osprey-gcc/gcc/config/mn10300/mn10300.c

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/* Subroutines for insn-output.c for Matsushita MN10300 series
   Copyright (C) 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004
   Free Software Foundation, Inc.
   Contributed by Jeff Law (law@cygnus.com).

This file is part of GCC.

GCC 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, or (at your option)
any later version.

GCC 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 GCC; see the file COPYING.  If not, write to
the Free Software Foundation, 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA.  */

#include "config.h"
#include "system.h"
#include "coretypes.h"
#include "tm.h"
#include "rtl.h"
#include "tree.h"
#include "regs.h"
#include "hard-reg-set.h"
#include "real.h"
#include "insn-config.h"
#include "conditions.h"
#include "output.h"
#include "insn-attr.h"
#include "flags.h"
#include "recog.h"
#include "expr.h"
#include "optabs.h"
#include "function.h"
#include "obstack.h"
#include "toplev.h"
#include "tm_p.h"
#include "target.h"
#include "target-def.h"

/* This is used by GOTaddr2picreg to uniquely identify
   UNSPEC_INT_LABELs.  */
int mn10300_unspec_int_label_counter;

/* This is used in the am33_2.0-linux-gnu port, in which global symbol
   names are not prefixed by underscores, to tell whether to prefix a
   label with a plus sign or not, so that the assembler can tell
   symbol names from register names.  */
int mn10300_protect_label;

/* The size of the callee register save area.  Right now we save everything
   on entry since it costs us nothing in code size.  It does cost us from a
   speed standpoint, so we want to optimize this sooner or later.  */
#define REG_SAVE_BYTES (4 * regs_ever_live[2] \
      + 4 * regs_ever_live[3] \
            + 4 * regs_ever_live[6] \
      + 4 * regs_ever_live[7] \
      + 16 * (regs_ever_live[14] || regs_ever_live[15] \
        || regs_ever_live[16] || regs_ever_live[17]))


static int mn10300_address_cost_1 (rtx, int *);
static int mn10300_address_cost (rtx);
static bool mn10300_rtx_costs (rtx, int, int, int *);
static void mn10300_file_start (void);
static bool mn10300_return_in_memory (tree, tree);
static rtx mn10300_builtin_saveregs (void);
static bool mn10300_pass_by_reference (CUMULATIVE_ARGS *, enum machine_mode,
               tree, bool);
static int mn10300_arg_partial_bytes (CUMULATIVE_ARGS *, enum machine_mode,
              tree, bool);

/* Initialize the GCC target structure.  */
#undef TARGET_ASM_ALIGNED_HI_OP
#define TARGET_ASM_ALIGNED_HI_OP "\t.hword\t"

#undef TARGET_RTX_COSTS
#define TARGET_RTX_COSTS mn10300_rtx_costs
#undef TARGET_ADDRESS_COST
#define TARGET_ADDRESS_COST mn10300_address_cost

#undef TARGET_ASM_FILE_START
#define TARGET_ASM_FILE_START mn10300_file_start
#undef TARGET_ASM_FILE_START_FILE_DIRECTIVE
#define TARGET_ASM_FILE_START_FILE_DIRECTIVE true

#undef  TARGET_ENCODE_SECTION_INFO
#define TARGET_ENCODE_SECTION_INFO mn10300_encode_section_info

#undef TARGET_PROMOTE_PROTOTYPES
#define TARGET_PROMOTE_PROTOTYPES hook_bool_tree_true
#undef TARGET_RETURN_IN_MEMORY
#define TARGET_RETURN_IN_MEMORY mn10300_return_in_memory
#undef TARGET_PASS_BY_REFERENCE
#define TARGET_PASS_BY_REFERENCE mn10300_pass_by_reference
#undef TARGET_CALLEE_COPIES
#define TARGET_CALLEE_COPIES hook_bool_CUMULATIVE_ARGS_mode_tree_bool_true
#undef TARGET_ARG_PARTIAL_BYTES
#define TARGET_ARG_PARTIAL_BYTES mn10300_arg_partial_bytes

#undef TARGET_EXPAND_BUILTIN_SAVEREGS
#define TARGET_EXPAND_BUILTIN_SAVEREGS mn10300_builtin_saveregs

static void mn10300_encode_section_info (tree, rtx, int);
struct gcc_target targetm = TARGET_INITIALIZER;

static void
mn10300_file_start (void)
{
  default_file_start ();

  if (TARGET_AM33_2)
    fprintf (asm_out_file, "\t.am33_2\n");
  else if (TARGET_AM33)
    fprintf (asm_out_file, "\t.am33\n");
}


/* Print operand X using operand code CODE to assembly language output file
   FILE.  */

void
print_operand (FILE *file, rtx x, int code)
{
  switch (code)
    {
      case 'b':
      case 'B':
  if (cc_status.mdep.fpCC)
    {
      switch (code == 'b' ? GET_CODE (x)
        : reverse_condition_maybe_unordered (GET_CODE (x)))
        {
        case NE:
    fprintf (file, "ne");
    break;
        case EQ:
    fprintf (file, "eq");
    break;
        case GE:
    fprintf (file, "ge");
    break;
        case GT:
    fprintf (file, "gt");
    break;
        case LE:
    fprintf (file, "le");
    break;
        case LT:
    fprintf (file, "lt");
    break;
        case ORDERED:
    fprintf (file, "lge");
    break;
        case UNORDERED:
    fprintf (file, "uo");
    break;
        case LTGT:
    fprintf (file, "lg");
    break;
        case UNEQ:
    fprintf (file, "ue");
    break;
        case UNGE:
    fprintf (file, "uge");
    break;
        case UNGT:
    fprintf (file, "ug");
    break;
        case UNLE:
    fprintf (file, "ule");
    break;
        case UNLT:
    fprintf (file, "ul");
    break;
        default:
    abort ();
        }
      break;
    }
  /* These are normal and reversed branches.  */
  switch (code == 'b' ? GET_CODE (x) : reverse_condition (GET_CODE (x)))
    {
    case NE:
      fprintf (file, "ne");
      break;
    case EQ:
      fprintf (file, "eq");
      break;
    case GE:
      fprintf (file, "ge");
      break;
    case GT:
      fprintf (file, "gt");
      break;
    case LE:
      fprintf (file, "le");
      break;
    case LT:
      fprintf (file, "lt");
      break;
    case GEU:
      fprintf (file, "cc");
      break;
    case GTU:
      fprintf (file, "hi");
      break;
    case LEU:
      fprintf (file, "ls");
      break;
    case LTU:
      fprintf (file, "cs");
      break;
    default:
      abort ();
    }
  break;
      case 'C':
  /* This is used for the operand to a call instruction;
     if it's a REG, enclose it in parens, else output
     the operand normally.  */
  if (GET_CODE (x) == REG)
    {
      fputc ('(', file);
      print_operand (file, x, 0);
      fputc (')', file);
    }
  else
    print_operand (file, x, 0);
  break;
     
      case 'D':
  switch (GET_CODE (x))
    {
    case MEM:
      fputc ('(', file);
      output_address (XEXP (x, 0));
      fputc (')', file);
      break;

    case REG:
      fprintf (file, "fd%d", REGNO (x) - 18);
      break;

    default:
      abort ();
    }
  break;

      /* These are the least significant word in a 64bit value.  */
      case 'L':
  switch (GET_CODE (x))
    {
    case MEM:
      fputc ('(', file);
      output_address (XEXP (x, 0));
      fputc (')', file);
      break;

    case REG:
      fprintf (file, "%s", reg_names[REGNO (x)]);
      break;

    case SUBREG:
      fprintf (file, "%s", reg_names[subreg_regno (x)]);
      break;

    case CONST_DOUBLE:
        {
    long val[2];
    REAL_VALUE_TYPE rv;

    switch (GET_MODE (x))
      {
        case DFmode:
          REAL_VALUE_FROM_CONST_DOUBLE (rv, x);
          REAL_VALUE_TO_TARGET_DOUBLE (rv, val);
          fprintf (file, "0x%lx", val[0]);
          break;;
        case SFmode:
          REAL_VALUE_FROM_CONST_DOUBLE (rv, x);
          REAL_VALUE_TO_TARGET_SINGLE (rv, val[0]);
          fprintf (file, "0x%lx", val[0]);
          break;;
        case VOIDmode:
        case DImode:
          print_operand_address (file,
               GEN_INT (CONST_DOUBLE_LOW (x)));
          break;
        default:
          break;
      }
    break;
        }

    case CONST_INT:
      {
        rtx low, high;
        split_double (x, &low, &high);
        fprintf (file, "%ld", (long)INTVAL (low));
        break;
      }

    default:
      abort ();
    }
  break;

