Add support for new target 'csky'.

2018-08-28  Jiangshuai Li  <jiangshuai_li@c-sky.com>
	    Hafiz Abid Qadeer  <abidh@codesourcery.com>
	    Don Breazeal  <donb@codesourcery.com>

	* csky-linux-tdep.c: New file.
	* csky-tdep.c: Likewise.
	* csky-tdep.h: Likewise.
	* Makefile.in (ALL_TARGET_OBS): Add csky-linux-tdep.o and
	csky-tdep.o.
	(HFILES_NO_SRCDIR): Add csky-tdep.h.
	(ALLDEPFILES): Add csky-linux-tdep.c and csky-tdep.c
	* configure.tgt: Add csky support.

1 files changed, 2295 insertions, 0 deletions

diff --git a/gdb/csky-tdep.c b/gdb/csky-tdep.c
new file mode 100644
index 0000000..997ca93
--- /dev/null
+++ b/gdb/csky-tdep.c
@@ -0,0 +1,2295 @@
+/* Target-dependent code for the CSKY architecture, for GDB.
+
+   Copyright (C) 2010-2018 Free Software Foundation, Inc.
+
+   Contributed by C-SKY Microsystems and Mentor Graphics.
+
+   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 3 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, see <http://www.gnu.org/licenses/>.  */
+
+#include "defs.h"
+#include "gdb_assert.h"
+#include "frame.h"
+#include "inferior.h"
+#include "symtab.h"
+#include "value.h"
+#include "gdbcmd.h"
+#include "language.h"
+#include "gdbcore.h"
+#include "symfile.h"
+#include "objfiles.h"
+#include "gdbtypes.h"
+#include "target.h"
+#include "arch-utils.h"
+#include "regcache.h"
+#include "osabi.h"
+#include "block.h"
+#include "reggroups.h"
+#include "elf/csky.h"
+#include "elf-bfd.h"
+#include "symcat.h"
+#include "sim-regno.h"
+#include "dis-asm.h"
+#include "frame-unwind.h"
+#include "frame-base.h"
+#include "trad-frame.h"
+#include "infcall.h"
+#include "floatformat.h"
+#include "remote.h"
+#include "target-descriptions.h"
+#include "dwarf2-frame.h"
+#include "user-regs.h"
+#include "valprint.h"
+#include "reggroups.h"
+#include "csky-tdep.h"
+#include "regset.h"
+#include "block.h"
+#include "opcode/csky.h"
+#include <algorithm>
+#include <vector>
+
+/* Control debugging information emitted in this file.  */
+static int csky_debug = 0;
+
+static struct reggroup *cr_reggroup;
+static struct reggroup *fr_reggroup;
+static struct reggroup *vr_reggroup;
+static struct reggroup *mmu_reggroup;
+static struct reggroup *prof_reggroup;
+
+/* Convenience function to print debug messages in prologue analysis.  */
+
+static void
+print_savedreg_msg (int regno, int offsets[], bool print_continuing)
+{
+  fprintf_unfiltered (gdb_stdlog, "csky: r%d saved at offset 0x%x\n",
+		      regno, offsets[regno]);
+  if (print_continuing)
+    fprintf_unfiltered (gdb_stdlog, "csky: continuing\n");
+}
+
+/*  Check whether the instruction at ADDR is 16-bit or not.  */
+
+static int
+csky_pc_is_csky16 (struct gdbarch *gdbarch, CORE_ADDR addr)
+{
+  gdb_byte target_mem[2];
+  int status;
+  unsigned int insn;
+  int ret = 1;
+  enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
+
+  status = target_read_memory (addr, target_mem, 2);
+  /* Assume a 16-bit instruction if we can't read memory.  */
+  if (status)
+    return 1;
+
+  /* Get instruction from memory.  */
+  insn = extract_unsigned_integer (target_mem, 2, byte_order);
+  if ((insn & CSKY_32_INSN_MASK) == CSKY_32_INSN_MASK)
+    ret = 0;
+  else if (insn == CSKY_BKPT_INSN)
+    {
+      /* Check for 32-bit bkpt instruction which is all 0.  */
+      status = target_read_memory (addr + 2, target_mem, 2);
+      if (status)
+	return 1;
+
+      insn = extract_unsigned_integer (target_mem, 2, byte_order);
+      if (insn == CSKY_BKPT_INSN)
+	ret = 0;
+    }
+  return ret;
+}
+
+/* Get one instruction at ADDR and store it in INSN.  Return 2 for
+   a 16-bit instruction or 4 for a 32-bit instruction.  */
+
+static int
+csky_get_insn (struct gdbarch *gdbarch, CORE_ADDR addr, unsigned int *insn)
+{
+  gdb_byte target_mem[2];
+  unsigned int insn_type;
+  int status;
+  int insn_len = 2;
+  enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
+
+  status = target_read_memory (addr, target_mem, 2);
+  if (status)
+    memory_error (TARGET_XFER_E_IO, addr);
+
+  insn_type = extract_unsigned_integer (target_mem, 2, byte_order);
+  if (CSKY_32_INSN_MASK == (insn_type & CSKY_32_INSN_MASK))
+    {
+      status = target_read_memory (addr + 2, target_mem, 2);
+      if (status)
+	memory_error (TARGET_XFER_E_IO, addr);
+      insn_type = ((insn_type << 16)
+		   | extract_unsigned_integer (target_mem, 2, byte_order));
+      insn_len = 4;
+    }
+  *insn = insn_type;
+  return insn_len;
+}
+
+/* Implement the read_pc gdbarch method.  */
+
+static CORE_ADDR
+csky_read_pc (readable_regcache *regcache)
+{
+  ULONGEST pc;
+  regcache->cooked_read (CSKY_PC_REGNUM, &pc);
+  return pc;
+}
+
+/* Implement the write_pc gdbarch method.  */
+
+static void
+csky_write_pc (regcache *regcache, CORE_ADDR val)
+{
+  regcache_cooked_write_unsigned (regcache, CSKY_PC_REGNUM, val);
+}
+
+/* Implement the unwind_sp gdbarch method.  */
+
+static CORE_ADDR
+csky_unwind_sp (struct gdbarch *gdbarch, struct frame_info *next_frame)
+{
+  return frame_unwind_register_unsigned (next_frame, CSKY_SP_REGNUM);
+}
+
+/* C-Sky ABI register names.  */
+
+static const char *csky_register_names[] =
+{
+  /* General registers 0 - 31.  */
+  "r0",  "r1",  "r2",  "r3",  "r4",  "r5",  "r6",  "r7",
+  "r8",  "r9",  "r10", "r11", "r12", "r13", "r14", "r15",
+  "r16", "r17", "r18", "r19", "r20", "r21", "r22", "r23",
+  "r24", "r25", "r26", "r27", "r28", "r29", "r30", "r31",
+
+  /* DSP hilo registers 36 and 37.  */
+  "",      "",    "",     "",     "hi",    "lo",   "",    "",
+
+  /* FPU/VPU general registers 40 - 71.  */
+  "fr0", "fr1", "fr2",  "fr3",  "fr4",  "fr5",  "fr6",  "fr7",
+  "fr8", "fr9", "fr10", "fr11", "fr12", "fr13", "fr14", "fr15",
+  "vr0", "vr1", "vr2",  "vr3",  "vr4",  "vr5",  "vr6",  "vr7",
+  "vr8", "vr9", "vr10", "vr11", "vr12", "vr13", "vr14", "vr15",
+
+  /* Program counter 72.  */
+  "pc",
+
+  /* Optional registers (ar) 73 - 88.  */
+  "ar0", "ar1", "ar2",  "ar3",  "ar4",  "ar5",  "ar6",  "ar7",
+  "ar8", "ar9", "ar10", "ar11", "ar12", "ar13", "ar14", "ar15",
+
+  /* Control registers (cr) 89 - 119.  */
+  "psr",  "vbr",  "epsr", "fpsr", "epc",  "fpc",  "ss0",  "ss1",
+  "ss2",  "ss3",  "ss4",  "gcr",  "gsr",  "cr13", "cr14", "cr15",
+  "cr16", "cr17", "cr18", "cr19", "cr20", "cr21", "cr22", "cr23",
+  "cr24", "cr25", "cr26", "cr27", "cr28", "cr29", "cr30", "cr31",
+
+  /* FPU/VPU control registers 121 ~ 123.  */
+  /* User sp 127.  */
+  "fid", "fcr", "fesr", "", "", "", "usp",
+
+  /* MMU control registers: 128 - 136.  */
+  "mcr0", "mcr2", "mcr3", "mcr4", "mcr6", "mcr8", "mcr29", "mcr30",
+  "mcr31", "", "", "",
+
+  /* Profiling control registers 140 - 143.  */
+  /* Profiling software general registers 144 - 157.  */
+  "profcr0",  "profcr1",  "profcr2",  "profcr3",  "profsgr0",  "profsgr1",
+  "profsgr2", "profsgr3", "profsgr4", "profsgr5", "profsgr6",  "profsgr7",
+  "profsgr8", "profsgr9", "profsgr10","profsgr11","profsgr12", "profsgr13",
+  "",	 "",
+
+  /* Profiling architecture general registers 160 - 174.  */
+  "profagr0", "profagr1", "profagr2", "profagr3", "profagr4", "profagr5",
+  "profagr6", "profagr7", "profagr8", "profagr9", "profagr10","profagr11",
+  "profagr12","profagr13","profagr14", "",
+
+  /* Profiling extension general registers 176 - 188.  */
+  "profxgr0", "profxgr1", "profxgr2", "profxgr3", "profxgr4", "profxgr5",
+  "profxgr6", "profxgr7", "profxgr8", "profxgr9", "profxgr10","profxgr11",
+  "profxgr12",
+
+  /* Control registers in bank1.  */
+  "", "", "", "", "", "", "", "",
+  "", "", "", "", "", "", "", "",
+  "cp1cr16", "cp1cr17", "cp1cr18", "cp1cr19", "cp1cr20", "", "", "",
+  "", "", "", "", "", "", "", "",
+
+  /* Control registers in bank3 (ICE).  */
+  "sepsr", "sevbr", "seepsr", "", "seepc", "", "nsssp", "seusp",
+  "sedcr", "", "", "", "", "", "", "",
