+	  ("write_stack_arguments - write %s=%s at %s=0x%x %s=0x%x %s=0x%x\n",
+	   "**arg", *arg, "start_block", start_block,
+	   "len", len, "start_arg", start_arg));
+    if (psim_write_memory(system, 0, *arg,
+			  start_block, len,
+			  raw_transfer, 0) != len)
+      error("write_arguments() - write of **arg (%s) at 0x%x failed\n",
+	    *arg, start_block);
+    if (psim_write_memory(system, 0, &start_block,
+			  start_arg, sizeof(start_block),
+			  cooked_transfer, 0) != sizeof(start_block))
+      error("write_arguments() - write of *arg failed\n");
+    start_block += ALIGN_8(len);
+    start_arg += sizeof(start_block);
+  }
+}
+
+STATIC_INLINE_PSIM void
+create_elf_stack_frame(psim *system,
+		       unsigned_word bottom_of_stack,
+		       char **argv,
+		       char **envp)
+{
+  /* fixme - this is over aligned */
+
+  /* information block */
+  const unsigned sizeof_envp_block = sizeof_argument_strings(envp);
+  const unsigned_word start_envp_block = bottom_of_stack - sizeof_envp_block;
+  const unsigned sizeof_argv_block = sizeof_argument_strings(argv);
+  const unsigned_word start_argv_block = start_envp_block - sizeof_argv_block;
+
+  /* auxiliary vector - contains only one entry */
+  const unsigned sizeof_aux_entry = 2*sizeof(unsigned_word); /* magic */
+  const unsigned_word start_aux = start_argv_block - ALIGN_8(sizeof_aux_entry);
+
+  /* environment points (including null sentinal) */
+  const unsigned sizeof_envp = sizeof_arguments(envp);
+  const unsigned_word start_envp = start_aux - sizeof_envp;
+
+  /* argument pointers (including null sentinal) */
+  const int argc = number_of_arguments(argv);
+  const unsigned sizeof_argv = sizeof_arguments(argv);
+  const unsigned_word start_argv = start_envp - sizeof_argv;
+
+  /* link register save address - alligned to a 16byte boundary */
+  const unsigned_word top_of_stack = ((start_argv
+				       - 2 * sizeof(unsigned_word))
+				      & ~0xf);
+
+  /* force some stack space */
+  if (CURRENT_ENVIRONMENT == VIRTUAL_ENVIRONMENT
+      && core_stack_lower_bound(system->memory) > top_of_stack) {
+    unsigned_word extra_stack_space = (core_stack_lower_bound(system->memory)
+				       - FLOOR_PAGE(top_of_stack));
+    TRACE(trace_create_stack,
+	  ("create_elf_stack_frame() - growing stack by 0x%x\n",
+	   extra_stack_space));
+    core_add_stack(system->memory, extra_stack_space);
+  }
+
+  /* install arguments on stack */
+  write_stack_arguments(system, envp, start_envp_block, start_envp);
+  write_stack_arguments(system, argv, start_argv_block, start_argv);
+
+  /* set up the registers */
+  psim_write_register(system, -1,
+		      &top_of_stack, "r1", cooked_transfer);
+  psim_write_register(system, -1,
+		      &argc, "r3", cooked_transfer);
+  psim_write_register(system, -1,
+		      &start_argv, "r4", cooked_transfer);
+  psim_write_register(system, -1,
+		      &start_envp, "r5", cooked_transfer);
+  psim_write_register(system, -1,
+		      &start_aux, "r6", cooked_transfer);
+}
+
+STATIC_INLINE_PSIM void
+create_aix_stack_frame(psim *system,
