* defs.h: If TARGET_BYTE_ORDER_SELECTABLE is defined by tm.h,

	define TARGET_BYTE_ORDER as target_byte_order, and declare
	target_byte_order as an extern int, and define BITS_BIG_ENDIAN as
	a test of TARGET_BYTE_ORDER.
	* top.c: Several additions if TARGET_BYTE_ORDER_SELECTABLE is
	defined:
	(endianlist, target_byte_order): New variables.
	(set_endian, set_endian_big, set_endian_little): New functions.
	(show_endian): New function.
	(init_cmd_lists): Initialize endianlist.
	(init_main): Add commands ``set endian big'', ``set endian
	little'', and ``show endian''.
	* a29k-pinsn.c: Rewrite uses of TARGET_BYTE_ORDER and
	BITS_BIG_ENDIAN to switch at run time rather than at compile time.
	* coffread.c, dwarfread.c, findvar.c, mips-tdep.c: Likewise.
	* remote-os9k.c, stabsread.c, valarith.c, valprint.c: Likewise.
	* values.c: Likewise.
	* mips-tdep.c: Rewrite uses of GDB_TARGET_IS_MIPS64 to switch at
	run time rather than at compile time.

6 files changed, 154 insertions, 71 deletions

diff --git a/gdb/a29k-pinsn.c b/gdb/a29k-pinsn.c
index a90cdc0..70e8e5b 100644
--- a/gdb/a29k-pinsn.c
+++ b/gdb/a29k-pinsn.c
@@ -33,9 +33,8 @@ print_insn (memaddr, stream)
 
   GDB_INIT_DISASSEMBLE_INFO(info, stream);
 
-#if TARGET_BYTE_ORDER == BIG_ENDIAN
-  return print_insn_big_a29k (memaddr, &info);
-#else
-  return print_insn_little_a29k (memaddr, &info);
-#endif
+  if (TARGET_BYTE_ORDER == BIG_ENDIAN)
+    return print_insn_big_a29k (memaddr, &info);
+  else
+    return print_insn_little_a29k (memaddr, &info);
 }
diff --git a/gdb/dwarfread.c b/gdb/dwarfread.c
index 150e1d8..aebe6bf 100644
--- a/gdb/dwarfread.c
+++ b/gdb/dwarfread.c
@@ -985,9 +985,7 @@ struct_type (dip, thisdie, enddie, objfile)
   int n;
   struct dieinfo mbr;
   char *nextdie;
-#if !BITS_BIG_ENDIAN
   int anonymous_size;
-#endif
   
   if ((type = lookup_utype (dip -> die_ref)) == NULL)
     {
@@ -1060,39 +1058,47 @@ struct_type (dip, thisdie, enddie, objfile)
 	  list -> field.bitpos = 8 * locval (mbr.at_location);
 	  /* Handle bit fields. */
 	  list -> field.bitsize = mbr.at_bit_size;
-#if BITS_BIG_ENDIAN
-	  /* For big endian bits, the at_bit_offset gives the additional
-	     bit offset from the MSB of the containing anonymous object to
-	     the MSB of the field.  We don't have to do anything special
-	     since we don't need to know the size of the anonymous object. */
-	  list -> field.bitpos += mbr.at_bit_offset;
-#else
-	  /* For little endian bits, we need to have a non-zero at_bit_size,
-	     so that we know we are in fact dealing with a bitfield.  Compute
-	     the bit offset to the MSB of the anonymous object, subtract off
-	     the number of bits from the MSB of the field to the MSB of the
-	     object, and then subtract off the number of bits of the field
-	     itself.  The result is the bit offset of the LSB of the field. */
-	  if (mbr.at_bit_size > 0)
+	  if (BITS_BIG_ENDIAN)
 	    {
-	      if (mbr.has_at_byte_size)
-		{
-		  /* The size of the anonymous object containing the bit field
-		     is explicit, so use the indicated size (in bytes). */
-		  anonymous_size = mbr.at_byte_size;
-		}
-	      else
+	      /* For big endian bits, the at_bit_offset gives the
+		 additional bit offset from the MSB of the containing
+		 anonymous object to the MSB of the field.  We don't
+		 have to do anything special since we don't need to
+		 know the size of the anonymous object. */
+	      list -> field.bitpos += mbr.at_bit_offset;
+	    }
+	  else
+	    {
+	      /* For little endian bits, we need to have a non-zero
+		 at_bit_size, so that we know we are in fact dealing
+		 with a bitfield.  Compute the bit offset to the MSB
+		 of the anonymous object, subtract off the number of
+		 bits from the MSB of the field to the MSB of the
+		 object, and then subtract off the number of bits of
+		 the field itself.  The result is the bit offset of
+		 the LSB of the field. */
+	      if (mbr.at_bit_size > 0)
 		{
-		  /* The size of the anonymous object containing the bit field
-		     matches the size of an object of the bit field's type.
-		     DWARF allows at_byte_size to be left out in such cases,
-		     as a debug information size optimization. */
-		  anonymous_size = TYPE_LENGTH (list -> field.type);
+		  if (mbr.has_at_byte_size)
+		    {
+		      /* The size of the anonymous object containing
+			 the bit field is explicit, so use the
+			 indicated size (in bytes). */
+		      anonymous_size = mbr.at_byte_size;
+		    }
+		  else
+		    {
+		      /* The size of the anonymous object containing
+			 the bit field matches the size of an object
+			 of the bit field's type.  DWARF allows
+			 at_byte_size to be left out in such cases, as
+			 a debug information size optimization. */
+		      anonymous_size = TYPE_LENGTH (list -> field.type);
+		    }
+		  list -> field.bitpos +=
+		    anonymous_size * 8 - mbr.at_bit_offset - mbr.at_bit_size;
 		}
-	      list -> field.bitpos +=
-		anonymous_size * 8 - mbr.at_bit_offset - mbr.at_bit_size;
 	    }
-#endif
 	  nfields++;
 	  break;
 	default:
diff --git a/gdb/remote-os9k.c b/gdb/remote-os9k.c
index cf4cd9b..a3f6774 100644
--- a/gdb/remote-os9k.c
+++ b/gdb/remote-os9k.c
@@ -270,13 +270,11 @@ get_hex_regs (n, regno)
       val = 0;
       for (j = 0; j < 4; j++)
 	{
-#if TARGET_BYTE_ORDER == BIG_ENDIAN
-	  get_hex_byte(&b);
-	  val = (val << 8) + b;
-#else
-	  get_hex_byte(&b);
-	  val = val + (b << (j*8));
-#endif
+	  get_hex_byte (&b);
+	  if (TARGET_BYTE_ORDER == BIG_ENDIAN)
+	    val = (val << 8) + b;
+	  else
+	    val = val + (b << (j*8));
 	}
       supply_register (regno++, (char *) &val);
     }
@@ -577,13 +575,11 @@ rombug_fetch_registers ()
 	  val = 0;
 	  for (j = 0; j < 2; j++)
             {
-#if TARGET_BYTE_ORDER == BIG_ENDIAN
-              get_hex_byte(&b);
-              val = (val << 8) + b;
-#else
-              get_hex_byte(&b);
-              val = val + (b << (j*8));
-#endif
+              get_hex_byte (&b);
+	      if (TARGET_BYTE_ORDER == BIG_ENDIAN)
+		val = (val << 8) + b;
+	      else
+		val = val + (b << (j*8));
             }
 
