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[RFC] New target, Renesas M32C


This target architecture has already been added to gcc and binutils.
Here's the gdb port.

2006-04-13  Michael Snyder  <msnyder@redhat.com>

	* 2006-03-22  Jim Blandy  <jimb@redhat.com>
	Add support for the Renesas M32C and M16C.

	* configure.tgt (m32c-*-*): New entry.
	* config/m32c/m32c.mt: New file.
	* m32c-tdep.c: New file.
	* Makefile.in (elf_m32c_h): New variable.
	(m32c-tdep.o): New rule.

	* testsuite/gdb.asm/asm-source.exp: Add m32c target.
	* testsuite/gdb.asm/m32c.inc: New target file.

Index: Makefile.in
===================================================================
RCS file: /cvs/src/src/gdb/Makefile.in,v
retrieving revision 1.809
diff -p -r1.809 Makefile.in
*** Makefile.in	9 Apr 2006 08:22:42 -0000	1.809
--- Makefile.in	13 Apr 2006 19:41:11 -0000
*************** elf_sh_h =	$(INCLUDE_DIR)/elf/sh.h
*** 582,587 ****
--- 582,588 ----
  elf_arm_h =	$(INCLUDE_DIR)/elf/arm.h $(elf_reloc_macros_h)
  elf_bfd_h =	$(BFD_SRC)/elf-bfd.h
  elf_frv_h =	$(INCLUDE_DIR)/elf/frv.h $(elf_reloc_macros_h)
+ elf_m32c_h =    $(INCLUDE_DIR)/elf/m32c.h $(elf_reloc_macros_h)
  libaout_h =	$(BFD_SRC)/libaout.h
  libiberty_h =	$(INCLUDE_DIR)/libiberty.h
  libbfd_h =	$(BFD_SRC)/libbfd.h
*************** gdb_callback_h = $(INCLUDE_DIR)/gdb/call
*** 598,603 ****
--- 599,605 ----
  gdb_sim_arm_h =	$(INCLUDE_DIR)/gdb/sim-arm.h
  gdb_sim_d10v_h = $(INCLUDE_DIR)/gdb/sim-d10v.h
  gdb_sim_frv_h = $(INCLUDE_DIR)/gdb/sim-frv.h
+ gdb_sim_m32c_h = $(INCLUDE_DIR)/gdb/sim-m32c.h
  gdb_sim_ppc_h =	$(INCLUDE_DIR)/gdb/sim-ppc.h
  gdb_sim_sh_h =	$(INCLUDE_DIR)/gdb/sim-sh.h
  splay_tree_h =  $(INCLUDE_DIR)/splay-tree.h
*************** m2-typeprint.o: m2-typeprint.c $(defs_h)
*** 2215,2220 ****
--- 2217,2227 ----
  	$(expression_h) $(value_h) $(gdbcore_h) $(target_h) $(m2_lang_h)
  m2-valprint.o: m2-valprint.c $(defs_h) $(symtab_h) $(gdbtypes_h) \
  	$(m2_lang_h) $(c_lang_h)
+ m32c-tdep.o: m32c-tdep.c $(defs_h) $(gdb_assert_h) $(elf_bfd_h)		\
+ 	$(elf_m32c_h) $(gdb_sim_m32c_h) $(dis_asm_h) $(gdbtypes_h)	\
+ 	$(regcache_h) $(arch_utils_h) $(frame_h) $(frame_unwind_h)	\
+ 	$(dwarf2_frame_h) $(dwarf2expr_h) $(symtab_h) $(gdbcore_h)	\
+ 	$(value_h) $(reggroups_h) $(prologue_value_h) $(target_h)
  m32r-linux-nat.o: m32r-linux-nat.c $(defs_h) $(inferior_h) $(gdbcore_h) \
  	$(regcache_h) $(linux_nat_h) $(gdb_assert_h) $(gdb_string_h) \
  	$(gregset_h) $(m32r_tdep_h) $(target_h)
Index: configure.tgt
===================================================================
RCS file: /cvs/src/src/gdb/configure.tgt,v
retrieving revision 1.171
diff -p -r1.171 configure.tgt
*** configure.tgt	29 Mar 2006 22:58:54 -0000	1.171
--- configure.tgt	13 Apr 2006 19:41:12 -0000
*************** ia64*-*-*)		gdb_target=ia64 ;;
*** 107,112 ****
--- 107,114 ----
  
  iq2000-*-*)		gdb_target=iq2000 ;;
  
+ m32c-*-*)		gdb_target=m32c ;;
+ 
  m32r*-*-linux*)		gdb_target=linux ;;
  m32r*-*-*)		gdb_target=m32r ;;
  
Index: m32c-tdep.c
===================================================================
RCS file: m32c-tdep.c
diff -N m32c-tdep.c
*** /dev/null	1 Jan 1970 00:00:00 -0000
--- m32c-tdep.c	13 Apr 2006 19:41:12 -0000
***************
*** 0 ****
--- 1,2549 ----
+ /* Renesas M32C target-dependent code for GDB, the GNU debugger.
+ 
+    Copyright 2004, 2005 Free Software Foundation, Inc.
+ 
+    This file is part of GDB.
+ 
+    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.  */
+ 
+ #include "defs.h"
+ 
+ #include <stdarg.h>
+ 
+ #if defined (HAVE_STRING_H)
+ #include <string.h>
+ #endif
+ 
+ #include "gdb_assert.h"
+ #include "elf-bfd.h"
+ #include "elf/m32c.h"
+ #include "gdb/sim-m32c.h"
+ #include "dis-asm.h"
+ #include "gdbtypes.h"
+ #include "regcache.h"
+ #include "arch-utils.h"
+ #include "frame.h"
+ #include "frame-unwind.h"
+ #include "dwarf2-frame.h"
+ #include "dwarf2expr.h"
+ #include "symtab.h"
+ #include "gdbcore.h"
+ #include "value.h"
+ #include "reggroups.h"
+ #include "prologue-value.h"
+ #include "target.h"
+ 
+ 
+ /* The m32c tdep structure.  */
+ 
+ static struct reggroup *m32c_dma_reggroup;
+ 
+ struct m32c_reg;
+ 
+ /* The type of a function that moves the value of REG between CACHE or
+    BUF --- in either direction.  */
+ typedef void (m32c_move_reg_t) (struct m32c_reg *reg,
+ 				struct regcache *cache,
+ 				void *buf);
+ 
+ struct m32c_reg
+ {
+   /* The name of this register.  */
+   const char *name;
+ 
+   /* Its type.  */
+   struct type *type;
+ 
+   /* The architecture this register belongs to.  */
+   struct gdbarch *arch;
+ 
+   /* Its GDB register number.  */
+   int num;
+ 
+   /* Its sim register number.  */
+   int sim_num;
+ 
+   /* Its DWARF register number, or -1 if it doesn't have one.  */
+   int dwarf_num;
+ 
+   /* Register group memberships.  */
+   unsigned int general_p : 1;
+   unsigned int dma_p : 1;
+   unsigned int system_p : 1;
+   unsigned int save_restore_p : 1;
+ 
+   /* Functions to read its value from a regcache, and write its value
+      to a regcache.  */
+   m32c_move_reg_t *read, *write;
+ 
+   /* Data for READ and WRITE functions.  The exact meaning depends on
+      the specific functions selected; see the comments for those
+      functions.  */
+   struct m32c_reg *rx, *ry;
+   int n;
+ };
+ 
+ 
+ /* An overestimate of the number of raw and pseudoregisters we will
+    have.  The exact answer depends on the variant of the architecture
+    at hand, but we can use this to declare statically allocated
+    arrays, and bump it up when needed.  */
+ #define M32C_MAX_NUM_REGS (75)
+ 
+ /* The largest assigned DWARF register number.  */
+ #define M32C_MAX_DWARF_REGNUM (40)
+ 
+ 
+ struct gdbarch_tdep
+ {
+   /* All the registers for this variant, indexed by GDB register
+      number, and the number of registers present.  */
+   struct m32c_reg regs[M32C_MAX_NUM_REGS];
+ 
+   /* The number of valid registers.  */
+   int num_regs;
+ 
+   /* Interesting registers.  These are pointers into REGS.  */
+   struct m32c_reg *pc, *flg;
+   struct m32c_reg *r0, *r1, *r2, *r3, *a0, *a1;
+   struct m32c_reg *r2r0, *r3r2r1r0, *r3r1r2r0;
+   struct m32c_reg *sb, *fb, *sp;
+ 
+   /* A table indexed by DWARF register numbers, pointing into
+      REGS.  */
+   struct m32c_reg *dwarf_regs[M32C_MAX_DWARF_REGNUM + 1];
+ 
+   /* Types for this architecture.  We can't use the builtin_type_foo
+      types, because they're not initialized when building a gdbarch
+      structure.  */
+   struct type *voyd, *ptr_voyd, *func_voyd;
+   struct type *uint8, *uint16;
+   struct type *int8, *int16, *int32, *int64;
+ 
+   /* The types for data address and code address registers.  */
+   struct type *data_addr_reg_type, *code_addr_reg_type;
+ 
+   /* The number of bytes a return address pushed by a 'jsr' instruction
+      occupies on the stack.  */
+   int ret_addr_bytes;
+ 
+   /* The number of bytes an address register occupies on the stack
+      when saved by an 'enter' or 'pushm' instruction.  */
+   int push_addr_bytes;
+ };
+ 
+ 
+ /* Types.  */
+ 
+ static void
+ make_types (struct gdbarch *arch)
+ {
+   struct gdbarch_tdep *tdep = gdbarch_tdep (arch);
+   unsigned long mach = gdbarch_bfd_arch_info (arch)->mach;
+   int data_addr_reg_bits, code_addr_reg_bits;
+   char type_name[50];
+ 
+ #if 0
+   /* This is used to clip CORE_ADDR values, so this value is
+      appropriate both on the m32c, where pointers are 32 bits long,
+      and on the m16c, where pointers are sixteen bits long, but there
+      may be code above the 64k boundary.  */
+   set_gdbarch_addr_bit (arch, 24);
+ #else
+   /* GCC uses 32 bits for addrs in the dwarf info, even though
+      only 16/24 bits are used.  Setting addr_bit to 24 causes
+      errors in reading the dwarf addresses.  */
+   set_gdbarch_addr_bit (arch, 32);
+ #endif
+ 
+   set_gdbarch_int_bit (arch, 16);
+   switch (mach)
+     {
+     case bfd_mach_m16c:
+       data_addr_reg_bits = 16;
+       code_addr_reg_bits = 24;
+       set_gdbarch_ptr_bit (arch, 16);
+       tdep->ret_addr_bytes = 3;
+       tdep->push_addr_bytes = 2;
+       break;
+ 
+     case bfd_mach_m32c:
+       data_addr_reg_bits = 24;
+       code_addr_reg_bits = 24;
+       set_gdbarch_ptr_bit (arch, 32);
+       tdep->ret_addr_bytes = 4;
+       tdep->push_addr_bytes = 4;
+       break;
+ 
+     default:
+       gdb_assert (0);
+     }
+ 
+   /* The builtin_type_mumble variables are sometimes uninitialized when
+      this is called, so we avoid using them.  */
+   tdep->voyd = init_type (TYPE_CODE_VOID, 1, 0, "void", NULL);
+   tdep->ptr_voyd = init_type (TYPE_CODE_PTR, gdbarch_ptr_bit (arch) / 8,
+ 			      TYPE_FLAG_UNSIGNED, NULL, NULL);
+   TYPE_TARGET_TYPE (tdep->ptr_voyd) = tdep->voyd;
+   tdep->func_voyd = lookup_function_type (tdep->voyd);
+ 
+   sprintf (type_name, "%s_data_addr_t",
+ 	   gdbarch_bfd_arch_info (arch)->printable_name);
+   tdep->data_addr_reg_type
+     = init_type (TYPE_CODE_PTR, data_addr_reg_bits / 8,
+ 		 TYPE_FLAG_UNSIGNED, xstrdup (type_name), NULL);
+   TYPE_TARGET_TYPE (tdep->data_addr_reg_type) = tdep->voyd;
+ 
+   sprintf (type_name, "%s_code_addr_t",
+ 	   gdbarch_bfd_arch_info (arch)->printable_name);
+   tdep->code_addr_reg_type
+     = init_type (TYPE_CODE_PTR, code_addr_reg_bits / 8,
+ 		 TYPE_FLAG_UNSIGNED, xstrdup (type_name), NULL);
+   TYPE_TARGET_TYPE (tdep->code_addr_reg_type) = tdep->func_voyd;
+ 
+   tdep->uint8  = init_type (TYPE_CODE_INT, 1, TYPE_FLAG_UNSIGNED,
+ 			    "uint8_t", NULL);
+   tdep->uint16 = init_type (TYPE_CODE_INT, 2, TYPE_FLAG_UNSIGNED,
+ 			    "uint16_t", NULL);
+   tdep->int8   = init_type (TYPE_CODE_INT, 1, 0, "int8_t", NULL);
+   tdep->int16  = init_type (TYPE_CODE_INT, 2, 0, "int16_t", NULL);
+   tdep->int32  = init_type (TYPE_CODE_INT, 4, 0, "int32_t", NULL);
+   tdep->int64  = init_type (TYPE_CODE_INT, 8, 0, "int64_t", NULL);
+ }
+ 
+ 
+ 
+ /* Register set.  */
+ 
+ static const char *
+ m32c_register_name (int num)
+ {
+   return gdbarch_tdep (current_gdbarch)->regs[num].name;
+ }
+ 
+ 
+ static struct type *
+ m32c_register_type (struct gdbarch *arch, int reg_nr)
+ {
+   return gdbarch_tdep (arch)->regs[reg_nr].type;
+ }
+ 
+ 
+ static int
+ m32c_register_sim_regno (int reg_nr)
+ {
+   return gdbarch_tdep (current_gdbarch)->regs[reg_nr].sim_num;
+ }
+ 
+ 
+ static int
+ m32c_debug_info_reg_to_regnum (int reg_nr)
+ {
+   struct gdbarch_tdep *tdep = gdbarch_tdep (current_gdbarch);
+   if (0 <= reg_nr && reg_nr <= M32C_MAX_DWARF_REGNUM
+       && tdep->dwarf_regs[reg_nr])
+     return tdep->dwarf_regs[reg_nr]->num;
+   else
+     /* The DWARF CFI code expects to see -1 for invalid register
+        numbers.  */
+     return -1;
+ }
+ 
+ 
+ int
+ m32c_register_reggroup_p (struct gdbarch *gdbarch, int regnum,
+ 			  struct reggroup *group)
+ {
+   struct gdbarch_tdep *tdep = gdbarch_tdep (current_gdbarch);
+   struct m32c_reg *reg = &tdep->regs[regnum];
+ 
+   /* The anonymous raw registers aren't in any groups.  */
+   if (! reg->name)
+     return 0;
+ 
+   if (group == all_reggroup)
+     return 1;
+ 
+   if (group == general_reggroup
+       && reg->general_p)
+     return 1;
+ 
+   if (group == m32c_dma_reggroup
+       && reg->dma_p)
+     return 1;
+ 
+   if (group == system_reggroup
+       && reg->system_p)
+     return 1;
+ 
+   /* Since the m32c DWARF register numbers refer to cooked registers, not
+      raw registers, and frame_pop depends on the save and restore groups
+      containing registers the DWARF CFI will actually mention, our save
+      and restore groups are cooked registers, not raw registers.  (This is
+      why we can't use the default reggroup function.)  */
+   if ((group == save_reggroup
+        || group == restore_reggroup)
+       && reg->save_restore_p)
+     return 1;
+ 
+   return 0;
+ }
+ 
+ 
+ /* Register move functions.  We declare them here using
+    m32c_move_reg_t to check the types.  */
+ static m32c_move_reg_t m32c_raw_read,      m32c_raw_write;
+ static m32c_move_reg_t m32c_banked_read,   m32c_banked_write;
+ static m32c_move_reg_t m32c_sb_read, 	   m32c_sb_write;
+ static m32c_move_reg_t m32c_part_read,     m32c_part_write;
+ static m32c_move_reg_t m32c_cat_read,      m32c_cat_write;
+ static m32c_move_reg_t m32c_r3r2r1r0_read, m32c_r3r2r1r0_write;
+ 
+ 
+ /* Copy the value of the raw register REG from CACHE to BUF.  */
+ static void
+ m32c_raw_read (struct m32c_reg *reg, struct regcache *cache, void *buf)
+ {
+   regcache_raw_read (cache, reg->num, buf);
+ }
+ 
+ 
+ /* Copy the value of the raw register REG from BUF to CACHE.  */
+ static void
+ m32c_raw_write (struct m32c_reg *reg, struct regcache *cache, void *buf)
+ {
+   regcache_raw_write (cache, reg->num, (const void *) buf);
+ }
+ 
+ 
+ /* Return the value of the 'flg' register in CACHE.  */
+ static int
+ m32c_read_flg (struct regcache *cache)
+ {
+   struct gdbarch_tdep *tdep = gdbarch_tdep (get_regcache_arch (cache));
+   ULONGEST flg;
+   regcache_raw_read_unsigned (cache, tdep->flg->num, &flg);
+   return flg & 0xffff;
+ }
+ 
+ 
+ /* Move the value of a banked register from CACHE to BUF.