+  "", "", "", "", "", "", "", "",
+  "", "", "", "", "", "", "", ""
+};
+
+/* Implement the register_name gdbarch method.  */
+
+static const char *
+csky_register_name (struct gdbarch *gdbarch, int reg_nr)
+{
+  if (tdesc_has_registers (gdbarch_target_desc (gdbarch)))
+    return tdesc_register_name (gdbarch, reg_nr);
+
+  if (reg_nr < 0)
+    return NULL;
+
+  if (reg_nr >= gdbarch_num_regs (gdbarch))
+    return NULL;
+
+  return csky_register_names[reg_nr];
+}
+
+/* Construct vector type for vrx registers.  */
+
+static struct type *
+csky_vector_type (struct gdbarch *gdbarch)
+{
+  const struct builtin_type *bt = builtin_type (gdbarch);
+
+  struct type *t;
+
+  t = arch_composite_type (gdbarch, "__gdb_builtin_type_vec128i",
+			   TYPE_CODE_UNION);
+
+  append_composite_type_field (t, "u32",
+			       init_vector_type (bt->builtin_int32, 4));
+  append_composite_type_field (t, "u16",
+			       init_vector_type (bt->builtin_int16, 8));
+  append_composite_type_field (t, "u8",
+			       init_vector_type (bt->builtin_int8, 16));
+
+  TYPE_VECTOR (t) = 1;
+  TYPE_NAME (t) = "builtin_type_vec128i";
+
+  return t;
+}
+
+/* Return the GDB type object for the "standard" data type
+   of data in register N.  */
+
+static struct type *
+csky_register_type (struct gdbarch *gdbarch, int reg_nr)
+{
+  /* PC, EPC, FPC is a text pointer.  */
+  if ((reg_nr == CSKY_PC_REGNUM)  || (reg_nr == CSKY_EPC_REGNUM)
+      || (reg_nr == CSKY_FPC_REGNUM))
+    return builtin_type (gdbarch)->builtin_func_ptr;
+
+  /* VBR is a data pointer.  */
+  if (reg_nr == CSKY_VBR_REGNUM)
+    return builtin_type (gdbarch)->builtin_data_ptr;
+
+  /* Float register has 64 bits, and only in ck810.  */
+  if ((reg_nr >=CSKY_FR0_REGNUM) && (reg_nr <= CSKY_FR0_REGNUM + 15))
+      return arch_float_type (gdbarch, 64, "builtin_type_csky_ext",
+			      floatformats_ieee_double);
+
+  /* Vector register has 128 bits, and only in ck810.  */
+  if ((reg_nr >= CSKY_VR0_REGNUM) && (reg_nr <= CSKY_VR0_REGNUM + 15))
+    return csky_vector_type (gdbarch);
+
+  /* Profiling general register has 48 bits, we use 64bit.  */
+  if ((reg_nr >= CSKY_PROFGR_REGNUM) && (reg_nr <= CSKY_PROFGR_REGNUM + 44))
+    return builtin_type (gdbarch)->builtin_uint64;
+
+  if (reg_nr == CSKY_SP_REGNUM)
+    return builtin_type (gdbarch)->builtin_data_ptr;
+
+  /* Others are 32 bits.  */
+  return builtin_type (gdbarch)->builtin_int32;
+}
+
+/* Data structure to marshall items in a dummy stack frame when
+   calling a function in the inferior.  */
+
+struct stack_item
+{
+  stack_item (int len_, const gdb_byte *data_)
+  : len (len_), data (data_)
+  {}
+
+  int len;
+  const gdb_byte *data;
+};
+
+/* Implement the push_dummy_call gdbarch method.  */
+
+static CORE_ADDR
+csky_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)
+{
+  int argnum;
+  int argreg = CSKY_ABI_A0_REGNUM;
+  int last_arg_regnum = CSKY_ABI_LAST_ARG_REGNUM;
+  int need_dummy_stack = 0;
+  enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
+  std::vector<stack_item> stack_items;
+
+  /* Set the return address.  For CSKY, the return breakpoint is
+     always at BP_ADDR.  */
+  regcache_cooked_write_unsigned (regcache, CSKY_LR_REGNUM, bp_addr);
+
+  /* The struct_return pointer occupies the first parameter
+     passing register.  */
+  if (struct_return)
+    {
+      if (csky_debug)
+	{
+	  fprintf_unfiltered (gdb_stdlog,
+			      "csky: struct return in %s = %s\n",
+			      gdbarch_register_name (gdbarch, argreg),
+			      paddress (gdbarch, struct_addr));
+	}
+      regcache_cooked_write_unsigned (regcache, argreg, struct_addr);
+      argreg++;
+    }
+
+  /* Put parameters into argument registers in REGCACHE.
+     In ABI argument registers are r0 through r3.  */
+  for (argnum = 0; argnum < nargs; argnum++)
+    {
+      int len;
+      struct type *arg_type;
+      const gdb_byte *val;
+
+      arg_type = check_typedef (value_type (args[argnum]));
+      len = TYPE_LENGTH (arg_type);
+      val = value_contents (args[argnum]);
+
+      /* Copy the argument to argument registers or the dummy stack.
+	 Large arguments are split between registers and stack.
+
+	 If len < 4, there is no need to worry about endianness since
+	 the arguments will always be stored in the low address.  */
+      if (len < 4)
+	{
+	  CORE_ADDR regval
+	    = extract_unsigned_integer (val, len, byte_order);
+	  regcache_cooked_write_unsigned (regcache, argreg, regval);
+	  argreg++;
+	}
+      else
+	{
+	  while (len > 0)
+	    {
+	      int partial_len = len < 4 ? len : 4;
+	      if (argreg <= last_arg_regnum)
+		{
+		  /* The argument is passed in an argument register.  */
+		  CORE_ADDR regval
+		    = extract_unsigned_integer (val, partial_len,
+						byte_order);
+		  if (byte_order == BFD_ENDIAN_BIG)
+		    regval <<= (4 - partial_len) * 8;
+
+		  /* Put regval into register in REGCACHE.  */
+		  regcache_cooked_write_unsigned (regcache, argreg,
+						  regval);
+		  argreg++;
+		}
+	      else
+		{
+		  /* The argument should be pushed onto the dummy stack.  */
+		  stack_items.emplace_back (4, val);
+		  need_dummy_stack += 4;
+		}
+	      len -= partial_len;
+	      val += partial_len;
+	    }
+	}
+    }
+
+  /* Transfer the dummy stack frame to the target.  */
+  std::vector<stack_item>::reverse_iterator iter;
+  for (iter = stack_items.rbegin (); iter != stack_items.rend (); ++iter)
+    {
+      sp -= iter->len;
+      write_memory (sp, iter->data, iter->len);
+    }
+
+  /* Finally, update the SP register.  */
+  regcache_cooked_write_unsigned (regcache, CSKY_SP_REGNUM, sp);
+  return sp;
+}
+
+/* Implement the return_value gdbarch method.  */
+
+static enum return_value_convention
+csky_return_value (struct gdbarch *gdbarch, struct value *function,
+		   struct type *valtype, struct regcache *regcache,
+		   gdb_byte *readbuf, const gdb_byte *writebuf)
+{
+  CORE_ADDR regval;
+  enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
+  int len = TYPE_LENGTH (valtype);
+  unsigned int ret_regnum = CSKY_RET_REGNUM;
+
+  /* Csky abi specifies that return values larger than 8 bytes
+     are put on the stack.  */
+  if (len > 8)
+    return RETURN_VALUE_STRUCT_CONVENTION;
+  else
+    {
+      if (readbuf != NULL)
+	{
+	  ULONGEST tmp;
+	  /* By using store_unsigned_integer we avoid having to do
+	     anything special for small big-endian values.  */
+	  regcache->cooked_read (ret_regnum, &tmp);
+	  store_unsigned_integer (readbuf, (len > 4 ? 4 : len),
+				  byte_order, tmp);
+	  if (len > 4)
+	    {
+	      regcache->cooked_read (ret_regnum + 1, &tmp);
+	      store_unsigned_integer (readbuf + 4,  4, byte_order, tmp);
+	    }
+	}
+      if (writebuf != NULL)
+	{
+	  regval = extract_unsigned_integer (writebuf, len > 4 ? 4 : len,
+					     byte_order);
+	  regcache_cooked_write_unsigned (regcache, ret_regnum, regval);
+	  if (len > 4)
+	    {
+	      regval = extract_unsigned_integer ((gdb_byte *) writebuf + 4,
+						 4, byte_order);
+	      regcache_cooked_write_unsigned (regcache, ret_regnum + 1,
+					      regval);
+	    }
+
+	}
+      return RETURN_VALUE_REGISTER_CONVENTION;
+    }
+}
+
+/* Implement the frame_align gdbarch method.
+
+   Adjust the address downward (direction of stack growth) so that it
+   is correctly aligned for a new stack frame.  */
+
+static CORE_ADDR
+csky_frame_align (struct gdbarch *gdbarch, CORE_ADDR addr)
+{
+  return align_down (addr, 4);
+}
+
+/* Unwind cache used for gdbarch fallback unwinder.  */
+
+struct csky_unwind_cache
+{
+  /* The stack pointer at the time this frame was created; i.e. the
+     caller's stack pointer when this function was called.  It is used
+     to identify this frame.  */
+  CORE_ADDR prev_sp;
+
+  /* The frame base for this frame is just prev_sp - frame size.
