* varasm.c (assemble_real): Use REAL_VALUE_TO_x and assemble_integer

[official-gcc.git] / gcc / config / mmix / mmix.c

/* Definitions of target machine for GNU compiler, for MMIX.
   Copyright (C) 2000, 2001 Free Software Foundation, Inc.
   Contributed by Hans-Peter Nilsson (hp@bitrange.com)

This file is part of GNU CC.

GNU CC 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.

GNU CC 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 GNU CC; 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 "rtl.h"
#include "regs.h"
#include "hard-reg-set.h"
#include "hashtab.h"
#include "insn-config.h"
#include "output.h"
#include "flags.h"
#include "tree.h"
#include "function.h"
#include "expr.h"
#include "toplev.h"
#include "recog.h"
#include "ggc.h"
#include "dwarf2.h"
#include "debug.h"
#include "tm_p.h"
#include "integrate.h"
#include "target.h"
#include "target-def.h"

/* First some local helper definitions.  */
#define MMIX_FIRST_GLOBAL_REGNUM 32

/* We'd need a current_function_has_landing_pad.  It's marked as such when
   a nonlocal_goto_receiver is expanded.  Not just a C++ thing, but
   mostly.  */
#define MMIX_CFUN_HAS_LANDING_PAD (cfun->machine->has_landing_pad != 0)

/* We have no means to tell DWARF 2 about the register stack, so we need
   to store the return address on the stack if an exception can get into
   this function.  FIXME: Narrow condition.  */
#define MMIX_CFUN_NEEDS_SAVED_EH_RETURN_ADDRESS \
 (flag_exceptions && ! leaf_function_p ())

#define IS_MMIX_EH_RETURN_DATA_REG(REGNO)       \
 (current_function_calls_eh_return              \
  && (EH_RETURN_DATA_REGNO (0) == REGNO         \
      || EH_RETURN_DATA_REGNO (1) == REGNO      \
      || EH_RETURN_DATA_REGNO (2) == REGNO      \
      || EH_RETURN_DATA_REGNO (3) == REGNO))

/* The canonical saved comparison operands for non-cc0 machines, set in
   the compare expander.  */
rtx mmix_compare_op0;
rtx mmix_compare_op1;

/* We ignore some options with arguments.  They are passed to the linker,
   but also ends up here because they start with "-m".  We tell the driver
   to store them in a variable we don't inspect.  */
const char *mmix_cc1_ignored_option;

/* Declarations of locals.  */

/* This is used in the prologue for what number to pass in a PUSHJ or
   PUSHGO insn.  */
static int mmix_highest_saved_stack_register;

/* Intermediate for insn output.  */
static int mmix_output_destination_register;

static void mmix_output_shiftvalue_op_from_str
  PARAMS ((FILE *, const char *, HOST_WIDEST_INT));
static void mmix_output_shifted_value PARAMS ((FILE *, HOST_WIDEST_INT));
static void mmix_output_condition PARAMS ((FILE *, rtx, int));
static HOST_WIDEST_INT mmix_intval PARAMS ((rtx));
static void mmix_output_octa PARAMS ((FILE *, HOST_WIDEST_INT, int));
static bool mmix_assemble_integer PARAMS ((rtx, unsigned int, int));
static void mmix_init_machine_status PARAMS ((struct function *));

extern void mmix_target_asm_function_prologue
  PARAMS ((FILE *, HOST_WIDE_INT));
extern void mmix_target_asm_function_epilogue
  PARAMS ((FILE *, HOST_WIDE_INT));


/* Target structure macros.  Listed by node.  See `Using and Porting GCC'
   for a general description.  */

/* Node: Function Entry */

#undef TARGET_ASM_BYTE_OP
#define TARGET_ASM_BYTE_OP NULL
#undef TARGET_ASM_ALIGNED_HI_OP
#define TARGET_ASM_ALIGNED_HI_OP NULL
#undef TARGET_ASM_ALIGNED_SI_OP
#define TARGET_ASM_ALIGNED_SI_OP NULL
#undef TARGET_ASM_ALIGNED_DI_OP
#define TARGET_ASM_ALIGNED_DI_OP NULL
#undef TARGET_ASM_INTEGER
#define TARGET_ASM_INTEGER mmix_assemble_integer

#undef TARGET_ASM_FUNCTION_PROLOGUE
#define TARGET_ASM_FUNCTION_PROLOGUE mmix_target_asm_function_prologue

#undef TARGET_ASM_FUNCTION_EPILOGUE
#define TARGET_ASM_FUNCTION_EPILOGUE mmix_target_asm_function_epilogue

struct gcc_target targetm = TARGET_INITIALIZER;

/* Functions that are expansions for target macros.
   See Target Macros in `Using and Porting GCC'.  */

/* OVERRIDE_OPTIONS.  */

void
mmix_override_options ()
{
  /* Should we err or should we warn?  Hmm.  At least we must neutralize
     it.  For example the wrong kind of case-tables will be generated with
     PIC; we use absolute address items for mmixal compatibility.  FIXME:
     They could be relative if we just elide them to after all pertinent
     labels.  */
  if (flag_pic)
    {
      warning ("-f%s not supported: ignored", (flag_pic > 1) ? "PIC" : "pic");
      flag_pic = 0;
    }

  /* All other targets add GC roots from their override_options function,
     so play along.  */
  ggc_add_rtx_root (&mmix_compare_op0, 1);
  ggc_add_rtx_root (&mmix_compare_op1, 1);
}

/* INIT_EXPANDERS.  */

void
mmix_init_expanders ()
{
  init_machine_status = mmix_init_machine_status;
}

/* Set the per-function data.  */

static void
mmix_init_machine_status (f)
     struct function *f;
{
  f->machine = xcalloc (1, sizeof (struct machine_function));
}

/* DATA_ALIGNMENT.
   We have trouble getting the address of stuff that is located at other
   than 32-bit alignments (GETA requirements), so try to give everything
   at least 32-bit alignment. */

int
mmix_data_alignment (type, basic_align)
     tree type ATTRIBUTE_UNUSED;
     int basic_align;
{
  if (basic_align < 32)
    return 32;

  return basic_align;
}

/* CONSTANT_ALIGNMENT.  */

int
mmix_constant_alignment (constant, basic_align)
     tree constant ATTRIBUTE_UNUSED;
     int basic_align;
{
  if (basic_align < 32)
    return 32;

  return basic_align;
}

/* LOCAL_ALIGNMENT.  */

int
mmix_local_alignment (type, basic_align)
     tree type ATTRIBUTE_UNUSED;
     int basic_align;
{
  if (basic_align < 32)
    return 32;

  return basic_align;
}

/* CONDITIONAL_REGISTER_USAGE.  */

void
mmix_conditional_register_usage ()
{
  int i;

  if (TARGET_ABI_GNU)
    {
      static const int gnu_abi_reg_alloc_order[]
        = MMIX_GNU_ABI_REG_ALLOC_ORDER;

      for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
        reg_alloc_order[i] = gnu_abi_reg_alloc_order[i];

      /* Change the default from the mmixware ABI.  For the GNU ABI,
         $15..$30 are call-saved just as $0..$14.  There must be one
         call-clobbered local register for the "hole" describing number of
         saved local registers saved by PUSHJ/PUSHGO during the function
         call, receiving the return value at return.  So best is to use
         the highest, $31.  It's already marked call-clobbered for the
         mmixware ABI.  */
      for (i = 15; i <= 30; i++)
        call_used_regs[i] = 0;
    }

  /* Step over the ":" in special register names.  */
  if (! TARGET_TOPLEVEL_SYMBOLS)
    for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
      if (reg_names[i][0] == ':')
        reg_names[i]++;
}

/* PREFERRED_RELOAD_CLASS.
   We need to extend the reload class of REMAINDER_REG and HIMULT_REG.  */

enum reg_class
mmix_preferred_reload_class (x, class)
     rtx x ATTRIBUTE_UNUSED;
     enum reg_class class;
{
  /* FIXME: Revisit.  */
  return GET_CODE (x) == MOD && GET_MODE (x) == DImode
    ? REMAINDER_REG : class;
}

/* PREFERRED_OUTPUT_RELOAD_CLASS.
   We need to extend the reload class of REMAINDER_REG and HIMULT_REG.  */

enum reg_class
mmix_preferred_output_reload_class (x, class)
     rtx x ATTRIBUTE_UNUSED;
     enum reg_class class;
{
  /* FIXME: Revisit.  */
  return GET_CODE (x) == MOD && GET_MODE (x) == DImode
    ? REMAINDER_REG : class;
}

/* SECONDARY_RELOAD_CLASS.
   We need to reload regs of REMAINDER_REG and HIMULT_REG elsewhere.  */

enum reg_class
mmix_secondary_reload_class (class, mode, x, in_p)
     enum reg_class class;
     enum machine_mode mode;
     rtx x;
     int in_p;
{
  if (class == REMAINDER_REG
      || class == HIMULT_REG
      || class == SYSTEM_REGS)
    return GENERAL_REGS;

  if (mode != DImode || in_p)
    return NO_REGS;

  /* We have to help reload. */
  if (mode == DImode && GET_CODE (x) == MEM
      && ! address_operand (XEXP (x, 0), GET_MODE (x)))
    return GENERAL_REGS;

  /* FIXME: Optimize this; there are lots of PLUS:es that don't need a
     reload register.  */
  if (GET_CODE (x) == PLUS)
    return GENERAL_REGS;

  return NO_REGS;
}

/* CONST_OK_FOR_LETTER_P.  */

int
mmix_const_ok_for_letter_p (value, c)
     HOST_WIDE_INT value;
     int c;
{
  return
    (c == 'I' ? value >= 0 && value <= 255
     : c == 'J' ? value >= 0 && value <= 65535
     : c == 'K' ? value <= 0 && value >= -255
     : c == 'L' ? mmix_shiftable_wyde_value (value)
     : c == 'M' ? value == 0
     : c == 'N' ? mmix_shiftable_wyde_value (~value)
     : c == 'O' ? (value == 3 || value == 5 || value == 9
                   || value == 17)
     : 0);
}

/* CONST_DOUBLE_OK_FOR_LETTER_P.  */

int
mmix_const_double_ok_for_letter_p (value, c)
     rtx value;
     int c;
{
  return
    (c == 'G' ? value == CONST0_RTX (GET_MODE (value))
     : 0);
}

/* EXTRA_CONSTRAINT.
   We need this since our constants are not always expressible as
   CONST_INT:s, but rather often as CONST_DOUBLE:s.  */

int
mmix_extra_constraint (x, c)
     rtx x;
     int c;
{
  HOST_WIDEST_INT value;

  if (c == 'U')
    return address_operand (x, Pmode);

  if (GET_CODE (x) != CONST_DOUBLE || GET_MODE (x) != VOIDmode)
    return 0;

  value = mmix_intval (x);

  /* We used to map Q->J, R->K, S->L, T->N, U->O, but we don't have to any
     more ('U' taken for address_operand).  Some letters map outside of
     CONST_INT, though; we still use 'S' and 'T'.  */
  if (c == 'S')
    return mmix_shiftable_wyde_value (value);
  else if (c == 'T')
    return mmix_shiftable_wyde_value (~value);
  return 0;
}

/* DYNAMIC_CHAIN_ADDRESS.  */

rtx
mmix_dynamic_chain_address (frame)
     rtx frame;
{
  /* FIXME: the frame-pointer is stored at offset -8 from the current
     frame-pointer.  Unfortunately, the caller assumes that a
     frame-pointer is present for *all* previous frames.  There should be
     a way to say that that cannot be done, like for RETURN_ADDR_RTX.  */
  return plus_constant (frame, -8);
}

/* STARTING_FRAME_OFFSET.  */

int
mmix_starting_frame_offset ()
{
  /* The old frame pointer is in the slot below the new one, so
     FIRST_PARM_OFFSET does not need to depend on whether the
     frame-pointer is needed or not.  We have to adjust for the register
     stack pointer being located below the saved frame pointer.
     Similarly, we store the return address on the stack too, for
     exception handling, and always if we save the register stack pointer.  */
  return
    (-8
     + (MMIX_CFUN_HAS_LANDING_PAD
        ? -16 : (MMIX_CFUN_NEEDS_SAVED_EH_RETURN_ADDRESS ? -8 : 0)));
}

/* RETURN_ADDR_RTX.  */

rtx
mmix_return_addr_rtx (count, frame)
     int count;
     rtx frame ATTRIBUTE_UNUSED;
{
  return count == 0
    ? (MMIX_CFUN_NEEDS_SAVED_EH_RETURN_ADDRESS
       /* FIXME: Set frame_alias_set on the following.  */
       ? validize_mem (gen_rtx_MEM (Pmode, plus_constant (frame_pointer_rtx, -16)))
       : get_hard_reg_initial_val (Pmode, MMIX_INCOMING_RETURN_ADDRESS_REGNUM))
    : NULL_RTX;
}

/* SETUP_FRAME_ADDRESSES.  */

void
mmix_setup_frame_addresses ()
{
  /* Nothing needed at the moment.  */
}

/* The difference between the (imaginary) frame pointer and the stack
   pointer.  Used to eliminate the frame pointer.  */

int
mmix_initial_elimination_offset (fromreg, toreg)
     int fromreg;
     int toreg;
{
  int regno;
  int fp_sp_offset
    = (get_frame_size () + current_function_outgoing_args_size + 7) & ~7;

  /* There is no actual difference between these two.  */
  if (fromreg == MMIX_ARG_POINTER_REGNUM
      && toreg == MMIX_FRAME_POINTER_REGNUM)
    return 0;

  /* The difference is the size of local variables plus the size of
     outgoing function arguments that would normally be passed as
     registers but must be passed on stack because we're out of
     function-argument registers.  Only global saved registers are
     counted; the others go on the register stack.

