Sync usage with man page.

[netbsd-mini2440.git] / gnu / dist / gcc4 / gcc / config / fr30 / fr30.c

/* FR30 specific functions.
   Copyright (C) 1998, 1999, 2000, 2001, 2002, 2004, 2005
   Free Software Foundation, Inc.
   Contributed by Cygnus Solutions.

   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, 51 Franklin Street, Fifth Floor,
   Boston, MA 02110-1301, USA.  */

/*{{{  Includes */ 

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

/*}}}*/
/*{{{  Function Prologues & Epilogues */ 

/* Define the information needed to generate branch and scc insns.  This is
   stored from the compare operation.  */

struct rtx_def * fr30_compare_op0;
struct rtx_def * fr30_compare_op1;

/* The FR30 stack looks like this:

             Before call                       After call
   FP ->|                       |       |                       |
        +-----------------------+       +-----------------------+       high 
        |                       |       |                       |       memory
        |  local variables,     |       |  local variables,     |
        |  reg save area, etc.  |       |  reg save area, etc.  |
        |                       |       |                       |
        +-----------------------+       +-----------------------+
        |                       |       |                       |
        | args to the func that |       |  args to this func.   |
        | is being called that  |       |                       |
   SP ->| do not fit in regs    |       |                       |
        +-----------------------+       +-----------------------+
                                        |  args that used to be |  \
                                        | in regs; only created |   |  pretend_size 
                                   AP-> |   for vararg funcs    |  /  
                                        +-----------------------+    
                                        |                       |  \  
                                        |  register save area   |   |
                                        |                       |   |
                                        +-----------------------+   |  reg_size
                                        |    return address     |   | 
                                        +-----------------------+   |
                                   FP ->|   previous frame ptr  |  /
                                        +-----------------------+    
                                        |                       |  \   
                                        |  local variables      |   |  var_size 
                                        |                       |  /  
                                        +-----------------------+    
                                        |                       |  \       
     low                                |  room for args to     |   |
     memory                             |  other funcs called   |   |  args_size     
                                        |  from this one        |   |
                                   SP ->|                       |  /  
                                        +-----------------------+    
   
   Note, AP is a fake hard register.  It will be eliminated in favor of
   SP or FP as appropriate.

   Note, Some or all of the stack sections above may be omitted if they 
   are not needed.  */

/* Structure to be filled in by fr30_compute_frame_size() with register
   save masks, and offsets for the current function.  */
struct fr30_frame_info
{
  unsigned int total_size;      /* # Bytes that the entire frame takes up.  */
  unsigned int pretend_size;    /* # Bytes we push and pretend caller did.  */
  unsigned int args_size;       /* # Bytes that outgoing arguments take up.  */
  unsigned int reg_size;        /* # Bytes needed to store regs.  */
  unsigned int var_size;        /* # Bytes that variables take up.  */
  unsigned int frame_size;      /* # Bytes in current frame.  */
  unsigned int gmask;           /* Mask of saved registers.  */
  unsigned int save_fp;         /* Nonzero if frame pointer must be saved.  */
  unsigned int save_rp;         /* Nonzero if return pointer must be saved.  */
  int          initialised;     /* Nonzero if frame size already calculated.  */
};

/* Current frame information calculated by fr30_compute_frame_size().  */
static struct fr30_frame_info   current_frame_info;

/* Zero structure to initialize current_frame_info.  */
static struct fr30_frame_info   zero_frame_info;

static void fr30_setup_incoming_varargs (CUMULATIVE_ARGS *, enum machine_mode,
                                         tree, int *, int);
static bool fr30_must_pass_in_stack (enum machine_mode, tree);
static int fr30_arg_partial_bytes (CUMULATIVE_ARGS *, enum machine_mode,
                                   tree, bool);


#define FRAME_POINTER_MASK      (1 << (FRAME_POINTER_REGNUM))
#define RETURN_POINTER_MASK     (1 << (RETURN_POINTER_REGNUM))