+     FRAMESIZE is the distance from the frame pointer to the
+     initial stack pointer.  */
+  int framesize;
+
+  /* The register used to hold the frame pointer for this frame.  */
+  int framereg;
+
+  /* Saved register offsets.  */
+  struct trad_frame_saved_reg *saved_regs;
+};
+
+/* Do prologue analysis, returning the PC of the first instruction
+   after the function prologue.  */
+
+static CORE_ADDR
+csky_analyze_prologue (struct gdbarch *gdbarch,
+		       CORE_ADDR start_pc,
+		       CORE_ADDR limit_pc,
+		       CORE_ADDR end_pc,
+		       struct frame_info *this_frame,
+		       struct csky_unwind_cache *this_cache,
+		       lr_type_t lr_type)
+{
+  CORE_ADDR addr;
+  unsigned int insn, rn;
+  int framesize = 0;
+  int stacksize = 0;
+  int register_offsets[CSKY_NUM_GREGS_SAVED_GREGS];
+  int insn_len;
+  /* For adjusting fp.  */
+  int is_fp_saved = 0;
+  int adjust_fp = 0;
+
+  /* REGISTER_OFFSETS will contain offsets from the top of the frame
+     (NOT the frame pointer) for the various saved registers, or -1
+     if the register is not saved.  */
+  for (rn = 0; rn < CSKY_NUM_GREGS_SAVED_GREGS; rn++)
+    register_offsets[rn] = -1;
+
+  /* Analyze the prologue.  Things we determine from analyzing the
+     prologue include the size of the frame and which registers are
+     saved (and where).  */
+  if (csky_debug)
+    {
+      fprintf_unfiltered (gdb_stdlog,
+			  "csky: Scanning prologue: start_pc = 0x%x,"
+			  "limit_pc = 0x%x\n", (unsigned int) start_pc,
+			  (unsigned int) limit_pc);
+    }
+
+  /* Default to 16 bit instruction.  */
+  insn_len = 2;
+  stacksize = 0;
+  for (addr = start_pc; addr < limit_pc; addr += insn_len)
+    {
+      /* Get next insn.  */
+      insn_len = csky_get_insn (gdbarch, addr, &insn);
+
+      /* Check if 32 bit.  */
+      if (insn_len == 4)
+	{
+	  /* subi32 sp,sp oimm12.  */
+	  if (CSKY_32_IS_SUBI0 (insn))
+	    {
+	      /* Got oimm12.  */
+	      int offset = CSKY_32_SUBI_IMM (insn);
+	      if (csky_debug)
+		{
+		  fprintf_unfiltered (gdb_stdlog,
+				      "csky: got subi sp,%d; continuing\n",
+				      offset);
+		}
+	      stacksize += offset;
+	      continue;
+	    }
+	  /* stm32 ry-rz,(sp).  */
+	  else if (CSKY_32_IS_STMx0 (insn))
+	    {
+	      /* Spill register(s).  */
+	      int start_register;
+	      int reg_count;
+	      int offset;
+
+	      /* BIG WARNING! The CKCore ABI does not restrict functions
+		 to taking only one stack allocation.  Therefore, when
+		 we save a register, we record the offset of where it was
+		 saved relative to the current stacksize.  This will
+		 then give an offset from the SP upon entry to our
+		 function.  Remember, stacksize is NOT constant until
+		 we're done scanning the prologue.  */
+	      start_register = CSKY_32_STM_VAL_REGNUM (insn);
+	      reg_count = CSKY_32_STM_SIZE (insn);
+	      if (csky_debug)
+		{
+		  fprintf_unfiltered (gdb_stdlog,
+				      "csky: got stm r%d-r%d,(sp)\n",
+				      start_register,
+				      start_register + reg_count);
+		}
+
+	      for (rn = start_register, offset = 0;
+		   rn <= start_register + reg_count;
+		   rn++, offset += 4)
+		{
+		  register_offsets[rn] = stacksize - offset;
+		  if (csky_debug)
+		    {
+		      fprintf_unfiltered (gdb_stdlog,
+					  "csky: r%d saved at 0x%x"
+					  " (offset %d)\n",
+					  rn, register_offsets[rn],
+					  offset);
+		    }
+		}
+	      if (csky_debug)
+		fprintf_unfiltered (gdb_stdlog, "csky: continuing\n");
+	      continue;
+	    }
+	  /* stw ry,(sp,disp).  */
+	  else if (CSKY_32_IS_STWx0 (insn))
+	    {
+	      /* Spill register: see note for IS_STM above.  */
+	      int disp;
+
+	      rn = CSKY_32_ST_VAL_REGNUM (insn);
+	      disp = CSKY_32_ST_OFFSET (insn);
+	      register_offsets[rn] = stacksize - disp;
+	      if (csky_debug)
+		print_savedreg_msg (rn, register_offsets, true);
+	      continue;
+	    }
+	  else if (CSKY_32_IS_MOV_FP_SP (insn))
+	    {
+	      /* SP is saved to FP reg, means code afer prologue may
+		 modify SP.  */
+	      is_fp_saved = 1;
+	      adjust_fp = stacksize;
+	      continue;
+	    }
+	  else if (CSKY_32_IS_MFCR_EPSR (insn))
+	    {
+	      unsigned int insn2;
+	      addr += 4;
+	      int mfcr_regnum = insn & 0x1f;
+	      insn_len = csky_get_insn (gdbarch, addr, &insn2);
+	      if (insn_len == 2)
+		{
+		  int stw_regnum = (insn2 >> 5) & 0x7;
+		  if (CSKY_16_IS_STWx0 (insn2) && (mfcr_regnum == stw_regnum))
+		    {
+		      int offset;
+
+		      /* CSKY_EPSR_REGNUM.  */
+		      rn  = CSKY_NUM_GREGS;
+		      offset = CSKY_16_STWx0_OFFSET (insn2);
+		      register_offsets[rn] = stacksize - offset;
+		      if (csky_debug)
+			print_savedreg_msg (rn, register_offsets, true);
+		      continue;
+		    }
+		  break;
+		}
+	      else
+		{
+		  /* INSN_LEN == 4.  */
+		  int stw_regnum = (insn2 >> 21) & 0x1f;
+		  if (CSKY_32_IS_STWx0 (insn2) && (mfcr_regnum == stw_regnum))
+		    {
+		      int offset;
+
+		      /* CSKY_EPSR_REGNUM.  */
+		      rn  = CSKY_NUM_GREGS;
+		      offset = CSKY_32_ST_OFFSET (insn2);
+		      register_offsets[rn] = framesize - offset;
+		      if (csky_debug)
+			print_savedreg_msg (rn, register_offsets, true);
+		      continue;
+		    }
+		  break;
+		}
+	    }
+	  else if (CSKY_32_IS_MFCR_FPSR (insn))
+	    {
+	      unsigned int insn2;
+	      addr += 4;
+	      int mfcr_regnum = insn & 0x1f;
+	      insn_len = csky_get_insn (gdbarch, addr, &insn2);
+	      if (insn_len == 2)
+		{
+		  int stw_regnum = (insn2 >> 5) & 0x7;
+		  if (CSKY_16_IS_STWx0 (insn2) && (mfcr_regnum
+						 == stw_regnum))
+		    {
+		      int offset;
+
+		      /* CSKY_FPSR_REGNUM.  */
+		      rn  = CSKY_NUM_GREGS + 1;
+		      offset = CSKY_16_STWx0_OFFSET (insn2);
+		      register_offsets[rn] = stacksize - offset;
+		      if (csky_debug)
+			print_savedreg_msg (rn, register_offsets, true);
+		      continue;
+		    }
+		  break;
+		}
+	      else
+		{
+		  /* INSN_LEN == 4.  */
+		  int stw_regnum = (insn2 >> 21) & 0x1f;
+		  if (CSKY_32_IS_STWx0 (insn2) && (mfcr_regnum == stw_regnum))
+		    {
+		      int offset;
+
+		      /* CSKY_FPSR_REGNUM.  */
+		      rn  = CSKY_NUM_GREGS + 1;
+		      offset = CSKY_32_ST_OFFSET (insn2);
+		      register_offsets[rn] = framesize - offset;
+		      if (csky_debug)
+			print_savedreg_msg (rn, register_offsets, true);
+		      continue;
+		    }
+		  break;
+		}
+	    }
+	  else if (CSKY_32_IS_MFCR_EPC (insn))
+	    {
+	      unsigned int insn2;
+	      addr += 4;
+	      int mfcr_regnum = insn & 0x1f;
+	      insn_len = csky_get_insn (gdbarch, addr, &insn2);
+	      if (insn_len == 2)
+		{
+		  int stw_regnum = (insn2 >> 5) & 0x7;
+		  if (CSKY_16_IS_STWx0 (insn2) && (mfcr_regnum == stw_regnum))
+		    {
+		      int offset;
+
+		      /* CSKY_EPC_REGNUM.  */
+		      rn  = CSKY_NUM_GREGS + 2;
+		      offset = CSKY_16_STWx0_OFFSET (insn2);
+		      register_offsets[rn] = stacksize - offset;
+		      if (csky_debug)
+			print_savedreg_msg (rn, register_offsets, true);
+		      continue;
+		    }
+		  break;
+		}
+	      else
+		{
+		  /* INSN_LEN == 4.  */
+		  int stw_regnum = (insn2 >> 21) & 0x1f;
+		  if (CSKY_32_IS_STWx0 (insn2) && (mfcr_regnum == stw_regnum))
+		    {
+		      int offset;
+
+		      /* CSKY_EPC_REGNUM.  */
+		      rn  = CSKY_NUM_GREGS + 2;
+		      offset = CSKY_32_ST_OFFSET (insn2);
+		      register_offsets[rn] = framesize - offset;
+		      if (csky_debug)
+			print_savedreg_msg (rn, register_offsets, true);
+		      continue;
+		    }
+		  break;
+		}
+	    }
+	  else if (CSKY_32_IS_MFCR_FPC (insn))
+	    {
+	      unsigned int insn2;
+	      addr += 4;
+	      int mfcr_regnum = insn & 0x1f;
+	      insn_len = csky_get_insn (gdbarch, addr, &insn2);
+	      if (insn_len == 2)
+		{
+		  int stw_regnum = (insn2 >> 5) & 0x7;
+		  if (CSKY_16_IS_STWx0 (insn2) && (mfcr_regnum == stw_regnum))
+		    {
+		      int offset;
+
+		      /* CSKY_FPC_REGNUM.  */
+		      rn  = CSKY_NUM_GREGS + 3;
+		      offset = CSKY_16_STWx0_OFFSET (insn2);
+		      register_offsets[rn] = stacksize - offset;
+		      if (csky_debug)
+			print_savedreg_msg (rn, register_offsets, true);
+		      continue;
+		    }
+		  break;
+		}
+	      else
+		{
+		  /* INSN_LEN == 4.  */
+		  int stw_regnum = (insn2 >> 21) & 0x1f;