     The frame-pointer is counted too if it is what is eliminated, as we
     need to balance the offset for it from STARTING_FRAME_OFFSET.

     Also add in the slot for the register stack pointer we save if we
     have a landing pad.

     Unfortunately, we can't access $0..$14, from unwinder code easily, so
     store the return address in a frame slot too.  FIXME: Only for
     non-leaf functions.  FIXME: Always with a landing pad, because it's
     hard to know whether we need the other at the time we know we need
     the offset for one (and have to state it).  It's a kludge until we
     can express the register stack in the EH frame info.

     We have to do alignment here; get_frame_size will not return a
     multiple of STACK_BOUNDARY.  FIXME: Add note in manual.  */

  for (regno = MMIX_FIRST_GLOBAL_REGNUM;
       regno <= 255;
       regno++)
    if ((regs_ever_live[regno] && ! call_used_regs[regno])
        || IS_MMIX_EH_RETURN_DATA_REG (regno))
      fp_sp_offset += 8;

  return fp_sp_offset
    + (MMIX_CFUN_HAS_LANDING_PAD
       ? 16 : (MMIX_CFUN_NEEDS_SAVED_EH_RETURN_ADDRESS ? 8 : 0))
    + (fromreg == MMIX_ARG_POINTER_REGNUM ? 0 : 8);
}

/* Return an rtx for a function argument to go in a register, and 0 for
   one that must go on stack.  */

rtx
mmix_function_arg (argsp, mode, type, named, incoming)
     const CUMULATIVE_ARGS * argsp;
     enum machine_mode mode;
     tree type;
     int named ATTRIBUTE_UNUSED;
     int incoming;
{
  /* Handling of the positional dummy parameter for varargs gets nasty.
     Check execute/991216-3 and function.c:assign_params.  We have to say
     that the dummy parameter goes on stack in order to get the correct
     offset when va_start and va_arg is applied.  FIXME: Should do TRT by
     itself in the gcc core.  */
  if ((! named && incoming && current_function_varargs) || argsp->now_varargs)
    return NULL_RTX;

  /* Last-argument marker.  */
  if (type == void_type_node)
    return (argsp->regs < MMIX_MAX_ARGS_IN_REGS)
      ? gen_rtx_REG (mode,
                     (incoming
                      ? MMIX_FIRST_INCOMING_ARG_REGNUM
                      : MMIX_FIRST_ARG_REGNUM) + argsp->regs)
      : NULL_RTX;

  return (argsp->regs < MMIX_MAX_ARGS_IN_REGS
          && !MUST_PASS_IN_STACK (mode, type)
          && (GET_MODE_BITSIZE (mode) <= 64
              || argsp->lib
              || TARGET_LIBFUNC))
    ? gen_rtx_REG (mode,
                   (incoming
                    ? MMIX_FIRST_INCOMING_ARG_REGNUM
                    : MMIX_FIRST_ARG_REGNUM)
                   + argsp->regs)
    : NULL_RTX;
}

/* Returns nonzero for everything that goes by reference, 0 for
   everything that goes by value.  */

int
mmix_function_arg_pass_by_reference (argsp, mode, type, named)
     const CUMULATIVE_ARGS * argsp;
     enum machine_mode mode;
     tree type;
     int named ATTRIBUTE_UNUSED;
{
  /* FIXME: Check: I'm not sure the MUST_PASS_IN_STACK check is
     necessary.  */
  return
    MUST_PASS_IN_STACK (mode, type)
    || (MMIX_FUNCTION_ARG_SIZE (mode, type) > 8
        && !TARGET_LIBFUNC
        && !argsp->lib);
}

/* Return nonzero if regno is a register number where a parameter is
   passed, and 0 otherwise.  */

int
mmix_function_arg_regno_p (regno, incoming)
     int regno;
     int incoming;
{
  int first_arg_regnum
    = incoming ? MMIX_FIRST_INCOMING_ARG_REGNUM : MMIX_FIRST_ARG_REGNUM;

  return regno >= first_arg_regnum
    && regno < first_arg_regnum + MMIX_MAX_ARGS_IN_REGS;
}

/* FUNCTION_OUTGOING_VALUE.  */

rtx
mmix_function_outgoing_value (valtype, func)
     tree valtype;
     tree func ATTRIBUTE_UNUSED;
{
  enum machine_mode mode = TYPE_MODE (valtype);
  enum machine_mode cmode;
  int first_val_regnum = MMIX_OUTGOING_RETURN_VALUE_REGNUM;
  rtx vec[MMIX_MAX_REGS_FOR_VALUE];
  int i;
  int nregs;

  /* Return values that fit in a register need no special handling.
     There's no register hole when parameters are passed in global
     registers.  */
  if (TARGET_ABI_GNU
      || GET_MODE_BITSIZE (mode) <= BITS_PER_WORD)
    return
      gen_rtx_REG (mode, MMIX_OUTGOING_RETURN_VALUE_REGNUM);

  /* A complex type, made up of components.  */
  cmode = TYPE_MODE (TREE_TYPE (valtype));
  nregs = ((GET_MODE_BITSIZE (mode) + BITS_PER_WORD - 1) / BITS_PER_WORD);

  /* We need to take care of the effect of the register hole on return
     values of large sizes; the last register will appear as the first
     register, with the rest shifted.  (For complex modes, this is just
     swapped registers.)  */

  if (nregs > MMIX_MAX_REGS_FOR_VALUE)
    internal_error ("too large function value type, needs %d registers,\
 have only %d registers for this", nregs, MMIX_MAX_REGS_FOR_VALUE);

  /* FIXME: Maybe we should handle structure values like this too
     (adjusted for BLKmode), perhaps for both ABI:s.  */
  for (i = 0; i < nregs - 1; i++)
    vec[i]
      = gen_rtx_EXPR_LIST (VOIDmode,
                           gen_rtx_REG (cmode, first_val_regnum + i),
                           GEN_INT ((i + 1) * BITS_PER_UNIT));

  vec[nregs - 1]
    = gen_rtx_EXPR_LIST (VOIDmode,
                         gen_rtx_REG (cmode, first_val_regnum + nregs - 1),
                         GEN_INT (0));

  return gen_rtx_PARALLEL (VOIDmode, gen_rtvec_v (nregs, vec));
}

/* EH_RETURN_DATA_REGNO. */

int
mmix_eh_return_data_regno (n)
     int n ATTRIBUTE_UNUSED;
{
  if (n >= 0 && n < 4)
    return MMIX_EH_RETURN_DATA_REGNO_START + n;

  return INVALID_REGNUM;
}

/* EH_RETURN_STACKADJ_RTX. */

rtx
mmix_eh_return_stackadj_rtx ()
{
  return gen_rtx_REG (Pmode, MMIX_EH_RETURN_STACKADJ_REGNUM);
}

/* EH_RETURN_HANDLER_RTX.  */

rtx
mmix_eh_return_handler_rtx ()
{
  return
    gen_rtx_REG (Pmode, MMIX_INCOMING_RETURN_ADDRESS_REGNUM);
}

/* ASM_PREFERRED_EH_DATA_FORMAT. */

int
mmix_asm_preferred_eh_data_format (code, global)
     int code ATTRIBUTE_UNUSED;
     int global ATTRIBUTE_UNUSED;
{
  /* This is the default (was at 2001-07-20).  Revisit when needed.  */
  return DW_EH_PE_absptr;
}

/* Emit the function prologue.  For simplicity while the port is still
   in a flux, we do it as text rather than the now preferred RTL way,
   as (define_insn "function_prologue").

   FIXME: Translate to RTL and/or optimize some of the DWARF 2 stuff.  */

void
mmix_target_asm_function_prologue (stream, locals_size)
     FILE *stream;
     HOST_WIDE_INT locals_size;
{
  int regno;
  int stack_space_to_allocate
    = (current_function_outgoing_args_size
       + current_function_pretend_args_size
       + (int) locals_size + 8 + 7) & ~7;
  int offset = -8;
  int empty_stack_frame
    = (current_function_outgoing_args_size == 0
       && locals_size == 0
       && current_function_pretend_args_size == 0
       && current_function_varargs == 0
       && current_function_stdarg == 0);
  int doing_dwarf = dwarf2out_do_frame ();
  long cfa_offset = 0;

  /* Guard our assumptions.  Very low priority FIXME.  */
  if (locals_size != (int) locals_size)
    error ("stack frame too big");

  /* Add room needed to save global non-register-stack registers.  */
  for (regno = 255;
       regno >= MMIX_FIRST_GLOBAL_REGNUM;
       regno--)
    /* Note that we assume that the frame-pointer-register is one of these
       registers, in which case we don't count it here.  */
    if ((((regno != MMIX_FRAME_POINTER_REGNUM || !frame_pointer_needed)
          && regs_ever_live[regno] && !call_used_regs[regno]))
        || IS_MMIX_EH_RETURN_DATA_REG (regno))
      stack_space_to_allocate += 8;

  /* If we do have a frame-pointer, add room for it.  */
  if (frame_pointer_needed)
    stack_space_to_allocate += 8;

  /* If we have a non-local label, we need to be able to unwind to it, so
     store the current register stack pointer.  Also store the return
     address if we do that.  */
  if (MMIX_CFUN_HAS_LANDING_PAD)
    stack_space_to_allocate += 16;
  else if (MMIX_CFUN_NEEDS_SAVED_EH_RETURN_ADDRESS)
    /* If we do have a saved return-address slot, add room for it.  */
    stack_space_to_allocate += 8;

  /* Make sure we don't get an unaligned stack.  */
  if ((stack_space_to_allocate % 8) != 0)
    internal_error ("stack frame not a multiple of 8 bytes: %d",
                    stack_space_to_allocate);

  if (current_function_pretend_args_size)
    {
      int mmix_first_vararg_reg
        = (MMIX_FIRST_INCOMING_ARG_REGNUM
           + (MMIX_MAX_ARGS_IN_REGS
              - current_function_pretend_args_size / 8));

      for (regno
             = MMIX_FIRST_INCOMING_ARG_REGNUM + MMIX_MAX_ARGS_IN_REGS - 1;
           regno >= mmix_first_vararg_reg;
           regno--)
        {
          if (offset < 0)
            {
              int stack_chunk
                = stack_space_to_allocate > (256 - 8)
                ? (256 - 8) : stack_space_to_allocate;

              fprintf (stream, "\tSUBU %s,%s,%d\n",
                       reg_names[MMIX_STACK_POINTER_REGNUM],
                       reg_names[MMIX_STACK_POINTER_REGNUM],
                       stack_chunk);

              if (doing_dwarf)
                {
                  /* Each call to dwarf2out_def_cfa overrides the previous
                     setting; they don't accumulate.  We must keep track
                     of the offset ourselves.  */
                  cfa_offset += stack_chunk;
                  dwarf2out_def_cfa ("", MMIX_STACK_POINTER_REGNUM,
                                     cfa_offset);
                }
              offset += stack_chunk;
              stack_space_to_allocate -= stack_chunk;
            }

          fprintf (stream, "\tSTOU %s,%s,%d\n", reg_names[regno],
                   reg_names[MMIX_STACK_POINTER_REGNUM],
                   offset);

          /* These registers aren't actually saved (as in "will be
             restored"), so don't tell DWARF2 they're saved.  */

          offset -= 8;
        }
    }

  /* In any case, skip over the return-address slot.  FIXME: Not needed
     now.  */
  offset -= 8;