      /* Similarly, but for the most significant word.  */
      case 'H':
  switch (GET_CODE (x))
    {
    case MEM:
      fputc ('(', file);
      x = adjust_address (x, SImode, 4);
      output_address (XEXP (x, 0));
      fputc (')', file);
      break;

    case REG:
      fprintf (file, "%s", reg_names[REGNO (x) + 1]);
      break;

    case SUBREG:
      fprintf (file, "%s", reg_names[subreg_regno (x) + 1]);
      break;

    case CONST_DOUBLE:
        {
    long val[2];
    REAL_VALUE_TYPE rv;

    switch (GET_MODE (x))
      {
        case DFmode:
          REAL_VALUE_FROM_CONST_DOUBLE (rv, x);
          REAL_VALUE_TO_TARGET_DOUBLE (rv, val);
          fprintf (file, "0x%lx", val[1]);
          break;;
        case SFmode:
          abort ();
        case VOIDmode:
        case DImode:
          print_operand_address (file, 
               GEN_INT (CONST_DOUBLE_HIGH (x)));
          break;
        default:
          break;
      }
    break;
        }

    case CONST_INT:
      {
        rtx low, high;
        split_double (x, &low, &high);
        fprintf (file, "%ld", (long)INTVAL (high));
        break;
      }

    default:
      abort ();
    }
  break;

      case 'A':
  fputc ('(', file);
  if (GET_CODE (XEXP (x, 0)) == REG)
    output_address (gen_rtx_PLUS (SImode, XEXP (x, 0), const0_rtx));
  else
    output_address (XEXP (x, 0));
  fputc (')', file);
  break;

      case 'N':
  if (INTVAL (x) < -128 || INTVAL (x) > 255)
    abort ();
  fprintf (file, "%d", (int)((~INTVAL (x)) & 0xff));
  break;

      case 'U':
  if (INTVAL (x) < -128 || INTVAL (x) > 255)
    abort ();
  fprintf (file, "%d", (int)(INTVAL (x) & 0xff));
  break;

      /* For shift counts.  The hardware ignores the upper bits of
   any immediate, but the assembler will flag an out of range
   shift count as an error.  So we mask off the high bits
   of the immediate here.  */
      case 'S':
  if (GET_CODE (x) == CONST_INT)
    {
      fprintf (file, "%d", (int)(INTVAL (x) & 0x1f));
      break;
    }
  /* FALL THROUGH */

      default:
  switch (GET_CODE (x))
    {
    case MEM:
      fputc ('(', file);
      output_address (XEXP (x, 0));
      fputc (')', file);
      break;

    case PLUS:
      output_address (x);
      break;

    case REG:
      fprintf (file, "%s", reg_names[REGNO (x)]);
      break;

    case SUBREG:
      fprintf (file, "%s", reg_names[subreg_regno (x)]);
      break;

    /* This will only be single precision....  */
    case CONST_DOUBLE:
      {
        unsigned long val;
        REAL_VALUE_TYPE rv;

        REAL_VALUE_FROM_CONST_DOUBLE (rv, x);
        REAL_VALUE_TO_TARGET_SINGLE (rv, val);
        fprintf (file, "0x%lx", val);
        break;
      }

    case CONST_INT:
    case SYMBOL_REF:
    case CONST:
    case LABEL_REF:
    case CODE_LABEL:
    case UNSPEC:
      print_operand_address (file, x);
      break;
    default:
      abort ();
    }
  break;
   }
}

/* Output assembly language output for the address ADDR to FILE.  */

void
print_operand_address (FILE *file, rtx addr)
{
  switch (GET_CODE (addr))
    {
    case POST_INC:
      print_operand_address (file, XEXP (addr, 0));
      fputc ('+', file);
      break;
    case REG:
      print_operand (file, addr, 0);
      break;
    case PLUS:
      {
  rtx base, index;
  if (REG_P (XEXP (addr, 0))
      && REG_OK_FOR_BASE_P (XEXP (addr, 0)))
    base = XEXP (addr, 0), index = XEXP (addr, 1);
  else if (REG_P (XEXP (addr, 1))
      && REG_OK_FOR_BASE_P (XEXP (addr, 1)))
    base = XEXP (addr, 1), index = XEXP (addr, 0);
        else
    abort ();
  print_operand (file, index, 0);
  fputc (',', file);
  print_operand (file, base, 0);;
  break;
      }
    case SYMBOL_REF:
      output_addr_const (file, addr);
      break;
    default:
      output_addr_const (file, addr);
      break;
    }
}

/* Count the number of FP registers that have to be saved.  */
static int
fp_regs_to_save (void)
{
  int i, n = 0;

  if (! TARGET_AM33_2)
    return 0;

  for (i = FIRST_FP_REGNUM; i <= LAST_FP_REGNUM; ++i)
    if (regs_ever_live[i] && ! call_used_regs[i])
      ++n;

  return n;
}

/* Print a set of registers in the format required by "movm" and "ret".
   Register K is saved if bit K of MASK is set.  The data and address
   registers can be stored individually, but the extended registers cannot.
   We assume that the mask alread takes that into account.  For instance,
   bits 14 to 17 must have the same value.  */

void
mn10300_print_reg_list (FILE *file, int mask)
{
  int need_comma;
  int i;

  need_comma = 0;
  fputc ('[', file);

  for (i = 0; i < FIRST_EXTENDED_REGNUM; i++)
    if ((mask & (1 << i)) != 0)
      {
  if (need_comma)
    fputc (',', file);
  fputs (reg_names [i], file);
  need_comma = 1;
      }

  if ((mask & 0x3c000) != 0)
    {
      if ((mask & 0x3c000) != 0x3c000)
  abort();
      if (need_comma)
  fputc (',', file);
      fputs ("exreg1", file);
      need_comma = 1;
    }

  fputc (']', file);
}

int
can_use_return_insn (void)
{
  /* size includes the fixed stack space needed for function calls.  */
  int size = get_frame_size () + current_function_outgoing_args_size;

  /* And space for the return pointer.  */
  size += current_function_outgoing_args_size ? 4 : 0;

  return (reload_completed
    && size == 0
    && !regs_ever_live[2]
    && !regs_ever_live[3]
    && !regs_ever_live[6]
    && !regs_ever_live[7]
    && !regs_ever_live[14]
    && !regs_ever_live[15]
    && !regs_ever_live[16]
    && !regs_ever_live[17]
    && fp_regs_to_save () == 0
    && !frame_pointer_needed);
}

/* Returns the set of live, callee-saved registers as a bitmask.  The
   callee-saved extended registers cannot be stored individually, so
   all of them will be included in the mask if any one of them is used.  */

int
mn10300_get_live_callee_saved_regs (void)
{
  int mask;
  int i;

  mask = 0;
  for (i = 0; i <= LAST_EXTENDED_REGNUM; i++)
    if (regs_ever_live[i] && ! call_used_regs[i])
      mask |= (1 << i);
  if ((mask & 0x3c000) != 0)
    mask |= 0x3c000;

  return mask;
}

/* Generate an instruction that pushes several registers onto the stack.
   Register K will be saved if bit K in MASK is set.  The function does
   nothing if MASK is zero.