+    If the value of the 'flg' register in CACHE has any of the bits
+    masked in REG->n set, then read REG->ry.  Otherwise, read
+    REG->rx.  */
+ static void
+ m32c_banked_read (struct m32c_reg *reg, struct regcache *cache, void *buf)
+ {
+   struct m32c_reg *bank_reg
+     = ((m32c_read_flg (cache) & reg->n) ? reg->ry : reg->rx);
+   regcache_raw_read (cache, bank_reg->num, buf);
+ }
+ 
+ 
+ /* Move the value of a banked register from BUF to CACHE.
+    If the value of the 'flg' register in CACHE has any of the bits
+    masked in REG->n set, then write REG->ry.  Otherwise, write
+    REG->rx.  */
+ static void
+ m32c_banked_write (struct m32c_reg *reg, struct regcache *cache, void *buf)
+ {
+   struct m32c_reg *bank_reg
+     = ((m32c_read_flg (cache) & reg->n) ? reg->ry : reg->rx);
+   regcache_raw_write (cache, bank_reg->num, (const void *) buf);
+ }
+ 
+ 
+ /* Move the value of SB from CACHE to BUF.  On bfd_mach_m32c, SB is a
+    banked register; on bfd_mach_m16c, it's not.  */
+ static void
+ m32c_sb_read (struct m32c_reg *reg, struct regcache *cache, void *buf)
+ {
+   if (gdbarch_bfd_arch_info (reg->arch)->mach == bfd_mach_m16c)
+     m32c_raw_read (reg->rx, cache, buf);
+   else
+     m32c_banked_read (reg, cache, buf);
+ }
+ 
+ 
+ /* Move the value of SB from BUF to CACHE.  On bfd_mach_m32c, SB is a
+    banked register; on bfd_mach_m16c, it's not.  */
+ static void
+ m32c_sb_write (struct m32c_reg *reg, struct regcache *cache, void *buf)
+ {
+   if (gdbarch_bfd_arch_info (reg->arch)->mach == bfd_mach_m16c)
+     m32c_raw_write (reg->rx, cache, buf);
+   else
+     m32c_banked_write (reg, cache, buf);
+ }
+ 
+ 
+ /* Assuming REG uses m32c_part_read and m32c_part_write, set *OFFSET_P
+    and *LEN_P to the offset and length, in bytes, of the part REG
+    occupies in its underlying register.  The offset is from the
+    lower-addressed end, regardless of the architecture's endianness.
+    (The M32C family is always little-endian, but let's keep those
+    assumptions out of here.)  */
+ static void
+ m32c_find_part (struct m32c_reg *reg, int *offset_p, int *len_p)
+ {
+   /* The length of the containing register, of which REG is one part.  */
+   int containing_len = TYPE_LENGTH (reg->rx->type);
+ 
+   /* The length of one "element" in our imaginary array.  */
+   int elt_len = TYPE_LENGTH (reg->type);
+ 
+   /* The offset of REG's "element" from the least significant end of
+      the containing register.  */
+   int elt_offset = reg->n * elt_len;
+ 
+   /* If we extend off the end, trim the length of the element.  */
+   if (elt_offset + elt_len > containing_len)
+     {
+       elt_len = containing_len - elt_offset;
+       /* We shouldn't be declaring partial registers that go off the
+ 	 end of their containing registers.  */
+       gdb_assert (elt_len > 0);
+     }
+ 
+   /* Flip the offset around if we're big-endian.  */
+   if (gdbarch_byte_order (reg->arch) == BFD_ENDIAN_BIG)
+     elt_offset = TYPE_LENGTH (reg->rx->type) - elt_offset - elt_len;
+ 
+   *offset_p = elt_offset;
+   *len_p = elt_len;
+ }
+ 
+ 
+ /* Move the value of a partial register (r0h, intbl, etc.) from CACHE
+    to BUF.  Treating the value of the register REG->rx as an array of
+    REG->type values, where higher indices refer to more significant
+    bits, read the value of the REG->n'th element.  */
+ static void
+ m32c_part_read (struct m32c_reg *reg, struct regcache *cache, void *buf)
+ {
+   int offset, len;
+   memset (buf, 0, TYPE_LENGTH (reg->type));
+   m32c_find_part (reg, &offset, &len);
+   regcache_cooked_read_part (cache, reg->rx->num, offset, len, buf);
+ }
+ 
+ 
+ /* Move the value of a banked register from BUF to CACHE.
+    Treating the value of the register REG->rx as an array of REG->type
+    values, where higher indices refer to more significant bits, write
+    the value of the REG->n'th element.  */
+ static void
+ m32c_part_write (struct m32c_reg *reg, struct regcache *cache, void *buf)
+ {
+   int offset, len;
+   m32c_find_part (reg, &offset, &len);
+   regcache_cooked_write_part (cache, reg->rx->num, offset, len, buf);
+ }
+ 
+ 
+ /* Move the value of REG from CACHE to BUF.  REG's value is the
+    concatenation of the values of the registers REG->rx and REG->ry,
+    with REG->rx contributing the more significant bits.  */
+ static void
+ m32c_cat_read (struct m32c_reg *reg, struct regcache *cache, void *buf)
+ {
+   int high_bytes = TYPE_LENGTH (reg->rx->type);
+   int low_bytes  = TYPE_LENGTH (reg->ry->type);
+   /* For address arithmetic.  */
+   unsigned char *cbuf = buf;
+ 
+   gdb_assert (TYPE_LENGTH (reg->type) == high_bytes + low_bytes);
+ 
+   if (gdbarch_byte_order (reg->arch) == BFD_ENDIAN_BIG)
+     {
+       regcache_cooked_read (cache, reg->rx->num, cbuf);
+       regcache_cooked_read (cache, reg->ry->num, cbuf + high_bytes);
+     }
+   else
+     {
+       regcache_cooked_read (cache, reg->rx->num, cbuf + low_bytes);
+       regcache_cooked_read (cache, reg->ry->num, cbuf);
+     }
+ }
+ 
+ 
+ /* Move the value of REG from CACHE to BUF.  REG's value is the
+    concatenation of the values of the registers REG->rx and REG->ry,
+    with REG->rx contributing the more significant bits.  */
+ static void
+ m32c_cat_write (struct m32c_reg *reg, struct regcache *cache, void *buf)
+ {
+   int high_bytes = TYPE_LENGTH (reg->rx->type);
+   int low_bytes  = TYPE_LENGTH (reg->ry->type);
+   /* For address arithmetic.  */
+   unsigned char *cbuf = buf;
+ 
+   gdb_assert (TYPE_LENGTH (reg->type) == high_bytes + low_bytes);
+ 
+   if (gdbarch_byte_order (reg->arch) == BFD_ENDIAN_BIG)
+     {
+       regcache_cooked_write (cache, reg->rx->num, cbuf);
+       regcache_cooked_write (cache, reg->ry->num, cbuf + high_bytes);
+     }
+   else
+     {
+       regcache_cooked_write (cache, reg->rx->num, cbuf + low_bytes);
+       regcache_cooked_write (cache, reg->ry->num, cbuf);
+     }
+ }
+ 
+ 
+ /* Copy the value of the raw register REG from CACHE to BUF.  REG is
+    the concatenation (from most significant to least) of r3, r2, r1,
+    and r0.  */
+ static void
+ m32c_r3r2r1r0_read (struct m32c_reg *reg, struct regcache *cache, void *buf)
+ {
+   struct gdbarch_tdep *tdep = gdbarch_tdep (reg->arch);
+   int len = TYPE_LENGTH (tdep->r0->type);
+ 
+   /* For address arithmetic.  */
+   unsigned char *cbuf = buf;
+ 
+   if (gdbarch_byte_order (reg->arch) == BFD_ENDIAN_BIG)
+     {
+       regcache_cooked_read (cache, tdep->r0->num, cbuf + len * 3);
+       regcache_cooked_read (cache, tdep->r1->num, cbuf + len * 2);
+       regcache_cooked_read (cache, tdep->r2->num, cbuf + len * 1);
+       regcache_cooked_read (cache, tdep->r3->num, cbuf);
+     }
+   else
+     {
+       regcache_cooked_read (cache, tdep->r0->num, cbuf);
+       regcache_cooked_read (cache, tdep->r1->num, cbuf + len * 1);
+       regcache_cooked_read (cache, tdep->r2->num, cbuf + len * 2);
+       regcache_cooked_read (cache, tdep->r3->num, cbuf + len * 3);
+     }
+ }
+ 
+ 
+ /* Copy the value of the raw register REG from BUF to CACHE.  REG is
+    the concatenation (from most significant to least) of r3, r2, r1,
+    and r0.  */
+ static void
+ m32c_r3r2r1r0_write (struct m32c_reg *reg, struct regcache *cache, void *buf)
+ {
+   struct gdbarch_tdep *tdep = gdbarch_tdep (reg->arch);
+   int len = TYPE_LENGTH (tdep->r0->type);
+ 
+   /* For address arithmetic.  */
+   unsigned char *cbuf = buf;
+ 
+   if (gdbarch_byte_order (reg->arch) == BFD_ENDIAN_BIG)
+     {
+       regcache_cooked_write (cache, tdep->r0->num, cbuf + len * 3);
+       regcache_cooked_write (cache, tdep->r1->num, cbuf + len * 2);
+       regcache_cooked_write (cache, tdep->r2->num, cbuf + len * 1);
+       regcache_cooked_write (cache, tdep->r3->num, cbuf);
+     }
+   else
+     {
+       regcache_cooked_write (cache, tdep->r0->num, cbuf);
+       regcache_cooked_write (cache, tdep->r1->num, cbuf + len * 1);
+       regcache_cooked_write (cache, tdep->r2->num, cbuf + len * 2);
+       regcache_cooked_write (cache, tdep->r3->num, cbuf + len * 3);
+     }
+ }
+ 
+ 
+ static void
+ m32c_pseudo_register_read (struct gdbarch *arch,
+ 			   struct regcache *cache,
+ 			   int cookednum,
+ 			   gdb_byte *buf)
+ {
+   struct gdbarch_tdep *tdep = gdbarch_tdep (arch);
+   struct m32c_reg *reg;
+ 
+   gdb_assert (0 <= cookednum && cookednum < tdep->num_regs);
+   gdb_assert (arch == get_regcache_arch (cache));
+   gdb_assert (arch == tdep->regs[cookednum].arch);
+   reg = &tdep->regs[cookednum];
+ 
+   reg->read (reg, cache, buf);
+ }
+ 
+ 
+ static void
+ m32c_pseudo_register_write (struct gdbarch *arch,
+ 			    struct regcache *cache,
+ 			    int cookednum,
+ 			    const gdb_byte *buf)
+ {
+   struct gdbarch_tdep *tdep = gdbarch_tdep (arch);
+   struct m32c_reg *reg;
+ 
+   gdb_assert (0 <= cookednum && cookednum < tdep->num_regs);
+   gdb_assert (arch == get_regcache_arch (cache));
+   gdb_assert (arch == tdep->regs[cookednum].arch);
+   reg = &tdep->regs[cookednum];
+ 
+   reg->write (reg, cache, (void *) buf);
+ }
+ 
+ 
+ /* Add a register with the given fields to the end of ARCH's table.