  /* Store the frame-pointer.  */

  if (frame_pointer_needed)
    {
      empty_stack_frame = 0;

      if (offset < 0)
        {
          /* Get 8 less than otherwise, since we need to reach offset + 8.  */
          int stack_chunk
            = stack_space_to_allocate > (256 - 8 - 8)
            ? (256 - 8 - 8) : stack_space_to_allocate;

          fprintf (stream, "\tSUBU %s,%s,%d\n",
                   reg_names[MMIX_STACK_POINTER_REGNUM],
                   reg_names[MMIX_STACK_POINTER_REGNUM],
                   stack_chunk);
          if (doing_dwarf)
            {
              cfa_offset += stack_chunk;
              dwarf2out_def_cfa ("", MMIX_STACK_POINTER_REGNUM,
                                 cfa_offset);
            }
          offset += stack_chunk;
          stack_space_to_allocate -= stack_chunk;
        }

      fprintf (stream, "\tSTOU %s,%s,%d\n\tADDU %s,%s,%d\n",
               reg_names[MMIX_FRAME_POINTER_REGNUM],
               reg_names[MMIX_STACK_POINTER_REGNUM],
               offset,
               reg_names[MMIX_FRAME_POINTER_REGNUM],
               reg_names[MMIX_STACK_POINTER_REGNUM],
               offset + 8);
      if (doing_dwarf)
        dwarf2out_reg_save ("", MMIX_FRAME_POINTER_REGNUM,
                            -cfa_offset + offset);

      offset -= 8;
    }

  if (MMIX_CFUN_NEEDS_SAVED_EH_RETURN_ADDRESS)
    {
      /* Store the return-address, if one is needed on the stack.  */
      empty_stack_frame = 0;

      if (offset < 0)
        {
          /* Get 8 less than otherwise, since we need to reach offset + 8.  */
          int stack_chunk
            = stack_space_to_allocate > (256 - 8 - 8)
            ? (256 - 8 - 8) : stack_space_to_allocate;

          fprintf (stream, "\tSUBU %s,%s,%d\n",
                   reg_names[MMIX_STACK_POINTER_REGNUM],
                   reg_names[MMIX_STACK_POINTER_REGNUM],
                   stack_chunk);
          if (doing_dwarf)
            {
              cfa_offset += stack_chunk;
              dwarf2out_def_cfa ("", MMIX_STACK_POINTER_REGNUM,
                                 cfa_offset);
            }
          offset += stack_chunk;
          stack_space_to_allocate -= stack_chunk;
        }

      fprintf (stream, "\tGET $255,rJ\n\tSTOU $255,%s,%d\n",
               reg_names[MMIX_STACK_POINTER_REGNUM],
               offset);
      if (doing_dwarf)
        dwarf2out_return_save ("", -cfa_offset + offset);
      offset -= 8;
    }
  else if (MMIX_CFUN_HAS_LANDING_PAD)
    offset -= 8;

  if (MMIX_CFUN_HAS_LANDING_PAD)
    {
      /* Store the register defining the numbering of local registers, so
         we know how long to unwind the register stack.  */

      empty_stack_frame = 0;

      if (offset < 0)
        {
          /* Get 8 less than otherwise, since we need to reach offset + 8.  */
          int stack_chunk
            = stack_space_to_allocate > (256 - 8 - 8)
            ? (256 - 8 - 8) : stack_space_to_allocate;

          fprintf (stream, "\tSUBU %s,%s,%d\n",
                   reg_names[MMIX_STACK_POINTER_REGNUM],
                   reg_names[MMIX_STACK_POINTER_REGNUM],
                   stack_chunk);
          offset += stack_chunk;
          stack_space_to_allocate -= stack_chunk;

          if (doing_dwarf)
            {
              cfa_offset += stack_chunk;
              dwarf2out_def_cfa ("", MMIX_STACK_POINTER_REGNUM,
                                 cfa_offset);
            }
        }

      /* We don't tell dwarf2 about this one; we just have it to unwind
         the register stack at landing pads.  FIXME: It's a kludge because
         we can't describe the effect of the PUSHJ and PUSHGO insns on the
         register stack at the moment.  Best thing would be to handle it
         like stack-pointer offsets.  Better: some hook into dwarf2out.c
         to produce DW_CFA_expression:s that specify the increment of rO,
         and unwind it at eh_return (preferred) or at the landing pad.
         Then saves to $0..$G-1 could be specified through that register.  */

      fprintf (stream, "\tGET $255,rO\n\tSTOU $255,%s,%d\n",
               reg_names[MMIX_STACK_POINTER_REGNUM], offset);

      offset -= 8;
    }

  /* After the return-address and the frame-pointer, we have the local
     variables.  They're the ones that may have an "unaligned" size.  */
  offset -= (locals_size + 7) & ~7;

  /* Now store all registers that are global, i.e. not saved by the
     register file machinery.

     It is assumed that the frame-pointer is one of these registers, so it
     is explicitly excluded in the count.  */

  for (regno = 255;
       regno >= MMIX_FIRST_GLOBAL_REGNUM;
       regno--)
    if (((regno != MMIX_FRAME_POINTER_REGNUM || !frame_pointer_needed)
         && regs_ever_live[regno] && ! call_used_regs[regno])
        || IS_MMIX_EH_RETURN_DATA_REG (regno))
      {
        empty_stack_frame = 0;

        if (offset < 0)
          {
            int stack_chunk;

            /* Since the local variables go above, we may get a large
               offset here.  */
            if (offset < -248)
              {
                /* We're not going to access the locals area in the
                   prologue, so we'll just silently subtract the slab we
                   will not access.  */
                stack_chunk =
                  stack_space_to_allocate > (256 - offset - 8)
                  ? (256 - offset - 8) : stack_space_to_allocate;

                mmix_output_register_setting (stream, 255, stack_chunk, 1);
                fprintf (stream, "\tSUBU %s,%s,$255\n",
                         reg_names[MMIX_STACK_POINTER_REGNUM],
                         reg_names[MMIX_STACK_POINTER_REGNUM]);

                if (doing_dwarf)
                  {
                    cfa_offset += stack_chunk;
                    dwarf2out_def_cfa ("", MMIX_STACK_POINTER_REGNUM,
                                       cfa_offset);
                  }
              }
            else
              {
                stack_chunk = stack_space_to_allocate > (256 - 8)
                  ? (256 - 8) : stack_space_to_allocate;

                fprintf (stream, "\tSUBU %s,%s,%d\n",
                         reg_names[MMIX_STACK_POINTER_REGNUM],
                         reg_names[MMIX_STACK_POINTER_REGNUM], stack_chunk);
                if (doing_dwarf)
                  {
                    cfa_offset += stack_chunk;
                    dwarf2out_def_cfa ("", MMIX_STACK_POINTER_REGNUM,
                                       cfa_offset);
                  }
              }

            offset += stack_chunk;
            stack_space_to_allocate -= stack_chunk;
          }

        fprintf (stream, "\tSTOU %s,%s,%d\n", reg_names[regno],
               reg_names[MMIX_STACK_POINTER_REGNUM], offset);
        if (doing_dwarf)
          dwarf2out_reg_save ("", regno, -cfa_offset + offset);
        offset -= 8;
      }

  /* Finally, allocate room for local vars (if they weren't allocated for
     above) and outgoing args.  This might be any number of bytes (well,
     we assume it fits in a host-int).
     Don't allocate (the return-address slot) if the stack frame is empty.  */
  if (stack_space_to_allocate && ! empty_stack_frame)
    {
      if (stack_space_to_allocate < 256)
        {
          fprintf (stream, "\tSUBU %s,%s,%d\n",
                   reg_names[MMIX_STACK_POINTER_REGNUM],
                   reg_names[MMIX_STACK_POINTER_REGNUM],
                   stack_space_to_allocate);
        }
      else
        {
          mmix_output_register_setting (stream, 255,
                                        stack_space_to_allocate, 1);
          fprintf (stream, "\tSUBU %s,%s,$255\n",
                   reg_names[MMIX_STACK_POINTER_REGNUM],
                   reg_names[MMIX_STACK_POINTER_REGNUM]);
        }

      if (doing_dwarf)
        {
          cfa_offset += stack_space_to_allocate;
          dwarf2out_def_cfa ("", MMIX_STACK_POINTER_REGNUM,
                             cfa_offset);
        }
    }

  /* We put the number of the highest saved register-file register in a
     location convenient for the call-patterns to output.  Note that we
     don't tell dwarf2 about these registers, since it can't restore them
     anyway.  */
  for (regno = MMIX_LAST_REGISTER_FILE_REGNUM;
       regno >= 0;
       regno--)
    if ((regs_ever_live[regno] && !call_used_regs[regno])
        || (regno == MMIX_FRAME_POINTER_REGNUM && frame_pointer_needed))
      break;

  mmix_highest_saved_stack_register = regno;

  /* FIXME: A kludge for the MMIXware ABI.  The return value comes back in
     L of the caller, not just the register number of the X field of
     PUSH{J,GO}.  So we need to make L agree with that number if there's a
     function call in this function that returns a value but takes no
     parameters (if there were parameters, L would be set to at least the
     first parameter register, $16).  A real solution includes a pass to
     test that settings of $15 (MMIX_RETURN_VALUE_REGNUM for the MMIXware
     ABI) dominate all function calls that return a value.  This could be
     done in the planned machine_dep_reorg pass to rename all registers.  */
  if (! TARGET_ABI_GNU && cfun->machine->has_call_value_without_parameters)
    fprintf (stream, "\tSET %s,%s\n",
             reg_names[MMIX_RETURN_VALUE_REGNUM],
             reg_names[MMIX_RETURN_VALUE_REGNUM]);
}

/* TARGET_ASM_FUNCTION_EPILOGUE.  */

void
mmix_target_asm_function_epilogue (stream, locals_size)
     FILE *stream;
     HOST_WIDE_INT locals_size;

{
  int regno;
  int stack_space_to_deallocate
    = (current_function_outgoing_args_size
       + current_function_pretend_args_size
       + (int) locals_size + 8 + 7) & ~7;

  /* The assumption that locals_size fits in an int is asserted in
     mmix_target_asm_function_prologue.  */

  /* The first address to access is beyond the outgoing_args area.  */
  int offset = current_function_outgoing_args_size;
  int empty_stack_frame
    = (current_function_outgoing_args_size == 0
       && locals_size == 0
       && current_function_pretend_args_size == 0
       && ! MMIX_CFUN_NEEDS_SAVED_EH_RETURN_ADDRESS
       && ! MMIX_CFUN_HAS_LANDING_PAD);

  /* Add the space for global non-register-stack registers.
     It is assumed that the frame-pointer register can be one of these
     registers, in which case it is excluded from the count when needed.  */
  for (regno = 255;
       regno >= MMIX_FIRST_GLOBAL_REGNUM;
       regno--)
    if (((regno != MMIX_FRAME_POINTER_REGNUM || !frame_pointer_needed)
         && regs_ever_live[regno] && !call_used_regs[regno])
        || IS_MMIX_EH_RETURN_DATA_REG (regno))
      stack_space_to_deallocate += 8;

  /* Add in the space for register stack-pointer.  If so, always add room
     for the saved PC.  */
  if (MMIX_CFUN_HAS_LANDING_PAD)
    stack_space_to_deallocate += 16;
  else if (MMIX_CFUN_NEEDS_SAVED_EH_RETURN_ADDRESS)
    /* If we have a saved return-address slot, add it in.  */
    stack_space_to_deallocate += 8;

  /* Add in the frame-pointer.  */
  if (frame_pointer_needed)
    stack_space_to_deallocate += 8;

  /* Make sure we don't get an unaligned stack. */
  if ((stack_space_to_deallocate % 8) != 0)
    internal_error ("stack frame not a multiple of octabyte: %d",
                    stack_space_to_deallocate);

  /* We will add back small offsets to the stack pointer as we go.
     First, we restore all registers that are global, i.e. not saved by
     the register file machinery.  */

  for (regno = MMIX_FIRST_GLOBAL_REGNUM;
       regno <= 255;
       regno++)
    if (((regno != MMIX_FRAME_POINTER_REGNUM || !frame_pointer_needed)
         && regs_ever_live[regno] && !call_used_regs[regno])
        || IS_MMIX_EH_RETURN_DATA_REG (regno))
      {
        empty_stack_frame = 0;

        if (offset > 255)
          {
            if (offset > 65535)
              {
                /* There's better support for incrementing than
                   decrementing, so we might be able to optimize this as
                   we see a need.  */
                mmix_output_register_setting (stream, 255, offset, 1);
                fprintf (stream, "\tADDU %s,%s,$255\n",
                         reg_names[MMIX_STACK_POINTER_REGNUM],
                         reg_names[MMIX_STACK_POINTER_REGNUM]);
              }
            else
              fprintf (stream, "\tINCL %s,%d\n",
                       reg_names[MMIX_STACK_POINTER_REGNUM], offset);

            stack_space_to_deallocate -= offset;
            offset = 0;
          }

        fprintf (stream, "\tLDOU %s,%s,%d\n",
                 reg_names[regno],
                 reg_names[MMIX_STACK_POINTER_REGNUM],
                 offset);
        offset += 8;
      }

  /* Here is where the local variables were.  As in the prologue, they
     might be of an unaligned size.  */
  offset += (locals_size + 7) & ~7;