/* Tell prologue and epilogue if register REGNO should be saved / restored.
   The return address and frame pointer are treated separately.
   Don't consider them here.  */
#define MUST_SAVE_REGISTER(regno)      \
  (   (regno) != RETURN_POINTER_REGNUM \
   && (regno) != FRAME_POINTER_REGNUM  \
   &&   regs_ever_live [regno]         \
   && ! call_used_regs [regno]         )

#define MUST_SAVE_FRAME_POINTER  (regs_ever_live [FRAME_POINTER_REGNUM]  || frame_pointer_needed)
#define MUST_SAVE_RETURN_POINTER (regs_ever_live [RETURN_POINTER_REGNUM] || current_function_profile)

#if UNITS_PER_WORD == 4
#define WORD_ALIGN(SIZE) (((SIZE) + 3) & ~3)
#endif
\f
/* Initialize the GCC target structure.  */
#undef  TARGET_ASM_ALIGNED_HI_OP
#define TARGET_ASM_ALIGNED_HI_OP "\t.hword\t"
#undef  TARGET_ASM_ALIGNED_SI_OP
#define TARGET_ASM_ALIGNED_SI_OP "\t.word\t"

#undef  TARGET_PROMOTE_PROTOTYPES
#define TARGET_PROMOTE_PROTOTYPES hook_bool_tree_true
#undef  TARGET_PASS_BY_REFERENCE
#define TARGET_PASS_BY_REFERENCE hook_pass_by_reference_must_pass_in_stack
#undef  TARGET_ARG_PARTIAL_BYTES
#define TARGET_ARG_PARTIAL_BYTES fr30_arg_partial_bytes

#undef  TARGET_SETUP_INCOMING_VARARGS
#define TARGET_SETUP_INCOMING_VARARGS fr30_setup_incoming_varargs
#undef  TARGET_MUST_PASS_IN_STACK
#define TARGET_MUST_PASS_IN_STACK fr30_must_pass_in_stack

struct gcc_target targetm = TARGET_INITIALIZER;
\f
/* Returns the number of bytes offset between FROM_REG and TO_REG
   for the current function.  As a side effect it fills in the 
   current_frame_info structure, if the data is available.  */
unsigned int
fr30_compute_frame_size (int from_reg, int to_reg)
{
  int           regno;
  unsigned int  return_value;
  unsigned int  var_size;
  unsigned int  args_size;
  unsigned int  pretend_size;
  unsigned int  reg_size;
  unsigned int  gmask;

  var_size      = WORD_ALIGN (get_frame_size ());
  args_size     = WORD_ALIGN (current_function_outgoing_args_size);
  pretend_size  = current_function_pretend_args_size;

  reg_size      = 0;
  gmask         = 0;

  /* Calculate space needed for registers.  */
  for (regno = 0; regno < FIRST_PSEUDO_REGISTER; regno ++)
    {
      if (MUST_SAVE_REGISTER (regno))
        {
          reg_size += UNITS_PER_WORD;
          gmask |= 1 << regno;
        }
    }

  current_frame_info.save_fp = MUST_SAVE_FRAME_POINTER;
  current_frame_info.save_rp = MUST_SAVE_RETURN_POINTER;

  reg_size += (current_frame_info.save_fp + current_frame_info.save_rp)
               * UNITS_PER_WORD;

  /* Save computed information.  */
  current_frame_info.pretend_size = pretend_size;
  current_frame_info.var_size     = var_size;
  current_frame_info.args_size    = args_size;
  current_frame_info.reg_size     = reg_size;
  current_frame_info.frame_size   = args_size + var_size;
  current_frame_info.total_size   = args_size + var_size + reg_size + pretend_size;
  current_frame_info.gmask        = gmask;
  current_frame_info.initialised  = reload_completed;