+    Return a pointer to the newly added register.  */
+ static struct m32c_reg *
+ add_reg (struct gdbarch *arch,
+ 	 const char *name,
+ 	 struct type *type,
+ 	 int sim_num,
+ 	 m32c_move_reg_t *read,
+ 	 m32c_move_reg_t *write,
+ 	 struct m32c_reg *rx,
+ 	 struct m32c_reg *ry,
+ 	 int n)
+ {
+   struct gdbarch_tdep *tdep = gdbarch_tdep (arch);
+   struct m32c_reg *r = &tdep->regs[tdep->num_regs];
+ 
+   gdb_assert (tdep->num_regs < M32C_MAX_NUM_REGS);
+ 
+   r->name           = name;
+   r->type           = type;
+   r->arch           = arch;
+   r->num            = tdep->num_regs;
+   r->sim_num        = sim_num;
+   r->dwarf_num      = -1;
+   r->general_p      = 0;
+   r->dma_p          = 0;
+   r->system_p       = 0;
+   r->save_restore_p = 0;
+   r->read           = read;
+   r->write          = write;
+   r->rx             = rx;
+   r->ry             = ry;
+   r->n              = n;
+ 
+   tdep->num_regs++;
+ 
+   return r;
+ }
+ 
+ 
+ /* Record NUM as REG's DWARF register number.  */
+ static void
+ set_dwarf_regnum (struct m32c_reg *reg, int num)
+ {
+   gdb_assert (num < M32C_MAX_NUM_REGS);
+ 
+   /* Update the reg->DWARF mapping.  Only count the first number
+      assigned to this register.  */
+   if (reg->dwarf_num == -1)
+     reg->dwarf_num = num;
+ 
+   /* Update the DWARF->reg mapping.  */
+   gdbarch_tdep (reg->arch)->dwarf_regs[num] = reg;
+ }
+ 
+ 
+ /* Mark REG as a general-purpose register, and return it.  */
+ static struct m32c_reg *
+ mark_general (struct m32c_reg *reg)
+ {
+   reg->general_p = 1;
+   return reg;
+ }
+ 
+ 
+ /* Mark REG as a DMA register, and return it.  */
+ static struct m32c_reg *
+ mark_dma (struct m32c_reg *reg)
+ {
+   reg->dma_p = 1;
+   return reg;
+ }
+ 
+ 
+ /* Mark REG as a SYSTEM register, and return it.  */
+ static struct m32c_reg *
+ mark_system (struct m32c_reg *reg)
+ {
+   reg->system_p = 1;
+   return reg;
+ }
+ 
+ 
+ /* Mark REG as a save-restore register, and return it.  */
+ static struct m32c_reg *
+ mark_save_restore (struct m32c_reg *reg)
+ {
+   reg->save_restore_p = 1;
+   return reg;
+ }
+ 
+ 
+ #define FLAGBIT_B	0x0010
+ #define FLAGBIT_U	0x0080
+ 
+ /* Handy macros for declaring registers.  These all evaluate to
+    pointers to the register declared.  Macros that define two
+    registers evaluate to a pointer to the first.  */
+ 
+ /* A raw register named NAME, with type TYPE and sim number SIM_NUM.  */
+ #define R(name, type, sim_num)					\
+   (add_reg (arch, (name), (type), (sim_num),			\
+ 	    m32c_raw_read, m32c_raw_write, NULL, NULL, 0))
+ 
+ /* The simulator register number for a raw register named NAME.  */
+ #define SIM(name) (m32c_sim_reg_ ## name)
+ 
+ /* A raw unsigned 16-bit data register named NAME.
+    NAME should be an identifier, not a string.  */
+ #define R16U(name)						\
+   (R(#name, tdep->uint16, SIM (name)))
+ 
+ /* A raw data address register named NAME.
+    NAME should be an identifier, not a string.  */
+ #define RA(name)						\
+   (R(#name, tdep->data_addr_reg_type, SIM (name)))
+ 
+ /* A raw code address register named NAME.  NAME should
+    be an identifier, not a string.  */
+ #define RC(name)						\
+   (R(#name, tdep->code_addr_reg_type, SIM (name)))
+ 
+ /* A pair of raw registers named NAME0 and NAME1, with type TYPE.
+    NAME should be an identifier, not a string.  */
+ #define RP(name, type)				\
+   (R(#name "0", (type), SIM (name ## 0)),	\
+    R(#name "1", (type), SIM (name ## 1)) - 1)
+ 
+ /* A raw banked general-purpose data register named NAME.
+    NAME should be an identifier, not a string.  */
+ #define RBD(name)						\
+   (R(NULL, tdep->int16, SIM (name ## _bank0)),		\
+    R(NULL, tdep->int16, SIM (name ## _bank1)) - 1)
+ 
+ /* A raw banked data address register named NAME.
+    NAME should be an identifier, not a string.  */
+ #define RBA(name)						\
+   (R(NULL, tdep->data_addr_reg_type, SIM (name ## _bank0)),	\
+    R(NULL, tdep->data_addr_reg_type, SIM (name ## _bank1)) - 1)
+ 
+ /* A cooked register named NAME referring to a raw banked register
+    from the bank selected by the current value of FLG.  RAW_PAIR
+    should be a pointer to the first register in the banked pair.
+    NAME must be an identifier, not a string.  */
+ #define CB(name, raw_pair)				\
+   (add_reg (arch, #name, (raw_pair)->type, 0,		\
+ 	    m32c_banked_read, m32c_banked_write,	\
+             (raw_pair), (raw_pair + 1), FLAGBIT_B))
+ 
+ /* A pair of registers named NAMEH and NAMEL, of type TYPE, that
+    access the top and bottom halves of the register pointed to by
+    NAME.  NAME should be an identifier.  */
+ #define CHL(name, type)							\
+   (add_reg (arch, #name "h", (type), 0,					\
+ 	    m32c_part_read, m32c_part_write, name, NULL, 1),		\
+    add_reg (arch, #name "l", (type), 0,					\
+ 	    m32c_part_read, m32c_part_write, name, NULL, 0) - 1)
+ 
+ /* A register constructed by concatenating the two registers HIGH and
+    LOW, whose name is HIGHLOW and whose type is TYPE.  */
+ #define CCAT(high, low, type)					\
+   (add_reg (arch, #high #low, (type), 0,			\
+ 	    m32c_cat_read, m32c_cat_write, (high), (low), 0))
+ 
+ /* Abbreviations for marking register group membership.  */
+ #define G(reg)   (mark_general (reg))
+ #define S(reg)   (mark_system  (reg))
+ #define DMA(reg) (mark_dma     (reg))
+ 
+ 
+ /* Construct the register set for ARCH.  */
+ static void
+ make_regs (struct gdbarch *arch)
+ {
+   struct gdbarch_tdep *tdep = gdbarch_tdep (arch);
+   int mach = gdbarch_bfd_arch_info (arch)->mach;
+ 
+   struct m32c_reg *raw_r0_pair = RBD (r0);
+   struct m32c_reg *raw_r1_pair = RBD (r1);
+   struct m32c_reg *raw_r2_pair = RBD (r2);
+   struct m32c_reg *raw_r3_pair = RBD (r3);
+   struct m32c_reg *raw_a0_pair = RBA (a0);
+   struct m32c_reg *raw_a1_pair = RBA (a1);
+   struct m32c_reg *raw_fb_pair = RBA (fb);
+ 
+   /* sb is banked on the bfd_mach_m32c, but not on bfd_mach_m16c.
+      We always declare both raw registers, and deal with the distinction
+      in the pseudoregister.  */
+   struct m32c_reg *raw_sb_pair = RBA (sb);
+ 
+   struct m32c_reg *usp         = S (RA (usp));
+   struct m32c_reg *isp         = S (RA (isp));
+   struct m32c_reg *intb        = S (RC (intb));
+   struct m32c_reg *pc          = G (RC (pc));
+   struct m32c_reg *flg         = G (R16U (flg));
+ 
+   if (mach == bfd_mach_m32c)
+     {
+       struct m32c_reg *svf     = S (R16U (svf));
+       struct m32c_reg *svp     = S (RC (svp));
+       struct m32c_reg *vct     = S (RC (vct));
+ 
+       struct m32c_reg *dmd01   = DMA (RP (dmd, tdep->uint8));
+       struct m32c_reg *dct01   = DMA (RP (dct, tdep->uint16));
+       struct m32c_reg *drc01   = DMA (RP (drc, tdep->uint16));
+       struct m32c_reg *dma01   = DMA (RP (dma, tdep->data_addr_reg_type));
+       struct m32c_reg *dsa01   = DMA (RP (dsa, tdep->data_addr_reg_type));
+       struct m32c_reg *dra01   = DMA (RP (dra, tdep->data_addr_reg_type));
+     }
+ 
+   int num_raw_regs = tdep->num_regs;
+ 
+   struct m32c_reg *r0 	       = G (CB (r0, raw_r0_pair));
+   struct m32c_reg *r1 	       = G (CB (r1, raw_r1_pair));
+   struct m32c_reg *r2          = G (CB (r2, raw_r2_pair));
+   struct m32c_reg *r3          = G (CB (r3, raw_r3_pair));
+   struct m32c_reg *a0          = G (CB (a0, raw_a0_pair));
+   struct m32c_reg *a1          = G (CB (a1, raw_a1_pair));
+   struct m32c_reg *fb          = G (CB (fb, raw_fb_pair));
+ 
+   /* sb is banked on the bfd_mach_m32c, but not on bfd_mach_m16c.
+      Specify custom read/write functions that do the right thing.  */
+   struct m32c_reg *sb
+     = G (add_reg (arch, "sb", raw_sb_pair->type, 0,
+ 		  m32c_sb_read, m32c_sb_write,
+ 		  raw_sb_pair, raw_sb_pair + 1, 0));
+ 
+   /* The current sp is either usp or isp, depending on the value of
+      the FLG register's U bit.  */
+   struct m32c_reg *sp
+     = G (add_reg (arch, "sp", usp->type, 0,
+ 		  m32c_banked_read, m32c_banked_write, isp, usp, FLAGBIT_U));
+ 
+   struct m32c_reg *r0hl        = CHL (r0, tdep->int8);
+   struct m32c_reg *r1hl        = CHL (r1, tdep->int8);
+   struct m32c_reg *r2hl        = CHL (r2, tdep->int8);
+   struct m32c_reg *r3hl        = CHL (r3, tdep->int8);
+   struct m32c_reg *intbhl      = CHL (intb, tdep->int16);
+ 
+   struct m32c_reg *r2r0        = CCAT (r2,   r0,   tdep->int32);
+   struct m32c_reg *r3r1        = CCAT (r3,   r1,   tdep->int32);
+   struct m32c_reg *r3r1r2r0    = CCAT (r3r1, r2r0, tdep->int64);
+ 
+   struct m32c_reg *r3r2r1r0
+     = add_reg (arch, "r3r2r1r0", tdep->int64, 0,
+ 	       m32c_r3r2r1r0_read, m32c_r3r2r1r0_write, NULL, NULL, 0);
+ 
+   struct m32c_reg *a1a0;
+   if (mach == bfd_mach_m16c)
+     a1a0 = CCAT (a1, a0, tdep->int32);
+   else
+     a1a0 = NULL;
+ 
+   int num_cooked_regs = tdep->num_regs - num_raw_regs;
+ 
+   tdep->pc   	 = pc;
+   tdep->flg  	 = flg;
+   tdep->r0   	 = r0;
+   tdep->r1   	 = r1;
+   tdep->r2   	 = r2;
+   tdep->r3   	 = r3;
+   tdep->r2r0 	 = r2r0;
+   tdep->r3r2r1r0 = r3r2r1r0;
+   tdep->r3r1r2r0 = r3r1r2r0;
+   tdep->a0       = a0;
+   tdep->a1       = a1;
+   tdep->sb       = sb;
+   tdep->fb   	 = fb;
+   tdep->sp   	 = sp;
+ 
+   /* Set up the DWARF register table.  */
+   memset (tdep->dwarf_regs, 0, sizeof (tdep->dwarf_regs));
+   set_dwarf_regnum (r0hl + 1, 0x01);
+   set_dwarf_regnum (r0hl + 0, 0x02);
+   set_dwarf_regnum (r1hl + 1, 0x03);
+   set_dwarf_regnum (r1hl + 0, 0x04);
+   set_dwarf_regnum (r0,       0x05);
+   set_dwarf_regnum (r1,       0x06);
+   set_dwarf_regnum (r2,       0x07);
+   set_dwarf_regnum (r3,       0x08);
+   set_dwarf_regnum (a0,       0x09);
+   set_dwarf_regnum (a1,       0x0a);
+   set_dwarf_regnum (fb,       0x0b);
+   set_dwarf_regnum (sp,       0x0c);
+   set_dwarf_regnum (pc,       0x0d); /* GCC's invention */
+   set_dwarf_regnum (sb,       0x13);
+   set_dwarf_regnum (r2r0,     0x15);
+   set_dwarf_regnum (r3r1,     0x16);
+   if (a1a0)
+     set_dwarf_regnum (a1a0,   0x17);
+ 
+   /* Enumerate the save/restore register group.