   To be compatible with the "movm" instruction, the lowest-numbered
   register must be stored in the lowest slot.  If MASK is the set
   { R1,...,RN }, where R1...RN are ordered least first, the generated
   instruction will have the form:

       (parallel
         (set (reg:SI 9) (plus:SI (reg:SI 9) (const_int -N*4)))
   (set (mem:SI (plus:SI (reg:SI 9)
                         (const_int -1*4)))
        (reg:SI RN))
   ...
   (set (mem:SI (plus:SI (reg:SI 9)
                         (const_int -N*4)))
        (reg:SI R1))) */

void
mn10300_gen_multiple_store (int mask)
{
  if (mask != 0)
    {
      int i;
      int count;
      rtx par;
      int pari;

      /* Count how many registers need to be saved.  */
      count = 0;
      for (i = 0; i <= LAST_EXTENDED_REGNUM; i++)
  if ((mask & (1 << i)) != 0)
    count += 1;

      /* We need one PARALLEL element to update the stack pointer and
   an additional element for each register that is stored.  */
      par = gen_rtx_PARALLEL (VOIDmode, rtvec_alloc (count + 1));

      /* Create the instruction that updates the stack pointer.  */
      XVECEXP (par, 0, 0)
  = gen_rtx_SET (SImode,
           stack_pointer_rtx,
           gen_rtx_PLUS (SImode,
             stack_pointer_rtx,
             GEN_INT (-count * 4)));

      /* Create each store.  */
      pari = 1;
      for (i = LAST_EXTENDED_REGNUM; i >= 0; i--)
  if ((mask & (1 << i)) != 0)
    {
      rtx address = gen_rtx_PLUS (SImode,
          stack_pointer_rtx,
          GEN_INT (-pari * 4));
      XVECEXP(par, 0, pari)
        = gen_rtx_SET (VOIDmode,
           gen_rtx_MEM (SImode, address),
           gen_rtx_REG (SImode, i));
      pari += 1;
    }

      par = emit_insn (par);
      RTX_FRAME_RELATED_P (par) = 1;
    }
}

void
expand_prologue (void)
{
  HOST_WIDE_INT size;

  /* SIZE includes the fixed stack space needed for function calls.  */
  size = get_frame_size () + current_function_outgoing_args_size;
  size += (current_function_outgoing_args_size ? 4 : 0);

  /* If we use any of the callee-saved registers, save them now.  */
  mn10300_gen_multiple_store (mn10300_get_live_callee_saved_regs ());

  if (TARGET_AM33_2 && fp_regs_to_save ())
    {
      int num_regs_to_save = fp_regs_to_save (), i;
      HOST_WIDE_INT xsize;
      enum { save_sp_merge,
       save_sp_no_merge,
       save_sp_partial_merge,
       save_a0_merge,
       save_a0_no_merge } strategy;
      unsigned int strategy_size = (unsigned)-1, this_strategy_size;
      rtx reg;
      rtx insn;

      /* We have several different strategies to save FP registers.
   We can store them using SP offsets, which is beneficial if
   there are just a few registers to save, or we can use `a0' in
   post-increment mode (`a0' is the only call-clobbered address
   register that is never used to pass information to a
   function).  Furthermore, if we don't need a frame pointer, we
   can merge the two SP adds into a single one, but this isn't
   always beneficial; sometimes we can just split the two adds
   so that we don't exceed a 16-bit constant size.  The code
   below will select which strategy to use, so as to generate
   smallest code.  Ties are broken in favor or shorter sequences
   (in terms of number of instructions).  */

#define SIZE_ADD_AX(S) ((((S) >= (1 << 15)) || ((S) < -(1 << 15))) ? 6 \
      : (((S) >= (1 << 7)) || ((S) < -(1 << 7))) ? 4 : 2)
#define SIZE_ADD_SP(S) ((((S) >= (1 << 15)) || ((S) < -(1 << 15))) ? 6 \
      : (((S) >= (1 << 7)) || ((S) < -(1 << 7))) ? 4 : 3)
#define SIZE_FMOV_LIMIT(S,N,L,SIZE1,SIZE2,ELSE) \
  (((S) >= (L)) ? (SIZE1) * (N) \
   : ((S) + 4 * (N) >= (L)) ? (((L) - (S)) / 4 * (SIZE2) \
             + ((S) + 4 * (N) - (L)) / 4 * (SIZE1)) \
   : (ELSE))
#define SIZE_FMOV_SP_(S,N) \
  (SIZE_FMOV_LIMIT ((S), (N), (1 << 24), 7, 6, \
                   SIZE_FMOV_LIMIT ((S), (N), (1 << 8), 6, 4, \
            (S) ? 4 * (N) : 3 + 4 * ((N) - 1))))
#define SIZE_FMOV_SP(S,N) (SIZE_FMOV_SP_ ((unsigned HOST_WIDE_INT)(S), (N)))

      /* Consider alternative save_sp_merge only if we don't need the
   frame pointer and size is nonzero.  */
      if (! frame_pointer_needed && size)
  {
    /* Insn: add -(size + 4 * num_regs_to_save), sp.  */
    this_strategy_size = SIZE_ADD_SP (-(size + 4 * num_regs_to_save));
    /* Insn: fmov fs#, (##, sp), for each fs# to be saved.  */
    this_strategy_size += SIZE_FMOV_SP (size, num_regs_to_save);

    if (this_strategy_size < strategy_size)
      {
        strategy = save_sp_merge;
        strategy_size = this_strategy_size;
      }
  }

      /* Consider alternative save_sp_no_merge unconditionally.  */
      /* Insn: add -4 * num_regs_to_save, sp.  */
      this_strategy_size = SIZE_ADD_SP (-4 * num_regs_to_save);
      /* Insn: fmov fs#, (##, sp), for each fs# to be saved.  */
      this_strategy_size += SIZE_FMOV_SP (0, num_regs_to_save);
      if (size)
  {
    /* Insn: add -size, sp.  */
    this_strategy_size += SIZE_ADD_SP (-size);
  }

      if (this_strategy_size < strategy_size)
  {
    strategy = save_sp_no_merge;
    strategy_size = this_strategy_size;
  }

      /* Consider alternative save_sp_partial_merge only if we don't
   need a frame pointer and size is reasonably large.  */
      if (! frame_pointer_needed && size + 4 * num_regs_to_save > 128)
  {
    /* Insn: add -128, sp.  */
    this_strategy_size = SIZE_ADD_SP (-128);
    /* Insn: fmov fs#, (##, sp), for each fs# to be saved.  */
    this_strategy_size += SIZE_FMOV_SP (128 - 4 * num_regs_to_save,
                num_regs_to_save);
    if (size)
      {
        /* Insn: add 128-size, sp.  */
        this_strategy_size += SIZE_ADD_SP (128 - size);
      }

    if (this_strategy_size < strategy_size)
      {
        strategy = save_sp_partial_merge;
        strategy_size = this_strategy_size;
      }
  }

      /* Consider alternative save_a0_merge only if we don't need a
   frame pointer, size is nonzero and the user hasn't
   changed the calling conventions of a0.  */
      if (! frame_pointer_needed && size
    && call_used_regs[FIRST_ADDRESS_REGNUM]
    && ! fixed_regs[FIRST_ADDRESS_REGNUM])
  {
    /* Insn: add -(size + 4 * num_regs_to_save), sp.  */
    this_strategy_size = SIZE_ADD_SP (-(size + 4 * num_regs_to_save));
    /* Insn: mov sp, a0.  */
    this_strategy_size++;
    if (size)
      {
        /* Insn: add size, a0.  */
        this_strategy_size += SIZE_ADD_AX (size);
      }
    /* Insn: fmov fs#, (a0+), for each fs# to be saved.  */
    this_strategy_size += 3 * num_regs_to_save;

    if (this_strategy_size < strategy_size)
      {
        strategy = save_a0_merge;
        strategy_size = this_strategy_size;
      }
  }

      /* Consider alternative save_a0_no_merge if the user hasn't
   changed the calling conventions of a0.  */
      if (call_used_regs[FIRST_ADDRESS_REGNUM]
    && ! fixed_regs[FIRST_ADDRESS_REGNUM])
  {
    /* Insn: add -4 * num_regs_to_save, sp.  */
    this_strategy_size = SIZE_ADD_SP (-4 * num_regs_to_save);
    /* Insn: mov sp, a0.  */
    this_strategy_size++;
    /* Insn: fmov fs#, (a0+), for each fs# to be saved.  */
    this_strategy_size += 3 * num_regs_to_save;
    if (size)
      {
        /* Insn: add -size, sp.  */
        this_strategy_size += SIZE_ADD_SP (-size);
      }

    if (this_strategy_size < strategy_size)
      {
        strategy = save_a0_no_merge;
        strategy_size = this_strategy_size;
      }
  }