  /* The saved register stack pointer is just below the frame-pointer
     register.  We don't need to restore it "manually"; the POP
     instruction does that.  */
  if (MMIX_CFUN_HAS_LANDING_PAD)
    offset += 16;
  else if (MMIX_CFUN_NEEDS_SAVED_EH_RETURN_ADDRESS)
    /* The return-address slot is just below the frame-pointer register.
       We don't need to restore it because we don't really use it.  */
    offset += 8;

  /* Get back the old frame-pointer-value.  */
  if (frame_pointer_needed)
    {
      empty_stack_frame = 0;

      if (offset > 255)
        {
          if (offset > 65535)
            {
              /* There's better support for incrementing than
                 decrementing, so we might be able to optimize this as
                 we see a need.  */
              mmix_output_register_setting (stream, 255, offset, 1);
              fprintf (stream, "\tADDU %s,%s,$255\n",
                       reg_names[MMIX_STACK_POINTER_REGNUM],
                       reg_names[MMIX_STACK_POINTER_REGNUM]);
            }
          else
            fprintf (stream, "\tINCL %s,%d\n",
                     reg_names[MMIX_STACK_POINTER_REGNUM], offset);

          stack_space_to_deallocate -= offset;
          offset = 0;
        }

      fprintf (stream, "\tLDOU %s,%s,%d\n",
               reg_names[MMIX_FRAME_POINTER_REGNUM],
               reg_names[MMIX_STACK_POINTER_REGNUM],
               offset);
      offset += 8;
    }

  /* Do not deallocate the return-address slot if the stack frame is
     empty, because then it was never allocated.  */
  if (! empty_stack_frame)
    {
      /* We do not need to restore pretended incoming args, just add
         back offset to sp.  */
      if (stack_space_to_deallocate > 65535)
        {
          /* There's better support for incrementing than decrementing, so
             we might be able to optimize this as we see a need.  */
          mmix_output_register_setting (stream, 255,
                                        stack_space_to_deallocate, 1);
          fprintf (stream, "\tADDU %s,%s,$255\n",
                   reg_names[MMIX_STACK_POINTER_REGNUM],
                   reg_names[MMIX_STACK_POINTER_REGNUM]);
        }
      else
        fprintf (stream, "\tINCL %s,%d\n",
                 reg_names[MMIX_STACK_POINTER_REGNUM],
                 stack_space_to_deallocate);
    }

  if (current_function_calls_eh_return)
    /* Adjustment the (normal) stack-pointer to that of the receiver.
       FIXME: It would be nice if we could also adjust the register stack
       here, but we need to express it through DWARF 2 too.  */
    fprintf (stream, "\tADDU %s,%s,%s\n",
             reg_names [MMIX_STACK_POINTER_REGNUM],
             reg_names [MMIX_STACK_POINTER_REGNUM],
             reg_names [MMIX_EH_RETURN_STACKADJ_REGNUM]);

  /* The extra \n is so we have a blank line between the assembly code of
     separate functions.  */
  fprintf (stream, "\tPOP %d,0\n\n",
           (! TARGET_ABI_GNU
            && current_function_return_rtx != NULL
            && ! current_function_returns_struct)
           ? (GET_CODE (current_function_return_rtx) == PARALLEL
              ? GET_NUM_ELEM (XVEC (current_function_return_rtx, 0)) : 1)
           : 0);
}

/* ASM_OUTPUT_MI_THUNK.  */

void
mmix_asm_output_mi_thunk (stream, fndecl, delta, func)
     FILE * stream;
     tree fndecl ATTRIBUTE_UNUSED;
     int delta;
     tree func;
{
  /* If you define STRUCT_VALUE to 0, rather than use STRUCT_VALUE_REGNUM,
     (i.e. pass location of structure to return as invisible first
     argument) you need to tweak this code too.  */
  const char *regname = reg_names[MMIX_FIRST_INCOMING_ARG_REGNUM];

  if (delta >= 0 && delta < 65536)
    asm_fprintf (stream, "\tINCL %s,%d\n", delta, regname);
  else if (delta < 0 && delta >= -255)
    asm_fprintf (stream, "\tSUBU %s,%s,%d\n", regname, regname, -delta);
  else
    {
      mmix_output_register_setting (stream, 255, delta, 1);
      asm_fprintf (stream, "\tADDU %s,%s,$255\n", regname, regname);
    }

  fprintf (stream, "\tJMP ");
  assemble_name (stream, XSTR (XEXP (DECL_RTL (func), 0), 0));
  fprintf (stream, "\n");
}

/* FUNCTION_PROFILER.  */

void
mmix_function_profiler (stream, labelno)
     FILE *stream ATTRIBUTE_UNUSED;
     int labelno ATTRIBUTE_UNUSED;
{
  sorry ("function_profiler support for MMIX");
}

/* SETUP_INCOMING_VARARGS.  */

void
mmix_setup_incoming_varargs (args_so_farp, mode, vartype, pretend_sizep,
                             second_time)
     CUMULATIVE_ARGS * args_so_farp;
     enum machine_mode mode;
     tree vartype;
     int * pretend_sizep;
     int second_time ATTRIBUTE_UNUSED;
{
  /* For stdarg, the last named variable has been handled, but
     args_so_farp has not been advanced for it.  For varargs, the current
     argument is to be counted to the anonymous ones.  */
  if (current_function_stdarg)
    {
      if (args_so_farp->regs + 1 < MMIX_MAX_ARGS_IN_REGS)
        *pretend_sizep
          = (MMIX_MAX_ARGS_IN_REGS - (args_so_farp->regs + 1)) * 8;
    }
  else if (current_function_varargs)
    {
      if (args_so_farp->regs < MMIX_MAX_ARGS_IN_REGS)
        *pretend_sizep
          = (MMIX_MAX_ARGS_IN_REGS - args_so_farp->regs) * 8;

      /* For varargs, we get here when we see the last named parameter,
         which will actually be passed on stack.  So make the next call
         (there will be one) to FUNCTION_ARG return 0, to count it on
         stack, so va_arg for it will get right.  FIXME: The GCC core
         should provide TRT.  */
      args_so_farp->now_varargs = 1;
    }
  else
    internal_error ("neither varargs or stdarg in mmix_setup_incoming_varargs");


  /* We assume that one argument takes up one register here.  That should
     be true until we start messing with multi-reg parameters.   */
  if ((7 + (MMIX_FUNCTION_ARG_SIZE (mode, vartype))) / 8 != 1)
    internal_error ("MMIX Internal: Last named vararg would not fit in a register");
}

/* EXPAND_BUILTIN_VA_ARG.  */

/* This is modified from the "standard" implementation of va_arg: read the
   value from the current (padded) address and increment by the (padded)
   size.  The difference for MMIX is that if the type is
   pass-by-reference, then perform an indirection.  */

rtx
mmix_expand_builtin_va_arg (valist, type)
     tree valist;
     tree type;
{
  tree addr_tree, t;
  HOST_WIDE_INT align;
  HOST_WIDE_INT rounded_size;
  rtx addr;

  /* Compute the rounded size of the type.  */
  align = PARM_BOUNDARY / BITS_PER_UNIT;
  rounded_size = (((int_size_in_bytes (type) + align - 1) / align) * align);

  /* Get AP.  */
  addr_tree = valist;

 if (AGGREGATE_TYPE_P (type)
     && GET_MODE_UNIT_SIZE (TYPE_MODE (type)) < 8
     && GET_MODE_UNIT_SIZE (TYPE_MODE (type)) != 0)
   {
     /* Adjust for big-endian the location of aggregates passed in a
        register, but where the aggregate is accessed in a shorter mode
        than the natural register mode (i.e. it is accessed as SFmode(?),
        SImode, HImode or QImode rather than DImode or DFmode(?)).  FIXME:
        Or should we adjust the mode in which the aggregate is read, to be
        a register size mode?  (Hum, nah, a small offset is generally
        cheaper than a wider memory access on MMIX.)  */
     addr_tree
       = build (PLUS_EXPR, TREE_TYPE (addr_tree), addr_tree,
                build_int_2 ((BITS_PER_WORD / BITS_PER_UNIT)
                             - GET_MODE_UNIT_SIZE (TYPE_MODE (type)), 0));
   }
 else
   {
    HOST_WIDE_INT adj;
    adj = TREE_INT_CST_LOW (TYPE_SIZE (type)) / BITS_PER_UNIT;
    if (rounded_size > align)
      adj = rounded_size;

    addr_tree = build (PLUS_EXPR, TREE_TYPE (addr_tree), addr_tree,
                       build_int_2 (rounded_size - adj, 0));

    /* If this type is larger than what fits in a register, then it is
       passed by reference.  */
    if (rounded_size > BITS_PER_WORD / BITS_PER_UNIT)
      {
        tree type_ptr = build_pointer_type (type);
        addr_tree = build1 (INDIRECT_REF, type_ptr, addr_tree);
      }
  }

  addr = expand_expr (addr_tree, NULL_RTX, Pmode, EXPAND_NORMAL);
  addr = copy_to_reg (addr);

  /* Compute new value for AP.  For MMIX, it is always advanced by the
     size of a register.  */
  t = build (MODIFY_EXPR, TREE_TYPE (valist), valist,
             build (PLUS_EXPR, TREE_TYPE (valist), valist,
                    build_int_2 (BITS_PER_WORD / BITS_PER_UNIT, 0)));
  TREE_SIDE_EFFECTS (t) = 1;
  expand_expr (t, const0_rtx, VOIDmode, EXPAND_NORMAL);

  return addr;
}

/* TRAMPOLINE_SIZE.  */
/* Four 4-byte insns plus two 8-byte values.  */
int mmix_trampoline_size = 32;


/* TRAMPOLINE_TEMPLATE.  */

void
mmix_trampoline_template (stream)
     FILE * stream;
{
  /* Read a value from to static-chain, jump somewhere.  The static chain
     is stored at offset 16, and the function address is stored at offset
     24.  */
  /* FIXME: GCC copies this using *intsize* (tetra), when it should use
     register size (octa).  */
  fprintf (stream, "\tGETA $255,1F\n\t");
  fprintf (stream, "LDOU %s,$255,0\n\t",
           reg_names[MMIX_STATIC_CHAIN_REGNUM]);
  fprintf (stream, "LDOU $255,$255,8\n\t");
  fprintf (stream, "GO $255,$255,0\n");
  fprintf (stream, "1H\tOCTA 0\n\t");
  fprintf (stream, "OCTA 0\n");
}

/* INITIALIZE_TRAMPOLINE.  */
/* Set the static chain and function pointer field in the trampoline.
   We also SYNCID here to be sure (doesn't matter in the simulator, but
   some day it will).  */

void
mmix_initialize_trampoline (trampaddr, fnaddr, static_chain)
     rtx trampaddr;
     rtx fnaddr;
     rtx static_chain;
{
  emit_move_insn (gen_rtx_MEM (DImode, plus_constant (trampaddr, 16)),
                  static_chain);
  emit_move_insn (gen_rtx_MEM (DImode,
                               plus_constant (trampaddr, 24)),
                  fnaddr);
  emit_insn (gen_sync_icache (validize_mem (gen_rtx_MEM (DImode,
                                                         trampaddr)),
                              GEN_INT (mmix_trampoline_size - 1)));
}

/* We must exclude constant addresses that have an increment that is not a
   multiple of four bytes because of restrictions of the GETA
   instruction.  FIXME: No, I don't think so.  Just add a constraint.  */

int
mmix_constant_address_p (x)
     rtx x;
{
  RTX_CODE code = GET_CODE (x);
  int addend = 0;

  if (code == LABEL_REF || code == SYMBOL_REF)
    return 1;

  if (code == CONSTANT_P_RTX || code == HIGH)
    /* FIXME: Don't know how to dissect these.  Avoid them for now.  */
    return 0;

  switch (code)
    {
    case LABEL_REF:
    case SYMBOL_REF:
      return 1;

    case PLUS:
      /* Can we get a naked PLUS? */
    case CONSTANT_P_RTX:
    case HIGH:
      /* FIXME: Don't know how to dissect these.  Avoid them for now.  */
      return 0;

    case CONST_INT:
      addend = INTVAL (x);
      break;

    case CONST_DOUBLE:
      if (GET_MODE (x) != VOIDmode)
        /* Strange that we got here.  FIXME: Check if we do.  */
        return 0;
      addend = CONST_DOUBLE_LOW (x);
      break;

    case CONST:
      /* Note that expressions with arithmetic on forward references don't
         work in mmixal.  People using gcc assembly code with mmixal might
         need to move arrays and such to before the point of use.  */
      if (GET_CODE (XEXP (x, 0)) == PLUS)
        {
          rtx x0 = XEXP (XEXP (x, 0), 0);
          rtx x1 = XEXP (XEXP (x, 0), 1);

          if ((GET_CODE (x0) == SYMBOL_REF
               || GET_CODE (x0) == LABEL_REF)
              && (GET_CODE (x1) == CONST_INT
                  || (GET_CODE (x1) == CONST_DOUBLE
                      && GET_MODE (x1) == VOIDmode)))
            addend = mmix_intval (x1);
          else
            return 0;
        }
      else
        return 0;
      break;

    default:
      return 0;
    }

  return (addend & 3) == 0;
}

/* Return 1 if the address is OK, otherwise 0.
   Used by GO_IF_LEGITIMATE_ADDRESS.  */

int
mmix_legitimate_address (mode, x, strict_checking)
     enum machine_mode mode ATTRIBUTE_UNUSED;
     rtx x;
     int strict_checking;
{
#define MMIX_REG_OK(X)                                                  \
  ((strict_checking                                                     \
    && (REGNO (X) <= MMIX_LAST_GENERAL_REGISTER                         \
        || (reg_renumber[REGNO (X)] > 0                                 \
            && reg_renumber[REGNO (X)] <= MMIX_LAST_GENERAL_REGISTER))) \
   || (!strict_checking                                                 \
       && (REGNO (X) <= MMIX_LAST_GENERAL_REGISTER                      \
           || REGNO (X) >= FIRST_PSEUDO_REGISTER                        \
           || REGNO (X) == ARG_POINTER_REGNUM)))