+		  if (CSKY_32_IS_STWx0 (insn2) && (mfcr_regnum == stw_regnum))
+		    {
+		      int offset;
+
+		      /* CSKY_FPC_REGNUM.  */
+		      rn  = CSKY_NUM_GREGS + 3;
+		      offset = CSKY_32_ST_OFFSET (insn2);
+		      register_offsets[rn] = framesize - offset;
+		      if (csky_debug)
+			print_savedreg_msg (rn, register_offsets, true);
+		      continue;
+		    }
+		  break;
+		}
+	    }
+	  else if (CSKY_32_IS_PUSH (insn))
+	    {
+	      /* Push for 32_bit.  */
+	      int offset = 0;
+	      if (CSKY_32_IS_PUSH_R29 (insn))
+		{
+		  stacksize += 4;
+		  register_offsets[29] = stacksize;
+		  if (csky_debug)
+		    print_savedreg_msg (29, register_offsets, false);
+		  offset += 4;
+		}
+	      if (CSKY_32_PUSH_LIST2 (insn))
+		{
+		  int num = CSKY_32_PUSH_LIST2 (insn);
+		  int tmp = 0;
+		  stacksize += num * 4;
+		  offset += num * 4;
+		  if (csky_debug)
+		    {
+		      fprintf_unfiltered (gdb_stdlog,
+					  "csky: push regs_array: r16-r%d\n",
+					  16 + num - 1);
+		    }
+		  for (rn = 16; rn <= 16 + num - 1; rn++)
+		    {
+		       register_offsets[rn] = stacksize - tmp;
+		       if (csky_debug)
+			 {
+			   fprintf_unfiltered (gdb_stdlog,
+					       "csky: r%d saved at 0x%x"
+					       " (offset %d)\n", rn,
+					       register_offsets[rn], tmp);
+			 }
+		       tmp += 4;
+		    }
+		}
+	      if (CSKY_32_IS_PUSH_R15 (insn))
+		{
+		  stacksize += 4;
+		  register_offsets[15] = stacksize;
+		  if (csky_debug)
+		    print_savedreg_msg (15, register_offsets, false);
+		  offset += 4;
+		}
+	      if (CSKY_32_PUSH_LIST1 (insn))
+		{
+		  int num = CSKY_32_PUSH_LIST1 (insn);
+		  int tmp = 0;
+		  stacksize += num * 4;
+		  offset += num * 4;
+		  if (csky_debug)
+		    {
+		      fprintf_unfiltered (gdb_stdlog,
+					  "csky: push regs_array: r4-r%d\n",
+					  4 + num - 1);
+		    }
+		  for (rn = 4; rn <= 4 + num - 1; rn++)
+		    {
+		       register_offsets[rn] = stacksize - tmp;
+		       if (csky_debug)
+			 {
+			   fprintf_unfiltered (gdb_stdlog,
+					       "csky: r%d saved at 0x%x"
+					       " (offset %d)\n", rn,
+					       register_offsets[rn], tmp);
+			 }
+			tmp += 4;
+		    }
+		}
+
+	      framesize = stacksize;
+	      if (csky_debug)
+		fprintf_unfiltered (gdb_stdlog, "csky: continuing\n");
+	      continue;
+	    }
+	  else if (CSKY_32_IS_LRW4 (insn) || CSKY_32_IS_MOVI4 (insn)
+		   || CSKY_32_IS_MOVIH4 (insn) || CSKY_32_IS_BMASKI4 (insn))
+	    {
+	      int adjust = 0;
+	      int offset = 0;
+	      unsigned int insn2;
+
+	      if (csky_debug)
+		{
+		  fprintf_unfiltered (gdb_stdlog,
+				      "csky: looking at large frame\n");
+		}
+	      if (CSKY_32_IS_LRW4 (insn))
+		{
+		  enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
+		  int literal_addr = (addr + ((insn & 0xffff) << 2))
+				     & 0xfffffffc;
+		  adjust = read_memory_unsigned_integer (literal_addr, 4,
+							 byte_order);
+		}
+	      else if (CSKY_32_IS_MOVI4 (insn))
+		adjust = (insn  & 0xffff);
+	      else if (CSKY_32_IS_MOVIH4 (insn))
+		adjust = (insn & 0xffff) << 16;
+	      else
+		{
+		  /* CSKY_32_IS_BMASKI4 (insn).  */
+		  adjust = (1 << (((insn & 0x3e00000) >> 21) + 1)) - 1;
+		}
+
+	      if (csky_debug)
+		{
+		  fprintf_unfiltered (gdb_stdlog,
+				      "csky: base stacksize=0x%x\n", adjust);
+
+		  /* May have zero or more insns which modify r4.  */
+		  fprintf_unfiltered (gdb_stdlog,
+				      "csky: looking for r4 adjusters...\n");
+		}
+
+	      offset = 4;
+	      insn_len = csky_get_insn (gdbarch, addr + offset, &insn2);
+	      while (CSKY_IS_R4_ADJUSTER (insn2))
+		{
+		  if (CSKY_32_IS_ADDI4 (insn2))
+		    {
+		      int imm = (insn2 & 0xfff) + 1;
+		      adjust += imm;
+		      if (csky_debug)
+			{
+			  fprintf_unfiltered (gdb_stdlog,
+					      "csky: addi r4,%d\n", imm);
+			}
+		    }
+		  else if (CSKY_32_IS_SUBI4 (insn2))
+		    {
+		      int imm = (insn2 & 0xfff) + 1;
+		      adjust -= imm;
+		      if (csky_debug)
+			{
+			  fprintf_unfiltered (gdb_stdlog,
+					      "csky: subi r4,%d\n", imm);
+			}
+		    }
+		  else if (CSKY_32_IS_NOR4 (insn2))
+		    {
+		      adjust = ~adjust;
+		      if (csky_debug)
+			{
+			  fprintf_unfiltered (gdb_stdlog,
+					      "csky: nor r4,r4,r4\n");
+			}
+		    }
+		  else if (CSKY_32_IS_ROTLI4 (insn2))
+		    {
+		      int imm = ((insn2 >> 21) & 0x1f);
+		      int temp = adjust >> (32 - imm);
+		      adjust <<= imm;
+		      adjust |= temp;
+		      if (csky_debug)
+			{
+			  fprintf_unfiltered (gdb_stdlog,
+					      "csky: rotli r4,r4,%d\n", imm);
+			}
+		    }
+		  else if (CSKY_32_IS_LISI4 (insn2))
+		    {
+		      int imm = ((insn2 >> 21) & 0x1f);
+		      adjust <<= imm;
+		      if (csky_debug)
+			{
+			  fprintf_unfiltered (gdb_stdlog,
+					      "csky: lsli r4,r4,%d\n", imm);
+			}
+		    }
+		  else if (CSKY_32_IS_BSETI4 (insn2))
+		    {
+		      int imm = ((insn2 >> 21) & 0x1f);
+		      adjust |= (1 << imm);
+		      if (csky_debug)
+			{
+			  fprintf_unfiltered (gdb_stdlog,
+					      "csky: bseti r4,r4 %d\n", imm);
+			}
+		    }
+		  else if (CSKY_32_IS_BCLRI4 (insn2))
+		    {
+		      int imm = ((insn2 >> 21) & 0x1f);
+		      adjust &= ~(1 << imm);
+		      if (csky_debug)
+			{
+			  fprintf_unfiltered (gdb_stdlog,
+					      "csky: bclri r4,r4 %d\n", imm);
+			}
+		    }
+		  else if (CSKY_32_IS_IXH4 (insn2))
+		    {
+		      adjust *= 3;
+		      if (csky_debug)
+			{
+			  fprintf_unfiltered (gdb_stdlog,
+					      "csky: ixh r4,r4,r4\n");
+			}
+		    }
+		  else if (CSKY_32_IS_IXW4 (insn2))
+		    {
+		      adjust *= 5;
+		      if (csky_debug)
+			{
+			  fprintf_unfiltered (gdb_stdlog,
+					      "csky: ixw r4,r4,r4\n");
+			}
+		    }
+		  else if (CSKY_16_IS_ADDI4 (insn2))
+		    {
+		      int imm = (insn2 & 0xff) + 1;
+		      adjust += imm;
+		      if (csky_debug)
+			{
+			  fprintf_unfiltered (gdb_stdlog,
+					      "csky: addi r4,%d\n", imm);
+			}
+		    }
+		  else if (CSKY_16_IS_SUBI4 (insn2))
+		    {
+		      int imm = (insn2 & 0xff) + 1;
+		      adjust -= imm;
+		      if (csky_debug)
+			{
+			  fprintf_unfiltered (gdb_stdlog,
+					      "csky: subi r4,%d\n", imm);
+			}
+		    }
+		  else if (CSKY_16_IS_NOR4 (insn2))
+		    {
+		      adjust = ~adjust;
+		      if (csky_debug)
+			{
+			  fprintf_unfiltered (gdb_stdlog,
+					      "csky: nor r4,r4\n");
+			}
+		    }
+		  else if (CSKY_16_IS_BSETI4 (insn2))
+		    {
+		      int imm = (insn2 & 0x1f);
+		      adjust |= (1 << imm);
+		      if (csky_debug)
+			{
+			  fprintf_unfiltered (gdb_stdlog,
+					      "csky: bseti r4, %d\n", imm);
+			}
+		    }
+		  else if (CSKY_16_IS_BCLRI4 (insn2))
+		    {
+		      int imm = (insn2 & 0x1f);
+		      adjust &= ~(1 << imm);
+		      if (csky_debug)
+			{
+			  fprintf_unfiltered (gdb_stdlog,
+					      "csky: bclri r4, %d\n", imm);
+			}
+		    }
+		  else if (CSKY_16_IS_LSLI4 (insn2))
+		    {
+		      int imm = (insn2 & 0x1f);
+		      adjust <<= imm;
+		      if (csky_debug)
+			{
+			  fprintf_unfiltered (gdb_stdlog,
+					      "csky: lsli r4,r4, %d\n", imm);
+			}
+		    }
+
+		  offset += insn_len;
+		  insn_len =  csky_get_insn (gdbarch, addr + offset, &insn2);
+		};
+
+	      if (csky_debug)
+		{
+		  fprintf_unfiltered (gdb_stdlog, "csky: done looking for"
+				      " r4 adjusters\n");
+		}
+
+	      /* If the next insn adjusts the stack pointer, we keep
+		 everything; if not, we scrap it and we've found the
+		 end of the prologue.  */
+	      if (CSKY_IS_SUBU4 (insn2))
+		{
+		  addr += offset;
+		  stacksize += adjust;
+		  if (csky_debug)
+		    {
+		      fprintf_unfiltered (gdb_stdlog,
+					  "csky: found stack adjustment of"
+					  " 0x%x bytes.\n", adjust);
+		      fprintf_unfiltered (gdb_stdlog,
+					  "csky: skipping to new address "
+					  "0x%lx\n", addr);
+		      fprintf_unfiltered (gdb_stdlog,
+					  "csky: continuing\n");
+		    }
+		  continue;
+		}
+
+	      /* None of these instructions are prologue, so don't touch
+		 anything.  */
+	      if (csky_debug)
+		{
+		  fprintf_unfiltered (gdb_stdlog,
+				      "csky: no subu sp,sp,r4; NOT altering"
+				      " stacksize.\n");
+		}
+	      break;
+	    }
+	}
+      else
+	{
+	  /* insn_len != 4.  */
+
+	  /* subi.sp sp,disp.  */
+	  if (CSKY_16_IS_SUBI0 (insn))