  /* Calculate the required distance.  */
  return_value = 0;
  
  if (to_reg == STACK_POINTER_REGNUM)
    return_value += args_size + var_size;
  
  if (from_reg == ARG_POINTER_REGNUM)
    return_value += reg_size;

  return return_value;
}

/* Called after register allocation to add any instructions needed for the
   prologue.  Using a prologue insn is favored compared to putting all of the
   instructions in output_function_prologue(), since it allows the scheduler
   to intermix instructions with the saves of the caller saved registers.  In
   some cases, it might be necessary to emit a barrier instruction as the last
   insn to prevent such scheduling.  */

void
fr30_expand_prologue (void)
{
  int regno;
  rtx insn;

  if (! current_frame_info.initialised)
    fr30_compute_frame_size (0, 0);

  /* This cases shouldn't happen.  Catch it now.  */
  gcc_assert (current_frame_info.total_size || !current_frame_info.gmask);

  /* Allocate space for register arguments if this is a variadic function.  */
  if (current_frame_info.pretend_size)
    {
      int regs_to_save = current_frame_info.pretend_size / UNITS_PER_WORD;
      
      /* Push argument registers into the pretend arg area.  */
      for (regno = FIRST_ARG_REGNUM + FR30_NUM_ARG_REGS; regno --, regs_to_save --;)
        {
          insn = emit_insn (gen_movsi_push (gen_rtx_REG (Pmode, regno)));
          RTX_FRAME_RELATED_P (insn) = 1;
        }
    }

  if (current_frame_info.gmask)
    {
      /* Save any needed call-saved regs.  */
      for (regno = STACK_POINTER_REGNUM; regno--;)
        {
          if ((current_frame_info.gmask & (1 << regno)) != 0)
            {
              insn = emit_insn (gen_movsi_push (gen_rtx_REG (Pmode, regno)));
              RTX_FRAME_RELATED_P (insn) = 1;
            }
        }
    }

  /* Save return address if necessary.  */
  if (current_frame_info.save_rp)
    {
      insn = emit_insn (gen_movsi_push (gen_rtx_REG (Pmode, 
                                                     RETURN_POINTER_REGNUM)));
      RTX_FRAME_RELATED_P (insn) = 1;
    }

  /* Save old frame pointer and create new one, if necessary.  */
  if (current_frame_info.save_fp)
    {
      if (current_frame_info.frame_size < ((1 << 10) - UNITS_PER_WORD))
        {
          int enter_size = current_frame_info.frame_size + UNITS_PER_WORD;
          rtx pattern;
          
          insn = emit_insn (gen_enter_func (GEN_INT (enter_size)));
          RTX_FRAME_RELATED_P (insn) = 1;
          
          pattern = PATTERN (insn);
          
          /* Also mark all 3 subexpressions as RTX_FRAME_RELATED_P. */
          if (GET_CODE (pattern) == PARALLEL)
            {
              int x;
              for (x = XVECLEN (pattern, 0); x--;)
                {
                  rtx part = XVECEXP (pattern, 0, x);
                  
                  /* One of the insns in the ENTER pattern updates the
                     frame pointer.  If we do not actually need the frame
                     pointer in this function then this is a side effect
                     rather than a desired effect, so we do not mark that
                     insn as being related to the frame set up.  Doing this
                     allows us to compile the crash66.C test file in the
                     G++ testsuite.  */
                  if (! frame_pointer_needed
                      && GET_CODE (part) == SET
                      && REGNO (SET_DEST (part)) == HARD_FRAME_POINTER_REGNUM)
                    RTX_FRAME_RELATED_P (part) = 0;
                  else
                    RTX_FRAME_RELATED_P (part) = 1;
                }
            }
        }
      else
        {
          insn = emit_insn (gen_movsi_push (frame_pointer_rtx));
          RTX_FRAME_RELATED_P (insn) = 1;

          if (frame_pointer_needed)
            {
              insn = emit_insn (gen_movsi (frame_pointer_rtx, stack_pointer_rtx));
              RTX_FRAME_RELATED_P (insn) = 1;
            }
        }
    }