  /* We only accept:
     (mem reg)
     (mem (plus reg reg))
     (mem (plus reg 0..255)).  */


    /* (mem reg) */
  if (REG_P (x) && MMIX_REG_OK (x))
    return 1;

  if (GET_CODE(x) == PLUS)
    {
      rtx x1 = XEXP (x, 0);
      rtx x2 = XEXP (x, 1);

      /* Try swapping the order.  FIXME: Do we need this?  */
      if (! REG_P (x1))
        {
          rtx tem = x1;
          x1 = x2;
          x2 = tem;
        }

      /* (mem (plus (reg) (?))) */
      if (!REG_P (x1) || !MMIX_REG_OK (x1))
        return 0;

      /* (mem (plus (reg) (reg))) */
      if (REG_P (x2) && MMIX_REG_OK (x2))
        return 1;

      /* (mem (plus (reg) (0..255))) */
      if (GET_CODE (x2) == CONST_INT
          && CONST_OK_FOR_LETTER_P (INTVAL (x2), 'I'))
        return 1;
    }

  return 0;
}

/* LEGITIMATE_CONSTANT_P.  */

int
mmix_legitimate_constant_p (x)
     rtx x;
{
  RTX_CODE code = GET_CODE (x);

  /* We must allow any number due to the way the cse passes works; if we
     do not allow any number here, general_operand will fail, and insns
     will fatally fail recognition instead of "softly".  */
  if (code == CONST_INT || code == CONST_DOUBLE)
    return 1;

  return CONSTANT_ADDRESS_P (x);
}

/* SELECT_CC_MODE.  */

enum machine_mode
mmix_select_cc_mode (op, x, y)
     RTX_CODE op;
     rtx x;
     rtx y ATTRIBUTE_UNUSED;
{
  /* We use CCmode, CC_UNSmode, CC_FPmode, CC_FPEQmode and CC_FUNmode to
     output different compare insns.  Note that we do not check the
     validity of the comparison here.  */

  if (GET_MODE_CLASS (GET_MODE (x)) == MODE_FLOAT)
    {
      if (op == ORDERED || op == UNORDERED || op == UNGE
          || op == UNGT || op == UNLE || op == UNLT)
        return CC_FUNmode;

      if (op == EQ || op == NE)
        return CC_FPEQmode;

      return CC_FPmode;
    }

  if (op == GTU || op == LTU || op == GEU || op == LEU)
    return CC_UNSmode;

  return CCmode;
}

/* CANONICALIZE_COMPARISON.
   FIXME: Check if the number adjustments trig.  */

void
mmix_canonicalize_comparison (codep, op0p, op1p)
     RTX_CODE * codep;
     rtx * op0p ATTRIBUTE_UNUSED;
     rtx * op1p;
{
  /* Change -1 to zero, if possible.  */
  if ((*codep == LE || *codep == GT)
      && GET_CODE (*op1p) == CONST_INT
      && *op1p == constm1_rtx)
    {
      *codep = *codep == LE ? LT : GE;
      *op1p = const0_rtx;
    }

  /* Fix up 256 to 255, if possible.  */
  if ((*codep == LT || *codep == LTU || *codep == GE || *codep == GEU)
      && GET_CODE (*op1p) == CONST_INT
      && INTVAL (*op1p) == 256)
    {
      /* FIXME: Remove when I know this trigs.  */
      fatal_insn ("oops, not debugged; fixing up value:", *op1p);
      *codep = *codep == LT ? LE : *codep == LTU ? LEU : *codep
        == GE ? GT : GTU;
      *op1p = GEN_INT (255);
    }
}

/* REVERSIBLE_CC_MODE.  */

int
mmix_reversible_cc_mode (mode)
     enum machine_mode mode;
{
  /* That is, all integer and the EQ, NE, ORDERED and UNORDERED float
     cmpares.  */
  return mode != CC_FPmode;
}

/* DEFAULT_RTX_COSTS.  */

int
mmix_rtx_cost_recalculated (x, code, outer_code, costp)
     rtx x ATTRIBUTE_UNUSED;
     RTX_CODE code ATTRIBUTE_UNUSED;
     RTX_CODE outer_code ATTRIBUTE_UNUSED;
     int *costp ATTRIBUTE_UNUSED;
{
  /* For the time being, this is just a stub and we'll accept the
     generic calculations, until we can do measurements, at least.
     Say we did not modify any calculated costs.  */
  return 0;
}

/* ADDRESS_COST.  */

int
mmix_address_cost (addr)
     rtx addr ATTRIBUTE_UNUSED;
{
  /* There's no difference in the address costs and we have lots of
     registers.  Some targets use constant 0, many others use 1 to say
     this.  Let's start with 1.  */
  return 1;
}

/* REGISTER_MOVE_COST.  */

int
mmix_register_move_cost (mode, from, to)
     enum machine_mode mode ATTRIBUTE_UNUSED;
     enum reg_class from;
     enum reg_class to;
{
  return (from == GENERAL_REGS && from == to) ? 2 : 3;
}

/* Note that we don't have a TEXT_SECTION_ASM_OP, because it has to be a
   compile-time constant; it's used in an asm in crtstuff.c, compiled for
   the target.  */

/* DATA_SECTION_ASM_OP.  */

const char *
mmix_data_section_asm_op ()
{
  return "\t.data ! mmixal:= 8H LOC 9B";
}

/* SELECT_SECTION.
   The meat is from elfos.h, which we will eventually consider using.  */

void
mmix_select_section (decl, reloc, align)
     tree decl;
     int reloc;
     int align ATTRIBUTE_UNUSED;
{
  if (TREE_CODE (decl) == STRING_CST)
    {
      if (! flag_writable_strings)
        const_section ();
      else
        data_section ();
    }
  else if (TREE_CODE (decl) == VAR_DECL)
    {
      if ((flag_pic && reloc)
          || !TREE_READONLY (decl) || TREE_SIDE_EFFECTS (decl)
          || !DECL_INITIAL (decl)
          || (DECL_INITIAL (decl) != error_mark_node
              && !TREE_CONSTANT (DECL_INITIAL (decl))))
        data_section ();
      else
        const_section ();
    }
  else if (TREE_CODE (decl) == CONSTRUCTOR)
    {
      if ((flag_pic && reloc)
          || !TREE_READONLY (decl) || TREE_SIDE_EFFECTS (decl)
          || ! TREE_CONSTANT (decl))
        data_section ();
      else
        const_section ();
    }
  else
    const_section ();
}

/* ENCODE_SECTION_INFO.  */

void
mmix_encode_section_info (decl)
     tree decl;
{
  /* Test for an external declaration, and do nothing if it is one.  */
  if ((TREE_CODE (decl) == VAR_DECL
       && (DECL_EXTERNAL (decl) || TREE_PUBLIC (decl))
       && ! TREE_STATIC (decl))
      || (TREE_CODE (decl) == FUNCTION_DECL
          && (DECL_EXTERNAL (decl) || TREE_PUBLIC (decl))))
    ;
  else if (DECL_P (decl))
    {
      /* For non-visible declarations, add a "@" prefix, which we skip
         when the label is output.  If the label does not have this
         prefix, a ":" is output.

         Note that this does not work for data that is declared extern and
         later defined as static.  If there's code in between, that code
         will refer to the extern declaration.  And vice versa.  Until we
         can get rid of mmixal, we have to assume that code is well-behaved
         or come up with a contorted scheme to work around bad code.  */

      const char *str = XSTR (XEXP (DECL_RTL (decl), 0), 0);
      int len = strlen (str);
      char *newstr;

      /* Doing as rs6000 seems safe; always use ggc.  Except don't copy
         the suspected off-by-one bug.
         FIXME: Is it still there? yes 2001-08-23
         Why is the return type of ggc_alloc_string const?  */
      newstr = (char *) ggc_alloc_string ("", len + 2);

      strcpy (newstr + 1, str);
      *newstr = '@';
      XSTR (XEXP (DECL_RTL (decl), 0), 0) = newstr;
    }

  /* FIXME: Later on, add SYMBOL_REF_FLAG for things that we can reach
     from here via GETA, to check in LEGITIMATE_CONSTANT_P.  Needs to have
     different options for the cases where we want *all* to be assumed
     reachable via GETA, or all constant symbols, or just text symbols in
     this file, or perhaps just the constant pool.  */
}

/* STRIP_NAME_ENCODING.  */

const char *
mmix_strip_name_encoding (name)
     const char *name;
{
  for (; (*name == '@' || *name == '*'); name++)
    ;

  return name;
}

/* UNIQUE_SECTION.
   The meat is from elfos.h, which we should consider using.  */

void
mmix_unique_section (decl, reloc)
     tree decl;
     int reloc;
{
  int len;
  int sec;
  const char *name;
  char *string;
  const char *prefix;
  static const char *const prefixes[4][2] =
  {
    { ".text.",   ".gnu.linkonce.t." },
    { ".rodata.", ".gnu.linkonce.r." },
    { ".data.",   ".gnu.linkonce.d." },
    { ".bss.",    ".gnu.linkonce.b." }
  };

  if (TREE_CODE (decl) == FUNCTION_DECL)
    sec = 0;
  else if (DECL_INITIAL (decl) == 0
           || DECL_INITIAL (decl) == error_mark_node)
    sec =  3;
  else if (DECL_READONLY_SECTION (decl, reloc))
    sec = 1;
  else
    sec = 2;

  name   = IDENTIFIER_POINTER (DECL_ASSEMBLER_NAME (decl));
  /* Strip off any encoding in name.  */
  STRIP_NAME_ENCODING (name, name);
  prefix = prefixes[sec][DECL_ONE_ONLY (decl)];
  len    = strlen (name) + strlen (prefix);
  string = alloca (len + 1);

  sprintf (string, "%s%s", prefix, name);

  DECL_SECTION_NAME (decl) = build_string (len, string);
}

/* ASM_FILE_START.  */

void
mmix_asm_file_start (stream)
     FILE * stream;
{
  /* We just emit a little comment for the time being.  FIXME: Perhaps add
     -mstandalone and some segment and prefix setup here.  */
  ASM_OUTPUT_SOURCE_FILENAME (stream, main_input_filename);

  fprintf (stream, "! mmixal:= 8H LOC Data_Section\n");

  /* Make sure each file starts with the text section. */
  text_section ();
}

/* ASM_FILE_END.  */

void
mmix_asm_file_end (stream)
     FILE * stream ATTRIBUTE_UNUSED;
{
  /* Make sure each file ends with the data section. */
  data_section ();
}

/* ASM_IDENTIFY_GCC.  */

void
mmix_asm_identify_gcc (stream)
     FILE * stream;
{
  /* No real need for the time being.  May be useful to GDB later on.  */
  fprintf (stream, "# Compiled by GCC version %s\n",
           version_string);
}

/* ASM_OUTPUT_SOURCE_FILENAME.  */

void
mmix_asm_output_source_filename (stream, name)
     FILE * stream;
     const char * name;
{
  fprintf (stream, "# 1 ");
  OUTPUT_QUOTED_STRING (stream, name);
  fprintf (stream, "\n");
}

/* OUTPUT_QUOTED_STRING.  */

void
mmix_output_quoted_string (stream, string, length)
     FILE * stream;
     const char * string;
     int length;
{
  const char * string_end = string + length;
  static const char *const unwanted_chars = "\"[]\\";

  /* Output "any character except newline and double quote character".  We
     play it safe and avoid all control characters too.  We also do not
     want [] as characters, should input be passed through m4 with [] as
     quotes.  Further, we avoid "\", because the GAS port handles it as a
     quoting character.  */
  while (string < string_end)
    {
      if (*string
          && (unsigned char) *string < 128
          && !ISCNTRL (*string)
          && strchr (unwanted_chars, *string) == NULL)
        {
          fputc ('"', stream);
          while (*string
                 && (unsigned char) *string < 128
                 && !ISCNTRL (*string)
                 && strchr (unwanted_chars, *string) == NULL
                 && string < string_end)
            {
              fputc (*string, stream);
              string++;
            }
          fputc ('"', stream);
          if (string < string_end)
            fprintf (stream, ",");
        }
      if (string < string_end)
        {
          fprintf (stream, "#%x", *string & 255);
          string++;
          if (string < string_end)
            fprintf (stream, ",");
        }
    }
}