+	    {
+	      int offset = CSKY_16_SUBI_IMM (insn);
+	      if (csky_debug)
+		{
+		  fprintf_unfiltered (gdb_stdlog,
+				      "csky: got subi r0,%d; continuing\n",
+				      offset);
+		}
+	      stacksize += offset;
+	      continue;
+	    }
+	  /* stw.16 rz,(sp,disp).  */
+	  else if (CSKY_16_IS_STWx0 (insn))
+	    {
+	      /* Spill register: see note for IS_STM above.  */
+	      int disp;
+
+	      rn = CSKY_16_ST_VAL_REGNUM (insn);
+	      disp = CSKY_16_ST_OFFSET (insn);
+	      register_offsets[rn] = stacksize - disp;
+	      if (csky_debug)
+		print_savedreg_msg (rn, register_offsets, true);
+	      continue;
+	    }
+	  else if (CSKY_16_IS_MOV_FP_SP (insn))
+	    {
+	      /* SP is saved to FP reg, means prologue may modify SP.  */
+	      is_fp_saved = 1;
+	      adjust_fp = stacksize;
+	      continue;
+	    }
+	  else if (CSKY_16_IS_PUSH (insn))
+	    {
+	      /* Push for 16_bit.  */
+	      int offset = 0;
+	      if (CSKY_16_IS_PUSH_R15 (insn))
+		{
+		  stacksize += 4;
+		  register_offsets[15] = stacksize;
+		  if (csky_debug)
+		    print_savedreg_msg (15, register_offsets, false);
+		  offset += 4;
+		 }
+	      if (CSKY_16_PUSH_LIST1 (insn))
+		{
+		  int num = CSKY_16_PUSH_LIST1 (insn);
+		  int tmp = 0;
+		  stacksize += num * 4;
+		  offset += num * 4;
+		  if (csky_debug)
+		    {
+		      fprintf_unfiltered (gdb_stdlog,
+					  "csky: push regs_array: r4-r%d\n",
+					  4 + num - 1);
+		    }
+		  for (rn = 4; rn <= 4 + num - 1; rn++)
+		    {
+		       register_offsets[rn] = stacksize - tmp;
+		       if (csky_debug)
+			 {
+			   fprintf_unfiltered (gdb_stdlog,
+					       "csky: r%d saved at 0x%x"
+					       " (offset %d)\n", rn,
+					       register_offsets[rn], offset);
+			 }
+		       tmp += 4;
+		    }
+		}
+
+	      framesize = stacksize;
+	      if (csky_debug)
+		fprintf_unfiltered (gdb_stdlog, "csky: continuing\n");
+	      continue;
+	    }
+	  else if (CSKY_16_IS_LRW4 (insn) || CSKY_16_IS_MOVI4 (insn))
+	    {
+	      int adjust = 0;
+	      int offset = 0;
+	      unsigned int insn2;
+
+	      if (csky_debug)
+		{
+		  fprintf_unfiltered (gdb_stdlog,
+				      "csky: looking at large frame\n");
+		}
+	      if (CSKY_16_IS_LRW4 (insn))
+		{
+		  enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
+		  int offset = ((insn & 0x300) >> 3) | (insn & 0x1f);
+		  int literal_addr = (addr + ( offset << 2)) & 0xfffffffc;
+		  adjust = read_memory_unsigned_integer (literal_addr, 4,
+							 byte_order);
+		}
+	      else
+		{
+		  /* CSKY_16_IS_MOVI4 (insn).  */
+		  adjust = (insn  & 0xff);
+		}
+
+	      if (csky_debug)
+		{
+		  fprintf_unfiltered (gdb_stdlog,
+				      "csky: base stacksize=0x%x\n", adjust);
+		}
+
+	      /* May have zero or more instructions which modify r4.  */
+	      if (csky_debug)
+		{
+		  fprintf_unfiltered (gdb_stdlog,
+				      "csky: looking for r4 adjusters...\n");
+		}
+	      offset = 2;
+	      insn_len = csky_get_insn (gdbarch, addr + offset, &insn2);
+	      while (CSKY_IS_R4_ADJUSTER (insn2))
+		{
+		  if (CSKY_32_IS_ADDI4 (insn2))
+		    {
+		      int imm = (insn2 & 0xfff) + 1;
+		      adjust += imm;
+		      if (csky_debug)
+			{
+			  fprintf_unfiltered (gdb_stdlog,
+					      "csky: addi r4,%d\n", imm);
+			}
+		    }
+		  else if (CSKY_32_IS_SUBI4 (insn2))
+		    {
+		      int imm = (insn2 & 0xfff) + 1;
+		      adjust -= imm;
+		      if (csky_debug)
+			{
+			  fprintf_unfiltered (gdb_stdlog,
+					      "csky: subi r4,%d\n", imm);
+			}
+		    }
+		  else if (CSKY_32_IS_NOR4 (insn2))
+		    {
+		      adjust = ~adjust;
+		      if (csky_debug)
+			{
+			  fprintf_unfiltered (gdb_stdlog,
+					      "csky: nor r4,r4,r4\n");
+			}
+		    }
+		  else if (CSKY_32_IS_ROTLI4 (insn2))
+		    {
+		      int imm = ((insn2 >> 21) & 0x1f);
+		      int temp = adjust >> (32 - imm);
+		      adjust <<= imm;
+		      adjust |= temp;
+		      if (csky_debug)
+			{
+			  fprintf_unfiltered (gdb_stdlog,
+					      "csky: rotli r4,r4,%d\n", imm);
+			}
+		    }
+		  else if (CSKY_32_IS_LISI4 (insn2))
+		    {
+		      int imm = ((insn2 >> 21) & 0x1f);
+		      adjust <<= imm;
+		      if (csky_debug)
+			{
+			  fprintf_unfiltered (gdb_stdlog,
+					      "csky: lsli r4,r4,%d\n", imm);
+			}
+		    }
+		  else if (CSKY_32_IS_BSETI4 (insn2))
+		    {
+		      int imm = ((insn2 >> 21) & 0x1f);
+		      adjust |= (1 << imm);
+		      if (csky_debug)
+			{
+			  fprintf_unfiltered (gdb_stdlog,
+					      "csky: bseti r4,r4 %d\n", imm);
+			}
+		    }
+		  else if (CSKY_32_IS_BCLRI4 (insn2))
+		    {
+		      int imm = ((insn2 >> 21) & 0x1f);
+		      adjust &= ~(1 << imm);
+		      if (csky_debug)
+			{
+			  fprintf_unfiltered (gdb_stdlog,
+					      "csky: bclri r4,r4 %d\n", imm);
+			}
+		    }
+		  else if (CSKY_32_IS_IXH4 (insn2))
+		    {
+		      adjust *= 3;
+		      if (csky_debug)
+			{
+			  fprintf_unfiltered (gdb_stdlog,
+					      "csky: ixh r4,r4,r4\n");
+			}
+		    }
+		  else if (CSKY_32_IS_IXW4 (insn2))
+		    {
+		      adjust *= 5;
+		      if (csky_debug)
+			{
+			  fprintf_unfiltered (gdb_stdlog,
+					      "csky: ixw r4,r4,r4\n");
+			}
+		    }
+		  else if (CSKY_16_IS_ADDI4 (insn2))
+		    {
+		      int imm = (insn2 & 0xff) + 1;
+		      adjust += imm;
+		      if (csky_debug)
+			{
+			  fprintf_unfiltered (gdb_stdlog,
+					      "csky: addi r4,%d\n", imm);
+			}
+		    }
+		  else if (CSKY_16_IS_SUBI4 (insn2))
+		    {
+		      int imm = (insn2 & 0xff) + 1;
+		      adjust -= imm;
+		      if (csky_debug)
+			{
+			  fprintf_unfiltered (gdb_stdlog,
+					      "csky: subi r4,%d\n", imm);
+			}
+		    }
+		  else if (CSKY_16_IS_NOR4 (insn2))
+		    {
+		      adjust = ~adjust;
+		      if (csky_debug)
+			{
+			  fprintf_unfiltered (gdb_stdlog,
+					      "csky: nor r4,r4\n");
+			}
+		    }
+		  else if (CSKY_16_IS_BSETI4 (insn2))
+		    {
+		      int imm = (insn2 & 0x1f);
+		      adjust |= (1 << imm);
+		      if (csky_debug)
+			{
+			  fprintf_unfiltered (gdb_stdlog,
+					      "csky: bseti r4, %d\n", imm);
+			}
+		    }
+		  else if (CSKY_16_IS_BCLRI4 (insn2))
+		    {
+		      int imm = (insn2 & 0x1f);
+		      adjust &= ~(1 << imm);
+		      if (csky_debug)
+			{
+			  fprintf_unfiltered (gdb_stdlog,
+					      "csky: bclri r4, %d\n", imm);
+			}
+		    }
+		  else if (CSKY_16_IS_LSLI4 (insn2))
+		    {
+		      int imm = (insn2 & 0x1f);
+		      adjust <<= imm;
+		      if (csky_debug)
+			{
+			  fprintf_unfiltered (gdb_stdlog,
+					      "csky: lsli r4,r4, %d\n", imm);
+			}
+		    }
+
+		  offset += insn_len;
+		  insn_len = csky_get_insn (gdbarch, addr + offset, &insn2);
+		};
+
+	      if (csky_debug)
+		{
+		  fprintf_unfiltered (gdb_stdlog, "csky: "
+				      "done looking for r4 adjusters\n");
+		}
+
+	      /* If the next instruction adjusts the stack pointer, we keep
+		 everything; if not, we scrap it and we've found the end
+		 of the prologue.  */
+	      if (CSKY_IS_SUBU4 (insn2))
+		{
+		  addr += offset;
+		  stacksize += adjust;
+		  if (csky_debug)
+		    {
+		      fprintf_unfiltered (gdb_stdlog, "csky: "
+					  "found stack adjustment of 0x%x"
+					  " bytes.\n", adjust);
+		      fprintf_unfiltered (gdb_stdlog, "csky: "
+					  "skipping to new address 0x%lx\n",
+					  addr);
+		      fprintf_unfiltered (gdb_stdlog, "csky: continuing\n");
+		    }
+		  continue;
+		}
+
+	      /* None of these instructions are prologue, so don't touch
+		 anything.  */
+	      if (csky_debug)
+		{
+		  fprintf_unfiltered (gdb_stdlog, "csky: no subu sp,r4; "
+				      "NOT altering stacksize.\n");
+		}
+	      break;
+	    }
+	}
+
+      /* This is not a prologue instruction, so stop here.  */
+      if (csky_debug)
+	{
+	  fprintf_unfiltered (gdb_stdlog, "csky: insn is not a prologue"
+			      " insn -- ending scan\n");
+	}
+      break;
+    }
+
+  if (this_cache)
+    {
+      CORE_ADDR unwound_fp;
+      enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
+      this_cache->framesize = framesize;
+
+      if (is_fp_saved)
+	{
+	  this_cache->framereg = CSKY_FP_REGNUM;
+	  unwound_fp = get_frame_register_unsigned (this_frame,
+						    this_cache->framereg);
+	  this_cache->prev_sp = unwound_fp + adjust_fp;
+	}
+      else
+	{
+	  this_cache->framereg = CSKY_SP_REGNUM;