  /* Allocate the stack frame.  */
  if (current_frame_info.frame_size == 0)
    ; /* Nothing to do.  */
  else if (current_frame_info.save_fp
           && current_frame_info.frame_size < ((1 << 10) - UNITS_PER_WORD))
    ; /* Nothing to do.  */
  else if (current_frame_info.frame_size <= 512)
    {
      insn = emit_insn (gen_add_to_stack (GEN_INT (- current_frame_info.frame_size)));
      RTX_FRAME_RELATED_P (insn) = 1;
    }
  else
    {
      rtx tmp = gen_rtx_REG (Pmode, PROLOGUE_TMP_REGNUM);
      insn = emit_insn (gen_movsi (tmp, GEN_INT (current_frame_info.frame_size)));
      RTX_FRAME_RELATED_P (insn) = 1;
      insn = emit_insn (gen_subsi3 (stack_pointer_rtx, stack_pointer_rtx, tmp));
      RTX_FRAME_RELATED_P (insn) = 1;
    }

  if (current_function_profile)
    emit_insn (gen_blockage ());
}

/* Called after register allocation to add any instructions needed for the
   epilogue.  Using an epilogue insn is favored compared to putting all of the
   instructions in output_function_epilogue(), since it allows the scheduler
   to intermix instructions with the restores of the caller saved registers.
   In some cases, it might be necessary to emit a barrier instruction as the
   first insn to prevent such scheduling.  */
void
fr30_expand_epilogue (void)
{
  int regno;

  /* Perform the inversion operations of the prologue.  */
  gcc_assert (current_frame_info.initialised);
  
  /* Pop local variables and arguments off the stack.
     If frame_pointer_needed is TRUE then the frame pointer register
     has actually been used as a frame pointer, and we can recover
     the stack pointer from it, otherwise we must unwind the stack
     manually.  */
  if (current_frame_info.frame_size > 0)
    {
      if (current_frame_info.save_fp && frame_pointer_needed)
        {
          emit_insn (gen_leave_func ());
          current_frame_info.save_fp = 0;
        }
      else if (current_frame_info.frame_size <= 508)
        emit_insn (gen_add_to_stack
                   (GEN_INT (current_frame_info.frame_size)));
      else
        {
          rtx tmp = gen_rtx_REG (Pmode, PROLOGUE_TMP_REGNUM);
          emit_insn (gen_movsi (tmp, GEN_INT (current_frame_info.frame_size)));
          emit_insn (gen_addsi3 (stack_pointer_rtx, stack_pointer_rtx, tmp));
        }
    }
  
  if (current_frame_info.save_fp)
    emit_insn (gen_movsi_pop (frame_pointer_rtx));
  
  /* Pop all the registers that were pushed.  */
  if (current_frame_info.save_rp)
    emit_insn (gen_movsi_pop (gen_rtx_REG (Pmode, RETURN_POINTER_REGNUM)));
    
  for (regno = 0; regno < STACK_POINTER_REGNUM; regno ++)
    if (current_frame_info.gmask & (1 << regno))
      emit_insn (gen_movsi_pop (gen_rtx_REG (Pmode, regno)));
  
  if (current_frame_info.pretend_size)
    emit_insn (gen_add_to_stack (GEN_INT (current_frame_info.pretend_size)));

  /* Reset state info for each function.  */
  current_frame_info = zero_frame_info;

  emit_jump_insn (gen_return_from_func ());
}

/* Do any needed setup for a variadic function.  We must create a register
   parameter block, and then copy any anonymous arguments, plus the last
   named argument, from registers into memory.  * copying actually done in
   fr30_expand_prologue().

   ARG_REGS_USED_SO_FAR has *not* been updated for the last named argument
   which has type TYPE and mode MODE, and we rely on this fact.  */
void
fr30_setup_incoming_varargs (CUMULATIVE_ARGS *arg_regs_used_so_far,
                             enum machine_mode mode,
                             tree type ATTRIBUTE_UNUSED,
                             int *pretend_size,
                             int second_time ATTRIBUTE_UNUSED)
{
  int size;

  /* All BLKmode values are passed by reference.  */
  gcc_assert (mode != BLKmode);