/* ASM_OUTPUT_SOURCE_LINE.  */

void
mmix_asm_output_source_line  (stream, lineno)
     FILE * stream;
     int lineno;
{
  fprintf (stream, "# %d ", lineno);
  OUTPUT_QUOTED_STRING (stream, main_input_filename);
  fprintf (stream, "\n");
}

/* Target hook for assembling integer objects.  Use mmix_print_operand
   for WYDE and TETRA.  Use mmix_output_octa to output 8-byte
   CONST_DOUBLEs.  */

static bool
mmix_assemble_integer (x, size, aligned_p)
     rtx x;
     unsigned int size;
     int aligned_p;
{
  if (aligned_p)
    switch (size)
      {
      case 1:
        fputs ("\tBYTE\t", asm_out_file);
        mmix_print_operand (asm_out_file, x, 'B');
        fputc ('\n', asm_out_file);
        return true;

      case 2:
        fputs ("\tWYDE\t", asm_out_file);
        mmix_print_operand (asm_out_file, x, 'W');
        fputc ('\n', asm_out_file);
        return true;

      case 4:
        fputs ("\tTETRA\t", asm_out_file);
        mmix_print_operand (asm_out_file, x, 'L');
        fputc ('\n', asm_out_file);
        return true;

      case 8:
        if (GET_CODE (x) == CONST_DOUBLE)
          mmix_output_octa (asm_out_file, mmix_intval (x), 0);
        else
          assemble_integer_with_op ("\tOCTA\t", x);
        return true;
      }
  return default_assemble_integer (x, size, aligned_p);
}

/* ASM_OUTPUT_ASCII.  */

void
mmix_asm_output_ascii (stream, string, length)
     FILE *stream;
     const char *string;
     int length;
{
  while (length > 0)
    {
      int chunk_size = length > 60 ? 60 : length;
      fprintf (stream, "\tBYTE ");
      mmix_output_quoted_string (stream, string, chunk_size);
      string += chunk_size;
      length -= chunk_size;
      fprintf (stream, "\n");
    }
}

/* ASM_OUTPUT_ALIGNED_COMMON.  */

void
mmix_asm_output_aligned_common (stream, name, size, align)
     FILE *stream;
     const char *name;
     int size;
     int align;
{
  /* This is mostly the elfos.h one.  There doesn't seem to be a way to
     express this in a mmixal-compatible way.  */
  fprintf (stream, "\t.comm\t");
  assemble_name (stream, name);
  fprintf (stream, ",%u,%u ! mmixal-incompatible COMMON\n",
           size, align / BITS_PER_UNIT);
}

/* ASM_OUTPUT_ALIGNED_LOCAL.  */

void
mmix_asm_output_aligned_local (stream, name, size, align)
     FILE * stream;
     const char * name;
     int size;
     int align;
{
  data_section ();

  ASM_OUTPUT_ALIGN (stream, exact_log2 (align/BITS_PER_UNIT));
  assemble_name (stream, name);
  fprintf (stream, "\tLOC @+%d\n", size);
}

/* ASM_OUTPUT_LABEL.  */

void
mmix_asm_output_label (stream, name)
     FILE *stream;
     const char * name;
{
  assemble_name (stream, name);
  fprintf (stream, "\tIS @\n");
}

/* ASM_DECLARE_REGISTER_GLOBAL.  */

void
mmix_asm_declare_register_global (stream, decl, regno, name)
     FILE *stream ATTRIBUTE_UNUSED;
     tree decl ATTRIBUTE_UNUSED;
     int regno ATTRIBUTE_UNUSED;
     const char *name ATTRIBUTE_UNUSED;
{
  /* Nothing to do here, but there *will* be, therefore the framework is
     here.  */
}

/* ASM_GLOBALIZE_LABEL.  */

void
mmix_asm_globalize_label (stream, name)
     FILE * stream ATTRIBUTE_UNUSED;
     const char * name ATTRIBUTE_UNUSED;
{
  asm_fprintf (stream, "\t.global ");
  assemble_name (stream, name);
  putc ('\n', stream);
}

/* ASM_WEAKEN_LABEL.  */

void
mmix_asm_weaken_label (stream, name)
     FILE * stream ATTRIBUTE_UNUSED;
     const char * name ATTRIBUTE_UNUSED;
{
  asm_fprintf (stream, "\t.weak ");
  assemble_name (stream, name);
  asm_fprintf (stream, " ! mmixal-incompatible\n");
}

/* MAKE_DECL_ONE_ONLY.  */

void
mmix_make_decl_one_only (decl)
     tree decl;
{
  DECL_WEAK (decl) = 1;
}

/* ASM_OUTPUT_LABELREF.
   Strip GCC's '*' and our own '@'.  No order is assumed.  */

void
mmix_asm_output_labelref (stream, name)
     FILE *stream;
     const char *name;
{
  int is_extern = 0;

  for (; (*name == '@' || *name == '*'); name++)
    if (*name == '@')
      is_extern = 1;

  asm_fprintf (stream, "%s%U%s",
               is_extern && TARGET_TOPLEVEL_SYMBOLS ? ":" : "",
               name);
}

/* ASM_OUTPUT_INTERNAL_LABEL.  */

void
mmix_asm_output_internal_label (stream, name, num)
     FILE * stream;
     const char * name;
     int num;
{
  fprintf (stream, "%s:%d\tIS @\n", name, num);
}

/* ASM_OUTPUT_DEF.  */

void
mmix_asm_output_def (stream, name, value)
     FILE * stream;
     const char * name;
     const char * value;
{
  assemble_name (stream, name);
  fprintf (stream, "\tIS ");
  assemble_name (stream, value);
  fputc ('\n', stream);
}

/* ASM_OUTPUT_DEFINE_LABEL_DIFFERENCE_SYMBOL.  */

void
mmix_asm_output_define_label_difference_symbol (stream, symbol, hi, lo)
     FILE *stream;
     const char *symbol;
     const char *hi;
     const char *lo;
{
  assemble_name (stream, symbol);
  fprintf (stream, "\tIS\t");
  assemble_name (stream, hi);
  fputc ('-', stream);
  assemble_name (stream, lo);
  fprintf (stream, "\n");
}

/* PRINT_OPERAND.  */

void
mmix_print_operand (stream, x, code)
     FILE * stream;
     rtx x;
     int code;
{
  /* When we add support for different codes later, we can, when needed,
     drop through to the main handler with a modified operand.  */
  rtx modified_x = x;

  switch (code)
    {
      /* Unrelated codes are in alphabetic order.  */

    case 'B':
      if (GET_CODE (x) != CONST_INT)
        fatal_insn ("MMIX Internal: Expected a CONST_INT, not this", x);
      fprintf (stream, "%d", (int) (INTVAL (x) & 0xff));
      return;

    case 'H':
      /* Highpart.  Must be general register, and not the last one, as
         that one cannot be part of a consecutive register pair.  */
      if (REGNO (x) > MMIX_LAST_GENERAL_REGISTER - 1)
        internal_error ("MMIX Internal: Bad register: %d", REGNO (x));

      /* This is big-endian, so the high-part is the first one.  */
      fprintf (stream, "%s", reg_names[REGNO (x)]);
      return;

    case 'L':
      /* Lowpart.  Must be CONST_INT or general register, and not the last
         one, as that one cannot be part of a consecutive register pair.  */
      if (GET_CODE (x) == CONST_INT)
        {
          fprintf (stream, "#%lx",
                   (unsigned long) (INTVAL (x)
                                    & ((unsigned int) 0x7fffffff * 2 + 1)));
          return;
        }

      if (GET_CODE (x) == SYMBOL_REF)
        {
          output_addr_const (stream, x);
          return;
        }

      if (REGNO (x) > MMIX_LAST_GENERAL_REGISTER - 1)
        internal_error ("MMIX Internal: Bad register: %d", REGNO (x));

      /* This is big-endian, so the low-part is + 1.  */
      fprintf (stream, "%s", reg_names[REGNO (x) + 1]);
      return;

      /* Can't use 'a' because that's a generic modifier for address
         output.  */
    case 'A':
      mmix_output_shiftvalue_op_from_str (stream, "ANDN",
                                          ~(unsigned HOST_WIDEST_INT)
                                          mmix_intval (x));
      return;

    case 'i':
      mmix_output_shiftvalue_op_from_str (stream, "INC",
                                          (unsigned HOST_WIDEST_INT)
                                          mmix_intval (x));
      return;

    case 'o':
      mmix_output_shiftvalue_op_from_str (stream, "OR",
                                          (unsigned HOST_WIDEST_INT)
                                          mmix_intval (x));
      return;

    case 's':
      mmix_output_shiftvalue_op_from_str (stream, "SET",
                                          (unsigned HOST_WIDEST_INT)
                                          mmix_intval (x));
      return;

    case 'd':
    case 'D':
      mmix_output_condition (stream, x, (code == 'D'));
      return;

    case 'e':
      /* Output an extra "e" to make fcmpe, fune.  */
      if (TARGET_FCMP_EPSILON)
        fprintf (stream, "e");
      return;

    case 'm':
      /* Output the number minus 1.  */
      if (GET_CODE (x) != CONST_INT)
        {
          fatal_insn ("MMIX Internal: Bad value for 'm', not a CONST_INT",
                      x);
        }
      fprintf (stream, HOST_WIDEST_INT_PRINT_DEC,
               (HOST_WIDEST_INT) (mmix_intval (x) - 1));
      return;

    case 'p':
      /* Store the number of registers we want to save.  This was setup
         by the prologue.  The actual operand contains the number of
         registers to pass, but we don't use it currently.  Anyway, we
         need to output the number of saved registers here.  */
      if (TARGET_ABI_GNU)
        fprintf (stream, "%d", mmix_highest_saved_stack_register + 1);
      else
        /* FIXME: Get the effect of renaming $16, $17.. to the first
           unused call-saved reg.  */
        fprintf (stream, "15");
      return;

    case 'r':
      /* Store the register to output a constant to.  */
      if (! REG_P (x))
        fatal_insn ("MMIX Internal: Expected a register, not this", x);
      mmix_output_destination_register = REGNO (x);
      return;

    case 'I':
      /* Output the constant.  Note that we use this for floats as well.  */
      if (GET_CODE (x) != CONST_INT
          && (GET_CODE (x) != CONST_DOUBLE
              || (GET_MODE (x) != VOIDmode && GET_MODE (x) != DFmode
                  && GET_MODE (x) != SFmode)))
        fatal_insn ("MMIX Internal: Expected a constant, not this", x);
      mmix_output_register_setting (stream,
                                    mmix_output_destination_register,
                                    mmix_intval (x), 0);
      return;

    case 'U':
      /* An U for unsigned, if TARGET_ZERO_EXTEND.  Ignore the operand.  */
      if (TARGET_ZERO_EXTEND)
        putc ('U', stream);
      return;

    case 'v':
      mmix_output_shifted_value (stream, (HOST_WIDEST_INT) mmix_intval (x));
      return;

    case 'V':
      mmix_output_shifted_value (stream, (HOST_WIDEST_INT) ~mmix_intval (x));
      return;

    case 'W':
      if (GET_CODE (x) != CONST_INT)
        fatal_insn ("MMIX Internal: Expected a CONST_INT, not this", x);
      fprintf (stream, "#%x", (int) (INTVAL (x) & 0xffff));
      return;

    case 0:
      /* Nothing to do.  */
      break;

    default:
      /* Presumably there's a missing case above if we get here.  */
      internal_error ("MMIX Internal: Missing `%c' case in mmix_print_operand", code);
    }

  switch (GET_CODE (modified_x))
    {
    case REG:
      if (REGNO (modified_x) >= FIRST_PSEUDO_REGISTER)
        internal_error ("MMIX Internal: Bad register: %d", REGNO (modified_x));
      fprintf (stream, "%s", reg_names[REGNO (modified_x)]);
      return;

    case MEM:
      output_address (XEXP (modified_x, 0));
      return;

    case CONST_INT:
      /* For -2147483648, mmixal complains that the constant does not fit
         in 4 bytes, so let's output it as hex.  Take care to handle hosts
         where HOST_WIDE_INT is longer than an int.