+	  unwound_fp = get_frame_register_unsigned (this_frame,
+						    this_cache->framereg);
+	  this_cache->prev_sp = unwound_fp + stacksize;
+	}
+
+      /* Note where saved registers are stored.  The offsets in
+	 REGISTER_OFFSETS are computed relative to the top of the frame.  */
+      for (rn = 0; rn < CSKY_NUM_GREGS; rn++)
+	{
+	  if (register_offsets[rn] >= 0)
+	    {
+	      this_cache->saved_regs[rn].addr
+		= this_cache->prev_sp - register_offsets[rn];
+	      if (csky_debug)
+		{
+		  CORE_ADDR rn_value = read_memory_unsigned_integer (
+		    this_cache->saved_regs[rn].addr, 4, byte_order);
+		  fprintf_unfiltered (gdb_stdlog, "Saved register %s "
+				      "stored at 0x%08lx, value=0x%08lx\n",
+				      csky_register_names[rn],
+				      (unsigned long)
+					this_cache->saved_regs[rn].addr,
+				      (unsigned long) rn_value);
+		}
+	    }
+	}
+      if (lr_type == LR_TYPE_EPC)
+	{
+	  /* rte || epc .  */
+	  this_cache->saved_regs[CSKY_PC_REGNUM]
+	    = this_cache->saved_regs[CSKY_EPC_REGNUM];
+	}
+      else if (lr_type == LR_TYPE_FPC)
+	{
+	  /* rfi || fpc .  */
+	  this_cache->saved_regs[CSKY_PC_REGNUM]
+	    = this_cache->saved_regs[CSKY_FPC_REGNUM];
+	}
+      else
+	{
+	  this_cache->saved_regs[CSKY_PC_REGNUM]
+	    = this_cache->saved_regs[CSKY_LR_REGNUM];
+	}
+    }
+
+  return addr;
+}
+
+/* Detect whether PC is at a point where the stack frame has been
+   destroyed.  */
+
+static int
+csky_stack_frame_destroyed_p (struct gdbarch *gdbarch, CORE_ADDR pc)
+{
+  unsigned int insn;
+  CORE_ADDR addr;
+  CORE_ADDR func_start, func_end;
+
+  if (!find_pc_partial_function (pc, NULL, &func_start, &func_end))
+    return 0;
+
+  bool fp_saved = false;
+  int insn_len;
+  for (addr = func_start; addr < func_end; addr += insn_len)
+    {
+      /* Get next insn.  */
+      insn_len = csky_get_insn (gdbarch, addr, &insn);
+
+      if (insn_len == 2)
+	{
+	  /* Is sp is saved to fp.  */
+	  if (CSKY_16_IS_MOV_FP_SP (insn))
+	    fp_saved = true;
+	  /* If sp was saved to fp and now being restored from
+	     fp then it indicates the start of epilog.  */
+	  else if (fp_saved && CSKY_16_IS_MOV_SP_FP (insn))
+	    return pc >= addr;
+	}
+    }
+  return 0;
+}
+
+/* Implement the skip_prologue gdbarch hook.  */
+
+static CORE_ADDR
+csky_skip_prologue (struct gdbarch *gdbarch, CORE_ADDR pc)
+{
+  CORE_ADDR func_addr, func_end;
+  struct symtab_and_line sal;
+  const int default_search_limit = 128;
+
+  /* See if we can find the end of the prologue using the symbol table.  */
+  if (find_pc_partial_function (pc, NULL, &func_addr, &func_end))
+    {
+      CORE_ADDR post_prologue_pc
+	= skip_prologue_using_sal (gdbarch, func_addr);
+
+      if (post_prologue_pc != 0)
+	return std::max (pc, post_prologue_pc);
+    }
+  else
+    func_end = pc + default_search_limit;
+
+  /* Find the end of prologue.  Default lr_type.  */
+  return csky_analyze_prologue (gdbarch, pc, func_end, func_end,
+				NULL, NULL, LR_TYPE_R15);
+}
+
+/* Implement the breakpoint_kind_from_pc gdbarch method.  */
+
+static int
+csky_breakpoint_kind_from_pc (struct gdbarch *gdbarch, CORE_ADDR *pcptr)
+{
+  if (csky_pc_is_csky16 (gdbarch, *pcptr))
+    return CSKY_INSN_SIZE16;
+  else
+    return CSKY_INSN_SIZE32;
+}
+
+/* Implement the sw_breakpoint_from_kind gdbarch method.  */
+
+static const gdb_byte *
+csky_sw_breakpoint_from_kind (struct gdbarch *gdbarch, int kind, int *size)
+{
+  *size = kind;
+  if (kind == CSKY_INSN_SIZE16)
+    {
+      static gdb_byte csky_16_breakpoint[] = { 0, 0 };
+      return csky_16_breakpoint;
+    }
+  else
+    {
+      static gdb_byte csky_32_breakpoint[] = { 0, 0, 0, 0 };
+      return csky_32_breakpoint;
+    }
+}
+
+/* Implement the memory_insert_breakpoint gdbarch method.  */
+
+static int
+csky_memory_insert_breakpoint (struct gdbarch *gdbarch,
+			       struct bp_target_info *bp_tgt)
+{
+  int val;
+  const unsigned char *bp;
+  gdb_byte bp_write_record1[] = { 0, 0, 0, 0 };
+  gdb_byte bp_write_record2[] = { 0, 0, 0, 0 };
+  gdb_byte bp_record[] = { 0, 0, 0, 0 };
+
+  /* Sanity-check bp_address.  */
+  if (bp_tgt->reqstd_address % 2)
+    warning (_("Invalid breakpoint address 0x%x is an odd number.\n"),
+	     (unsigned int) bp_tgt->reqstd_address);
+  scoped_restore restore_memory
+    = make_scoped_restore_show_memory_breakpoints (1);
+
+  /* Determine appropriate breakpoint_kind for this address.  */
+  bp_tgt->kind = csky_breakpoint_kind_from_pc (gdbarch,
+					       &bp_tgt->reqstd_address);
+
+  /* Save the memory contents.  */
+  bp_tgt->shadow_len = bp_tgt->kind;
+
+  /* Fill bp_tgt->placed_address.  */
+  bp_tgt->placed_address = bp_tgt->reqstd_address;
+
+  if (bp_tgt->kind == CSKY_INSN_SIZE16)
+    {
+      if ((bp_tgt->reqstd_address % 4) == 0)
+	{
+	  /* Read two bytes.  */
+	  val = target_read_memory (bp_tgt->reqstd_address,
+				    bp_tgt->shadow_contents, 2);
+	  if (val)
+	    return val;
+
+	  /* Read two bytes.  */
+	  val = target_read_memory (bp_tgt->reqstd_address + 2,
+				    bp_record, 2);
+	  if (val)
+	    return val;
+
+	  /* Write the breakpoint.  */
+	  bp_write_record1[2] = bp_record[0];
+	  bp_write_record1[3] = bp_record[1];
+	  bp = bp_write_record1;
+	  val = target_write_raw_memory (bp_tgt->reqstd_address, bp,
+					 CSKY_WR_BKPT_MODE);
+	}
+      else
+	{
+	  val = target_read_memory (bp_tgt->reqstd_address,
+				    bp_tgt->shadow_contents, 2);
+	  if (val)
+	    return val;
+
+	  val = target_read_memory (bp_tgt->reqstd_address - 2,
+				    bp_record, 2);
+	  if (val)
+	    return val;
+
+	  /* Write the breakpoint.  */
+	  bp_write_record1[0] = bp_record[0];
+	  bp_write_record1[1] = bp_record[1];
+	  bp = bp_write_record1;
+	  val = target_write_raw_memory (bp_tgt->reqstd_address - 2,
+					 bp, CSKY_WR_BKPT_MODE);
+	}
+    }
+  else
+    {
+      if (bp_tgt->placed_address % 4 == 0)
+	{
+	  val = target_read_memory (bp_tgt->reqstd_address,
+				    bp_tgt->shadow_contents,
+				    CSKY_WR_BKPT_MODE);
+	  if (val)
+	    return val;
+
+	  /* Write the breakpoint.  */
+	  bp = bp_write_record1;
+	  val = target_write_raw_memory (bp_tgt->reqstd_address,
+					 bp, CSKY_WR_BKPT_MODE);
+	}
+      else
+	{
+	  val = target_read_memory (bp_tgt->reqstd_address,
+				    bp_tgt->shadow_contents,
+				    CSKY_WR_BKPT_MODE);
+	  if (val)
+	    return val;
+
+	  val = target_read_memory (bp_tgt->reqstd_address - 2,
+				    bp_record, 2);
+	  if (val)
+	    return val;
+
+	  val = target_read_memory (bp_tgt->reqstd_address + 4,
+				    bp_record + 2, 2);
+	  if (val)
+	    return val;
+
+	  bp_write_record1[0] = bp_record[0];
+	  bp_write_record1[1] = bp_record[1];
+	  bp_write_record2[2] = bp_record[2];
+	  bp_write_record2[3] = bp_record[3];
+
+	  /* Write the breakpoint.  */
+	  bp = bp_write_record1;
+	  val = target_write_raw_memory (bp_tgt->reqstd_address - 2, bp,
+					 CSKY_WR_BKPT_MODE);
+	  if (val)
+	    return val;
+
+	  /* Write the breakpoint.  */
+	  bp = bp_write_record2;
+	  val = target_write_raw_memory (bp_tgt->reqstd_address + 2, bp,
+					 CSKY_WR_BKPT_MODE);
+	}
+    }
+  return val;
+}
+
+/* Restore the breakpoint shadow_contents to the target.  */
+
+static int
+csky_memory_remove_breakpoint (struct gdbarch *gdbarch,
+			       struct bp_target_info *bp_tgt)
+{
+  int val;
+  gdb_byte bp_record[] = { 0, 0, 0, 0, 0, 0, 0, 0 };
+  /* Different for shadow_len 2 or 4.  */
+  if (bp_tgt->shadow_len == 2)
+    {
+      /* Do word-sized writes on word-aligned boundaries and read
+	 padding bytes as necessary.  */
+      if (bp_tgt->reqstd_address % 4 == 0)
+	{
+	  val = target_read_memory (bp_tgt->reqstd_address + 2,
+				    bp_record + 2, 2);
+	  if (val)
+	    return val;
+	  bp_record[0] = bp_tgt->shadow_contents[0];
+	  bp_record[1] = bp_tgt->shadow_contents[1];
+	  return target_write_raw_memory (bp_tgt->reqstd_address,
+					  bp_record, CSKY_WR_BKPT_MODE);
+	}
+      else
+	{
+	  val = target_read_memory (bp_tgt->reqstd_address - 2,
+				    bp_record, 2);
+	  if (val)
+	    return val;
+	  bp_record[2] = bp_tgt->shadow_contents[0];
+	  bp_record[3] = bp_tgt->shadow_contents[1];
+	  return target_write_raw_memory (bp_tgt->reqstd_address - 2,
+					  bp_record, CSKY_WR_BKPT_MODE);
+	}
+    }
+  else
+    {