      /* Emit the initial SP add, common to all strategies.  */
      switch (strategy)
  {
  case save_sp_no_merge:
  case save_a0_no_merge:
    emit_insn (gen_addsi3 (stack_pointer_rtx,
         stack_pointer_rtx,
         GEN_INT (-4 * num_regs_to_save)));
    xsize = 0;
    break;

  case save_sp_partial_merge:
    emit_insn (gen_addsi3 (stack_pointer_rtx,
         stack_pointer_rtx,
         GEN_INT (-128)));
    xsize = 128 - 4 * num_regs_to_save;
    size -= xsize;
    break;

  case save_sp_merge:
  case save_a0_merge:
    emit_insn (gen_addsi3 (stack_pointer_rtx,
         stack_pointer_rtx,
         GEN_INT (-(size + 4 * num_regs_to_save))));
    /* We'll have to adjust FP register saves according to the
       frame size.  */
    xsize = size;
    /* Since we've already created the stack frame, don't do it
       again at the end of the function.  */
    size = 0;
    break;

  default:
    abort ();
  }
    
      /* Now prepare register a0, if we have decided to use it.  */
      switch (strategy)
  {
  case save_sp_merge:
  case save_sp_no_merge:
  case save_sp_partial_merge:
    reg = 0;
    break;

  case save_a0_merge:
  case save_a0_no_merge:
    reg = gen_rtx_REG (SImode, FIRST_ADDRESS_REGNUM);
    emit_insn (gen_movsi (reg, stack_pointer_rtx));
    if (xsize)
      emit_insn (gen_addsi3 (reg, reg, GEN_INT (xsize)));
    reg = gen_rtx_POST_INC (SImode, reg);
    break;
    
  default:
    abort ();
  }
      
      /* Now actually save the FP registers.  */
      for (i = FIRST_FP_REGNUM; i <= LAST_FP_REGNUM; ++i)
  if (regs_ever_live[i] && ! call_used_regs[i])
    {
      rtx addr;

      if (reg)
        addr = reg;
      else
        {
    /* If we aren't using `a0', use an SP offset.  */
    if (xsize)
      {
        addr = gen_rtx_PLUS (SImode,
           stack_pointer_rtx,
           GEN_INT (xsize));
      }
    else
      addr = stack_pointer_rtx;
    
    xsize += 4;
        }

      insn = emit_insn (gen_movsi (gen_rtx_MEM (SImode, addr),
           gen_rtx_REG (SImode, i)));

      RTX_FRAME_RELATED_P (insn) = 1;
    }
    }

  /* Now put the frame pointer into the frame pointer register.  */
  if (frame_pointer_needed)
    emit_move_insn (frame_pointer_rtx, stack_pointer_rtx);

  /* Allocate stack for this frame.  */
  if (size)
    emit_insn (gen_addsi3 (stack_pointer_rtx,
         stack_pointer_rtx,
         GEN_INT (-size)));
  if (flag_pic && regs_ever_live[PIC_OFFSET_TABLE_REGNUM])
    {
      rtx insn = get_last_insn ();
      rtx last = emit_insn (gen_GOTaddr2picreg ());

      /* Mark these insns as possibly dead.  Sometimes, flow2 may
   delete all uses of the PIC register.  In this case, let it
   delete the initialization too.  */
      do
  {
    insn = NEXT_INSN (insn);

    REG_NOTES (insn) = gen_rtx_EXPR_LIST (REG_MAYBE_DEAD,
            const0_rtx,
            REG_NOTES (insn));
  }
      while (insn != last);
    }
}

void
expand_epilogue (void)
{
  HOST_WIDE_INT size;

  /* SIZE includes the fixed stack space needed for function calls.  */
  size = get_frame_size () + current_function_outgoing_args_size;
  size += (current_function_outgoing_args_size ? 4 : 0);

  if (TARGET_AM33_2 && fp_regs_to_save ())
    {
      int num_regs_to_save = fp_regs_to_save (), i;
      rtx reg = 0;

      /* We have several options to restore FP registers.  We could
   load them from SP offsets, but, if there are enough FP
   registers to restore, we win if we use a post-increment
   addressing mode.  */

      /* If we have a frame pointer, it's the best option, because we
   already know it has the value we want.  */
      if (frame_pointer_needed)
  reg = gen_rtx_REG (SImode, FRAME_POINTER_REGNUM);
      /* Otherwise, we may use `a1', since it's call-clobbered and
   it's never used for return values.  But only do so if it's
   smaller than using SP offsets.  */
      else
  {
    enum { restore_sp_post_adjust,
     restore_sp_pre_adjust,
     restore_sp_partial_adjust,
     restore_a1 } strategy;
    unsigned int this_strategy_size, strategy_size = (unsigned)-1;

    /* Consider using sp offsets before adjusting sp.  */
    /* Insn: fmov (##,sp),fs#, for each fs# to be restored.  */
    this_strategy_size = SIZE_FMOV_SP (size, num_regs_to_save);
    /* If size is too large, we'll have to adjust SP with an
     add.  */
    if (size + 4 * num_regs_to_save + REG_SAVE_BYTES > 255)
      {
        /* Insn: add size + 4 * num_regs_to_save, sp.  */
        this_strategy_size += SIZE_ADD_SP (size + 4 * num_regs_to_save);
      }
    /* If we don't have to restore any non-FP registers,
     we'll be able to save one byte by using rets.  */
    if (! REG_SAVE_BYTES)
      this_strategy_size--;

    if (this_strategy_size < strategy_size)
      {
        strategy = restore_sp_post_adjust;
        strategy_size = this_strategy_size;
      }

    /* Consider using sp offsets after adjusting sp.  */
    /* Insn: add size, sp.  */
    this_strategy_size = SIZE_ADD_SP (size);
    /* Insn: fmov (##,sp),fs#, for each fs# to be restored.  */
    this_strategy_size += SIZE_FMOV_SP (0, num_regs_to_save);
    /* We're going to use ret to release the FP registers
     save area, so, no savings.  */

    if (this_strategy_size < strategy_size)
      {
        strategy = restore_sp_pre_adjust;
        strategy_size = this_strategy_size;
      }

    /* Consider using sp offsets after partially adjusting sp.
       When size is close to 32Kb, we may be able to adjust SP
       with an imm16 add instruction while still using fmov
       (d8,sp).  */
    if (size + 4 * num_regs_to_save + REG_SAVE_BYTES > 255)
      {
        /* Insn: add size + 4 * num_regs_to_save
        + REG_SAVE_BYTES - 252,sp.  */
        this_strategy_size = SIZE_ADD_SP (size + 4 * num_regs_to_save
            + REG_SAVE_BYTES - 252);
        /* Insn: fmov (##,sp),fs#, fo each fs# to be restored.  */
        this_strategy_size += SIZE_FMOV_SP (252 - REG_SAVE_BYTES
              - 4 * num_regs_to_save,
              num_regs_to_save);
        /* We're going to use ret to release the FP registers
     save area, so, no savings.  */

        if (this_strategy_size < strategy_size)
    {
      strategy = restore_sp_partial_adjust;
      strategy_size = this_strategy_size;
    }
      }

    /* Consider using a1 in post-increment mode, as long as the
       user hasn't changed the calling conventions of a1.  */
    if (call_used_regs[FIRST_ADDRESS_REGNUM+1]
        && ! fixed_regs[FIRST_ADDRESS_REGNUM+1])
      {
        /* Insn: mov sp,a1.  */
        this_strategy_size = 1;
        if (size)
    {
      /* Insn: add size,a1.  */
      this_strategy_size += SIZE_ADD_AX (size);
    }
        /* Insn: fmov (a1+),fs#, for each fs# to be restored.  */
        this_strategy_size += 3 * num_regs_to_save;
        /* If size is large enough, we may be able to save a
     couple of bytes.  */
        if (size + 4 * num_regs_to_save + REG_SAVE_BYTES > 255)
    {
      /* Insn: mov a1,sp.  */
      this_strategy_size += 2;
    }
        /* If we don't have to restore any non-FP registers,
     we'll be able to save one byte by using rets.  */
        if (! REG_SAVE_BYTES)
    this_strategy_size--;

        if (this_strategy_size < strategy_size)
    {
      strategy = restore_a1;
      strategy_size = this_strategy_size;
    }
      }

    switch (strategy)
      {
      case restore_sp_post_adjust:
        break;

      case restore_sp_pre_adjust:
        emit_insn (gen_addsi3 (stack_pointer_rtx,
             stack_pointer_rtx,
             GEN_INT (size)));
        size = 0;
        break;