         Print small constants +-255 using decimal.  */

      if (INTVAL (modified_x) > -256 && INTVAL (modified_x) < 256)
        fprintf (stream, "%d", (int) (INTVAL (modified_x)));
      else
        fprintf (stream, "#%x",
                 (int) (INTVAL (modified_x)) & (unsigned int) ~0);
      return;

    case CONST_DOUBLE:
      /* Do somewhat as CONST_INT.  */
      mmix_output_octa (stream, mmix_intval (modified_x), 0);
      return;

    case CONST:
      output_addr_const (stream, modified_x);
      return;

    default:
      /* No need to test for all strange things.  Let output_addr_const do
         it for us.  */
      if (CONSTANT_P (modified_x)
          /* Strangely enough, this is not included in CONSTANT_P.
             FIXME: Ask/check about sanity here.  */
          || GET_CODE (modified_x) == CODE_LABEL)
        {
          output_addr_const (stream, modified_x);
          return;
        }

      /* We need the original here.  */
      fatal_insn ("MMIX Internal: Cannot decode this operand", x);
    }
}

/* PRINT_OPERAND_PUNCT_VALID_P.  */

int
mmix_print_operand_punct_valid_p (code)
     int code ATTRIBUTE_UNUSED;
{
  /* None at the moment.  */
  return 0;
}

/* PRINT_OPERAND_ADDRESS.  */

void
mmix_print_operand_address (stream, x)
     FILE *stream;
     rtx x;
{
  if (REG_P (x))
    {
      /* I find the generated assembly code harder to read without
         the ",0".  */
      fprintf (stream, "%s,0",reg_names[REGNO (x)]);
      return;
    }
  else if (GET_CODE (x) == PLUS)
    {
      rtx x1 = XEXP (x, 0);
      rtx x2 = XEXP (x, 1);

      /* Try swap the order.  FIXME: Do we need this?  */
      if (! REG_P (x1))
        {
          rtx tem = x1;
          x1 = x2;
          x2 = tem;
        }

      if (REG_P (x1))
        {
          fprintf (stream, "%s,", reg_names[REGNO (x1)]);

          if (REG_P (x2))
            {
              fprintf (stream, "%s", reg_names[REGNO (x2)]);
              return;
            }
          else if (GET_CODE (x2) == CONST_INT
                   && CONST_OK_FOR_LETTER_P (INTVAL (x2), 'I'))
            {
              output_addr_const (stream, x2);
              return;
            }
        }
    }

  fatal_insn ("MMIX Internal: This is not a recognized address", x);
}

/* ASM_OUTPUT_REG_PUSH.  */

void
mmix_asm_output_reg_push (stream, regno)
     FILE * stream;
     int regno;
{
  fprintf (stream, "\tSUBU %s,%s,8\n\tSTOU %s,%s,0\n",
           reg_names[MMIX_STACK_POINTER_REGNUM],
           reg_names[MMIX_STACK_POINTER_REGNUM],
           reg_names[regno],
           reg_names[MMIX_STACK_POINTER_REGNUM]);
}

/* ASM_OUTPUT_REG_POP.  */

void
mmix_asm_output_reg_pop (stream, regno)
     FILE * stream;
     int regno;
{
  fprintf (stream, "\tLDOU %s,%s,0\n\tINCL %s,8\n",
           reg_names[regno],
           reg_names[MMIX_STACK_POINTER_REGNUM],
           reg_names[MMIX_STACK_POINTER_REGNUM]);
}

/* ASM_OUTPUT_ADDR_DIFF_ELT.  */

void
mmix_asm_output_addr_diff_elt (stream, body, value, rel)
     FILE *stream;
     rtx body ATTRIBUTE_UNUSED;
     int value;
     int rel;
{
  fprintf (stream, "\tTETRA L%d-L%d\n", value, rel);
}

/* ASM_OUTPUT_ADDR_VEC_ELT.  */

void
mmix_asm_output_addr_vec_elt (stream, value)
     FILE *stream;
     int value;
{
  fprintf (stream, "\tOCTA L:%d\n", value);
}

/* ASM_OUTPUT_SKIP.  */

void
mmix_asm_output_skip (stream, nbytes)
     FILE *stream;
     int nbytes;
{
  fprintf (stream, "\tLOC @+%d\n", nbytes);
}

/* ASM_OUTPUT_ALIGN.  */

void
mmix_asm_output_align (stream, power)
     FILE *stream;
     int power;
{
  /* We need to record the needed alignment of this section in the object,
     so we have to output an alignment directive.  Use a .p2align (not
     .align) so people will never have to wonder about whether the
     argument is in number of bytes or the log2 thereof.  We do it in
     addition to the LOC directive, so nothing needs tweaking when
     copy-pasting assembly into mmixal.  */
 fprintf (stream, "\t.p2align %d\n", power);
 fprintf (stream, "\tLOC @+(%d-@)&%d\n", 1 << power, (1 << power) - 1);
}

/* DBX_REGISTER_NUMBER.  */

int
mmix_dbx_register_number (regno)
     int regno;
{
  /* FIXME: Implement final register renumbering if necessary.  (Use
     target state in cfun).  */

  /* We need to renumber registers to get the number of the return address
     register in the range 0..255.  It is also space-saving if registers
     mentioned in the call-frame information (which uses this function by
     defaulting DWARF_FRAME_REGNUM to DBX_REGISTER_NUMBER) are numbered
     0 .. 63.  So map 224 .. 256+15 -> 0 .. 47 and 0 .. 223 -> 48..223+48.  */
  return regno >= 224 ? (regno - 224) : (regno + 48);
}

/* End of target macro support functions.

   Now MMIX's own functions.  First the exported ones.  */

/* Output an optimal sequence for setting a register to a specific
   constant.  Used in an alternative for const_ints in movdi, and when
   using large stack-frame offsets.

   Use do_begin_end to say if a line-starting TAB and newline before the
   first insn and after the last insn is wanted.  */

void
mmix_output_register_setting (stream, regno, value, do_begin_end)
     FILE *stream;
     int regno;
     HOST_WIDEST_INT value;
     int do_begin_end;
{
  if (do_begin_end)
    fprintf (stream, "\t");

  if (mmix_shiftable_wyde_value ((unsigned HOST_WIDEST_INT) value))
    {
      /* First, the one-insn cases.  */
      mmix_output_shiftvalue_op_from_str (stream, "SET",
                                          (unsigned HOST_WIDEST_INT)
                                          value);
      fprintf (stream, " %s,", reg_names[regno]);
      mmix_output_shifted_value (stream, (unsigned HOST_WIDEST_INT) value);
    }
  else if (mmix_shiftable_wyde_value (-(unsigned HOST_WIDEST_INT) value))
    {
      /* We do this to get a bit more legible assembly code.  The next
         alternative is mostly redundant with this.  */

      mmix_output_shiftvalue_op_from_str (stream, "SET",
                                          -(unsigned HOST_WIDEST_INT)
                                          value);
      fprintf (stream, " %s,", reg_names[regno]);
      mmix_output_shifted_value (stream, -(unsigned HOST_WIDEST_INT) value);
      fprintf (stream, "\n\tNEGU %s,0,%s", reg_names[regno],
               reg_names[regno]);
    }
  else if (mmix_shiftable_wyde_value (~(unsigned HOST_WIDEST_INT) value))
    {
      /* Slightly more expensive, the two-insn cases.  */

      /* FIXME: We could of course also test if 0..255-N or ~(N | 1..255)
         is shiftable, or any other one-insn transformation of the value.
         FIXME: Check first if the value is "shiftable" by two loading
         with two insns, since it makes more readable assembly code (if
         anyone else cares).  */

      mmix_output_shiftvalue_op_from_str (stream, "SET",
                                          ~(unsigned HOST_WIDEST_INT)
                                          value);
      fprintf (stream, " %s,", reg_names[regno]);
      mmix_output_shifted_value (stream, ~(unsigned HOST_WIDEST_INT) value);
      fprintf (stream, "\n\tNOR %s,%s,0", reg_names[regno],
               reg_names[regno]);
    }
  else
    {
      /* The generic case.  2..4 insns.  */
      static const char *const higher_parts[] = {"L", "ML", "MH", "H"};
      const char *op = "SET";
      const char *line_begin = "";
      int i;

      /* Output pertinent parts of the 4-wyde sequence.
         Still more to do if we want this to be optimal, but hey...
         Note that the zero case has been handled above.  */
      for (i = 0; i < 4 && value != 0; i++)
        {
          if (value & 65535)
            {
              fprintf (stream, "%s%s%s %s,#%x", line_begin, op,
                       higher_parts[i], reg_names[regno],
                       (int) (value & 65535));
              /* The first one sets the rest of the bits to 0, the next
                 ones add set bits.  */
              op = "INC";
              line_begin = "\n\t";
            }

          value >>= 16;
        }
    }

  if (do_begin_end)
    fprintf (stream, "\n");
}

/* Return 1 if value is 0..65535*2**(16*N) for N=0..3.
   else return 0.  */

int
mmix_shiftable_wyde_value (value)
     unsigned HOST_WIDEST_INT value;
{
  /* Shift by 16 bits per group, stop when we've found two groups with
     nonzero bits.  */
  int i;
  int has_candidate = 0;

  for (i = 0; i < 4; i++)
    {
      if (value & 65535)
        {
          if (has_candidate)
            return 0;
          else
            has_candidate = 1;
        }

      value >>= 16;
    }

  return 1;
}

/* True if this is an address_operand or a symbolic operand.  */

int
mmix_symbolic_or_address_operand (op, mode)
     rtx op;
     enum machine_mode mode;
{
  switch (GET_CODE (op))
    {
    case SYMBOL_REF:
    case LABEL_REF:
      return 1;
    case CONST:
      op = XEXP (op, 0);
      if ((GET_CODE (XEXP (op, 0)) == SYMBOL_REF
           || GET_CODE (XEXP (op, 0)) == LABEL_REF)
          && (GET_CODE (XEXP (op, 1)) == CONST_INT
              || (GET_CODE (XEXP (op, 1)) == CONST_DOUBLE
                  && GET_MODE (XEXP (op, 1)) == VOIDmode)))
        return 1;
      /* FALLTHROUGH */
    default:
      return address_operand (op, mode);
    }
}

/* True if this is a register or CONST_INT (or CONST_DOUBLE for DImode).
   We could narrow the value down with a couple of predicated, but that
   doesn't seem to be worth it at the moment.  */

int
mmix_reg_or_constant_operand (op, mode)
     rtx op;
     enum machine_mode mode;
{
  return register_operand (op, mode)
    || (GET_CODE (op) == CONST_DOUBLE && GET_MODE (op) == VOIDmode)
    || GET_CODE (op) == CONST_INT;
}

/* True if this is a register with a condition-code mode.  */

int
mmix_reg_cc_operand (op, mode)
     rtx op;
     enum machine_mode mode;
{
  if (mode == VOIDmode)
    mode = GET_MODE (op);

  return register_operand (op, mode)
    && (mode == CCmode || mode == CC_UNSmode || mode == CC_FPmode
        || mode == CC_FPEQmode || mode == CC_FUNmode);
}

/* True if this is a foldable comparison operator
   - one where a the result of (compare:CC (reg) (const_int 0)) can be
   replaced by (reg).  */

int
mmix_foldable_comparison_operator (op, mode)
     rtx op;
     enum machine_mode mode;
{
  RTX_CODE code = GET_CODE (op);

  if (mode == VOIDmode)
    mode = GET_MODE (op);

  if (mode == VOIDmode && GET_RTX_CLASS (GET_CODE (op)) == '<')
    mode = GET_MODE (XEXP (op, 0));

  return ((mode == CCmode || mode == DImode)
          && (code == NE || code == EQ || code == GE || code == GT
              || code == LE))
    /* FIXME: This may be a stupid trick.  What happens when GCC wants to
       reverse the condition?  Can it do that by itself?  Maybe it can
       even reverse the condition to fit a foldable one in the first
       place?  */
    || (mode == CC_UNSmode && (code == GTU || code == LEU));
}

/* Like comparison_operator, but only true if this comparison operator is
   applied to a valid mode.  Needed to avoid jump.c generating invalid
   code with -ffast-math (gcc.dg/20001228-1.c).  */

int
mmix_comparison_operator (op, mode)
     rtx op;
     enum machine_mode mode;
{
  RTX_CODE code = GET_CODE (op);

  /* Comparison operators usually don't have a mode, but let's try and get
     one anyway for the day that changes.  */
  if (mode == VOIDmode)
    mode = GET_MODE (op);

  /* Get the mode from the first operand if we don't have one.  */
  if (mode == VOIDmode && GET_RTX_CLASS (GET_CODE (op)) == '<')
    mode = GET_MODE (XEXP (op, 0));

  /* FIXME: This needs to be kept in sync with the tables in
     mmix_output_condition.  */
  return
    (mode == VOIDmode && GET_RTX_CLASS (GET_CODE (op)) == '<')
    || (mode == CC_FUNmode
        && (code == ORDERED || code == UNORDERED))
    || (mode == CC_FPmode
        && (code == GT || code == LT))
    || (mode == CC_FPEQmode
        && (code == NE || code == EQ))
    || (mode == CC_UNSmode
        && (code == GEU || code == GTU || code == LEU || code == LTU))
    || (mode == CCmode
        && (code == NE || code == EQ || code == GE || code == GT
            || code == LE || code == LT))
    || (mode == DImode
        && (code == NE || code == EQ || code == GE || code == GT
            || code == LE || code == LT || code == LEU || code == GTU));
}