 	  if (regno == 8) i = 10;
@@ -640,13 +636,11 @@ rombug_fetch_register (regno)
 	  val = 0;
 	  for (j = 0; j < 2; j++)
             {
-#if TARGET_BYTE_ORDER == BIG_ENDIAN
-              get_hex_byte(&b);
-              val = (val << 8) + b;
-#else
-              get_hex_byte(&b);
-              val = val + (b << (j*8));
-#endif
+              get_hex_byte (&b);
+	      if (TARGET_BYTE_ORDER == BIG_ENDIAN)
+		val = (val << 8) + b;
+	      else
+		val = val + (b << (j*8));
             }
 	  supply_register (regno, (char *) &val);
 	}
diff --git a/gdb/stabsread.c b/gdb/stabsread.c
index 5b5fee5..042d450 100644
--- a/gdb/stabsread.c
+++ b/gdb/stabsread.c
@@ -867,11 +867,13 @@ define_symbol (valu, string, desc, type, objfile)
 #endif
       add_symbol_to_list (sym, &local_symbols);
 
-#if TARGET_BYTE_ORDER == LITTLE_ENDIAN
-      /* On little-endian machines, this crud is never necessary, and,
-	 if the extra bytes contain garbage, is harmful.  */
-      break;
-#else /* Big endian.  */
+      if (TARGET_BYTE_ORDER != BIG_ENDIAN)
+	{
+	  /* On little-endian machines, this crud is never necessary,
+	     and, if the extra bytes contain garbage, is harmful.  */
+	  break;
+	}
+
       /* If it's gcc-compiled, if it says `short', believe it.  */
       if (processing_gcc_compilation || BELIEVE_PCC_PROMOTION)
 	break;
@@ -950,7 +952,6 @@ define_symbol (valu, string, desc, type, objfile)
 #endif /* no BELIEVE_PCC_PROMOTION_TYPE.  */
       }
 #endif /* !BELIEVE_PCC_PROMOTION.  */
-#endif /* Big endian.  */
 
     case 'P':
       /* acc seems to use P to delare the prototypes of functions that
diff --git a/gdb/top.c b/gdb/top.c
index c052302..113c8bb 100644
--- a/gdb/top.c
+++ b/gdb/top.c
@@ -92,6 +92,18 @@ static void init_signals PARAMS ((void));
 
 static void set_verbose PARAMS ((char *, int, struct cmd_list_element *));
 