      case restore_sp_partial_adjust:
        emit_insn (gen_addsi3 (stack_pointer_rtx,
             stack_pointer_rtx,
             GEN_INT (size + 4 * num_regs_to_save
                + REG_SAVE_BYTES - 252)));
        size = 252 - REG_SAVE_BYTES - 4 * num_regs_to_save;
        break;
        
      case restore_a1:
        reg = gen_rtx_REG (SImode, FIRST_ADDRESS_REGNUM + 1);
        emit_insn (gen_movsi (reg, stack_pointer_rtx));
        if (size)
    emit_insn (gen_addsi3 (reg, reg, GEN_INT (size)));
        break;

      default:
        abort ();
      }
  }

      /* Adjust the selected register, if any, for post-increment.  */
      if (reg)
  reg = gen_rtx_POST_INC (SImode, reg);

      for (i = FIRST_FP_REGNUM; i <= LAST_FP_REGNUM; ++i)
  if (regs_ever_live[i] && ! call_used_regs[i])
    {
      rtx addr;
      
      if (reg)
        addr = reg;
      else if (size)
        {
    /* If we aren't using a post-increment register, use an
       SP offset.  */
    addr = gen_rtx_PLUS (SImode,
             stack_pointer_rtx,
             GEN_INT (size));
        }
      else
        addr = stack_pointer_rtx;

      size += 4;

      emit_insn (gen_movsi (gen_rtx_REG (SImode, i),
          gen_rtx_MEM (SImode, addr)));
    }

      /* If we were using the restore_a1 strategy and the number of
   bytes to be released won't fit in the `ret' byte, copy `a1'
   to `sp', to avoid having to use `add' to adjust it.  */
      if (! frame_pointer_needed && reg && size + REG_SAVE_BYTES > 255)
  {
    emit_move_insn (stack_pointer_rtx, XEXP (reg, 0));
    size = 0;
  }
    }

  /* Maybe cut back the stack, except for the register save area.

     If the frame pointer exists, then use the frame pointer to
     cut back the stack.

     If the stack size + register save area is more than 255 bytes,
     then the stack must be cut back here since the size + register
     save size is too big for a ret/retf instruction. 

     Else leave it alone, it will be cut back as part of the
     ret/retf instruction, or there wasn't any stack to begin with.

     Under no circumstances should the register save area be
     deallocated here, that would leave a window where an interrupt
     could occur and trash the register save area.  */
  if (frame_pointer_needed)
    {
      emit_move_insn (stack_pointer_rtx, frame_pointer_rtx);
      size = 0;
    }
  else if (size + REG_SAVE_BYTES > 255)
    {
      emit_insn (gen_addsi3 (stack_pointer_rtx,
           stack_pointer_rtx,
           GEN_INT (size)));
      size = 0;
    }

  /* Adjust the stack and restore callee-saved registers, if any.  */
  if (size || regs_ever_live[2] || regs_ever_live[3]
      || regs_ever_live[6] || regs_ever_live[7]
      || regs_ever_live[14] || regs_ever_live[15]
      || regs_ever_live[16] || regs_ever_live[17]
      || frame_pointer_needed)
    emit_jump_insn (gen_return_internal_regs
        (GEN_INT (size + REG_SAVE_BYTES)));
  else
    emit_jump_insn (gen_return_internal ());
}

/* Update the condition code from the insn.  */

void
notice_update_cc (rtx body, rtx insn)
{
  switch (get_attr_cc (insn))
    {
    case CC_NONE:
      /* Insn does not affect CC at all.  */
      break;

    case CC_NONE_0HIT:
      /* Insn does not change CC, but the 0'th operand has been changed.  */
      if (cc_status.value1 != 0
    && reg_overlap_mentioned_p (recog_data.operand[0], cc_status.value1))
  cc_status.value1 = 0;
      break;

    case CC_SET_ZN:
      /* Insn sets the Z,N flags of CC to recog_data.operand[0].
   V,C are unusable.  */
      CC_STATUS_INIT;
      cc_status.flags |= CC_NO_CARRY | CC_OVERFLOW_UNUSABLE;
      cc_status.value1 = recog_data.operand[0];
      break;

    case CC_SET_ZNV:
      /* Insn sets the Z,N,V flags of CC to recog_data.operand[0].
   C is unusable.  */
      CC_STATUS_INIT;
      cc_status.flags |= CC_NO_CARRY;
      cc_status.value1 = recog_data.operand[0];
      break;

    case CC_COMPARE:
      /* The insn is a compare instruction.  */
      CC_STATUS_INIT;
      cc_status.value1 = SET_SRC (body);
      if (GET_CODE (cc_status.value1) == COMPARE
    && GET_MODE (XEXP (cc_status.value1, 0)) == SFmode)
  cc_status.mdep.fpCC = 1;
      break;

    case CC_CLOBBER:
      /* Insn doesn't leave CC in a usable state.  */
      CC_STATUS_INIT;
      break;

    default:
      abort ();
    }
}

/* Recognize the PARALLEL rtx generated by mn10300_gen_multiple_store().
   This function is for MATCH_PARALLEL and so assumes OP is known to be
   parallel.  If OP is a multiple store, return a mask indicating which
   registers it saves.  Return 0 otherwise.  */

int
store_multiple_operation (rtx op, enum machine_mode mode ATTRIBUTE_UNUSED)
{
  int count;
  int mask;
  int i;
  unsigned int last;
  rtx elt;

  count = XVECLEN (op, 0);
  if (count < 2)
    return 0;

  /* Check that first instruction has the form (set (sp) (plus A B)) */
  elt = XVECEXP (op, 0, 0);
  if (GET_CODE (elt) != SET
      || GET_CODE (SET_DEST (elt)) != REG
      || REGNO (SET_DEST (elt)) != STACK_POINTER_REGNUM
      || GET_CODE (SET_SRC (elt)) != PLUS)
    return 0;

  /* Check that A is the stack pointer and B is the expected stack size.
     For OP to match, each subsequent instruction should push a word onto
     the stack.  We therefore expect the first instruction to create
     COUNT-1 stack slots.  */
  elt = SET_SRC (elt);
  if (GET_CODE (XEXP (elt, 0)) != REG
      || REGNO (XEXP (elt, 0)) != STACK_POINTER_REGNUM
      || GET_CODE (XEXP (elt, 1)) != CONST_INT
      || INTVAL (XEXP (elt, 1)) != -(count - 1) * 4)
    return 0;

  /* Now go through the rest of the vector elements.  They must be
     ordered so that the first instruction stores the highest-numbered
     register to the highest stack slot and that subsequent instructions
     store a lower-numbered register to the slot below.

     LAST keeps track of the smallest-numbered register stored so far.
     MASK is the set of stored registers.  */
  last = LAST_EXTENDED_REGNUM + 1;
  mask = 0;
  for (i = 1; i < count; i++)
    {
      /* Check that element i is a (set (mem M) R) and that R is valid.  */
      elt = XVECEXP (op, 0, i);
      if (GET_CODE (elt) != SET
    || GET_CODE (SET_DEST (elt)) != MEM
    || GET_CODE (SET_SRC (elt)) != REG
    || REGNO (SET_SRC (elt)) >= last)
  return 0;

      /* R was OK, so provisionally add it to MASK.  We return 0 in any
   case if the rest of the instruction has a flaw.  */
      last = REGNO (SET_SRC (elt));
      mask |= (1 << last);

      /* Check that M has the form (plus (sp) (const_int -I*4)) */
      elt = XEXP (SET_DEST (elt), 0);
      if (GET_CODE (elt) != PLUS
    || GET_CODE (XEXP (elt, 0)) != REG
    || REGNO (XEXP (elt, 0)) != STACK_POINTER_REGNUM
    || GET_CODE (XEXP (elt, 1)) != CONST_INT
    || INTVAL (XEXP (elt, 1)) != -i * 4)
  return 0;
    }

  /* All or none of the callee-saved extended registers must be in the set.  */
  if ((mask & 0x3c000) != 0
      && (mask & 0x3c000) != 0x3c000)
    return 0;

  return mask;
}

/* Return true if OP is a valid call operand.  */

int
call_address_operand (rtx op, enum machine_mode mode ATTRIBUTE_UNUSED)
{
  if (flag_pic)
    return (EXTRA_CONSTRAINT (op, 'S') || GET_CODE (op) == REG);

  return (GET_CODE (op) == SYMBOL_REF || GET_CODE (op) == REG);
}

/* What (if any) secondary registers are needed to move IN with mode
   MODE into a register in register class CLASS. 