/* True if this is a register or 0 (int or float).  */

int
mmix_reg_or_0_operand (op, mode)
     rtx op;
     enum machine_mode mode;
{
  /* FIXME: Is mode calculation necessary and correct?  */
  return
    op == CONST0_RTX (mode == VOIDmode ? GET_MODE (op) : mode)
    || register_operand (op, mode);
}

/* True if this is a register or an int 0..255.  */

int
mmix_reg_or_8bit_operand (op, mode)
     rtx op;
     enum machine_mode mode;
{
  return register_operand (op, mode)
    || (GET_CODE (op) == CONST_INT
        && CONST_OK_FOR_LETTER_P (INTVAL (op), 'I'));
}

/* True if this is a register or an int 0..256.  We include 256,
   because it can be canonicalized into 255 for comparisons, which is
   currently the only use of this predicate.
   FIXME:  Check that this happens and does TRT.  */

int
mmix_reg_or_8bit_or_256_operand (op, mode)
     rtx op;
     enum machine_mode mode;
{
  return mmix_reg_or_8bit_operand (op, mode)
    || (GET_CODE (op) == CONST_INT && INTVAL (op) == 256);
}

/* Returns zero if code and mode is not a valid condition from a
   compare-type insn.  Nonzero if it is.  The parameter op, if non-NULL,
   is the comparison of mode is CC-somethingmode.  */

int
mmix_valid_comparison (code, mode, op)
     RTX_CODE code;
     enum machine_mode mode;
     rtx op;
{
  if (mode == VOIDmode && op != NULL_RTX)
    mode = GET_MODE (op);

  /* We don't care to look at these, they should always be valid.  */
  if (mode == CCmode || mode == CC_UNSmode || mode == DImode)
    return 1;

  if ((mode == CC_FPmode || mode == DFmode)
      && (code == GT || code == LT))
    return 1;

  if ((mode == CC_FPEQmode || mode == DFmode)
      && (code == EQ || code == NE))
    return 1;

  if ((mode == CC_FUNmode || mode == DFmode)
      && (code == ORDERED || code == UNORDERED))
    return 1;

  return 0;
}

/* X and Y are two things to compare using CODE.  Emit a compare insn if
   possible and return the rtx for the cc-reg in the proper mode, or
   NULL_RTX if this is not a valid comparison.  */

rtx
mmix_gen_compare_reg (code, x, y)
     RTX_CODE code;
     rtx x, y;
{
  enum machine_mode ccmode = SELECT_CC_MODE (code, x, y);
  rtx cc_reg;

  /* FIXME: Do we get constants here?  Of double mode?  */
  enum machine_mode mode
    = GET_MODE (x) == VOIDmode
    ? GET_MODE (y)
    : GET_MODE_CLASS (GET_MODE (x)) == MODE_FLOAT ? DFmode : DImode;

  if (! mmix_valid_comparison (code, mode, x))
    return NULL_RTX;

  cc_reg = gen_reg_rtx (ccmode);

  /* FIXME:  Can we avoid emitting a compare insn here?  */
  if (! REG_P (x) && ! REG_P (y))
    x = force_reg (mode, x);

  CANONICALIZE_COMPARISON (code, x, y);

  /* If it's not quite right yet, put y in a register.  */
  if (! REG_P (y)
      && (GET_CODE (y) != CONST_INT
          || ! CONST_OK_FOR_LETTER_P (INTVAL (y), 'I')))
    y = force_reg (mode, y);

  emit_insn (gen_rtx_SET (VOIDmode, cc_reg,
                          gen_rtx_COMPARE (ccmode, x, y)));

  return cc_reg;
}

/* Local (static) helper functions.  */

/* Print operator suitable for doing something with a shiftable
   wyde.  The type of operator is passed as a asm output modifier.  */

static void
mmix_output_shiftvalue_op_from_str (stream, mainop, value)
     FILE *stream;
     const char *mainop;
     HOST_WIDEST_INT value;
{
  static const char *const op_part[] = {"L", "ML", "MH", "H"};
  int i;

  if (! mmix_shiftable_wyde_value (value))
    {
      char s[sizeof ("0xffffffffffffffff")];
      sprintf (s, HOST_WIDEST_INT_PRINT_HEX, value);
      internal_error ("MMIX Internal: %s is not a shiftable int", s);
    }

  for (i = 0; i < 4; i++)
    {
      /* We know we're through when we find one-bits in the low
         16 bits.  */
      if (value & 0xffff)
        {
          fprintf (stream, "%s%s", mainop, op_part[i]);
          return;
        }
      value >>= 16;
    }

  /* No bits set?  Then it must have been zero.  */
  fprintf (stream, "%sL", mainop);
}

/* Print a 64-bit value, optionally prefixed by assembly pseudo.  */

static void
mmix_output_octa (stream, value, do_begin_end)
     FILE *stream;
     HOST_WIDEST_INT value;
     int do_begin_end;
{
  /* Snipped from final.c:output_addr_const.  We need to avoid the
     presumed universal "0x" prefix.  We can do it by replacing "0x" with
     "#0" here; we must avoid a space in the operands and no, the zero
     won't cause the number to be assumed in octal format.  */
  char hex_format[sizeof (HOST_WIDEST_INT_PRINT_HEX)];

  if (do_begin_end)
    fprintf (stream, "\tOCTA ");

  strcpy (hex_format, HOST_WIDEST_INT_PRINT_HEX);
  hex_format[0] = '#';
  hex_format[1] = '0';

  /* Provide a few alternative output formats depending on the number, to
     improve legibility of assembler output.  */
  if ((value < (HOST_WIDEST_INT) 0 && value > (HOST_WIDEST_INT) -10000)
      || (value >= (HOST_WIDEST_INT) 0 && value <= (HOST_WIDEST_INT) 16384))
    fprintf (stream, "%d", (int) value);
  else if (value > (HOST_WIDEST_INT) 0
           && value < ((HOST_WIDEST_INT) 1 << 31) * 2)
    fprintf (stream, "#%x", (unsigned int) value);
  else
    fprintf (stream, hex_format, value);

  if (do_begin_end)
    fprintf (stream, "\n");
}

/* Print the presumed shiftable wyde argument shifted into place (to
   be output with an operand).  */

static void
mmix_output_shifted_value (stream, value)
     FILE * stream;
     HOST_WIDEST_INT value;
{
  int i;

  if (! mmix_shiftable_wyde_value (value))
    {
      char s[16+2+1];
      sprintf (s, HOST_WIDEST_INT_PRINT_HEX, value);
      internal_error ("MMIX Internal: %s is not a shiftable int", s);
    }

  for (i = 0; i < 4; i++)
  {
    /* We know we're through when we find one-bits in the low 16 bits.  */
    if (value & 0xffff)
    {
      fprintf (stream, "#%x", (int) (value & 0xffff));
      return;
    }

    value >>= 16;
  }

  /* No bits set?  Then it must have been zero.  */
  fprintf (stream, "0");
}

/* Output an MMIX condition name corresponding to an operator
   and operands:
   (comparison_operator [(comparison_operator ...) (const_int 0)])
   which means we have to look at *two* operators.

   The argument "reversed" refers to reversal of the condition (not the
   same as swapping the arguments).  */

static void
mmix_output_condition (stream, x, reversed)
     FILE *stream;
     rtx x;
     int reversed;
{
  struct cc_conv
  {
    RTX_CODE cc;

    /* The normal output cc-code.  */
    const char *const normal;

    /* The reversed cc-code, or NULL if invalid.  */
    const char *const reversed;
  };

  struct cc_type_conv
  {
    enum machine_mode cc_mode;

    /* Terminated with {NIL, NULL, NULL} */
    const struct cc_conv *const convs;
  };

#undef CCEND
#define CCEND {NIL, NULL, NULL}

  static const struct cc_conv cc_fun_convs[]
    = {{ORDERED, "Z", "P"},
       {UNORDERED, "P", "Z"},
       CCEND};
  static const struct cc_conv cc_fp_convs[]
    = {{GT, "P", NULL},
       {LT, "N", NULL},
       CCEND};
  static const struct cc_conv cc_fpeq_convs[]
    = {{NE, "Z", "P"},
       {EQ, "P", "Z"},
       CCEND};
  static const struct cc_conv cc_uns_convs[]
    = {{GEU, "NN", "N"},
       {GTU, "P", "NP"},
       {LEU, "NP", "P"},
       {LTU, "N", "NN"},
       CCEND};
  static const struct cc_conv cc_signed_convs[]
    = {{NE, "NZ", "Z"},
       {EQ, "Z", "NZ"},
       {GE, "NN", "N"},
       {GT, "P", "NP"},
       {LE, "NP", "P"},
       {LT, "N", "NN"},
       CCEND};
  static const struct cc_conv cc_di_convs[]
    = {{NE, "NZ", "Z"},
       {EQ, "Z", "NZ"},
       {GE, "NN", "N"},
       {GT, "P", "NP"},
       {LE, "NP", "P"},
       {LT, "N", "NN"},
       {GTU, "NZ", "Z"},
       {LEU, "Z", "NZ"},
       CCEND};
#undef CCEND

  static const struct cc_type_conv cc_convs[]
    = {{CC_FUNmode, cc_fun_convs},
       {CC_FPmode, cc_fp_convs},
       {CC_FPEQmode, cc_fpeq_convs},
       {CC_UNSmode, cc_uns_convs},
       {CCmode, cc_signed_convs},
       {DImode, cc_di_convs}};

  unsigned int i;
  int j;

  enum machine_mode mode = GET_MODE (XEXP (x, 0));
  RTX_CODE cc = GET_CODE (x);

  for (i = 0; i < sizeof (cc_convs)/sizeof(*cc_convs); i++)
    {
      if (mode == cc_convs[i].cc_mode)
        {
          for (j = 0; cc_convs[i].convs[j].cc != NIL; j++)
            if (cc == cc_convs[i].convs[j].cc)
              {
                const char *mmix_cc
                  = (reversed ? cc_convs[i].convs[j].reversed
                     : cc_convs[i].convs[j].normal);

                if (mmix_cc == NULL)
                  fatal_insn ("MMIX Internal: Trying to output invalidly\
 reversed condition:", x);

                fprintf (stream, "%s", mmix_cc);
                return;
              }

          fatal_insn ("MMIX Internal: What's the CC of this?", x);
        }
    }

  fatal_insn ("MMIX Internal: What is the CC of this?", x);
}

/* Return the bit-value for a const_int or const_double.  */

static HOST_WIDEST_INT
mmix_intval (x)
     rtx x;
{
  unsigned HOST_WIDEST_INT retval;

  if (GET_CODE (x) == CONST_INT)
    return INTVAL (x);

  /* We make a little song and dance because converting to long long in
     gcc-2.7.2 is broken.  I still want people to be able to use it for
     cross-compilation to MMIX.  */
  if (GET_CODE (x) == CONST_DOUBLE && GET_MODE (x) == VOIDmode)
    {
      if (sizeof (HOST_WIDE_INT) < sizeof (HOST_WIDEST_INT))
        {
          retval = (unsigned) CONST_DOUBLE_LOW (x) / 2;
          retval *= 2;
          retval |= CONST_DOUBLE_LOW (x) & 1;

          retval |=
            (unsigned HOST_WIDEST_INT) CONST_DOUBLE_HIGH (x)
              << (HOST_BITS_PER_LONG);
        }
      else
        retval = CONST_DOUBLE_HIGH (x);

      return retval;
    }

  if (GET_CODE (x) == CONST_DOUBLE)
    {
      REAL_VALUE_TYPE value;

      /* FIXME:  This macro is not in the manual but should be.  */
      REAL_VALUE_FROM_CONST_DOUBLE (value, x);

      if (GET_MODE (x) == DFmode)
        {
          long bits[2];

          REAL_VALUE_TO_TARGET_DOUBLE (value, bits);

          if (sizeof (long) < sizeof (HOST_WIDEST_INT))
            {
              retval = (unsigned long) bits[1] / 2;
              retval *= 2;
              retval |= (unsigned long) bits[1] & 1;
              retval
                |= (unsigned HOST_WIDEST_INT) bits[0]
                  << (sizeof (bits[0]) * 8);
            }
          else
            retval = (unsigned long) bits[1];

          return retval;
        }
      else if (GET_MODE (x) == SFmode)
        {
          long bits;
          REAL_VALUE_TO_TARGET_SINGLE (value, bits);

          return (unsigned long) bits;
        }
    }

  fatal_insn ("MMIX Internal: This is not a constant:", x);
}

/*
 * Local variables:
 * eval: (c-set-style "gnu")
 * indent-tabs-mode: t
 * End:
 */