+ 
+      The regcache_save and regcache_restore functions apply their read
+      function to each register in this group.
+ 
+      Since frame_pop supplies frame_unwind_register as its read
+      function, the registers meaningful to the Dwarf unwinder need to
+      be in this group.
+ 
+      On the other hand, when we make inferior calls, save_inferior_status
+      and restore_inferior_status use them to preserve the current register
+      values across the inferior call.  For this, you'd kind of like to
+      preserve all the raw registers, to protect the interrupted code from
+      any sort of bank switching the callee might have done.  But we handle
+      those cases so badly anyway --- for example, it matters whether we
+      restore FLG before or after we restore the general-purpose registers,
+      but there's no way to express that --- that it isn't worth worrying
+      about.
+ 
+      We omit control registers like inthl: if you call a function that
+      changes those, it's probably because you wanted that change to be
+      visible to the interrupted code.  */
+   mark_save_restore (r0);
+   mark_save_restore (r1);
+   mark_save_restore (r2);
+   mark_save_restore (r3);
+   mark_save_restore (a0);
+   mark_save_restore (a1);
+   mark_save_restore (sb);
+   mark_save_restore (fb);
+   mark_save_restore (sp);
+   mark_save_restore (pc);
+   mark_save_restore (flg);
+ 
+   set_gdbarch_num_regs (arch, num_raw_regs);
+   set_gdbarch_num_pseudo_regs (arch, num_cooked_regs);
+   set_gdbarch_pc_regnum (arch, pc->num);
+   set_gdbarch_sp_regnum (arch, sp->num);
+   set_gdbarch_register_name (arch, m32c_register_name);
+   set_gdbarch_register_type (arch, m32c_register_type);
+   set_gdbarch_pseudo_register_read (arch, m32c_pseudo_register_read);
+   set_gdbarch_pseudo_register_write (arch, m32c_pseudo_register_write);
+   set_gdbarch_register_sim_regno (arch, m32c_register_sim_regno);
+   set_gdbarch_stab_reg_to_regnum (arch, m32c_debug_info_reg_to_regnum);
+   set_gdbarch_dwarf_reg_to_regnum (arch, m32c_debug_info_reg_to_regnum);
+   set_gdbarch_dwarf2_reg_to_regnum (arch, m32c_debug_info_reg_to_regnum);
+   set_gdbarch_register_reggroup_p (arch, m32c_register_reggroup_p);
+ 
+   reggroup_add (arch, general_reggroup);
+   reggroup_add (arch, all_reggroup);
+   reggroup_add (arch, save_reggroup);
+   reggroup_add (arch, restore_reggroup);
+   reggroup_add (arch, system_reggroup);
+   reggroup_add (arch, m32c_dma_reggroup);
+ }
+ 
+ 
+ 
+ /* Breakpoints.  */
+ 
+ static const unsigned char *
+ m32c_breakpoint_from_pc (CORE_ADDR *pc, int *len)
+ {
+   static unsigned char break_insn[] = { 0x00 };	/* brk */
+ 
+   *len = sizeof (break_insn);
+   return break_insn;
+ }
+ 
+ 
+ 
+ /* Prologue analysis.  */
+ 
+ struct m32c_prologue
+ {
+   /* For consistency with the DWARF 2 .debug_frame info generated by
+      GCC, a frame's CFA is the address immediately after the saved
+      return address.  */
+ 
+   /* The architecture for which we generated this prologue info.  */
+   struct gdbarch *arch;
+ 
+   enum {
+     /* This function uses a frame pointer.  */
+     prologue_with_frame_ptr,
+ 
+     /* This function has no frame pointer.  */
+     prologue_sans_frame_ptr,
+ 
+     /* This function sets up the stack, so its frame is the first
+        frame on the stack.  */
+     prologue_first_frame
+ 
+   } kind;
+ 
+   /* If KIND is prologue_with_frame_ptr, this is the offset from the
+      CFA to where the frame pointer points.  This is always zero or
+      negative.  */
+   LONGEST frame_ptr_offset;
+ 
+   /* If KIND is prologue_sans_frame_ptr, the offset from the CFA to
+      the stack pointer --- always zero or negative.
+ 
+      Calling this a "size" is a bit misleading, but given that the
+      stack grows downwards, using offsets for everything keeps one
+      from going completely sign-crazy: you never change anything's
+      sign for an ADD instruction; always change the second operand's
+      sign for a SUB instruction; and everything takes care of
+      itself.
+ 
+      Functions that use alloca don't have a constant frame size.  But
+      they always have frame pointers, so we must use that to find the
+      CFA (and perhaps to unwind the stack pointer).  */
+   LONGEST frame_size;
+ 
+   /* The address of the first instruction at which the frame has been
+      set up and the arguments are where the debug info says they are
+      --- as best as we can tell.  */
+   CORE_ADDR prologue_end;
+ 
+   /* reg_offset[R] is the offset from the CFA at which register R is
+      saved, or 1 if register R has not been saved.  (Real values are
+      always zero or negative.)  */
+   LONGEST reg_offset[M32C_MAX_NUM_REGS];
+ };
+ 
+ 
+ /* The longest I've seen, anyway.  */
+ #define M32C_MAX_INSN_LEN (9)
+ 
+ /* Processor state, for the prologue analyzer.  */
+ struct m32c_pv_state
+ {
+   struct gdbarch *arch;
+   pv_t r0, r1, r2, r3;
+   pv_t a0, a1;
+   pv_t sb, fb, sp;
+   pv_t pc;
+   struct pv_area *stack;
+ 
+   /* Bytes from the current PC, the address they were read from,
+      and the address of the next unconsumed byte.  */
+   gdb_byte insn[M32C_MAX_INSN_LEN];
+   CORE_ADDR scan_pc, next_addr;
+ };
+ 
+ 
+ /* Push VALUE on STATE's stack, occupying SIZE bytes.  Return zero if
+    all went well, or non-zero if simulating the action would trash our
+    state.  */
+ static int
+ m32c_pv_push (struct m32c_pv_state *state, pv_t value, int size)
+ {
+   if (pv_area_store_would_trash (state->stack, state->sp))
+     return 1;
+ 
+   state->sp = pv_add_constant (state->sp, -size);
+   pv_area_store (state->stack, state->sp, size, value);
+ 
+   return 0;
+ }
+ 
+ 
+ /* A source or destination location for an m16c or m32c
+    instruction.  */
+ struct srcdest
+ {
+   /* If srcdest_reg, the location is a register pointed to by REG.
+      If srcdest_partial_reg, the location is part of a register pointed
+      to by REG.  We don't try to handle this too well.
+      If srcdest_mem, the location is memory whose address is ADDR.  */
+   enum { srcdest_reg, srcdest_partial_reg, srcdest_mem } kind;
+   pv_t *reg, addr;
+ };
+ 
+ 
+ /* Return the SIZE-byte value at LOC in STATE.  */
+ static pv_t
+ m32c_srcdest_fetch (struct m32c_pv_state *state, struct srcdest loc, int size)
+ {
+   if (loc.kind == srcdest_mem)
+     return pv_area_fetch (state->stack, loc.addr, size);
+   else if (loc.kind == srcdest_partial_reg)
+     return pv_unknown ();
+   else
+     return *loc.reg;
+ }
+ 
+ 
+ /* Write VALUE, a SIZE-byte value, to LOC in STATE.  Return zero if
+    all went well, or non-zero if simulating the store would trash our
+    state.  */
+ static int
+ m32c_srcdest_store (struct m32c_pv_state *state, struct srcdest loc,
+ 		    pv_t value, int size)
+ {
+   if (loc.kind == srcdest_mem)
+     {
+       if (pv_area_store_would_trash (state->stack, loc.addr))
+ 	return 1;
+       pv_area_store (state->stack, loc.addr, size, value);
+     }
+   else if (loc.kind == srcdest_partial_reg)
+     *loc.reg = pv_unknown ();
+   else
+     *loc.reg = value;
+ 
+   return 0;
+ }
+ 
+ 
+ static int
+ m32c_sign_ext (int v, int bits)
+ {
+   int mask = 1 << (bits - 1);
+   return (v ^ mask) - mask;
+ }
+ 
+ static unsigned int
+ m32c_next_byte (struct m32c_pv_state *st)
+ {
+   gdb_assert (st->next_addr - st->scan_pc < sizeof (st->insn));
+   return st->insn[st->next_addr++ - st->scan_pc];
+ }
+ 
+ static int
+ m32c_udisp8 (struct m32c_pv_state *st)
+ {
+   return m32c_next_byte (st);
+ }
+ 
+ 
+ static int
+ m32c_sdisp8 (struct m32c_pv_state *st)
+ {
+   return m32c_sign_ext (m32c_next_byte (st), 8);
+ }
+ 
+ 
+ static int
+ m32c_udisp16 (struct m32c_pv_state *st)
+ {
+   int low  = m32c_next_byte (st);
+   int high = m32c_next_byte (st);
+ 
+   return low + (high << 8);
+ }
+ 
+ 
+ static int
+ m32c_sdisp16 (struct m32c_pv_state *st)
+ {
+   int low  = m32c_next_byte (st);
+   int high = m32c_next_byte (st);
+ 
+   return m32c_sign_ext (low + (high << 8), 16);
+ }
+ 
+ 
+ static int
+ m32c_udisp24 (struct m32c_pv_state *st)
+ {
+   int low  = m32c_next_byte (st);
+   int mid  = m32c_next_byte (st);
+   int high = m32c_next_byte (st);
+ 
+   return low + (mid << 8) + (high << 16);
+ }
+ 
+ 
+ /* Extract the 'source' field from an m32c MOV.size:G-format instruction.  */
+ static int
+ m32c_get_src23 (unsigned char *i)
+ {
+   return (((i[0] & 0x70) >> 2)
+ 	  | ((i[1] & 0x30) >> 4));
+ }
+ 
+ 
+ /* Extract the 'dest' field from an m32c MOV.size:G-format instruction.  */
+ static int
+ m32c_get_dest23 (unsigned char *i)
+ {
+   return (((i[0] & 0x0e) << 1)
+ 	  | ((i[1] & 0xc0) >> 6));
+ }
+ 
+ 
+ static struct srcdest
+ m32c_decode_srcdest4 (struct m32c_pv_state *st,
+ 		      int code, int size)
+ {
+   struct srcdest sd;
+ 
+   if (code < 6)
+     sd.kind = (size == 2 ? srcdest_reg : srcdest_partial_reg);
+   else
+     sd.kind = srcdest_mem;
+ 
+   switch (code)
+     {
+     case 0x0: sd.reg = (size == 1 ? &st->r0 : &st->r0); break;
+     case 0x1: sd.reg = (size == 1 ? &st->r0 : &st->r1); break;
+     case 0x2: sd.reg = (size == 1 ? &st->r1 : &st->r2); break;
+     case 0x3: sd.reg = (size == 1 ? &st->r1 : &st->r3); break;
+ 
+     case 0x4: sd.reg = &st->a0; break;
+     case 0x5: sd.reg = &st->a1; break;
+ 
+     case 0x6: sd.addr = st->a0; break;
+     case 0x7: sd.addr = st->a1; break;
+ 
+     case 0x8: sd.addr = pv_add_constant (st->a0, m32c_udisp8 (st)); break;
+     case 0x9: sd.addr = pv_add_constant (st->a1, m32c_udisp8 (st)); break;
+     case 0xa: sd.addr = pv_add_constant (st->sb, m32c_udisp8 (st)); break;
+     case 0xb: sd.addr = pv_add_constant (st->fb, m32c_sdisp8 (st)); break;
+ 
+     case 0xc: sd.addr = pv_add_constant (st->a0, m32c_udisp16 (st)); break;
+     case 0xd: sd.addr = pv_add_constant (st->a1, m32c_udisp16 (st)); break;
+     case 0xe: sd.addr = pv_add_constant (st->sb, m32c_udisp16 (st)); break;
+     case 0xf: sd.addr = pv_constant (m32c_udisp16 (st)); break;
+ 
+     default:
+       gdb_assert (0);
+     }
+ 
+   return sd;
+ }
+ 
+ 
+ static struct srcdest
+ m32c_decode_sd23 (struct m32c_pv_state *st, int code, int size, int ind)
+ {
+   struct srcdest sd;
+ 
+   switch (code)
+     {
+     case 0x12:
+     case 0x13:
+     case 0x10:
+     case 0x11:
+       sd.kind = (size == 1) ? srcdest_partial_reg : srcdest_reg;
+       break;
+ 
+     case 0x02:
+     case 0x03:
+       sd.kind = (size == 4) ? srcdest_reg : srcdest_partial_reg;
+       break;
+ 
+     default:
+       sd.kind = srcdest_mem;
+       break;
+ 
+     }
+ 
+   switch (code)
+     {
+     case 0x12: sd.reg = &st->r0; break;
+     case 0x13: sd.reg = &st->r1; break;
+     case 0x10: sd.reg = ((size == 1) ? &st->r0 : &st->r2); break;
+     case 0x11: sd.reg = ((size == 1) ? &st->r1 : &st->r3); break;
+     case 0x02: sd.reg = &st->a0; break;
+     case 0x03: sd.reg = &st->a1; break;
+ 
+     case 0x00: sd.addr = st->a0; break;
+     case 0x01: sd.addr = st->a1; break;
+     case 0x04: sd.addr = pv_add_constant (st->a0, m32c_udisp8 (st)); break;
+     case 0x05: sd.addr = pv_add_constant (st->a1, m32c_udisp8 (st)); break;
+     case 0x06: sd.addr = pv_add_constant (st->sb, m32c_udisp8 (st)); break;
+     case 0x07: sd.addr = pv_add_constant (st->fb, m32c_sdisp8 (st)); break;
+     case 0x08: sd.addr = pv_add_constant (st->a0, m32c_udisp16 (st)); break;
+     case 0x09: sd.addr = pv_add_constant (st->a1, m32c_udisp16 (st)); break;
+     case 0x0a: sd.addr = pv_add_constant (st->sb, m32c_udisp16 (st)); break;
+     case 0x0b: sd.addr = pv_add_constant (st->fb, m32c_sdisp16 (st)); break;
+     case 0x0c: sd.addr = pv_add_constant (st->a0, m32c_udisp24 (st)); break;
+     case 0x0d: sd.addr = pv_add_constant (st->a1, m32c_udisp24 (st)); break;
+     case 0x0f: sd.addr = pv_constant (m32c_udisp16 (st)); break;
+     case 0x0e: sd.addr = pv_constant (m32c_udisp24 (st)); break;
+     default:
+       gdb_assert (0);
+     }
+ 
+   if (ind)
+     {
+       sd.addr = m32c_srcdest_fetch (st, sd, 4);
+       sd.kind = srcdest_mem;
+     }
+ 
+   return sd;
+ }
+ 
+ 
+ /* The r16c and r32c machines have instructions with similar
+    semantics, but completely different machine language encodings.  So
+    we break out the semantics into their own functions, and leave
+    machine-specific decoding in m32c_analyze_prologue.