+		       unsigned_word bottom_of_stack,
+		       char **argv,
+		       char **envp)
+{
+  unsigned_word core_envp;
+  unsigned_word core_argv;
+  unsigned_word core_argc;
+  unsigned_word core_aux;
+  unsigned_word top_of_stack;
+
+  /* cheat - create an elf stack frame */
+  create_elf_stack_frame(system, bottom_of_stack, argv, envp);
+  
+  /* extract argument addresses from registers */
+  psim_read_register(system, 0, &top_of_stack, "r1", cooked_transfer);
+  psim_read_register(system, 0, &core_argc, "r3", cooked_transfer);
+  psim_read_register(system, 0, &core_argv, "r4", cooked_transfer);
+  psim_read_register(system, 0, &core_envp, "r5", cooked_transfer);
+  psim_read_register(system, 0, &core_aux, "r6", cooked_transfer);
+
+  /* check stack fits at least this much */
+  if (CURRENT_ENVIRONMENT == VIRTUAL_ENVIRONMENT
+      && core_stack_lower_bound(system->memory) > top_of_stack) {
+    unsigned_word extra_stack_space = (core_stack_lower_bound(system->memory)
+				       - FLOOR_PAGE(top_of_stack));
+    TRACE(trace_create_stack,
+	  ("create_aix_stack_frame() - growing stack by 0x%x\n",
+	   extra_stack_space));
+    core_add_stack(system->memory, extra_stack_space);
+  }
+
+  /* extract arguments from registers */
+  error("create_aix_stack_frame() - what happens next?\n");
+}
+
+
+INLINE_PSIM void
+psim_load(psim *system)
+{
+  unsigned_word program_counter;
+  msreg msr;
+
+  /* load in core data */
+  core_init(system->memory);
+
+  /* set up all processor entry points (to same thing).  Maybe
+     someday, the device tree could include information specifying the
+     entry point for each processor, one day */
+  TRACE(trace_tbd,
+	("TBD - device tree specifying entry point of each processor\n"));
+  program_counter = device_tree_find_int(system->devices,
+					 "/options/program-counter");
+  psim_write_register(system, -1,
+		      &program_counter,
+		      "pc", cooked_transfer);
+  system->last_cpu = system->nr_cpus - 1; /* force loop to restart */
+
+  /* set up the MSR for at least be/le mode */
+  msr = (device_tree_find_boolean(system->devices,
+				  "/options/little-endian?")
+	 ? msr_little_endian_mode
+	 : 0);
+  psim_write_register(system, -1,
+		      &msr,
+		      "msr", cooked_transfer);
+}
+
+INLINE_PSIM void
+psim_stack(psim *system,
+	   char **argv,
+	   char **envp)
+{
+  unsigned_word stack_pointer = device_tree_find_int(system->devices,
+						     "/options/stack-pointer");
+  if (device_tree_find_boolean(system->devices,
+			       "/options/elf?"))
+    create_elf_stack_frame(system, stack_pointer, argv, envp);
+  else
+    create_aix_stack_frame(system, stack_pointer, argv, envp);
+}
+
+
+
+/* EXECUTE REAL CODE: 
+
+   Unfortunatly, there are multiple cases to consider vis:
+
+   	<icache> X <smp> X <events> X <keep-running-flag> X ...
+
+   Consequently this function is written in multiple different ways */
+
+STATIC_INLINE_PSIM void
+run_until_stop(psim *system,
+	       volatile int *keep_running)
+{
+
+#if (WITH_IDECODE_CACHE == 0 && WITH_SMP == 0)
+
+  /* CASE 1: No instruction cache and no SMP.