  /* ??? This run-time test as well as the code inside the if
     statement is probably unnecessary.  */
  if (targetm.calls.strict_argument_naming (arg_regs_used_so_far))
    /* If TARGET_STRICT_ARGUMENT_NAMING returns true, then the last named
       arg must not be treated as an anonymous arg.  */
    arg_regs_used_so_far += fr30_num_arg_regs (mode, type);

  size = FR30_NUM_ARG_REGS - (* arg_regs_used_so_far);

  if (size <= 0)
    return;

  * pretend_size = (size * UNITS_PER_WORD);
}

/*}}}*/
/*{{{  Printing operands */ 

/* Print a memory address as an operand to reference that memory location.  */

void
fr30_print_operand_address (FILE *stream, rtx address)
{
  switch (GET_CODE (address))
    {
    case SYMBOL_REF:
      output_addr_const (stream, address);
      break;
      
    default:
      fprintf (stderr, "code = %x\n", GET_CODE (address));
      debug_rtx (address);
      output_operand_lossage ("fr30_print_operand_address: unhandled address");
      break;
    }
}

/* Print an operand.  */

void
fr30_print_operand (FILE *file, rtx x, int code)
{
  rtx x0;
  
  switch (code)
    {
    case '#':
      /* Output a :D if this instruction is delayed.  */
      if (dbr_sequence_length () != 0)
        fputs (":D", file);
      return;
      
    case 'p':
      /* Compute the register name of the second register in a hi/lo
         register pair.  */
      if (GET_CODE (x) != REG)
        output_operand_lossage ("fr30_print_operand: unrecognized %%p code");
      else
        fprintf (file, "r%d", REGNO (x) + 1);
      return;
      
    case 'b':
      /* Convert GCC's comparison operators into FR30 comparison codes.  */
      switch (GET_CODE (x))
        {
        case EQ:  fprintf (file, "eq"); break;
        case NE:  fprintf (file, "ne"); break;
        case LT:  fprintf (file, "lt"); break;
        case LE:  fprintf (file, "le"); break;
        case GT:  fprintf (file, "gt"); break;
        case GE:  fprintf (file, "ge"); break;
        case LTU: fprintf (file, "c"); break;
        case LEU: fprintf (file, "ls"); break;
        case GTU: fprintf (file, "hi"); break;
        case GEU: fprintf (file, "nc");  break;
        default:
          output_operand_lossage ("fr30_print_operand: unrecognized %%b code");
          break;
        }
      return;
      
    case 'B':
      /* Convert GCC's comparison operators into the complimentary FR30
         comparison codes.  */
      switch (GET_CODE (x))
        {
        case EQ:  fprintf (file, "ne"); break;
        case NE:  fprintf (file, "eq"); break;
        case LT:  fprintf (file, "ge"); break;
        case LE:  fprintf (file, "gt"); break;
        case GT:  fprintf (file, "le"); break;
        case GE:  fprintf (file, "lt"); break;
        case LTU: fprintf (file, "nc"); break;
        case LEU: fprintf (file, "hi"); break;
        case GTU: fprintf (file, "ls"); break;
        case GEU: fprintf (file, "c"); break;
        default:
          output_operand_lossage ("fr30_print_operand: unrecognized %%B code");
          break;
        }
      return;

    case 'A':
      /* Print a signed byte value as an unsigned value.  */
      if (GET_CODE (x) != CONST_INT)
        output_operand_lossage ("fr30_print_operand: invalid operand to %%A code");
      else
        {
          HOST_WIDE_INT val;
          
          val = INTVAL (x);

          val &= 0xff;

          fprintf (file, HOST_WIDE_INT_PRINT_DEC, val);
        }
      return;
      
    case 'x':
      if (GET_CODE (x) != CONST_INT
          || INTVAL (x) < 16
          || INTVAL (x) > 32)
        output_operand_lossage ("fr30_print_operand: invalid %%x code");
      else
        fprintf (file, HOST_WIDE_INT_PRINT_DEC, INTVAL (x) - 16);
      return;