+ 
+    The following functions all expect their arguments already decoded,
+    and they all return zero if analysis should continue past this
+    instruction, or non-zero if analysis should stop.  */
+ 
+ 
+ /* Simulate an 'enter SIZE' instruction in STATE.  */
+ static int
+ m32c_pv_enter (struct m32c_pv_state *state, int size)
+ {
+   struct gdbarch_tdep *tdep = gdbarch_tdep (state->arch);
+ 
+   /* If simulating this store would require us to forget
+      everything we know about the stack frame in the name of
+      accuracy, it would be better to just quit now.  */
+   if (pv_area_store_would_trash (state->stack, state->sp))
+     return 1;
+ 
+   if (m32c_pv_push (state, state->fb, tdep->push_addr_bytes))
+     return 1;
+   state->fb = state->sp;
+   state->sp = pv_add_constant (state->sp, -size);
+ 
+   return 0;
+ }
+ 
+ 
+ static int
+ m32c_pv_pushm_one (struct m32c_pv_state *state, pv_t reg,
+ 		   int bit, int src, int size)
+ {
+   if (bit & src)
+     {
+       if (m32c_pv_push (state, reg, size))
+ 	return 1;
+     }
+ 
+   return 0;
+ }
+ 
+ 
+ /* Simulate a 'pushm SRC' instruction in STATE.  */
+ static int
+ m32c_pv_pushm (struct m32c_pv_state *state, int src)
+ {
+   struct gdbarch_tdep *tdep = gdbarch_tdep (state->arch);
+ 
+   /* The bits in SRC indicating which registers to save are:
+      r0 r1 r2 r3 a0 a1 sb fb */
+   return
+     (   m32c_pv_pushm_one (state, state->fb, 0x01, src, tdep->push_addr_bytes)
+      || m32c_pv_pushm_one (state, state->sb, 0x02, src, tdep->push_addr_bytes)
+      || m32c_pv_pushm_one (state, state->a1, 0x04, src, tdep->push_addr_bytes)
+      || m32c_pv_pushm_one (state, state->a0, 0x08, src, tdep->push_addr_bytes)
+      || m32c_pv_pushm_one (state, state->r3, 0x10, src, 2)
+      || m32c_pv_pushm_one (state, state->r2, 0x20, src, 2)
+      || m32c_pv_pushm_one (state, state->r1, 0x40, src, 2)
+      || m32c_pv_pushm_one (state, state->r0, 0x80, src, 2));
+ }
+ 
+ /* Return non-zero if VALUE is the first incoming argument register.  */
+ 
+ static int
+ m32c_is_1st_arg_reg (struct m32c_pv_state *state, pv_t value)
+ {
+   struct gdbarch_tdep *tdep = gdbarch_tdep (state->arch);
+   return (value.kind == pvk_register
+           && (gdbarch_bfd_arch_info (state->arch)->mach == bfd_mach_m16c
+ 	      ? (value.reg == tdep->r1->num)
+ 	      : (value.reg == tdep->r0->num))
+           && value.k == 0);
+ }
+ 
+ /* Return non-zero if VALUE is an incoming argument register.  */
+ 
+ static int
+ m32c_is_arg_reg (struct m32c_pv_state *state, pv_t value)
+ {
+   struct gdbarch_tdep *tdep = gdbarch_tdep (state->arch);
+   return (value.kind == pvk_register
+           && (gdbarch_bfd_arch_info (state->arch)->mach == bfd_mach_m16c
+ 	      ? (value.reg == tdep->r1->num || value.reg == tdep->r2->num)
+ 	      : (value.reg == tdep->r0->num))
+           && value.k == 0);
+ }
+ 
+ /* Return non-zero if a store of VALUE to LOC is probably spilling an
+    argument register to its stack slot in STATE.  Such instructions
+    should be included in the prologue, if possible.
+ 
+    The store is a spill if:
+    - the value being stored is the original value of an argument register;
+    - the value has not already been stored somewhere in STACK; and
+    - LOC is a stack slot (e.g., a memory location whose address is
+      relative to the original value of the SP).  */
+ 
+ static int
+ m32c_is_arg_spill (struct m32c_pv_state *st, 
+ 		   struct srcdest loc, 
+ 		   pv_t value)
+ {
+   struct gdbarch_tdep *tdep = gdbarch_tdep (st->arch);
+ 
+   return (m32c_is_arg_reg (st, value)
+ 	  && loc.kind == srcdest_mem
+           && pv_is_register (loc.addr, tdep->sp->num)
+           && ! pv_area_find_reg (st->stack, st->arch, value.reg, 0));
+ }
+ 
+ /* Return non-zero if a store of VALUE to LOC is probably 
+    copying the struct return address into an address register
+    for immediate use.  This is basically a "spill" into the
+    address register, instead of onto the stack. 
+ 
+    The prerequisites are:
+    - value being stored is original value of the FIRST arg register;
+    - value has not already been stored on stack; and
+    - LOC is an address register (a0 or a1).  */
+ 
+ static int
+ m32c_is_struct_return (struct m32c_pv_state *st,
+ 		       struct srcdest loc, 
+ 		       pv_t value)
+ {
+   struct gdbarch_tdep *tdep = gdbarch_tdep (st->arch);
+ 
+   return (m32c_is_1st_arg_reg (st, value)
+ 	  && !pv_area_find_reg (st->stack, st->arch, value.reg, 0)
+ 	  && loc.kind == srcdest_reg
+ 	  && (pv_is_register (*loc.reg, tdep->a0->num)
+ 	      || pv_is_register (*loc.reg, tdep->a1->num)));
+ }
+ 
+ /* Return non-zero if a 'pushm' saving the registers indicated by SRC
+    was a register save:
+    - all the named registers should have their original values, and
+    - the stack pointer should be at a constant offset from the
+      original stack pointer.  */
+ static int
+ m32c_pushm_is_reg_save (struct m32c_pv_state *st, int src)
+ {
+   struct gdbarch_tdep *tdep = gdbarch_tdep (st->arch);
+   /* The bits in SRC indicating which registers to save are:
+      r0 r1 r2 r3 a0 a1 sb fb */
+   return
+     (pv_is_register (st->sp, tdep->sp->num)
+      && (! (src & 0x01) || pv_is_register_k (st->fb, tdep->fb->num, 0))
+      && (! (src & 0x02) || pv_is_register_k (st->sb, tdep->sb->num, 0))
+      && (! (src & 0x04) || pv_is_register_k (st->a1, tdep->a1->num, 0))
+      && (! (src & 0x08) || pv_is_register_k (st->a0, tdep->a0->num, 0))
+      && (! (src & 0x10) || pv_is_register_k (st->r3, tdep->r3->num, 0))
+      && (! (src & 0x20) || pv_is_register_k (st->r2, tdep->r2->num, 0))
+      && (! (src & 0x40) || pv_is_register_k (st->r1, tdep->r1->num, 0))
+      && (! (src & 0x80) || pv_is_register_k (st->r0, tdep->r0->num, 0)));
+ }
+ 
+ 
+ /* Function for finding saved registers in a 'struct pv_area'; we pass
+    this to pv_area_scan.
+ 
+    If VALUE is a saved register, ADDR says it was saved at a constant
+    offset from the frame base, and SIZE indicates that the whole
+    register was saved, record its offset in RESULT_UNTYPED.  */
+ static void
+ check_for_saved (void *prologue_untyped, pv_t addr, CORE_ADDR size, pv_t value)
+ {
+   struct m32c_prologue *prologue = (struct m32c_prologue *) prologue_untyped;
+   struct gdbarch *arch = prologue->arch;
+   struct gdbarch_tdep *tdep = gdbarch_tdep (arch);
+ 
+   /* Is this the unchanged value of some register being saved on the
+      stack?  */
+   if (value.kind == pvk_register
+       && value.k == 0
+       && pv_is_register (addr, tdep->sp->num))
+     {
+       /* Some registers require special handling: they're saved as a
+ 	 larger value than the register itself.  */
+       CORE_ADDR saved_size = register_size (arch, value.reg);
+ 
+       if (value.reg == tdep->pc->num)
+ 	saved_size = tdep->ret_addr_bytes;
+       else if (gdbarch_register_type (arch, value.reg)
+ 	       == tdep->data_addr_reg_type)
+ 	saved_size = tdep->push_addr_bytes;
+ 
+       if (size == saved_size)
+ 	{
+ 	  /* Find which end of the saved value corresponds to our
+ 	     register.  */
+ 	  if (gdbarch_byte_order (arch) == BFD_ENDIAN_BIG)
+ 	    prologue->reg_offset[value.reg]
+ 	      = (addr.k + saved_size - register_size (arch, value.reg));
+ 	  else
+ 	    prologue->reg_offset[value.reg] = addr.k;
+ 	}
+     }
+ }
+ 
+ 
+ /* Analyze the function prologue for ARCH at START, going no further
+    than LIMIT, and place a description of what we found in
+    PROLOGUE.  */
+ void
+ m32c_analyze_prologue (struct gdbarch *arch,
+ 		       CORE_ADDR start, CORE_ADDR limit,
+ 		       struct m32c_prologue *prologue)
+ {
+   struct gdbarch_tdep *tdep = gdbarch_tdep (arch);
+   unsigned long mach = gdbarch_bfd_arch_info (arch)->mach;
+   CORE_ADDR after_last_frame_related_insn;
+   struct cleanup *back_to;
+   struct m32c_pv_state st;
+ 
+   st.arch = arch;
+   st.r0 = pv_register (tdep->r0->num, 0);
+   st.r1 = pv_register (tdep->r1->num, 0);
+   st.r2 = pv_register (tdep->r2->num, 0);
+   st.r3 = pv_register (tdep->r3->num, 0);
+   st.a0 = pv_register (tdep->a0->num, 0);
+   st.a1 = pv_register (tdep->a1->num, 0);
+   st.sb = pv_register (tdep->sb->num, 0);
+   st.fb = pv_register (tdep->fb->num, 0);
+   st.sp = pv_register (tdep->sp->num, 0);
+   st.pc = pv_register (tdep->pc->num, 0);
+   st.stack = make_pv_area (tdep->sp->num);
+   back_to = make_cleanup_free_pv_area (st.stack);
+ 
+   /* Record that the call instruction has saved the return address on
+      the stack.  */
+   m32c_pv_push (&st, st.pc, tdep->ret_addr_bytes);
+ 
+   memset (prologue, 0, sizeof (*prologue));
+   prologue->arch = arch;
+   {
+     int i;
+     for (i = 0; i < M32C_MAX_NUM_REGS; i++)
+       prologue->reg_offset[i] = 1;
+   }
+ 
+   st.scan_pc = after_last_frame_related_insn = start;
+ 
+   while (st.scan_pc < limit)
+     {
+       pv_t pre_insn_fb = st.fb;
+       pv_t pre_insn_sp = st.sp;
+ 
+       /* In theory we could get in trouble by trying to read ahead
+ 	 here, when we only know we're expecting one byte.  In
+ 	 practice I doubt anyone will care, and it makes the rest of
+ 	 the code easier.  */
+       if (target_read_memory (st.scan_pc, st.insn, sizeof (st.insn)))
+ 	/* If we can't fetch the instruction from memory, stop here
+ 	   and hope for the best.  */
+ 	break;
+       st.next_addr = st.scan_pc;
+ 
+       /* The assembly instructions are written as they appear in the
+ 	 section of the processor manuals that describe the
+ 	 instruction encodings.
+ 
+ 	 When a single assembly language instruction has several
+ 	 different machine-language encodings, the manual
+ 	 distinguishes them by a number in parens, before the
+ 	 mnemonic.  Those numbers are included, as well.