+
+     In this case, we can take advantage of the fact that the current
+     instruction address does not need to be returned to the cpu
+     object after every execution of an instruction.  Instead it only
+     needs to be saved when either A. the main loop exits or B. a
+     cpu-{halt,restart} call forces the loop to be re-entered.  The
+     later functions always save the current cpu instruction
+     address. */
+
+  jmp_buf halt;
+  jmp_buf restart;
+  psim_set_halt_and_restart(system, &halt, &restart);
+  if (!setjmp(halt)) {
+    do {
+      if (!setjmp(restart)) {
+	cpu *const processor = system->processors[0];
+	unsigned_word cia = cpu_get_program_counter(processor);
+	do {
+	  if (WITH_EVENTS) {
+	    if (event_queue_tick(system->events)) {
+	      cpu_set_program_counter(processor, cia);
+	      event_queue_process(system->events);
+	      cia = cpu_get_program_counter(processor);
+	    }
+	  }
+	  {
+	    instruction_word const instruction
+	      = vm_instruction_map_read(cpu_instruction_map(processor),
+					processor, cia);
+	    cia = idecode_issue(processor, instruction, cia);
+	  }
+	} while (keep_running == NULL || *keep_running);
+	cpu_set_program_counter(processor, cia);
+      }
+    } while(keep_running == NULL || *keep_running);
+  }
+  psim_clear_halt_and_restart(system);
+#endif
+
+
+#if (WITH_IDECODE_CACHE > 0 && WITH_SMP == 0)
+
+  /* CASE 2: Instruction case but no SMP
+
+     Here, the additional complexity comes from there being two
+     different cache implementations.  A simple function address cache
+     or a full cracked instruction cache */
+
+  jmp_buf halt;
+  jmp_buf restart;
+  psim_set_halt_and_restart(system, &halt, &restart);
+  if (!setjmp(halt)) {
+    do {
+      if (!setjmp(restart)) {
+	cpu *const processor = system->processors[0];
+	unsigned_word cia = cpu_get_program_counter(processor);
+	do {
+	  if (WITH_EVENTS)
+	    if (event_queue_tick(system->events)) {
+	      cpu_set_program_counter(processor, cia);
+	      event_queue_process(system->events);
+	      cia = cpu_get_program_counter(processor);
+	    }
+	  { 
+	    idecode_cache *const cache_entry
+	      = cpu_icache(processor) + (cia / 4 % IDECODE_CACHE_SIZE);
+	    if (cache_entry->address == cia) {
+	      idecode_semantic *const semantic = cache_entry->semantic;
+#if WITH_IDECODE_CACHE == 1
+	      cia = semantic(processor, cache_entry->instruction, cia);
+#else
+	      cia = semantic(processor, cache_entry, cia);
+#endif
+	    }
+	    else {
+	      instruction_word const instruction
+		= vm_instruction_map_read(cpu_instruction_map(processor),
+					  processor,
+					  cia);
+#if WITH_IDECODE_CACHE == 1
+	      idecode_semantic *const semantic = idecode(processor,
+							 instruction,
+							 cia);
+#else
+	      idecode_semantic *const semantic = idecode(processor,
+							 instruction,
+							 cia,
+							 cache_entry);
+#endif
+	      cache_entry->address = cia;
+	      cache_entry->semantic = semantic;
+#if WITH_IDECODE_CACHE == 1
+	      cache_entry->instruction = instruction;
+	      cia = semantic(processor, instruction, cia);
+#else
+	      cia = semantic(processor, cache_entry, cia);
+#endif
+	    }
+	  }
+	} while (keep_running == NULL || *keep_running);
+	cpu_set_program_counter(processor, cia);
+      }
+    } while(keep_running == NULL || *keep_running);
+  }
+  psim_clear_halt_and_restart(system);
+#endif
+
+