    case 'F':
      if (GET_CODE (x) != CONST_DOUBLE)
        output_operand_lossage ("fr30_print_operand: invalid %%F code");
      else
        {
          char str[30];

          real_to_decimal (str, CONST_DOUBLE_REAL_VALUE (x),
                           sizeof (str), 0, 1);
          fputs (str, file);
        }
      return;
      
    case 0:
      /* Handled below.  */
      break;
      
    default:
      fprintf (stderr, "unknown code = %x\n", code);
      output_operand_lossage ("fr30_print_operand: unknown code");
      return;
    }

  switch (GET_CODE (x))
    {
    case REG:
      fputs (reg_names [REGNO (x)], file);
      break;

    case MEM:
      x0 = XEXP (x,0);
      
      switch (GET_CODE (x0))
        {
        case REG:
          gcc_assert ((unsigned) REGNO (x0) < ARRAY_SIZE (reg_names));
          fprintf (file, "@%s", reg_names [REGNO (x0)]);
          break;

        case PLUS:
          if (GET_CODE (XEXP (x0, 0)) != REG
              || REGNO (XEXP (x0, 0)) < FRAME_POINTER_REGNUM
              || REGNO (XEXP (x0, 0)) > STACK_POINTER_REGNUM
              || GET_CODE (XEXP (x0, 1)) != CONST_INT)
            {
              fprintf (stderr, "bad INDEXed address:");
              debug_rtx (x);
              output_operand_lossage ("fr30_print_operand: unhandled MEM");
            }
          else if (REGNO (XEXP (x0, 0)) == FRAME_POINTER_REGNUM)
            {
              HOST_WIDE_INT val = INTVAL (XEXP (x0, 1));
              if (val < -(1 << 9) || val > ((1 << 9) - 4))
                {
                  fprintf (stderr, "frame INDEX out of range:");
                  debug_rtx (x);
                  output_operand_lossage ("fr30_print_operand: unhandled MEM");
                }
              fprintf (file, "@(r14, #" HOST_WIDE_INT_PRINT_DEC ")", val);
            }
          else
            {
              HOST_WIDE_INT val = INTVAL (XEXP (x0, 1));
              if (val < 0 || val > ((1 << 6) - 4))
                {
                  fprintf (stderr, "stack INDEX out of range:");
                  debug_rtx (x);
                  output_operand_lossage ("fr30_print_operand: unhandled MEM");
                }
              fprintf (file, "@(r15, #" HOST_WIDE_INT_PRINT_DEC ")", val);
            }
          break;
          
        case SYMBOL_REF:
          output_address (x0);
          break;
          
        default:
          fprintf (stderr, "bad MEM code = %x\n", GET_CODE (x0));
          debug_rtx (x);
          output_operand_lossage ("fr30_print_operand: unhandled MEM");
          break;
        }
      break;
      
    case CONST_DOUBLE :
      /* We handle SFmode constants here as output_addr_const doesn't.  */
      if (GET_MODE (x) == SFmode)
        {
          REAL_VALUE_TYPE d;
          long l;

          REAL_VALUE_FROM_CONST_DOUBLE (d, x);
          REAL_VALUE_TO_TARGET_SINGLE (d, l);
          fprintf (file, "0x%08lx", l);
          break;
        }

      /* Fall through.  Let output_addr_const deal with it.  */
    default:
      output_addr_const (file, x);
      break;
    }

  return;
}

/*}}}*/
/*{{{  Function arguments */ 

/* Return true if we should pass an argument on the stack rather than
   in registers.  */

static bool
fr30_must_pass_in_stack (enum machine_mode mode, tree type)
{
  if (mode == BLKmode)
    return true;
  if (type == NULL)
    return false;
  return AGGREGATE_TYPE_P (type);
}

/* Compute the number of word sized registers needed to hold a
   function argument of mode INT_MODE and tree type TYPE.  */
int
fr30_num_arg_regs (enum machine_mode mode, tree type)
{
  int size;

  if (targetm.calls.must_pass_in_stack (mode, type))
    return 0;