   We might be able to simplify this.  */
enum reg_class
secondary_reload_class (enum reg_class class, enum machine_mode mode, rtx in)
{
  /* Memory loads less than a full word wide can't have an
     address or stack pointer destination.  They must use
     a data register as an intermediate register.  */
  if ((GET_CODE (in) == MEM
       || (GET_CODE (in) == REG
     && REGNO (in) >= FIRST_PSEUDO_REGISTER)
       || (GET_CODE (in) == SUBREG
     && GET_CODE (SUBREG_REG (in)) == REG
     && REGNO (SUBREG_REG (in)) >= FIRST_PSEUDO_REGISTER))
      && (mode == QImode || mode == HImode)
      && (class == ADDRESS_REGS || class == SP_REGS
    || class == SP_OR_ADDRESS_REGS))
    {
      if (TARGET_AM33)
  return DATA_OR_EXTENDED_REGS;
      return DATA_REGS;
    }

  /* We can't directly load sp + const_int into a data register;
     we must use an address register as an intermediate.  */
  if (class != SP_REGS
      && class != ADDRESS_REGS
      && class != SP_OR_ADDRESS_REGS
      && class != SP_OR_EXTENDED_REGS
      && class != ADDRESS_OR_EXTENDED_REGS
      && class != SP_OR_ADDRESS_OR_EXTENDED_REGS
      && (in == stack_pointer_rtx
    || (GET_CODE (in) == PLUS
        && (XEXP (in, 0) == stack_pointer_rtx
      || XEXP (in, 1) == stack_pointer_rtx))))
    return ADDRESS_REGS;

  if (GET_CODE (in) == PLUS
      && (XEXP (in, 0) == stack_pointer_rtx
    || XEXP (in, 1) == stack_pointer_rtx))
    {
      if (TARGET_AM33)
  return DATA_OR_EXTENDED_REGS;
      return DATA_REGS;
    }
 
  if (TARGET_AM33_2 && class == FP_REGS
      && GET_CODE (in) == MEM && ! OK_FOR_Q (in))
    {
      if (TARGET_AM33)
  return DATA_OR_EXTENDED_REGS;
      return DATA_REGS;
    }

  /* Otherwise assume no secondary reloads are needed.  */
  return NO_REGS;
}

int
initial_offset (int from, int to)
{
  /* The difference between the argument pointer and the frame pointer
     is the size of the callee register save area.  */
  if (from == ARG_POINTER_REGNUM && to == FRAME_POINTER_REGNUM)
    {
      if (regs_ever_live[2] || regs_ever_live[3]
    || regs_ever_live[6] || regs_ever_live[7]
    || regs_ever_live[14] || regs_ever_live[15]
    || regs_ever_live[16] || regs_ever_live[17]
    || fp_regs_to_save ()
    || frame_pointer_needed)
  return REG_SAVE_BYTES
    + 4 * fp_regs_to_save ();
      else
  return 0;
    }

  /* The difference between the argument pointer and the stack pointer is
     the sum of the size of this function's frame, the callee register save
     area, and the fixed stack space needed for function calls (if any).  */
  if (from == ARG_POINTER_REGNUM && to == STACK_POINTER_REGNUM)
    {
      if (regs_ever_live[2] || regs_ever_live[3]
    || regs_ever_live[6] || regs_ever_live[7]
    || regs_ever_live[14] || regs_ever_live[15]
    || regs_ever_live[16] || regs_ever_live[17]
    || fp_regs_to_save ()
    || frame_pointer_needed)
  return (get_frame_size () + REG_SAVE_BYTES
    + 4 * fp_regs_to_save ()
    + (current_function_outgoing_args_size
       ? current_function_outgoing_args_size + 4 : 0)); 
      else
  return (get_frame_size ()
    + (current_function_outgoing_args_size
       ? current_function_outgoing_args_size + 4 : 0)); 
    }

  /* The difference between the frame pointer and stack pointer is the sum
     of the size of this function's frame and the fixed stack space needed
     for function calls (if any).  */
  if (from == FRAME_POINTER_REGNUM && to == STACK_POINTER_REGNUM)
    return (get_frame_size ()
      + (current_function_outgoing_args_size
         ? current_function_outgoing_args_size + 4 : 0)); 

  abort ();
}

/* Worker function for TARGET_RETURN_IN_MEMORY.  */

static bool
mn10300_return_in_memory (tree type, tree fntype ATTRIBUTE_UNUSED)
{
  /* Return values > 8 bytes in length in memory.  */
  return int_size_in_bytes (type) > 8 || TYPE_MODE (type) == BLKmode;
}

/* Flush the argument registers to the stack for a stdarg function;
   return the new argument pointer.  */
static rtx
mn10300_builtin_saveregs (void)
{
  rtx offset, mem;
  tree fntype = TREE_TYPE (current_function_decl);
  int argadj = ((!(TYPE_ARG_TYPES (fntype) != 0
                   && (TREE_VALUE (tree_last (TYPE_ARG_TYPES (fntype)))
                       != void_type_node)))
                ? UNITS_PER_WORD : 0);
  int set = get_varargs_alias_set ();

  if (argadj)
    offset = plus_constant (current_function_arg_offset_rtx, argadj);
  else
    offset = current_function_arg_offset_rtx;

  mem = gen_rtx_MEM (SImode, current_function_internal_arg_pointer);
  set_mem_alias_set (mem, set);
  emit_move_insn (mem, gen_rtx_REG (SImode, 0));

  mem = gen_rtx_MEM (SImode,
         plus_constant (current_function_internal_arg_pointer, 4));
  set_mem_alias_set (mem, set);
  emit_move_insn (mem, gen_rtx_REG (SImode, 1));

  return copy_to_reg (expand_binop (Pmode, add_optab,
            current_function_internal_arg_pointer,
            offset, 0, 0, OPTAB_LIB_WIDEN));
}

void
mn10300_va_start (tree valist, rtx nextarg)
{
  nextarg = expand_builtin_saveregs ();
  std_expand_builtin_va_start (valist, nextarg);
}

/* Return true when a parameter should be passed by reference.  */

static bool
mn10300_pass_by_reference (CUMULATIVE_ARGS *cum ATTRIBUTE_UNUSED,
         enum machine_mode mode, tree type,
         bool named ATTRIBUTE_UNUSED)
{
  unsigned HOST_WIDE_INT size;

  if (type)
    size = int_size_in_bytes (type);
  else
    size = GET_MODE_SIZE (mode);

  return size > 8;
}

/* Return an RTX to represent where a value with mode MODE will be returned
   from a function.  If the result is 0, the argument is pushed.  */

rtx
function_arg (CUMULATIVE_ARGS *cum, enum machine_mode mode,
        tree type, int named ATTRIBUTE_UNUSED)
{
  rtx result = 0;
  int size, align;

  /* We only support using 2 data registers as argument registers.  */
  int nregs = 2;

  /* Figure out the size of the object to be passed.  */
  if (mode == BLKmode)
    size = int_size_in_bytes (type);
  else
    size = GET_MODE_SIZE (mode);

  /* Figure out the alignment of the object to be passed.  */
  align = size;

  cum->nbytes = (cum->nbytes + 3) & ~3;

  /* Don't pass this arg via a register if all the argument registers
     are used up.  */
  if (cum->nbytes > nregs * UNITS_PER_WORD)
    return 0;

  /* Don't pass this arg via a register if it would be split between
     registers and memory.  */
  if (type == NULL_TREE
      && cum->nbytes + size > nregs * UNITS_PER_WORD)
    return 0;

  switch (cum->nbytes / UNITS_PER_WORD)
    {
    case 0:
      result = gen_rtx_REG (mode, 0);
      break;
    case 1:
      result = gen_rtx_REG (mode, 1);
      break;
    default:
      result = 0;
    }

  return result;
}

/* Return the number of bytes of registers to use for an argument passed
   partially in registers and partially in memory.  */

static int
mn10300_arg_partial_bytes (CUMULATIVE_ARGS *cum, enum machine_mode mode,
         tree type, bool named ATTRIBUTE_UNUSED)
{
  int size, align;

  /* We only support using 2 data registers as argument registers.  */
  int nregs = 2;

  /* Figure out the size of the object to be passed.  */
  if (mode == BLKmode)
    size = int_size_in_bytes (type);
  else
    size = GET_MODE_SIZE (mode);