+#if (WITH_IDECODE_CACHE == 0 && WITH_SMP > 0)
+
+  /* CASE 3: No ICACHE but SMP
+
+     The complexity here comes from needing to correctly restart the
+     system when it is aborted.  In particular if cpu0 requests a
+     restart, the next cpu is still cpu1.  Cpu0 being restarted after
+     all the other CPU's and the event queue have been processed */
+
+  jmp_buf halt;
+  jmp_buf restart;
+  psim_set_halt_and_restart(system, &halt, &restart);
+
+  if (!setjmp(halt)) {
+    int first_cpu = setjmp(restart);
+    if (first_cpu == 0)
+      first_cpu = system->last_cpu + 1;
+    do {
+      int current_cpu;
+      for (current_cpu = first_cpu, first_cpu = 0;
+	   current_cpu < system->nr_cpus + (WITH_EVENTS ? 1 : 0);
+	   current_cpu++) {
+	if (WITH_EVENTS && current_cpu == system->nr_cpus) {
+	  if (event_queue_tick(system->events))
+	    event_queue_process(system->events);
+	}
+	else {
+	  cpu *const processor = system->processors[current_cpu];
+	  unsigned_word const cia = cpu_get_program_counter(processor);
+	  instruction_word instruction =
+	    vm_instruction_map_read(cpu_instruction_map(processor),
+				    processor,
+				    cia);
+	  cpu_set_program_counter(processor,
+				  idecode_issue(processor, instruction, cia));
+	}
+	if (!(keep_running == NULL || *keep_running)) {
+	  system->last_cpu = current_cpu;
+	  break;
+	}
+      }
+    } while (keep_running == NULL || *keep_running);
+  }
+  psim_clear_halt_and_restart(system);
+#endif
+
+#if (WITH_IDECODE_CACHE > 0 && WITH_SMP > 0)
+
+  /* CASE 4: ICACHE and SMP ...
+
+     This time, everything goes wrong.  Need to restart loops
+     correctly, need to save the program counter and finally need to
+     keep track of each processors current address! */
+
+  jmp_buf halt;
+  jmp_buf restart;
+  psim_set_halt_and_restart(system, &halt, &restart);
+
+  if (!setjmp(halt)) {
+    int first_cpu = setjmp(restart);
+    if (!first_cpu)
+      first_cpu = system->last_cpu + 1;
+    do {
+      int current_cpu;
+      for (current_cpu = first_cpu, first_cpu = 0;
+	   current_cpu < system->nr_cpus + (WITH_EVENTS ? 1 : 0);
+	   current_cpu++) {
+	if (WITH_EVENTS && current_cpu == system->nr_cpus) {
+	  if (event_queue_tick(system->events))
+	    event_queue_process(system->events);
+	}
+	else {
+	  cpu *processor = system->processors[current_cpu];
+	  unsigned_word const cia = cpu_get_program_counter(processor);
+	  idecode_cache *cache_entry
+	    = (cpu_icache(processor) + (cia / 4 % IDECODE_CACHE_SIZE));
+	  if (cache_entry->address == cia) {
+	    idecode_semantic *semantic = cache_entry->semantic;
+#if WITH_IDECODE_CACHE == 1
+	    cpu_set_program_counter(processor,
+				    semantic(processor,
+					     cache_entry->instruction,
+					     cia);
+#else
+	    cpu_set_program_counter(processor,
+				    semantic(processor,
+					     cache_entry,
+					     cia);
+#endif
+	  }
+	  else {
+	    instruction_word instruction =
+	      vm_instruction_map_read(cpu_instruction_map(processor),
+				      processor,
+				      cia);
+#if WITH_IDECODE_CACHE == 1
+	    idecode_semantic *semantic = idecode(processor,
+						 instruction,
+						 cia);
+#else
+	    idecode_semantic *semantic = idecode(processor,
+						 instruction,
+						 cia,
+						 cache_entry);
+#endif
+	    cache_entry->address = cia;
+	    cache_entry->semantic = semantic;
+#if WITH_IDECODE_CACHE == 1
+	    cache_entry->instruction = instruction;