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

  return (size + UNITS_PER_WORD - 1) / UNITS_PER_WORD;
}

/* Returns the number of bytes in which *part* of a parameter of machine
   mode MODE and tree type TYPE (which may be NULL if the type is not known).
   If the argument fits entirely in the argument registers, or entirely on
   the stack, then 0 is returned.
   CUM is the number of argument registers already used by earlier
   parameters to the function.  */

static int
fr30_arg_partial_bytes (CUMULATIVE_ARGS *cum, enum machine_mode mode,
                        tree type, bool named)
{
  /* Unnamed arguments, i.e. those that are prototyped as ...
     are always passed on the stack.
     Also check here to see if all the argument registers are full.  */
  if (named == 0 || *cum >= FR30_NUM_ARG_REGS)
    return 0;

  /* Work out how many argument registers would be needed if this
     parameter were to be passed entirely in registers.  If there
     are sufficient argument registers available (or if no registers
     are needed because the parameter must be passed on the stack)
     then return zero, as this parameter does not require partial
     register, partial stack stack space.  */
  if (*cum + fr30_num_arg_regs (mode, type) <= FR30_NUM_ARG_REGS)
    return 0;
  
  return (FR30_NUM_ARG_REGS - *cum) * UNITS_PER_WORD;
}

/*}}}*/
/*{{{  Operand predicates */ 

#ifndef Mmode
#define Mmode enum machine_mode
#endif

/* Returns true iff all the registers in the operands array
   are in descending or ascending order.  */
int
fr30_check_multiple_regs (rtx *operands, int num_operands, int descending)
{
  if (descending)
    {
      unsigned int prev_regno = 0;
      
      while (num_operands --)
        {
          if (GET_CODE (operands [num_operands]) != REG)
            return 0;
          
          if (REGNO (operands [num_operands]) < prev_regno)
            return 0;
          
          prev_regno = REGNO (operands [num_operands]);
        }
    }
  else
    {
      unsigned int prev_regno = CONDITION_CODE_REGNUM;
      
      while (num_operands --)
        {
          if (GET_CODE (operands [num_operands]) != REG)
            return 0;
          
          if (REGNO (operands [num_operands]) > prev_regno)
            return 0;
          
          prev_regno = REGNO (operands [num_operands]);
        }
    }

  return 1;
}

int
fr30_const_double_is_zero (rtx operand)
{
  REAL_VALUE_TYPE d;

  if (operand == NULL || GET_CODE (operand) != CONST_DOUBLE)
    return 0;

  REAL_VALUE_FROM_CONST_DOUBLE (d, operand);

  return REAL_VALUES_EQUAL (d, dconst0);
}

/*}}}*/
/*{{{  Instruction Output Routines  */

/* Output a double word move.
   It must be REG<-REG, REG<-MEM, MEM<-REG or REG<-CONST.
   On the FR30 we are constrained by the fact that it does not
   support offsetable addresses, and so we have to load the
   address of the secnd word into the second destination register
   before we can use it.  */

rtx
fr30_move_double (rtx * operands)
{
  rtx src  = operands[1];
  rtx dest = operands[0];
  enum rtx_code src_code = GET_CODE (src);
  enum rtx_code dest_code = GET_CODE (dest);
  enum machine_mode mode = GET_MODE (dest);
  rtx val;

  start_sequence ();

  if (dest_code == REG)
    {
      if (src_code == REG)
        {
          int reverse = (REGNO (dest) == REGNO (src) + 1);
          
          /* We normally copy the low-numbered register first.  However, if
             the first register of operand 0 is the same as the second register
             of operand 1, we must copy in the opposite order.  */
          emit_insn (gen_rtx_SET (VOIDmode,
                                  operand_subword (dest, reverse, TRUE, mode),
                                  operand_subword (src,  reverse, TRUE, mode)));
          
          emit_insn (gen_rtx_SET (VOIDmode,
                              operand_subword (dest, !reverse, TRUE, mode),
                              operand_subword (src,  !reverse, TRUE, mode)));
        }
      else if (src_code == MEM)
        {
          rtx addr = XEXP (src, 0);
          int dregno = REGNO (dest);
          rtx dest0;
          rtx dest1;
          rtx new_mem;
          