  /* Figure out the alignment of the object to be passed.  */
  align = size;

  cum->nbytes = (cum->nbytes + 3) & ~3;

  /* Don't pass this arg via a register if all the argument registers
     are used up.  */
  if (cum->nbytes > nregs * UNITS_PER_WORD)
    return 0;

  if (cum->nbytes + size <= nregs * UNITS_PER_WORD)
    return 0;

  /* Don't pass this arg via a register if it would be split between
     registers and memory.  */
  if (type == NULL_TREE
      && cum->nbytes + size > nregs * UNITS_PER_WORD)
    return 0;

  return nregs * UNITS_PER_WORD - cum->nbytes;
}

/* Output a tst insn.  */
const char *
output_tst (rtx operand, rtx insn)
{
  rtx temp;
  int past_call = 0;

  /* We can save a byte if we can find a register which has the value
     zero in it.  */
  temp = PREV_INSN (insn);
  while (optimize && temp)
    {
      rtx set;

      /* We allow the search to go through call insns.  We record
   the fact that we've past a CALL_INSN and reject matches which
   use call clobbered registers.  */
      if (GET_CODE (temp) == CODE_LABEL
    || GET_CODE (temp) == JUMP_INSN
    || GET_CODE (temp) == BARRIER)
  break;

      if (GET_CODE (temp) == CALL_INSN)
  past_call = 1;

      if (GET_CODE (temp) == NOTE)
  {
    temp = PREV_INSN (temp);
    continue;
  }

      /* It must be an insn, see if it is a simple set.  */
      set = single_set (temp);
      if (!set)
  {
    temp = PREV_INSN (temp);
    continue;
  }

      /* Are we setting a data register to zero (this does not win for
   address registers)? 

   If it's a call clobbered register, have we past a call?

   Make sure the register we find isn't the same as ourself;
   the mn10300 can't encode that.

   ??? reg_set_between_p return nonzero anytime we pass a CALL_INSN
   so the code to detect calls here isn't doing anything useful.  */
      if (REG_P (SET_DEST (set))
    && SET_SRC (set) == CONST0_RTX (GET_MODE (SET_DEST (set)))
    && !reg_set_between_p (SET_DEST (set), temp, insn)
    && (REGNO_REG_CLASS (REGNO (SET_DEST (set)))
        == REGNO_REG_CLASS (REGNO (operand)))
    && REGNO_REG_CLASS (REGNO (SET_DEST (set))) != EXTENDED_REGS
    && REGNO (SET_DEST (set)) != REGNO (operand)
    && (!past_call 
        || !call_used_regs[REGNO (SET_DEST (set))]))
  {
    rtx xoperands[2];
    xoperands[0] = operand;
    xoperands[1] = SET_DEST (set);

    output_asm_insn ("cmp %1,%0", xoperands);
    return "";
  }

      if (REGNO_REG_CLASS (REGNO (operand)) == EXTENDED_REGS
    && REG_P (SET_DEST (set))
    && SET_SRC (set) == CONST0_RTX (GET_MODE (SET_DEST (set)))
    && !reg_set_between_p (SET_DEST (set), temp, insn)
    && (REGNO_REG_CLASS (REGNO (SET_DEST (set)))
        != REGNO_REG_CLASS (REGNO (operand)))
    && REGNO_REG_CLASS (REGNO (SET_DEST (set))) == EXTENDED_REGS
    && REGNO (SET_DEST (set)) != REGNO (operand)
    && (!past_call 
        || !call_used_regs[REGNO (SET_DEST (set))]))
  {
    rtx xoperands[2];
    xoperands[0] = operand;
    xoperands[1] = SET_DEST (set);

    output_asm_insn ("cmp %1,%0", xoperands);
    return "";
  }
      temp = PREV_INSN (temp);
    }
  return "cmp 0,%0";
}

int
impossible_plus_operand (rtx op, enum machine_mode mode ATTRIBUTE_UNUSED)
{
  if (GET_CODE (op) != PLUS)
    return 0;

  if (XEXP (op, 0) == stack_pointer_rtx
      || XEXP (op, 1) == stack_pointer_rtx)
    return 1;

  return 0;
}

/* Return 1 if X is a CONST_INT that is only 8 bits wide.  This is used
   for the btst insn which may examine memory or a register (the memory
   variant only allows an unsigned 8 bit integer).  */
int
const_8bit_operand (register rtx op, enum machine_mode mode ATTRIBUTE_UNUSED)
{
  return (GET_CODE (op) == CONST_INT
    && INTVAL (op) >= 0
    && INTVAL (op) < 256);
}

/* Return true if the operand is the 1.0f constant.  */
int
const_1f_operand (register rtx op, enum machine_mode mode ATTRIBUTE_UNUSED)
{
  return (op == CONST1_RTX (SFmode));
}

/* Similarly, but when using a zero_extract pattern for a btst where
   the source operand might end up in memory.  */
int
mask_ok_for_mem_btst (int len, int bit)
{
  unsigned int mask = 0;

  while (len > 0)
    {
      mask |= (1 << bit);
      bit++;
      len--;
    }

  /* MASK must bit into an 8bit value.  */
  return (((mask & 0xff) == mask)
    || ((mask & 0xff00) == mask)
    || ((mask & 0xff0000) == mask)
    || ((mask & 0xff000000) == mask));
}

/* Return 1 if X contains a symbolic expression.  We know these
   expressions will have one of a few well defined forms, so
   we need only check those forms.  */
int
symbolic_operand (register rtx op, enum machine_mode mode ATTRIBUTE_UNUSED)
{
  switch (GET_CODE (op))
    {
    case SYMBOL_REF:
    case LABEL_REF:
      return 1;
    case CONST:
      op = XEXP (op, 0);
      return ((GET_CODE (XEXP (op, 0)) == SYMBOL_REF
               || GET_CODE (XEXP (op, 0)) == LABEL_REF)
              && GET_CODE (XEXP (op, 1)) == CONST_INT);
    default:
      return 0;
    }
}

/* Try machine dependent ways of modifying an illegitimate address
   to be legitimate.  If we find one, return the new valid address.
   This macro is used in only one place: `memory_address' in explow.c.

   OLDX is the address as it was before break_out_memory_refs was called.
   In some cases it is useful to look at this to decide what needs to be done.

   MODE and WIN are passed so that this macro can use
   GO_IF_LEGITIMATE_ADDRESS.

   Normally it is always safe for this macro to do nothing.  It exists to
   recognize opportunities to optimize the output.

   But on a few ports with segmented architectures and indexed addressing
   (mn10300, hppa) it is used to rewrite certain problematical addresses.  */
rtx
legitimize_address (rtx x, rtx oldx ATTRIBUTE_UNUSED,
        enum machine_mode mode ATTRIBUTE_UNUSED)
{
  if (flag_pic && ! legitimate_pic_operand_p (x))
    x = legitimize_pic_address (oldx, NULL_RTX);

  /* Uh-oh.  We might have an address for x[n-100000].  This needs
     special handling to avoid creating an indexed memory address
     with x-100000 as the base.  */
  if (GET_CODE (x) == PLUS
      && symbolic_operand (XEXP (x, 1), VOIDmode))
    {
      /* Ugly.  We modify things here so that the address offset specified
         by the index expression is computed first, then added to x to form
         the entire address.  */

      rtx regx1, regy1, regy2, y;

      /* Strip off any CONST.  */
      y = XEXP (x, 1);
      if (GET_CODE (y) == CONST)
        y = XEXP (y, 0);

      if (GET_CODE (y) == PLUS || GET_CODE (y) == MINUS)
  {
    regx1 = force_reg (Pmode, force_operand (XEXP (x, 0), 0));
    regy1 = force_reg (Pmode, force_operand (XEXP (y, 0), 0));
    regy2 = force_reg (Pmode, force_operand (XEXP (y, 1), 0));
    regx1 = force_reg (Pmode,
           gen_rtx_fmt_ee (GET_CODE (y), Pmode, regx1, regy2));
    return force_reg (Pmode, gen_rtx_PLUS (Pmode, regx1, regy1));
  }
    }
  return x;
}