+	    cpu_set_program_counter(processor,
+				    semantic(processor, instruction, cia));
+#else
+	    cpu_set_program_counter(processor,
+				    semantic(processor, cache_entry, cia);
+#endif
+	  }
+	}
+	if (!(keep_running == NULL || *keep_running))
+	  break;
+      }
+    } while (keep_running == NULL || *keep_running);
+  }
+  psim_clear_halt_and_restart(system);
+#endif
+}
+
+
+/* SIMULATE INSTRUCTIONS, various different ways of achieving the same
+   thing */
+
+INLINE_PSIM void
+psim_step(psim *system)
+{
+  volatile int keep_running = 0;
+  psim_run_until_stop(system, &keep_running);
+}
+
+INLINE_PSIM void
+psim_run(psim *system)
+{
+  run_until_stop(system, NULL);
+}
+
+INLINE_PSIM void
+psim_run_until_stop(psim *system,
+		    volatile int *keep_running)
+{
+  run_until_stop(system, keep_running);
+}
+
+
+
+/* storage manipulation functions */
+
+INLINE_PSIM void
+psim_read_register(psim *system,
+		   int which_cpu,
+		   void *buf,
+		   const char reg[],
+		   transfer_mode mode)
+{
+  register_descriptions description;
+  char cooked_buf[sizeof(natural_word)];
+  cpu *processor;
+
+  /* find our processor */
+  if (which_cpu < 0 || which_cpu > system->nr_cpus)
+    error("psim_read_register() - invalid processor %d\n", which_cpu);
+  if (which_cpu == system->nr_cpus)
+    which_cpu = system->last_cpu;
+  processor = system->processors[which_cpu];
+
+  /* find the register description */
+  description = register_description(reg);
+  if (description.type == reg_invalid)
+    error("psim_read_register() invalid register name `%s'\n", reg);
+
+  /* get the cooked value */
+  switch (description.type) {
+
+  case reg_gpr:
+    *(gpreg*)cooked_buf = cpu_registers(processor)->gpr[description.index];
+    break;
+
+  case reg_spr:
+    *(spreg*)cooked_buf = cpu_registers(processor)->spr[description.index];
+    break;
+    
+  case reg_sr:
+    *(sreg*)cooked_buf = cpu_registers(processor)->sr[description.index];
+    break;
+
+  case reg_fpr:
+    *(fpreg*)cooked_buf = cpu_registers(processor)->fpr[description.index];
+    break;
+
+  case reg_pc:
+    *(unsigned_word*)cooked_buf = cpu_get_program_counter(processor);
+    break;
+
+  case reg_cr:
+    *(creg*)cooked_buf = cpu_registers(processor)->cr;
+    break;
+
+  case reg_msr:
+    *(msreg*)cooked_buf = cpu_registers(processor)->msr;
+    break;
+
+  default:
+    printf_filtered("psim_read_register(processor=0x%x,buf=0x%x,reg=%s) %s\n",
+		    processor, buf, reg,
+		    "read of this register unimplemented");
+    break;
+
+  }
+
+  /* the PSIM internal values are in host order.  To fetch raw data,
+     they need to be converted into target order and then returned */
+  if (mode == raw_transfer) {
+    /* FIXME - assumes that all registers are simple integers */
+    switch (description.size) {
+    case 1: 
+      *(unsigned_1*)buf = H2T_1(*(unsigned_1*)cooked_buf);
+      break;
+    case 2:
+      *(unsigned_2*)buf = H2T_2(*(unsigned_2*)cooked_buf);
+      break;
+    case 4:
+      *(unsigned_4*)buf = H2T_4(*(unsigned_4*)cooked_buf);
+      break;
+    case 8:
+      *(unsigned_8*)buf = H2T_8(*(unsigned_8*)cooked_buf);
+      break;
+    }
+  }
+  else {
+    bcopy(cooked_buf, buf, description.size);
+  }
+
+}
+
+
+
+INLINE_PSIM void
+psim_write_register(psim *system,
+		    int which_cpu,
+		    const void *buf,
+		    const char reg[],
+		    transfer_mode mode)
+{
+  cpu *processor;