          /* If the high-address word is used in the address, we
             must load it last.  Otherwise, load it first.  */
          int reverse = (refers_to_regno_p (dregno, dregno + 1, addr, 0) != 0);

          gcc_assert (GET_CODE (addr) == REG);
          
          dest0 = operand_subword (dest, reverse, TRUE, mode);
          dest1 = operand_subword (dest, !reverse, TRUE, mode);

          if (reverse)
            {
              emit_insn (gen_rtx_SET (VOIDmode, dest1,
                                      adjust_address (src, SImode, 0)));
              emit_insn (gen_rtx_SET (SImode, dest0,
                                      gen_rtx_REG (SImode, REGNO (addr))));
              emit_insn (gen_rtx_SET (SImode, dest0,
                                      plus_constant (dest0, UNITS_PER_WORD)));

              new_mem = gen_rtx_MEM (SImode, dest0);
              MEM_COPY_ATTRIBUTES (new_mem, src);
              
              emit_insn (gen_rtx_SET (VOIDmode, dest0, new_mem));
            }
          else
            {
              emit_insn (gen_rtx_SET (VOIDmode, dest0,
                                      adjust_address (src, SImode, 0)));
              emit_insn (gen_rtx_SET (SImode, dest1,
                                      gen_rtx_REG (SImode, REGNO (addr))));
              emit_insn (gen_rtx_SET (SImode, dest1,
                                      plus_constant (dest1, UNITS_PER_WORD)));

              new_mem = gen_rtx_MEM (SImode, dest1);
              MEM_COPY_ATTRIBUTES (new_mem, src);
              
              emit_insn (gen_rtx_SET (VOIDmode, dest1, new_mem));
            }
        }
      else if (src_code == CONST_INT || src_code == CONST_DOUBLE)
        {
          rtx words[2];
          split_double (src, &words[0], &words[1]);
          emit_insn (gen_rtx_SET (VOIDmode,
                                  operand_subword (dest, 0, TRUE, mode),
                                  words[0]));
      
          emit_insn (gen_rtx_SET (VOIDmode,
                                  operand_subword (dest, 1, TRUE, mode),
                                  words[1]));
        }
    }
  else if (src_code == REG && dest_code == MEM)
    {
      rtx addr = XEXP (dest, 0);
      rtx src0;
      rtx src1;

      gcc_assert (GET_CODE (addr) == REG);
      
      src0 = operand_subword (src, 0, TRUE, mode);
      src1 = operand_subword (src, 1, TRUE, mode);
      
      emit_insn (gen_rtx_SET (VOIDmode, adjust_address (dest, SImode, 0),
                              src0));

      if (REGNO (addr) == STACK_POINTER_REGNUM
          || REGNO (addr) == FRAME_POINTER_REGNUM)
        emit_insn (gen_rtx_SET (VOIDmode,
                                adjust_address (dest, SImode, UNITS_PER_WORD),
                                src1));
      else
        {
          rtx new_mem;
          
          /* We need a scratch register to hold the value of 'address + 4'.
             We ought to allow gcc to find one for us, but for now, just
             push one of the source registers.  */
          emit_insn (gen_movsi_push (src0));
          emit_insn (gen_movsi_internal (src0, addr));
          emit_insn (gen_addsi_small_int (src0, src0, GEN_INT (UNITS_PER_WORD)));
          
          new_mem = gen_rtx_MEM (SImode, src0);
          MEM_COPY_ATTRIBUTES (new_mem, dest);
          
          emit_insn (gen_rtx_SET (VOIDmode, new_mem, src1));
          emit_insn (gen_movsi_pop (src0));
        }
    }
  else
    /* This should have been prevented by the constraints on movdi_insn.  */
    gcc_unreachable ();
  
  val = get_insns ();
  end_sequence ();

  return val;
}
/*}}}*/
/* Local Variables: */
/* folded-file: t   */
/* End:             */