+#ifdef TARGET_BYTE_ORDER_SELECTABLE
+
+static void set_endian PARAMS ((char *, int));
+
+static void set_endian_big PARAMS ((char *, int));
+
+static void set_endian_little PARAMS ((char *, int));
+
+static void show_endian PARAMS ((char *, int));
+
+#endif
+
 static void show_history PARAMS ((char *, int));
 
 static void set_history PARAMS ((char *, int));
@@ -205,6 +217,12 @@ struct cmd_list_element *unsetlist;
 
 struct cmd_list_element *showlist;
 
+#ifdef TARGET_BYTE_ORDER_SELECTABLE
+/* Chain containing the \"set endian\" commands.  */
+
+struct cmd_list_element *endianlist;
+#endif
+
 /* Chain containing all defined \"set history\".  */
 
 struct cmd_list_element *sethistlist;
@@ -2626,6 +2644,56 @@ echo_command (text, from_tty)
 }
 
 
+#ifdef TARGET_BYTE_ORDER_SELECTABLE
+
+/* Functions to manipulate the endianness of the target.  */
+
+#ifndef TARGET_BYTE_ORDER_DEFAULT
+#define TARGET_BYTE_ORDER_DEFAULT BIG_ENDIAN
+#endif
+
+int target_byte_order = TARGET_BYTE_ORDER_DEFAULT;
+
+/* Called if the user enters ``set endian'' without an argument.  */
+static void
+set_endian (args, from_tty)
+     char *args;
+     int from_tty;
+{
+  printf_unfiltered ("\"set endian\" must be followed by \"big\" or \"little\".\n");
+  show_endian (args, from_tty);
+}
+
+/* Called by ``set endian big''.  */
+static void
+set_endian_big (args, from_tty)
+     char *args;
+     int from_tty;
+{
+  target_byte_order = BIG_ENDIAN;
+}
+
+/* Called by ``set endian little''.  */
+static void
+set_endian_little (args, from_tty)
+     char *args;
+     int from_tty;
+{
+  target_byte_order = LITTLE_ENDIAN;
+}
+
+/* Called by ``show endian''.  */
+static void
+show_endian (args, from_tty)
+     char *args;
+     int from_tty;
+{
+  printf_unfiltered ("The target is assumed to be %s endian.\n",
+		     TARGET_BYTE_ORDER == BIG_ENDIAN ? "big" : "little");
+}
+
+#endif /* defined (TARGET_BYTE_ORDER_SELECTABLE) */
+
 /* Functions to manipulate command line editing control variables.  */
 
 /* Number of commands to print in each call to show_commands.  */
@@ -2795,6 +2863,9 @@ init_cmd_lists ()
   setlist = NULL;
   unsetlist = NULL;
   showlist = NULL;
+#ifdef TARGET_BYTE_ORDER_SELECTABLE
+  endianlist = NULL;
+#endif
   sethistlist = NULL;
   showhistlist = NULL;
   unsethistlist = NULL;
@@ -2845,6 +2916,20 @@ init_main ()
 {
   struct cmd_list_element *c;
 
+#ifdef TARGET_BYTE_ORDER_SELECTABLE
+
+  add_prefix_cmd ("endian", class_support, set_endian,
+		  "Set endianness of target.",
+		  &endianlist, "set endian ", 0, &setlist);
+  add_cmd ("big", class_support, set_endian_big,
+	   "Set target as being big endian.", &endianlist);
+  add_cmd ("little", class_support, set_endian_little,
+	   "Set target as being little endian.", &endianlist);
+  add_cmd ("endian", class_support, show_endian,
+	   "Show endianness of target.", &showlist);
+
+#endif /* defined (TARGET_BYTE_ORDER_SELECTABLE) */
+
 #ifdef DEFAULT_PROMPT
   prompt = savestring (DEFAULT_PROMPT, strlen(DEFAULT_PROMPT));
 #else
diff --git a/gdb/values.c b/gdb/values.c
index 81fa4e7..916bf6f 100644
--- a/gdb/values.c
+++ b/gdb/values.c
@@ -1249,11 +1249,10 @@ unpack_field_as_long (type, valaddr, fieldno)
 
   /* Extract bits.  See comment above. */
 
-#if BITS_BIG_ENDIAN
-  lsbcount = (sizeof val * 8 - bitpos % 8 - bitsize);
-#else
-  lsbcount = (bitpos % 8);
-#endif
+  if (BITS_BIG_ENDIAN)
+    lsbcount = (sizeof val * 8 - bitpos % 8 - bitsize);
+  else
+    lsbcount = (bitpos % 8);
   val >>= lsbcount;
 
   /* If the field does not entirely fill a LONGEST, then zero the sign bits.
@@ -1300,9 +1299,8 @@ modify_field (addr, fieldval, bitpos, bitsize)
   oword = extract_signed_integer (addr, sizeof oword);
 
   /* Shifting for bit field depends on endianness of the target machine.  */
-#if BITS_BIG_ENDIAN
-  bitpos = sizeof (oword) * 8 - bitpos - bitsize;
-#endif
+  if (BITS_BIG_ENDIAN)
+    bitpos = sizeof (oword) * 8 - bitpos - bitsize;
 
   /* Mask out old value, while avoiding shifts >= size of oword */
   if (bitsize < 8 * sizeof (oword))