+  register_descriptions description;
+  char cooked_buf[sizeof(natural_word)];
+
+  /* find our processor */
+  if (which_cpu == -1) {
+    int i;
+    for (i = 0; i < system->nr_cpus; i++)
+      psim_write_register(system, i, buf, reg, mode);
+    return;
+  }
+  else if (which_cpu == system->nr_cpus) {
+    which_cpu = system->last_cpu;
+  }
+  else if (which_cpu < 0 || which_cpu >= system->nr_cpus) {
+    error("psim_read_register() - invalid processor %d\n", which_cpu);
+  }
+
+  processor = system->processors[which_cpu];
+
+  /* find the description of the register */
+  description = register_description(reg);
+  if (description.type == reg_invalid)
+    error("psim_write_register() invalid register name %s\n", reg);
+
+  /* If the data is comming in raw (target order), need to cook it
+     into host order before putting it into PSIM's internal structures */
+  if (mode == raw_transfer) {
+    switch (description.size) {
+    case 1: 
+      *(unsigned_1*)cooked_buf = T2H_1(*(unsigned_1*)buf);
+      break;
+    case 2:
+      *(unsigned_2*)cooked_buf = T2H_2(*(unsigned_2*)buf);
+      break;
+    case 4:
+      *(unsigned_4*)cooked_buf = T2H_4(*(unsigned_4*)buf);
+      break;
+    case 8:
+      *(unsigned_8*)cooked_buf = T2H_8(*(unsigned_8*)buf);
+      break;
+    }
+  }
+  else {
+    bcopy(buf, cooked_buf, description.size);
+  }
+
+  /* put the cooked value into the register */
+  switch (description.type) {
+
+  case reg_gpr:
+    cpu_registers(processor)->gpr[description.index] = *(gpreg*)cooked_buf;
+    break;
+
+  case reg_fpr:
+    cpu_registers(processor)->fpr[description.index] = *(fpreg*)cooked_buf;
+    break;
+
+  case reg_pc:
+    cpu_set_program_counter(processor, *(unsigned_word*)cooked_buf);
+    break;
+
+  case reg_spr:
+    cpu_registers(processor)->spr[description.index] = *(spreg*)cooked_buf;
+    break;
+
+  case reg_sr:
+    cpu_registers(processor)->sr[description.index] = *(sreg*)cooked_buf;
+    break;
+
+  case reg_cr:
+    cpu_registers(processor)->cr = *(creg*)cooked_buf;
+    break;
+
+  case reg_msr:
+    cpu_registers(processor)->msr = *(msreg*)cooked_buf;
+    break;
+
+  default:
+    printf_filtered("psim_write_register(processor=0x%x,cooked_buf=0x%x,reg=%s) %s\n",
+		    processor, cooked_buf, reg,
+		    "read of this register unimplemented");
+    break;
+
+  }
+
+}
+
+
+
+INLINE_PSIM unsigned
+psim_read_memory(psim *system,
+		 int which_cpu,
+		 void *buffer,
+		 unsigned_word vaddr,
+		 unsigned len,
+		 transfer_mode mode)
+{
+  cpu *processor;
+  if (which_cpu < 0 || which_cpu > system->nr_cpus)
+    error("psim_read_memory() invalid cpu\n");
+  if (which_cpu == system->nr_cpus)
+    which_cpu = system->last_cpu;
+  processor = system->processors[which_cpu];
+  return vm_data_map_read_buffer(cpu_data_map(processor),
+				 buffer, vaddr, len, mode);
+}
+
+
+INLINE_PSIM unsigned
+psim_write_memory(psim *system,
+		  int which_cpu,
+		  const void *buffer,
+		  unsigned_word vaddr,
+		  unsigned len,
+		  transfer_mode mode,
+		  int violate_read_only_section)
+{
+  cpu *processor;
+  if (which_cpu < 0 || which_cpu > system->nr_cpus)
+    error("psim_read_memory() invalid cpu\n");
+  if (which_cpu == system->nr_cpus)
+    which_cpu = system->last_cpu;
+  processor = system->processors[which_cpu];
+  return vm_data_map_write_buffer(cpu_data_map(processor),
+				  buffer, vaddr, len, mode, 1);
+}
+
+
+#endif /* _PSIM_C_ */