+ 
+ 	 The srcdest decoding instructions have the same names as the
+ 	 analogous functions in the simulator.  */
+       if (mach == bfd_mach_m16c)
+ 	{
+ 	  /* (1) ENTER #imm8 */
+ 	  if (st.insn[0] == 0x7c && st.insn[1] == 0xf2)
+ 	    {
+ 	      if (m32c_pv_enter (&st, st.insn[2]))
+ 		break;
+ 	      st.next_addr += 3;
+ 	    }
+ 	  /* (1) PUSHM src */
+ 	  else if (st.insn[0] == 0xec)
+ 	    {
+ 	      int src = st.insn[1];
+ 	      if (m32c_pv_pushm (&st, src))
+ 		break;
+ 	      st.next_addr += 2;
+ 
+ 	      if (m32c_pushm_is_reg_save (&st, src))
+ 		after_last_frame_related_insn = st.next_addr;
+ 	    }
+ 
+ 	  /* (6) MOV.size:G src, dest */
+ 	  else if ((st.insn[0] & 0xfe) == 0x72)
+ 	    {
+ 	      int size = (st.insn[0] & 0x01) ? 2 : 1;
+ 
+ 	      st.next_addr += 2;
+ 
+ 	      struct srcdest src
+ 		= m32c_decode_srcdest4 (&st, (st.insn[1] >> 4) & 0xf, size);
+ 	      struct srcdest dest
+ 		= m32c_decode_srcdest4 (&st, st.insn[1] & 0xf, size);
+ 	      pv_t src_value = m32c_srcdest_fetch (&st, src, size);
+ 
+ 	      if (m32c_is_arg_spill (&st, dest, src_value))
+ 		after_last_frame_related_insn = st.next_addr;
+ 	      else if (m32c_is_struct_return (&st, dest, src_value))
+ 		after_last_frame_related_insn = st.next_addr;
+ 
+ 	      if (m32c_srcdest_store (&st, dest, src_value, size))
+ 		break;
+ 	    }
+ 
+ 	  /* (1) LDC #IMM16, sp */
+ 	  else if (st.insn[0] == 0xeb
+ 		   && st.insn[1] == 0x50)
+ 	    {
+ 	      st.next_addr += 2;
+ 	      st.sp = pv_constant (m32c_udisp16 (&st));
+ 	    }
+ 
+ 	  else
+ 	    /* We've hit some instruction we don't know how to simulate.
+ 	       Strictly speaking, we should set every value we're
+ 	       tracking to "unknown".  But we'll be optimistic, assume
+ 	       that we have enough information already, and stop
+ 	       analysis here.  */
+ 	    break;
+ 	}
+       else
+ 	{
+ 	  int src_indirect = 0;
+ 	  int dest_indirect = 0;
+ 	  int i = 0;
+ 
+ 	  gdb_assert (mach == bfd_mach_m32c);
+ 
+ 	  /* Check for prefix bytes indicating indirect addressing.  */
+ 	  if (st.insn[0] == 0x41)
+ 	    {
+ 	      src_indirect = 1;
+ 	      i++;
+ 	    }
+ 	  else if (st.insn[0] == 0x09)
+ 	    {
+ 	      dest_indirect = 1;
+ 	      i++;
+ 	    }
+ 	  else if (st.insn[0] == 0x49)
+ 	    {
+ 	      src_indirect = dest_indirect = 1;
+ 	      i++;
+ 	    }
+ 
+ 	  /* (1) ENTER #imm8 */
+ 	  if (st.insn[i] == 0xec)
+ 	    {
+ 	      if (m32c_pv_enter (&st, st.insn[i + 1]))
+ 		break;
+ 	      st.next_addr += 2;
+ 	    }
+ 
+ 	  /* (1) PUSHM src */
+ 	  else if (st.insn[i] == 0x8f)
+ 	    {
+ 	      int src = st.insn[i + 1];
+ 	      if (m32c_pv_pushm (&st, src))
+ 		break;
+ 	      st.next_addr += 2;
+ 
+ 	      if (m32c_pushm_is_reg_save (&st, src))
+ 		after_last_frame_related_insn = st.next_addr;
+ 	    }
+ 
+ 	  /* (7) MOV.size:G src, dest */
+ 	  else if ((st.insn[i] & 0x80) == 0x80
+ 		   && (st.insn[i + 1] & 0x0f) == 0x0b
+ 		   && m32c_get_src23 (&st.insn[i]) < 20
+ 		   && m32c_get_dest23 (&st.insn[i]) < 20)
+ 	    {
+ 	      int bw = st.insn[i] & 0x01;
+ 	      int size = bw ? 2 : 1;
+ 
+ 	      st.next_addr += 2;
+ 
+ 	      struct srcdest src
+ 		= m32c_decode_sd23 (&st, m32c_get_src23 (&st.insn[i]),
+ 				    size, src_indirect);
+ 	      struct srcdest dest
+ 		= m32c_decode_sd23 (&st, m32c_get_dest23 (&st.insn[i]),
+ 				    size, dest_indirect);
+ 	      pv_t src_value = m32c_srcdest_fetch (&st, src, size);
+ 
+ 	      if (m32c_is_arg_spill (&st, dest, src_value))
+ 		after_last_frame_related_insn = st.next_addr;
+ 
+ 	      if (m32c_srcdest_store (&st, dest, src_value, size))
+ 		break;
+ 	    }
+ 	  /* (2) LDC #IMM24, sp */
+ 	  else if (st.insn[i] == 0xd5
+ 		   && st.insn[i + 1] == 0x29)
+ 	    {
+ 	      st.next_addr += 2;
+ 	      st.sp = pv_constant (m32c_udisp24 (&st));
+ 	    }
+ 	  else
+ 	    /* We've hit some instruction we don't know how to simulate.
+ 	       Strictly speaking, we should set every value we're
+ 	       tracking to "unknown".  But we'll be optimistic, assume
+ 	       that we have enough information already, and stop
+ 	       analysis here.  */
+ 	    break;
+ 	}
+ 
+       /* If this instruction changed the FB or decreased the SP (i.e.,
+          allocated more stack space), then this may be a good place to
+          declare the prologue finished.  However, there are some
+          exceptions:
+ 
+          - If the instruction just changed the FB back to its original
+            value, then that's probably a restore instruction.  The
+            prologue should definitely end before that.
+ 
+          - If the instruction increased the value of the SP (that is,
+            shrunk the frame), then it's probably part of a frame
+            teardown sequence, and the prologue should end before
+            that.  */
+ 
+       if (! pv_is_identical (st.fb, pre_insn_fb))
+         {
+           if (! pv_is_register_k (st.fb, tdep->fb->num, 0))
+             after_last_frame_related_insn = st.next_addr;
+         }
+       else if (! pv_is_identical (st.sp, pre_insn_sp))
+         {
+           /* The comparison of the constants looks odd, there, because
+              .k is unsigned.  All it really means is that the SP is
+              lower than it was before the instruction.  */
+           if (   pv_is_register (pre_insn_sp, tdep->sp->num)
+               && pv_is_register (st.sp,       tdep->sp->num)
+               && ((pre_insn_sp.k - st.sp.k) < (st.sp.k - pre_insn_sp.k)))
+             after_last_frame_related_insn = st.next_addr;
+         }
+ 
+       st.scan_pc = st.next_addr;
+     }
+ 
+   /* Did we load a constant value into the stack pointer?  */
+   if (pv_is_constant (st.sp))
+     prologue->kind = prologue_first_frame;
+ 
+   /* Alternatively, did we initialize the frame pointer?  Remember
+      that the CFA is the address after the return address.  */
+   if (pv_is_register (st.fb, tdep->sp->num))
+     {
+       prologue->kind = prologue_with_frame_ptr;
+       prologue->frame_ptr_offset = st.fb.k;
+     }
+ 
+   /* Is the frame size a known constant?  Remember that frame_size is
+      actually the offset from the CFA to the SP (i.e., a negative
+      value).  */
+   else if (pv_is_register (st.sp, tdep->sp->num))
+     {
+       prologue->kind = prologue_sans_frame_ptr;
+       prologue->frame_size = st.sp.k;
+     }
+ 
+   /* We haven't been able to make sense of this function's frame.  Treat
+      it as the first frame.  */
+   else
+     prologue->kind = prologue_first_frame;
+ 
+   /* Record where all the registers were saved.  */
+   pv_area_scan (st.stack, check_for_saved, (void *) prologue);
+ 
+   prologue->prologue_end = after_last_frame_related_insn;
+ 
+   do_cleanups (back_to);
+ }
+ 
+ 
+ static CORE_ADDR
+ m32c_skip_prologue (CORE_ADDR ip)
+ {
+   char *name;
+   CORE_ADDR func_addr, func_end, sal_end;
+   struct m32c_prologue p;
+ 
+   /* Try to find the extent of the function that contains IP.  */
+   if (! find_pc_partial_function (ip, &name, &func_addr, &func_end))
+     return ip;
+ 
+   /* Find end by prologue analysis.  */
+   m32c_analyze_prologue (current_gdbarch, ip, func_end, &p);
+   /* Find end by line info.  */
+   sal_end = skip_prologue_using_sal (ip);
+   /* Return whichever is lower.  */
+   if (sal_end != 0 && sal_end != ip && sal_end < p.prologue_end)
+     return sal_end;
+   else
+     return p.prologue_end;
+ }
+ 
+ 
+ 
+ /* Stack unwinding.  */
+ 
+ static struct m32c_prologue *
+ m32c_analyze_frame_prologue (struct frame_info *next_frame,
+ 			     void **this_prologue_cache)
+ {
+   if (! *this_prologue_cache)
+     {
+       CORE_ADDR func_start = frame_func_unwind (next_frame);
+       CORE_ADDR stop_addr = frame_pc_unwind (next_frame);
+ 
+       /* If we couldn't find any function containing the PC, then
+          just initialize the prologue cache, but don't do anything.  */
+       if (! func_start)
+         stop_addr = func_start;
+ 
+       *this_prologue_cache = FRAME_OBSTACK_ZALLOC (struct m32c_prologue);
+       m32c_analyze_prologue (get_frame_arch (next_frame),
+ 			     func_start, stop_addr, *this_prologue_cache);
+     }
+ 
+   return *this_prologue_cache;
+ }
+ 
+ 
+ static CORE_ADDR
+ m32c_frame_base (struct frame_info *next_frame,
+                 void **this_prologue_cache)
+ {
+   struct m32c_prologue *p
+     = m32c_analyze_frame_prologue (next_frame, this_prologue_cache);
+   struct gdbarch_tdep *tdep = gdbarch_tdep (get_frame_arch (next_frame));
+ 
+   /* In functions that use alloca, the distance between the stack
+      pointer and the frame base varies dynamically, so we can't use
+      the SP plus static information like prologue analysis to find the
+      frame base.  However, such functions must have a frame pointer,
+      to be able to restore the SP on exit.  So whenever we do have a
+      frame pointer, use that to find the base.  */
+   switch (p->kind)
+     {
+     case prologue_with_frame_ptr:
+       {
+ 	CORE_ADDR fb
+ 	  = frame_unwind_register_unsigned (next_frame, tdep->fb->num);
+ 	return fb - p->frame_ptr_offset;
+       }
+ 
+     case prologue_sans_frame_ptr:
+       {
+ 	CORE_ADDR sp
+ 	  = frame_unwind_register_unsigned (next_frame, tdep->sp->num);
+ 	return sp - p->frame_size;
+       }
+ 
+     case prologue_first_frame:
+       return 0;
+ 
+     default:
+       gdb_assert (0);
+     }
+ }
+ 
+ 
+ static void
+ m32c_this_id (struct frame_info *next_frame,
+ 	      void **this_prologue_cache,
+ 	      struct frame_id *this_id)
+ {
+   CORE_ADDR base = m32c_frame_base (next_frame, this_prologue_cache);
+ 
+   if (base)
+     *this_id = frame_id_build (base, frame_func_unwind (next_frame));
+   /* Otherwise, leave it unset, and that will terminate the backtrace.  */
+ }
+ 
+ 
+ static void
+ m32c_prev_register (struct frame_info *next_frame,
+ 		    void **this_prologue_cache,
+ 		    int regnum, int *optimizedp,
+ 		    enum lval_type *lvalp, CORE_ADDR *addrp,
+ 		    int *realnump, gdb_byte *bufferp)
+ {
+   struct gdbarch_tdep *tdep = gdbarch_tdep (get_frame_arch (next_frame));
+   struct m32c_prologue *p
+     = m32c_analyze_frame_prologue (next_frame, this_prologue_cache);
+   CORE_ADDR frame_base = m32c_frame_base (next_frame, this_prologue_cache);
+   int reg_size = register_size (get_frame_arch (next_frame), regnum);
+ 
+   if (regnum == tdep->sp->num)
+     {
+       *optimizedp = 0;
+       *lvalp = not_lval;
+       *addrp = 0;
+       *realnump = -1;
+       if (bufferp)
+ 	store_unsigned_integer (bufferp, reg_size, frame_base);
+     }
+ 
+   /* If prologue analysis says we saved this register somewhere,
+      return a description of the stack slot holding it.  */
+   else if (p->reg_offset[regnum] != 1)
+     {
+       *optimizedp = 0;
+       *lvalp = lval_memory;
+       *addrp = frame_base + p->reg_offset[regnum];
+       *realnump = -1;
+       if (bufferp)
+ 	get_frame_memory (next_frame, *addrp, bufferp, reg_size);
+     }
+ 
+   /* Otherwise, presume we haven't changed the value of this
+      register, and get it from the next frame.  */
+   else
+     frame_register_unwind (next_frame, regnum,
+ 			   optimizedp, lvalp, addrp, realnump, bufferp);
+ }
+ 
+ 
+ static const struct frame_unwind m32c_unwind = {
+   NORMAL_FRAME,
+   m32c_this_id,
+   m32c_prev_register
+ };
+ 
+ 
+ static const struct frame_unwind *
+ m32c_frame_sniffer (struct frame_info *next_frame)
+ {
+   return &m32c_unwind;
+ }
+ 
+ 
+ static CORE_ADDR
+ m32c_unwind_pc (struct gdbarch *arch, struct frame_info *next_frame)
+ {
+   struct gdbarch_tdep *tdep = gdbarch_tdep (arch);
+   return frame_unwind_register_unsigned (next_frame, tdep->pc->num);
+ }
+ 
+ 
+ static CORE_ADDR
+ m32c_unwind_sp (struct gdbarch *arch, struct frame_info *next_frame)
+ {
+   struct gdbarch_tdep *tdep = gdbarch_tdep (arch);
+   return frame_unwind_register_unsigned (next_frame, tdep->sp->num);
+ }
+ 
+ 
+ /* Inferior calls.  */
+ 
+ /* The calling conventions, according to GCC:
+ 
+    r8c, m16c
+    ---------
+    First arg may be passed in r1l or r1 if it (1) fits (QImode or
+    HImode), (2) is named, and (3) is an integer or pointer type (no
+    structs, floats, etc).  Otherwise, it's passed on the stack.