/* Convert a non-PIC address in `orig' to a PIC address using @GOT or
   @GOTOFF in `reg'.  */
rtx
legitimize_pic_address (rtx orig, rtx reg)
{
  if (GET_CODE (orig) == LABEL_REF
      || (GET_CODE (orig) == SYMBOL_REF
    && (CONSTANT_POOL_ADDRESS_P (orig)
        || ! MN10300_GLOBAL_P (orig))))
    {
      if (reg == 0)
  reg = gen_reg_rtx (Pmode);

      emit_insn (gen_symGOTOFF2reg (reg, orig));
      return reg;
    }
  else if (GET_CODE (orig) == SYMBOL_REF)
    {
      if (reg == 0)
  reg = gen_reg_rtx (Pmode);

      emit_insn (gen_symGOT2reg (reg, orig));
      return reg;
    }
  return orig;
}

/* Return zero if X references a SYMBOL_REF or LABEL_REF whose symbol
   isn't protected by a PIC unspec; nonzero otherwise.  */
int
legitimate_pic_operand_p (rtx x)
{
  register const char *fmt;
  register int i;

  if (GET_CODE (x) == SYMBOL_REF || GET_CODE (x) == LABEL_REF)
    return 0;

  if (GET_CODE (x) == UNSPEC
      && (XINT (x, 1) == UNSPEC_PIC
    || XINT (x, 1) == UNSPEC_GOT
    || XINT (x, 1) == UNSPEC_GOTOFF
    || XINT (x, 1) == UNSPEC_PLT))
      return 1;

  fmt = GET_RTX_FORMAT (GET_CODE (x));
  for (i = GET_RTX_LENGTH (GET_CODE (x)) - 1; i >= 0; i--)
    {
      if (fmt[i] == 'E')
  {
    register int j;

    for (j = XVECLEN (x, i) - 1; j >= 0; j--)
      if (! legitimate_pic_operand_p (XVECEXP (x, i, j)))
        return 0;
  }
      else if (fmt[i] == 'e' && ! legitimate_pic_operand_p (XEXP (x, i)))
  return 0;
    }

  return 1;
}

/* Return TRUE if the address X, taken from a (MEM:MODE X) rtx, is
   legitimate, and FALSE otherwise.  */
bool
legitimate_address_p (enum machine_mode mode, rtx x, int strict)
{
  if (CONSTANT_ADDRESS_P (x)
      && (! flag_pic || legitimate_pic_operand_p (x)))
    return TRUE;

  if (RTX_OK_FOR_BASE_P (x, strict))
    return TRUE;

  if (TARGET_AM33
      && GET_CODE (x) == POST_INC
      && RTX_OK_FOR_BASE_P (XEXP (x, 0), strict)
      && (mode == SImode || mode == SFmode || mode == HImode))
    return TRUE;

  if (GET_CODE (x) == PLUS)
    {
      rtx base = 0, index = 0;

      if (REG_P (XEXP (x, 0))
    && REGNO_STRICT_OK_FOR_BASE_P (REGNO (XEXP (x, 0)), strict))
  {
    base = XEXP (x, 0);
    index = XEXP (x, 1);
  }

      if (REG_P (XEXP (x, 1))
    && REGNO_STRICT_OK_FOR_BASE_P (REGNO (XEXP (x, 1)), strict))
  {
    base = XEXP (x, 1);
    index = XEXP (x, 0);
  }

      if (base != 0 && index != 0)
  {
    if (GET_CODE (index) == CONST_INT)
      return TRUE;
    if (GET_CODE (index) == CONST
        && GET_CODE (XEXP (index, 0)) != PLUS
        && (! flag_pic
      || legitimate_pic_operand_p (index)))
      return TRUE;
  }
    }

  return FALSE;
}

static int
mn10300_address_cost_1 (rtx x, int *unsig)
{
  switch (GET_CODE (x))
    {
    case REG:
      switch (REGNO_REG_CLASS (REGNO (x)))
  {
  case SP_REGS:
    *unsig = 1;
    return 0;

  case ADDRESS_REGS:
    return 1;

  case DATA_REGS:
  case EXTENDED_REGS:
  case FP_REGS:
    return 3;

  case NO_REGS:
    return 5;

  default:
    abort ();
  }

    case PLUS:
    case MINUS:
    case ASHIFT:
    case AND:
    case IOR:
      return (mn10300_address_cost_1 (XEXP (x, 0), unsig)
        + mn10300_address_cost_1 (XEXP (x, 1), unsig));

    case EXPR_LIST:
    case SUBREG:
    case MEM:
      return mn10300_address_cost (XEXP (x, 0));

    case ZERO_EXTEND:
      *unsig = 1;
      return mn10300_address_cost_1 (XEXP (x, 0), unsig);

    case CONST_INT:
      if (INTVAL (x) == 0)
  return 0;
      if (INTVAL (x) + (*unsig ? 0 : 0x80) < 0x100)
  return 1;
      if (INTVAL (x) + (*unsig ? 0 : 0x8000) < 0x10000)
  return 3;
      if (INTVAL (x) + (*unsig ? 0 : 0x800000) < 0x1000000)
  return 5;
      return 7;

    case CONST:
    case SYMBOL_REF:
    case LABEL_REF:
      return 8;

    default:
      abort ();

    }
}

static int
mn10300_address_cost (rtx x)
{
  int s = 0;
  return mn10300_address_cost_1 (x, &s);
}

static bool
mn10300_rtx_costs (rtx x, int code, int outer_code, int *total)
{
  switch (code)
    {
    case CONST_INT:
      /* Zeros are extremely cheap.  */
      if (INTVAL (x) == 0 && outer_code == SET)
  *total = 0;
      /* If it fits in 8 bits, then it's still relatively cheap.  */
      else if (INT_8_BITS (INTVAL (x)))
  *total = 1;
      /* This is the "base" cost, includes constants where either the
   upper or lower 16bits are all zeros.  */
      else if (INT_16_BITS (INTVAL (x))
         || (INTVAL (x) & 0xffff) == 0
         || (INTVAL (x) & 0xffff0000) == 0)
  *total = 2;
      else
  *total = 4;
      return true;

    case CONST:
    case LABEL_REF:
    case SYMBOL_REF:
      /* These are more costly than a CONST_INT, but we can relax them,
   so they're less costly than a CONST_DOUBLE.  */
      *total = 6;
      return true;

    case CONST_DOUBLE:
      /* We don't optimize CONST_DOUBLEs well nor do we relax them well,
   so their cost is very high.  */
      *total = 8;
      return true;

   /* ??? This probably needs more work.  */
    case MOD:
    case DIV:
    case MULT:
      *total = 8;
      return true;

    default:
      return false;
    }
}

/* Check whether a constant used to initialize a DImode or DFmode can
   use a clr instruction.  The code here must be kept in sync with
   movdf and movdi.  */

bool
mn10300_wide_const_load_uses_clr (rtx operands[2])
{
  long val[2];

  if (GET_CODE (operands[0]) != REG
      || REGNO_REG_CLASS (REGNO (operands[0])) != DATA_REGS)
    return false;

  switch (GET_CODE (operands[1]))
    {
    case CONST_INT:
      {
  rtx low, high;
  split_double (operands[1], &low, &high);
  val[0] = INTVAL (low);
  val[1] = INTVAL (high);
      }
      break;
      
    case CONST_DOUBLE:
      if (GET_MODE (operands[1]) == DFmode)
  {
    REAL_VALUE_TYPE rv;

    REAL_VALUE_FROM_CONST_DOUBLE (rv, operands[1]);
    REAL_VALUE_TO_TARGET_DOUBLE (rv, val);
  }
      else if (GET_MODE (operands[1]) == VOIDmode
         || GET_MODE (operands[1]) == DImode)
  {
    val[0] = CONST_DOUBLE_LOW (operands[1]);
    val[1] = CONST_DOUBLE_HIGH (operands[1]);
  }
      break;
      
    default:
      return false;
    }

  return val[0] == 0 || val[1] == 0;
}
/* If using PIC, mark a SYMBOL_REF for a non-global symbol so that we
   may access it using GOTOFF instead of GOT.  */

static void
mn10300_encode_section_info (tree decl, rtx rtl, int first ATTRIBUTE_UNUSED)
{
  rtx symbol;

  if (GET_CODE (rtl) != MEM)
    return;
  symbol = XEXP (rtl, 0);
  if (GET_CODE (symbol) != SYMBOL_REF)
    return;

  if (flag_pic)
    SYMBOL_REF_FLAG (symbol) = (*targetm.binds_local_p) (decl);
}

---