+      /* Do word-sized writes on word-aligned boundaries and read
+	 padding bytes as necessary.  */
+      if (bp_tgt->placed_address % 4 == 0)
+	{
+	  return target_write_raw_memory (bp_tgt->reqstd_address,
+					  bp_tgt->shadow_contents,
+					  CSKY_WR_BKPT_MODE);
+	}
+      else
+	{
+	  val = target_read_memory (bp_tgt->reqstd_address - 2,
+				    bp_record, 2);
+	  if (val)
+	    return val;
+	  val = target_read_memory (bp_tgt->reqstd_address + 4,
+				    bp_record+6, 2);
+	  if (val)
+	    return val;
+
+	  bp_record[2] = bp_tgt->shadow_contents[0];
+	  bp_record[3] = bp_tgt->shadow_contents[1];
+	  bp_record[4] = bp_tgt->shadow_contents[2];
+	  bp_record[5] = bp_tgt->shadow_contents[3];
+
+	  return target_write_raw_memory (bp_tgt->reqstd_address - 2,
+					  bp_record,
+					  CSKY_WR_BKPT_MODE * 2);
+	}
+    }
+}
+
+/* Determine link register type.  */
+
+static lr_type_t
+csky_analyze_lr_type (struct gdbarch *gdbarch,
+		      CORE_ADDR start_pc, CORE_ADDR end_pc)
+{
+  CORE_ADDR addr;
+  unsigned int insn, insn_len;
+  insn_len = 2;
+
+  for (addr = start_pc; addr < end_pc; addr += insn_len)
+    {
+      insn_len = csky_get_insn (gdbarch, addr, &insn);
+      if (insn_len == 4)
+	{
+	  if (CSKY_32_IS_MFCR_EPSR (insn) || CSKY_32_IS_MFCR_EPC (insn)
+	      || CSKY_32_IS_RTE (insn))
+	    return LR_TYPE_EPC;
+	}
+      else if (CSKY_32_IS_MFCR_FPSR (insn) || CSKY_32_IS_MFCR_FPC (insn)
+	       || CSKY_32_IS_RFI (insn))
+	return LR_TYPE_FPC;
+      else if (CSKY_32_IS_JMP (insn) || CSKY_32_IS_BR (insn)
+	       || CSKY_32_IS_JMPIX (insn) || CSKY_32_IS_JMPI (insn))
+	return LR_TYPE_R15;
+      else
+	{
+	  /* 16 bit instruction.  */
+	  if (CSKY_16_IS_JMP (insn) || CSKY_16_IS_BR (insn)
+	      || CSKY_16_IS_JMPIX (insn))
+	    return LR_TYPE_R15;
+	}
+    }
+    return LR_TYPE_R15;
+}
+
+/* Heuristic unwinder.  */
+
+static struct csky_unwind_cache *
+csky_frame_unwind_cache (struct frame_info *this_frame)
+{
+  CORE_ADDR prologue_start, prologue_end, func_end, prev_pc, block_addr;
+  struct csky_unwind_cache *cache;
+  const struct block *bl;
+  unsigned long func_size = 0;
+  struct gdbarch *gdbarch = get_frame_arch (this_frame);
+  unsigned int sp_regnum = CSKY_SP_REGNUM;
+
+  /* Default lr type is r15.  */
+  lr_type_t lr_type = LR_TYPE_R15;
+
+  cache = FRAME_OBSTACK_ZALLOC (struct csky_unwind_cache);
+  cache->saved_regs = trad_frame_alloc_saved_regs (this_frame);
+
+  /* Assume there is no frame until proven otherwise.  */
+  cache->framereg = sp_regnum;
+
+  cache->framesize = 0;
+
+  prev_pc = get_frame_pc (this_frame);
+  block_addr = get_frame_address_in_block (this_frame);
+  if (find_pc_partial_function (block_addr, NULL, &prologue_start,
+				&func_end) == 0)
+    /* We couldn't find a function containing block_addr, so bail out
+       and hope for the best.  */
+    return cache;
+
+  /* Get the (function) symbol matching prologue_start.  */
+  bl = block_for_pc (prologue_start);
+  if (bl != NULL)
+    func_size = bl->endaddr - bl->startaddr;
+  else
+    {
+      struct bound_minimal_symbol msymbol
+	= lookup_minimal_symbol_by_pc (prologue_start);
+      if (msymbol.minsym != NULL)
+	func_size = MSYMBOL_SIZE (msymbol.minsym);
+    }
+
+  /* If FUNC_SIZE is 0 we may have a special-case use of lr
+     e.g. exception or interrupt.  */
+  if (func_size == 0)
+    lr_type = csky_analyze_lr_type (gdbarch, prologue_start, func_end);
+
+  prologue_end = std::min (func_end, prev_pc);
+
+  /* Analyze the function prologue.  */
+  csky_analyze_prologue (gdbarch, prologue_start, prologue_end,
+			    func_end, this_frame, cache, lr_type);
+
+  /* gdbarch_sp_regnum contains the value and not the address.  */
+  trad_frame_set_value (cache->saved_regs, sp_regnum, cache->prev_sp);
+  return cache;
+}
+
+/* Implement the unwind_pc gdbarch method.  */
+
+static CORE_ADDR
+csky_unwind_pc (struct gdbarch *gdbarch, struct frame_info *next_frame)
+{
+  return frame_unwind_register_unsigned (next_frame, CSKY_PC_REGNUM);
+}
+
+/* Implement the this_id function for the normal unwinder.  */
+
+static void
+csky_frame_this_id (struct frame_info *this_frame,
+		    void **this_prologue_cache, struct frame_id *this_id)
+{
+  struct csky_unwind_cache *cache;
+  struct frame_id id;
+
+  if (*this_prologue_cache == NULL)
+    *this_prologue_cache = csky_frame_unwind_cache (this_frame);
+  cache = (struct csky_unwind_cache *) *this_prologue_cache;
+
+  /* This marks the outermost frame.  */
+  if (cache->prev_sp == 0)
+    return;
+
+  id = frame_id_build (cache->prev_sp, get_frame_func (this_frame));
+  *this_id = id;
+}
+
+/* Implement the prev_register function for the normal unwinder.  */
+
+static struct value *
+csky_frame_prev_register (struct frame_info *this_frame,
+			  void **this_prologue_cache, int regnum)
+{
+  struct csky_unwind_cache *cache;
+
+  if (*this_prologue_cache == NULL)
+    *this_prologue_cache = csky_frame_unwind_cache (this_frame);
+  cache = (struct csky_unwind_cache *) *this_prologue_cache;
+
+  return trad_frame_get_prev_register (this_frame, cache->saved_regs,
+				       regnum);
+}
+
+/* Data structures for the normal prologue-analysis-based
+   unwinder.  */
+
+static const struct frame_unwind csky_unwind_cache = {
+  NORMAL_FRAME,
+  default_frame_unwind_stop_reason,
+  csky_frame_this_id,
+  csky_frame_prev_register,
+  NULL,
+  default_frame_sniffer,
+  NULL,
+  NULL
+};
+
+
+
+static int
+csky_stub_unwind_sniffer (const struct frame_unwind *self,
+			 struct frame_info *this_frame,
+			 void **this_prologue_cache)
+{
+  CORE_ADDR addr_in_block;
+
+  addr_in_block = get_frame_address_in_block (this_frame);
+
+  if (find_pc_partial_function (addr_in_block, NULL, NULL, NULL) == 0
+      || in_plt_section (addr_in_block))
+    return 1;
+
+  return 0;
+}
+
+static struct csky_unwind_cache *
+csky_make_stub_cache (struct frame_info *this_frame)
+{
+  struct csky_unwind_cache *cache;
+
+  cache = FRAME_OBSTACK_ZALLOC (struct csky_unwind_cache);
+  cache->saved_regs = trad_frame_alloc_saved_regs (this_frame);
+  cache->prev_sp = get_frame_register_unsigned (this_frame, CSKY_SP_REGNUM);
+
+  return cache;
+}
+
+static void
+csky_stub_this_id (struct frame_info *this_frame,
+		  void **this_cache,
+		  struct frame_id *this_id)
+{
+  struct csky_unwind_cache *cache;
+
+  if (*this_cache == NULL)
+    *this_cache = csky_make_stub_cache (this_frame);
+  cache = (struct csky_unwind_cache *) *this_cache;
+
+  /* Our frame ID for a stub frame is the current SP and LR.  */
+  *this_id = frame_id_build (cache->prev_sp, get_frame_pc (this_frame));
+}
+
+static struct value *
+csky_stub_prev_register (struct frame_info *this_frame,
+			    void **this_cache,
+			    int prev_regnum)
+{
+  struct csky_unwind_cache *cache;
+
+  if (*this_cache == NULL)
+    *this_cache = csky_make_stub_cache (this_frame);
+  cache = (struct csky_unwind_cache *) *this_cache;
+
+  /* If we are asked to unwind the PC, then return the LR.  */
+  if (prev_regnum == CSKY_PC_REGNUM)
+    {
+      CORE_ADDR lr;
+
+      lr = frame_unwind_register_unsigned (this_frame, CSKY_LR_REGNUM);
+      return frame_unwind_got_constant (this_frame, prev_regnum, lr);
+    }
+
+  if (prev_regnum == CSKY_SP_REGNUM)
+    return frame_unwind_got_constant (this_frame, prev_regnum, cache->prev_sp);
+
+  return trad_frame_get_prev_register (this_frame, cache->saved_regs,
+				       prev_regnum);
+}
+
+struct frame_unwind csky_stub_unwind = {
+  NORMAL_FRAME,
+  default_frame_unwind_stop_reason,
+  csky_stub_this_id,
+  csky_stub_prev_register,
+  NULL,
+  csky_stub_unwind_sniffer
+};
+
+/* Implement the this_base, this_locals, and this_args hooks
+   for the normal unwinder.  */
+
+static CORE_ADDR
+csky_frame_base_address (struct frame_info *this_frame, void **this_cache)
+{
+  struct csky_unwind_cache *cache;
+
+  if (*this_cache == NULL)
+    *this_cache = csky_frame_unwind_cache (this_frame);
+  cache = (struct csky_unwind_cache *) *this_cache;
+
+  return cache->prev_sp - cache->framesize;
+}
+
+static const struct frame_base csky_frame_base = {
+  &csky_unwind_cache,
+  csky_frame_base_address,
+  csky_frame_base_address,
+  csky_frame_base_address
+};
+
+/* Implement the dummy_id gdbarch method.  The frame ID's base