+ 
+    Second arg may be passed in r2, same restrictions (but not QImode),
+    even if the first arg is passed on the stack.
+ 
+    Third and further args are passed on the stack.  No padding is
+    used, stack "alignment" is 8 bits.
+ 
+    m32cm, m32c
+    -----------
+ 
+    First arg may be passed in r0l or r0, same restrictions as above.
+ 
+    Second and further args are passed on the stack.  Padding is used
+    after QImode parameters (i.e. lower-addressed byte is the value,
+    higher-addressed byte is the padding), stack "alignment" is 16
+    bits.  */
+ 
+ 
+ /* Return true if TYPE is a type that can be passed in registers.  (We
+    ignore the size, and pay attention only to the type code;
+    acceptable sizes depends on which register is being considered to
+    hold it.)  */
+ static int
+ m32c_reg_arg_type (struct type *type)
+ {
+   enum type_code code = TYPE_CODE (type);
+ 
+   return (code == TYPE_CODE_INT
+ 	  || code == TYPE_CODE_ENUM
+ 	  || code == TYPE_CODE_PTR
+ 	  || code == TYPE_CODE_REF
+ 	  || code == TYPE_CODE_BOOL
+ 	  || code == TYPE_CODE_CHAR);
+ }
+ 
+ 
+ static CORE_ADDR
+ m32c_push_dummy_call (struct gdbarch *gdbarch, struct value *function,
+ 		      struct regcache *regcache, CORE_ADDR bp_addr, int nargs,
+ 		      struct value **args, CORE_ADDR sp, int struct_return,
+ 		      CORE_ADDR struct_addr)
+ {
+   struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+   unsigned long mach = gdbarch_bfd_arch_info (gdbarch)->mach;
+   CORE_ADDR cfa;
+   int i;
+ 
+   /* The number of arguments given in this function's prototype, or
+      zero if it has a non-prototyped function type.  The m32c ABI
+      passes arguments mentioned in the prototype differently from
+      those in the ellipsis of a varargs function, or from those passed
+      to a non-prototyped function.  */
+   int num_prototyped_args = 0;
+ 
+   {
+     struct type *func_type = value_type (function);
+ 
+     gdb_assert (TYPE_CODE (func_type) == TYPE_CODE_FUNC);
+ 
+ #if 0
+     /* The ABI description in gcc/config/m32c/m32c.abi says that
+        we need to handle prototyped and non-prototyped functions
+        separately, but the code in GCC doesn't actually do so.  */
+     if (TYPE_PROTOTYPED (func_type))
+ #endif
+       num_prototyped_args = TYPE_NFIELDS (func_type);
+   }
+ 
+   /* First, if the function returns an aggregate by value, push a
+      pointer to a buffer for it.  This doesn't affect the way
+      subsequent arguments are allocated to registers.  */
+   if (struct_return)
+     {
+       int ptr_len = TYPE_LENGTH (tdep->ptr_voyd);
+       sp -= ptr_len;
+       write_memory_unsigned_integer (sp, ptr_len, struct_addr);
+     }
+ 
+   /* Push the arguments.  */
+   for (i = nargs - 1; i >= 0; i--)
+     {
+       struct value *arg = args[i];
+       const gdb_byte *arg_bits = value_contents (arg);
+       struct type *arg_type = value_type (arg);
+       ULONGEST arg_size = TYPE_LENGTH (arg_type);
+ 
+       /* Can it go in r1 or r1l (for m16c) or r0 or r0l (for m32c)?  */
+       if (i == 0
+ 	  && arg_size <= 2
+ 	  && i < num_prototyped_args
+ 	  && m32c_reg_arg_type (arg_type))
+ 	{
+ 	  /* Extract and re-store as an integer as a terse way to make
+ 	     sure it ends up in the least significant end of r1.  (GDB
+ 	     should avoid assuming endianness, even on uni-endian
+ 	     processors.)  */
+ 	  ULONGEST u = extract_unsigned_integer (arg_bits, arg_size);
+ 	  struct m32c_reg *reg = (mach == bfd_mach_m16c) ? tdep->r1 : tdep->r0;
+ 	  regcache_cooked_write_unsigned (regcache, reg->num, u);
+ 	}
+ 
+       /* Can it go in r2?  */
+       else if (mach == bfd_mach_m16c
+ 	       && i == 1
+ 	       && arg_size == 2
+ 	       && i < num_prototyped_args
+ 	       && m32c_reg_arg_type (arg_type))
+ 	regcache_cooked_write (regcache, tdep->r2->num, arg_bits);
+ 
+       /* Everything else goes on the stack.  */
+       else
+ 	{
+ 	  sp -= arg_size;
+ 
+ 	  /* Align the stack.  */
+ 	  if (mach == bfd_mach_m32c)
+ 	    sp &= ~1;
+ 
+ 	  write_memory (sp, arg_bits, arg_size);
+ 	}
+     }
+ 
+   /* This is the CFA we use to identify the dummy frame.  */
+   cfa = sp;
+ 
+   /* Push the return address.  */
+   sp -= tdep->ret_addr_bytes;
+   write_memory_unsigned_integer (sp, tdep->ret_addr_bytes, bp_addr);
+ 
+   /* Update the stack pointer.  */
+   regcache_cooked_write_unsigned (regcache, tdep->sp->num, sp);
+ 
+   /* We need to borrow an odd trick from the i386 target here.
+ 
+      The value we return from this function gets used as the stack
+      address (the CFA) for the dummy frame's ID.  The obvious thing is
+      to return the new TOS.  However, that points at the return
+      address, saved on the stack, which is inconsistent with the CFA's
+      described by GCC's DWARF 2 .debug_frame information: DWARF 2
+      .debug_frame info uses the address immediately after the saved
+      return address.  So you end up with a dummy frame whose CFA
+      points at the return address, but the frame for the function
+      being called has a CFA pointing after the return address: the
+      younger CFA is *greater than* the older CFA.  The sanity checks
+      in frame.c don't like that.
+ 
+      So we try to be consistent with the CFA's used by DWARF 2.
+      Having a dummy frame and a real frame with the *same* CFA is
+      tolerable.  */
+   return cfa;
+ }
+ 
+ 
+ static struct frame_id
+ m32c_unwind_dummy_id (struct gdbarch *gdbarch, struct frame_info *next_frame)
+ {
+   /* This needs to return a frame ID whose PC is the return address
+      passed to m32c_push_dummy_call, and whose stack_addr is the SP
+      m32c_push_dummy_call returned.
+ 
+      m32c_unwind_sp gives us the CFA, which is the value the SP had
+      before the return address was pushed.  */
+   return frame_id_build (m32c_unwind_sp (gdbarch, next_frame),
+                          frame_pc_unwind (next_frame));
+ }
+ 
+ 
+ 
+ /* Return values.  */
+ 
+ /* Return value conventions, according to GCC:
+ 
+    r8c, m16c
+    ---------
+ 
+    QImode in r0l
+    HImode in r0
+    SImode in r2r0
+    near pointer in r0
+    far pointer in r2r0
+ 
+    Aggregate values (regardless of size) are returned by pushing a
+    pointer to a temporary area on the stack after the args are pushed.
+    The function fills in this area with the value.  Note that this
+    pointer on the stack does not affect how register arguments, if any,
+    are configured.
+ 
+    m32cm, m32c
+    -----------
+    Same.  */
+ 
+ /* Return non-zero if values of type TYPE are returned by storing them
+    in a buffer whose address is passed on the stack, ahead of the
+    other arguments.  */
+ static int
+ m32c_return_by_passed_buf (struct type *type)
+ {
+   enum type_code code = TYPE_CODE (type);
+ 
+   return (code == TYPE_CODE_STRUCT
+ 	  || code == TYPE_CODE_UNION);
+ }
+ 
+ static enum return_value_convention
+ m32c_return_value (struct gdbarch *gdbarch,
+ 		   struct type *valtype,
+ 		   struct regcache *regcache,
+ 		   gdb_byte *readbuf,
+ 		   const gdb_byte *writebuf)
+ {
+   struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+   enum return_value_convention conv;
+   ULONGEST valtype_len = TYPE_LENGTH (valtype);
+ 
+   if (m32c_return_by_passed_buf (valtype))
+     conv = RETURN_VALUE_STRUCT_CONVENTION;
+   else
+     conv = RETURN_VALUE_REGISTER_CONVENTION;
+ 
+   if (readbuf)
+     {
+       /* We should never be called to find values being returned by
+ 	 RETURN_VALUE_STRUCT_CONVENTION.  Those can't be located,
+ 	 unless we made the call ourselves.  */
+       gdb_assert (conv == RETURN_VALUE_REGISTER_CONVENTION);
+ 
+       gdb_assert (valtype_len <= 8);
+ 
+       /* Anything that fits in r0 is returned there.  */
+       if (valtype_len <= TYPE_LENGTH (tdep->r0->type))
+ 	{
+ 	  ULONGEST u;
+ 	  regcache_cooked_read_unsigned (regcache, tdep->r0->num, &u);
+ 	  store_unsigned_integer (readbuf, valtype_len, u);
+ 	}
+       else
+ 	{
+ 	  /* Everything else is passed in mem0, using as many bytes as
+ 	     needed.  This is not what the Renesas tools do, but it's
+ 	     what GCC does at the moment.  */
+ 	  struct minimal_symbol *mem0
+ 	    = lookup_minimal_symbol ("mem0", NULL, NULL);
+ 
+ 	  if (! mem0)
+ 	    error ("The return value is stored in memory at 'mem0', "
+ 		   "but GDB cannot find\n"
+ 		   "its address.");
+ 	  read_memory (SYMBOL_VALUE_ADDRESS (mem0), readbuf, valtype_len);
+ 	}
+     }
+ 
+   if (writebuf)
+     {
+       /* We should never be called to store values to be returned
+ 	 using RETURN_VALUE_STRUCT_CONVENTION.  We have no way of
+ 	 finding the buffer, unless we made the call ourselves.  */
+       gdb_assert (conv == RETURN_VALUE_REGISTER_CONVENTION);
+ 
+       gdb_assert (valtype_len <= 8);
+ 
+       /* Anything that fits in r0 is returned there.  */
+       if (valtype_len <= TYPE_LENGTH (tdep->r0->type))
+ 	{
+ 	  ULONGEST u = extract_unsigned_integer (writebuf, valtype_len);
+ 	  regcache_cooked_write_unsigned (regcache, tdep->r0->num, u);
+ 	}
+       else
+ 	{
+ 	  /* Everything else is passed in mem0, using as many bytes as
+ 	     needed.  This is not what the Renesas tools do, but it's
+ 	     what GCC does at the moment.  */
+ 	  struct minimal_symbol *mem0
+ 	    = lookup_minimal_symbol ("mem0", NULL, NULL);
+ 
+ 	  if (! mem0)
+ 	    error ("The return value is stored in memory at 'mem0', "
+ 		   "but GDB cannot find\n"
+ 		   " its address.");
+ 	  write_memory (SYMBOL_VALUE_ADDRESS (mem0),
+                         (char *) writebuf, valtype_len);
+ 	}
+     }
+ 
+   return conv;
+ }
+ 
+ 
+ 
+ /* Trampolines.  */
+ 
+ /* The m16c and m32c use a trampoline function for indirect function
+    calls.  An indirect call looks like this:
+ 
+ 	     ... push arguments ...
+ 	     ... push target function address ...
+ 	     jsr.a m32c_jsri16
+ 
+    The code for m32c_jsri16 looks like this:
+ 
+      m32c_jsri16:
+ 
+              # Save return address.
+ 	     pop.w	m32c_jsri_ret
+ 	     pop.b	m32c_jsri_ret+2
+ 
+              # Store target function address.
+ 	     pop.w	m32c_jsri_addr
+ 
+ 	     # Re-push return address.
+ 	     push.b	m32c_jsri_ret+2
+ 	     push.w	m32c_jsri_ret
+ 
+ 	     # Call the target function.
+ 	     jmpi.a	m32c_jsri_addr
+ 
+    Without further information, GDB will treat calls to m32c_jsri16
+    like calls to any other function.  Since m32c_jsri16 doesn't have
+    debugging information, that normally means that GDB sets a step-
+    resume breakpoint and lets the program continue --- which is not
+    what the user wanted.  (Giving the trampoline debugging info
+    doesn't help: the user expects the program to stop in the function
+    their program is calling, not in some trampoline code they've never
+    seen before.)
+ 
+    The SKIP_TRAMPOLINE_CODE gdbarch method tells GDB how to step
+    through such trampoline functions transparently to the user.  When
+    given the address of a trampoline function's first instruction,
+    SKIP_TRAMPOLINE_CODE should return the address of the first
+    instruction of the function really being called.  If GDB decides it
+    wants to step into that function, it will set a breakpoint there
+    and silently continue to it.
+ 
+    We recognize the trampoline by name, and extract the target address
+    directly from the stack.  This isn't great, but recognizing by its
+    code sequence seems more fragile.  */
+ 
+ static CORE_ADDR
+ m32c_skip_trampoline_code (CORE_ADDR stop_pc)
+ {
+   struct gdbarch_tdep *tdep = gdbarch_tdep (current_gdbarch);
+ 
+   /* It would be nicer to simply look up the addresses of known
+      trampolines once, and then compare stop_pc with them.  However,
+      we'd need to ensure that that cached address got invalidated when
+      someone loaded a new executable, and I'm not quite sure of the
+      best way to do that.  find_pc_partial_function does do some
+      caching, so we'll see how this goes.  */
+   char *name;
+   CORE_ADDR start, end;
+ 
+   if (find_pc_partial_function (stop_pc, &name, &start, &end))
+     {
+       /* Are we stopped at the beginning of the trampoline function?  */
+       if (strcmp (name, "m32c_jsri16") == 0
+ 	  && stop_pc == start)
+ 	{
+ 	  /* Get the stack pointer.  The return address is at the top,
+ 	     and the target function's address is just below that.  We
+ 	     know it's a two-byte address, since the trampoline is
+ 	     m32c_jsri*16*.  */
+ 	  CORE_ADDR sp = get_frame_sp (get_current_frame ());
+ 	  CORE_ADDR target
+ 	    = read_memory_unsigned_integer (sp + tdep->ret_addr_bytes, 2);
+ 
+ 	  /* What we have now is the address of a jump instruction.
+ 	     What we need is the destination of that jump.
+ 	     The opcode is 1 byte, and the destination is the next 3 bytes.
+ 	  */
+ 	  target = read_memory_unsigned_integer (target + 1, 3);
+ 	  return target;
+ 	}
+     }
+ 
+   return 0;
+ }
+ 
+ 
+ /* Address/pointer conversions.  */
+ 
+ /* On the m16c, there is a 24-bit address space, but only a very few
+    instructions can generate addresses larger than 0xffff: jumps,
+    jumps to subroutines, and the lde/std (load/store extended)
+    instructions.
+ 
+    Since GCC can only support one size of pointer, we can't have
+    distinct 'near' and 'far' pointer types; we have to pick one size
+    for everything.  If we wanted to use 24-bit pointers, then GCC
+    would have to use lde and ste for all memory references, which
+    would be terrible for performance and code size.  So the GNU
+    toolchain uses 16-bit pointers for everything, and gives up the
+    ability to have pointers point outside the first 64k of memory.
+ 
+    However, as a special hack, we let the linker place functions at
+    addresses above 0xffff, as long as it also places a trampoline in
+    the low 64k for every function whose address is taken.  Each
+    trampoline consists of a single jmp.a instruction that jumps to the
+    function's real entry point.  Pointers to functions can be 16 bits
+    long, even though the functions themselves are at higher addresses:
+    the pointers refer to the trampolines, not the functions.
+ 
+    This complicates things for GDB, however: given the address of a
+    function (from debug info or linker symbols, say) which could be
+    anywhere in the 24-bit address space, how can we find an
+    appropriate 16-bit value to use as a pointer to it?
+ 
+    If the linker has not generated a trampoline for the function,
+    we're out of luck.  Well, I guess we could malloc some space and
+    write a jmp.a instruction to it, but I'm not going to get into that
+    at the moment.
+ 
+    If the linker has generated a trampoline for the function, then it
+    also emitted a symbol for the trampoline: if the function's linker
+    symbol is named NAME, then the function's trampoline's linker
+    symbol is named NAME.plt.
+ 
+    So, given a code address:
+    - We try to find a linker symbol at that address.
+    - If we find such a symbol named NAME, we look for a linker symbol
+      named NAME.plt.
+    - If we find such a symbol, we assume it is a trampoline, and use
+      its address as the pointer value.
+ 
+    And, given a function pointer:
+    - We try to find a linker symbol at that address named NAME.plt.
+    - If we find such a symbol, we look for a linker symbol named NAME.
+    - If we find that, we provide that as the function's address.
+    - If any of the above steps fail, we return the original address
+      unchanged; it might really be a function in the low 64k.
+ 
+    See?  You *knew* there was a reason you wanted to be a computer
+    programmer!  :)  */
+ 
+ static void
+ m32c_m16c_address_to_pointer (struct type *type, gdb_byte *buf, CORE_ADDR addr)
+ {
+   gdb_assert (TYPE_CODE (type) == TYPE_CODE_PTR);
+ 
+   enum type_code target_code = TYPE_CODE (TYPE_TARGET_TYPE (type));
+ 
+   if (target_code == TYPE_CODE_FUNC || target_code == TYPE_CODE_METHOD)
+     {
+       /* Try to find a linker symbol at this address.  */
+       struct minimal_symbol *func_msym = lookup_minimal_symbol_by_pc (addr);
+ 
+       if (! func_msym)
+         error ("Cannot convert code address %s to function pointer:\n"
+                "couldn't find a symbol at that address, to find trampoline.",
+                paddr_nz (addr));
+ 
+       char *func_name = SYMBOL_LINKAGE_NAME (func_msym);
+       char *tramp_name = xmalloc (strlen (func_name) + 5);
+       strcpy (tramp_name, func_name);
+       strcat (tramp_name, ".plt");
+ 
+       /* Try to find a linker symbol for the trampoline.  */
+       struct minimal_symbol *tramp_msym
+         = lookup_minimal_symbol (tramp_name, NULL, NULL);
+ 
+       /* We've either got another copy of the name now, or don't need
+          the name any more.  */
+       xfree (tramp_name);
+ 
+       if (! tramp_msym)
+         error ("Cannot convert code address %s to function pointer:\n"
+                "couldn't find trampoline named '%s.plt'.",
+                paddr_nz (addr), func_name);
+ 
+       /* The trampoline's address is our pointer.  */
+       addr = SYMBOL_VALUE_ADDRESS (tramp_msym);
+     }
+ 
+   store_unsigned_integer (buf, TYPE_LENGTH (type), addr);
+ }
+ 
+ 
+ static CORE_ADDR
+ m32c_m16c_pointer_to_address (struct type *type, const gdb_byte *buf)
+ {
+   gdb_assert (TYPE_CODE (type) == TYPE_CODE_PTR);
+ 
+   CORE_ADDR ptr = extract_unsigned_integer (buf, TYPE_LENGTH (type));
+ 
+   enum type_code target_code = TYPE_CODE (TYPE_TARGET_TYPE (type));
+ 
+   if (target_code == TYPE_CODE_FUNC || target_code == TYPE_CODE_METHOD)
+     {
+       /* See if there is a minimal symbol at that address whose name is
+          "NAME.plt".  */
+       struct minimal_symbol *ptr_msym = lookup_minimal_symbol_by_pc (ptr);
+ 
+       if (ptr_msym)
+         {
+           char *ptr_msym_name = SYMBOL_LINKAGE_NAME (ptr_msym);
+           int len = strlen (ptr_msym_name);
+ 
+           if (len > 4
+               && strcmp (ptr_msym_name + len - 4, ".plt") == 0)
+             {
+               /* We have a .plt symbol; try to find the symbol for the
+                  corresponding function.
+ 
+                  Since the trampoline contains a jump instruction, we
+                  could also just extract the jump's target address.  I
+                  don't see much advantage one way or the other.  */
+               char *func_name = xmalloc (len - 4 + 1);
+               memcpy (func_name, ptr_msym_name, len - 4);
+               func_name[len - 4] = '\0';
+               struct minimal_symbol *func_msym
+                 = lookup_minimal_symbol (func_name, NULL, NULL);
+ 
+               /* If we do have such a symbol, return its value as the
+                  function's true address.  */
+               if (func_msym)
+                 ptr = SYMBOL_VALUE_ADDRESS (func_msym);
+             }
+         }
+     }
+ 
+   return ptr;
+ }
+ 
+ 
+ 
+ /* Initialization.  */
+ 
+ static struct gdbarch *
+ m32c_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
+ {
+   struct gdbarch *arch;
+   struct gdbarch_tdep *tdep;
+   unsigned long mach = info.bfd_arch_info->mach;
+ 
+   /* Find a candidate among the list of architectures we've created
+      already.  */
+   for (arches = gdbarch_list_lookup_by_info (arches, &info);
+        arches != NULL;
+        arches = gdbarch_list_lookup_by_info (arches->next, &info))
+     return arches->gdbarch;
+ 
+   tdep = xcalloc (1, sizeof (*tdep));
+   arch = gdbarch_alloc (&info, tdep);
+ 
+   /* Essential types.  */
+   make_types (arch);
+ 
+   /* Address/pointer conversions.  */
+   if (mach == bfd_mach_m16c)
+     {
+       set_gdbarch_address_to_pointer (arch, m32c_m16c_address_to_pointer);
+       set_gdbarch_pointer_to_address (arch, m32c_m16c_pointer_to_address);
+     }
+ 
+   /* Register set.  */
+   make_regs (arch);
+ 
+   /* Disassembly.  */
+   set_gdbarch_print_insn (arch, print_insn_m32c);
+ 
+   /* Breakpoints.  */
+   set_gdbarch_breakpoint_from_pc (arch, m32c_breakpoint_from_pc);
+ 
+   /* Prologue analysis and unwinding.  */
+   set_gdbarch_inner_than (arch, core_addr_lessthan);
+   set_gdbarch_skip_prologue (arch, m32c_skip_prologue);
+   set_gdbarch_unwind_pc (arch, m32c_unwind_pc);
+   set_gdbarch_unwind_sp (arch, m32c_unwind_sp);
+ #if 0
+   /* I'm dropping the dwarf2 sniffer because it has a few problems.
+      They may be in the dwarf2 cfi code in GDB, or they may be in
+      the debug info emitted by the upstream toolchain.  I don't 
+      know which, but I do know that the prologue analyzer works better.
+      MVS 04/13/06
+   */
+   frame_unwind_append_sniffer (arch, dwarf2_frame_sniffer);
+ #endif
+   frame_unwind_append_sniffer (arch, m32c_frame_sniffer);
+ 
+   /* Inferior calls.  */
+   set_gdbarch_push_dummy_call (arch, m32c_push_dummy_call);
+   set_gdbarch_return_value (arch, m32c_return_value);
+   set_gdbarch_unwind_dummy_id (arch, m32c_unwind_dummy_id);
+ 
+   /* Trampolines.  */
+   set_gdbarch_skip_trampoline_code (arch, m32c_skip_trampoline_code);
+ 
+   return arch;
+ }
+ 
+ 
+ void
+ _initialize_m32c_tdep (void)
+ {
+   register_gdbarch_init (bfd_arch_m32c, m32c_gdbarch_init);
+ 
+   m32c_dma_reggroup = reggroup_new ("dma", USER_REGGROUP);
+ }
Index: config/m32c/m32c.mt
===================================================================
RCS file: config/m32c/m32c.mt
diff -N config/m32c/m32c.mt
*** /dev/null	1 Jan 1970 00:00:00 -0000
--- config/m32c/m32c.mt	13 Apr 2006 19:41:13 -0000
***************
*** 0 ****
--- 1,7 ----
+ # Target: Renesas M32C family
+ TDEPFILES = m32c-tdep.o prologue-value.o
+ 
+ # There may also be a SID / CGEN simulator for this, but we do have DJ
+ # Delorie's mini-sim.
+ SIM_OBS = remote-sim.o
+ SIM = ../sim/m32c/libsim.a
Index: testsuite/gdb.asm/asm-source.exp
===================================================================
RCS file: /cvs/src/src/gdb/testsuite/gdb.asm/asm-source.exp,v
retrieving revision 1.61
diff -p -r1.61 asm-source.exp
*** testsuite/gdb.asm/asm-source.exp	12 Jan 2006 00:51:45 -0000	1.61
--- testsuite/gdb.asm/asm-source.exp	13 Apr 2006 19:41:13 -0000
*************** switch -glob -- [istarget] {
*** 73,78 ****
--- 73,81 ----
      "m32r*-linux*" {
          set asm-arch m32r-linux
      }
+     "m32c-*-*" {
+         set asm-arch m32c
+     }
      "m32r*-*" {
          set asm-arch m32r
          append link-flags "--whole-archive -lgloss --no-whole-archive"
Index: testsuite/gdb.asm/m32c.inc
===================================================================
RCS file: testsuite/gdb.asm/m32c.inc
diff -N testsuite/gdb.asm/m32c.inc
*** /dev/null	1 Jan 1970 00:00:00 -0000
--- testsuite/gdb.asm/m32c.inc	13 Apr 2006 19:41:13 -0000
***************
*** 0 ****
--- 1,33 ----
+ 	comment "subroutine prologue"
+ 	.macro gdbasm_enter
+ 	enter #0
+ 	.endm
+ 
+ 	comment "subroutine epilogue"
+ 	.macro gdbasm_leave
+ 	exitd
+ 	.endm
+ 
+ 	.macro gdbasm_call subr
+ 	jsr.a \subr
+ 	.endm
+ 
+ 	.macro gdbasm_several_nops
+ 	nop
+ 	nop
+ 	nop
+ 	nop
+ 	.endm
+ 
+ 	comment "exit (0)"
+ 	.macro gdbasm_exit0
+ 	mov.w #0, r1
+        	mov.b #1, r0l
+ 	ste.b r0l,0xe0000
+ 	.endm
+ 
+ 	comment "crt0 startup"
+ 	.macro gdbasm_startup
+      	ldc #0xfc00, sp
+ 	.endm
+ 

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