+   needs to match the TOS value saved by save_dummy_frame_tos,
+   and the PC should match the dummy frame's breakpoint.  */
+
+static struct frame_id
+csky_dummy_id (struct gdbarch *gdbarch, struct frame_info *this_frame)
+{
+  unsigned int sp_regnum = CSKY_SP_REGNUM;
+
+  CORE_ADDR sp = get_frame_register_unsigned (this_frame, sp_regnum);
+  return frame_id_build (sp, get_frame_pc (this_frame));
+}
+
+/* Initialize register access method.  */
+
+static void
+csky_dwarf2_frame_init_reg (struct gdbarch *gdbarch, int regnum,
+			    struct dwarf2_frame_state_reg *reg,
+			    struct frame_info *this_frame)
+{
+  if (regnum == gdbarch_pc_regnum (gdbarch))
+    reg->how = DWARF2_FRAME_REG_RA;
+  else if (regnum == gdbarch_sp_regnum (gdbarch))
+    reg->how = DWARF2_FRAME_REG_CFA;
+}
+
+/* Create csky register groups.  */
+
+static void
+csky_init_reggroup ()
+{
+  cr_reggroup = reggroup_new ("cr", USER_REGGROUP);
+  fr_reggroup = reggroup_new ("fr", USER_REGGROUP);
+  vr_reggroup = reggroup_new ("vr", USER_REGGROUP);
+  mmu_reggroup = reggroup_new ("mmu", USER_REGGROUP);
+  prof_reggroup = reggroup_new ("profiling", USER_REGGROUP);
+}
+
+/* Add register groups into reggroup list.  */
+
+static void
+csky_add_reggroups (struct gdbarch *gdbarch)
+{
+  reggroup_add (gdbarch, all_reggroup);
+  reggroup_add (gdbarch, general_reggroup);
+  reggroup_add (gdbarch, cr_reggroup);
+  reggroup_add (gdbarch, fr_reggroup);
+  reggroup_add (gdbarch, vr_reggroup);
+  reggroup_add (gdbarch, mmu_reggroup);
+  reggroup_add (gdbarch, prof_reggroup);
+}
+
+/* Return the groups that a CSKY register can be categorised into.  */
+
+static int
+csky_register_reggroup_p (struct gdbarch *gdbarch, int regnum,
+			  struct reggroup *reggroup)
+{
+  int raw_p;
+
+  if (gdbarch_register_name (gdbarch, regnum) == NULL
+      || gdbarch_register_name (gdbarch, regnum)[0] == '\0')
+    return 0;
+
+  if (reggroup == all_reggroup)
+    return 1;
+
+  raw_p = regnum < gdbarch_num_regs (gdbarch);
+  if (reggroup == save_reggroup || reggroup == restore_reggroup)
+    return raw_p;
+
+  if (((regnum >= CSKY_R0_REGNUM) && (regnum <= CSKY_R0_REGNUM + 31))
+      && (reggroup == general_reggroup))
+    return 1;
+
+  if (((regnum == CSKY_PC_REGNUM)
+       || ((regnum >= CSKY_CR0_REGNUM)
+	   && (regnum <= CSKY_CR0_REGNUM + 30)))
+      && (reggroup == cr_reggroup))
+    return 2;
+
+  if ((((regnum >= CSKY_VR0_REGNUM) && (regnum <= CSKY_VR0_REGNUM + 15))
+       || ((regnum >= CSKY_VCR0_REGNUM)
+	   && (regnum <= CSKY_VCR0_REGNUM + 2)))
+      && (reggroup == vr_reggroup))
+    return 3;
+
+  if (((regnum >= CSKY_MMU_REGNUM) && (regnum <= CSKY_MMU_REGNUM + 8))
+      && (reggroup == mmu_reggroup))
+    return 4;
+
+  if (((regnum >= CSKY_PROFCR_REGNUM)
+       && (regnum <= CSKY_PROFCR_REGNUM + 48))
+      && (reggroup == prof_reggroup))
+    return 5;
+
+  if ((((regnum >= CSKY_FR0_REGNUM) && (regnum <= CSKY_FR0_REGNUM + 15))
+       || ((regnum >= CSKY_VCR0_REGNUM) && (regnum <= CSKY_VCR0_REGNUM + 2)))
+      && (reggroup == fr_reggroup))
+    return 6;
+
+  return 0;
+}
+
+/* Implement the dwarf2_reg_to_regnum gdbarch method.  */
+
+static int
+csky_dwarf_reg_to_regnum (struct gdbarch *gdbarch, int dw_reg)
+{
+  if (dw_reg < 0 || dw_reg >= CSKY_NUM_REGS)
+    return -1;
+  return dw_reg;
+}
+
+/* Override interface for command: info register.  */
+
+static void
+csky_print_registers_info (struct gdbarch *gdbarch, struct ui_file *file,
+			   struct frame_info *frame, int regnum, int all)
+{
+  /* Call default print_registers_info function.  */
+  default_print_registers_info (gdbarch, file, frame, regnum, all);
+
+  /* For command: info register.  */
+  if (regnum == -1 && all == 0)
+    {
+      default_print_registers_info (gdbarch, file, frame,
+				    CSKY_PC_REGNUM, 0);
+      default_print_registers_info (gdbarch, file, frame,
+				    CSKY_EPC_REGNUM, 0);
+      default_print_registers_info (gdbarch, file, frame,
+				    CSKY_CR0_REGNUM, 0);
+      default_print_registers_info (gdbarch, file, frame,
+				    CSKY_EPSR_REGNUM, 0);
+    }
+  return;
+}
+
+/* Initialize the current architecture based on INFO.  If possible,
+   re-use an architecture from ARCHES, which is a list of
+   architectures already created during this debugging session.
+
+   Called at program startup, when reading a core file, and when
+   reading a binary file.  */
+
+static struct gdbarch *
+csky_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
+{
+  struct gdbarch *gdbarch;
+  struct gdbarch_tdep *tdep;
+
+  /* Find a candidate among the list of pre-declared architectures.  */
+  arches = gdbarch_list_lookup_by_info (arches, &info);
+  if (arches != NULL)
+    return arches->gdbarch;
+
+  /* None found, create a new architecture from the information
+     provided.  */
+  tdep = XCNEW (struct gdbarch_tdep);
+  gdbarch = gdbarch_alloc (&info, tdep);
+
+  /* Target data types.  */
+  set_gdbarch_ptr_bit (gdbarch, 32);
+  set_gdbarch_addr_bit (gdbarch, 32);
+  set_gdbarch_short_bit (gdbarch, 16);
+  set_gdbarch_int_bit (gdbarch, 32);
+  set_gdbarch_long_bit (gdbarch, 32);
+  set_gdbarch_long_long_bit (gdbarch, 64);
+  set_gdbarch_float_bit (gdbarch, 32);
+  set_gdbarch_double_bit (gdbarch, 64);
+  set_gdbarch_float_format (gdbarch, floatformats_ieee_single);
+  set_gdbarch_double_format (gdbarch, floatformats_ieee_double);
+
+  /* Information about the target architecture.  */
+  set_gdbarch_return_value (gdbarch, csky_return_value);
+  set_gdbarch_breakpoint_kind_from_pc (gdbarch, csky_breakpoint_kind_from_pc);
+  set_gdbarch_sw_breakpoint_from_kind (gdbarch, csky_sw_breakpoint_from_kind);
+
+  /* Register architecture.  */
+  set_gdbarch_num_regs (gdbarch, CSKY_NUM_REGS);
+  set_gdbarch_pc_regnum (gdbarch, CSKY_PC_REGNUM);
+  set_gdbarch_sp_regnum (gdbarch, CSKY_SP_REGNUM);
+  set_gdbarch_register_name (gdbarch, csky_register_name);
+  set_gdbarch_register_type (gdbarch, csky_register_type);
+  set_gdbarch_read_pc (gdbarch, csky_read_pc);
+  set_gdbarch_write_pc (gdbarch, csky_write_pc);
+  set_gdbarch_print_registers_info (gdbarch, csky_print_registers_info);
+  csky_add_reggroups (gdbarch);
+  set_gdbarch_register_reggroup_p (gdbarch, csky_register_reggroup_p);
+  set_gdbarch_stab_reg_to_regnum (gdbarch, csky_dwarf_reg_to_regnum);
+  set_gdbarch_dwarf2_reg_to_regnum (gdbarch, csky_dwarf_reg_to_regnum);
+  dwarf2_frame_set_init_reg (gdbarch, csky_dwarf2_frame_init_reg);
+
+  /* Functions to analyze frames.  */
+  frame_base_set_default (gdbarch, &csky_frame_base);
+  set_gdbarch_skip_prologue (gdbarch, csky_skip_prologue);
+  set_gdbarch_inner_than (gdbarch, core_addr_lessthan);
+  set_gdbarch_frame_align (gdbarch, csky_frame_align);
+  set_gdbarch_stack_frame_destroyed_p (gdbarch, csky_stack_frame_destroyed_p);
+
+  /* Functions to access frame data.  */
+  set_gdbarch_unwind_pc (gdbarch, csky_unwind_pc);
+  set_gdbarch_unwind_sp (gdbarch, csky_unwind_sp);
+
+  /* Functions handling dummy frames.  */
+  set_gdbarch_push_dummy_call (gdbarch, csky_push_dummy_call);
+  set_gdbarch_dummy_id (gdbarch, csky_dummy_id);
+
+  /* Frame unwinders.  Use DWARF debug info if available,
+     otherwise use our own unwinder.  */
+  dwarf2_append_unwinders (gdbarch);
+  frame_unwind_append_unwinder (gdbarch, &csky_stub_unwind);
+  frame_unwind_append_unwinder (gdbarch, &csky_unwind_cache);
+
+  /* Breakpoints.  */
+  set_gdbarch_memory_insert_breakpoint (gdbarch,
+					csky_memory_insert_breakpoint);
+  set_gdbarch_memory_remove_breakpoint (gdbarch,
+					csky_memory_remove_breakpoint);
+
+  /* Hook in ABI-specific overrides, if they have been registered.  */
+  gdbarch_init_osabi (info, gdbarch);
+
+  /* Support simple overlay manager.  */
+  set_gdbarch_overlay_update (gdbarch, simple_overlay_update);
+  set_gdbarch_char_signed (gdbarch, 0);
+  return gdbarch;
+}
+
+void
+_initialize_csky_tdep (void)
+{
+
+  register_gdbarch_init (bfd_arch_csky, csky_gdbarch_init);
+
+  csky_init_reggroup ();
+
+  /* Allow debugging this file's internals.  */
+  add_setshow_boolean_cmd ("csky", class_maintenance, &csky_debug,
+			   _("Set C-Sky debugging."),
+			   _("Show C-Sky debugging."),
+			   _("When on, C-Sky specific debugging is enabled."),
+			   NULL,
+			   NULL,
+			   &setdebuglist, &showdebuglist);
+}