sh.c

GUN开源阻止下的编译器GCC

/* Output routines for GCC for Hitachi Super-H.
   Copyright (C) 1993, 1994, 1995 Free Software Foundation, Inc.

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.  */

/* Contributed by Steve Chamberlain ([e-mail]).
   Improved by Jim Wilson ([e-mail]).  */

#include "config.h"

#include <stdio.h>

#include "rtl.h"
#include "tree.h"
#include "flags.h"
#include "insn-flags.h"
#include "expr.h"
#include "regs.h"
#include "hard-reg-set.h"
#include "output.h"

#define MSW (TARGET_LITTLE_ENDIAN ? 1 : 0)
#define LSW (TARGET_LITTLE_ENDIAN ? 0 : 1)

/* ??? The pragma interrupt support will not work for SH3.  */
/* This is set by #pragma interrupt and #pragma trapa, and causes gcc to
   output code for the next function appropriate for an interrupt handler.  */
int pragma_interrupt;

/* This is set by #pragma trapa, and is similar to the above, except that
   the compiler doesn't emit code to preserve all registers.  */
static int pragma_trapa;

/* This is used for communication between SETUP_INCOMING_VARARGS and
   sh_expand_prologue.  */
int current_function_anonymous_args;

/* Global variables from toplev.c and final.c that are used within, but
   not declared in any header file.  */
extern char *version_string;
extern int *insn_addresses;

/* Global variables for machine-dependent things. */

/* Which cpu are we scheduling for.  */
enum processor_type sh_cpu;

/* Saved operands from the last compare to use when we generate an scc
   or bcc insn.  */

rtx sh_compare_op0;
rtx sh_compare_op1;

/* Provides the class number of the smallest class containing
   reg number.  */

int regno_reg_class[FIRST_PSEUDO_REGISTER] =
{
  R0_REGS, GENERAL_REGS, GENERAL_REGS, GENERAL_REGS,
  GENERAL_REGS, GENERAL_REGS, GENERAL_REGS, GENERAL_REGS,
  GENERAL_REGS, GENERAL_REGS, GENERAL_REGS, GENERAL_REGS,
  GENERAL_REGS, GENERAL_REGS, GENERAL_REGS, GENERAL_REGS,
  GENERAL_REGS, PR_REGS, T_REGS, NO_REGS,
  MAC_REGS, MAC_REGS,
};

/* Provide reg_class from a letter such as appears in the machine
   description.  */

enum reg_class reg_class_from_letter[] =
{
  /* a */ NO_REGS, /* b */ NO_REGS, /* c */ NO_REGS, /* d */ NO_REGS,
  /* e */ NO_REGS, /* f */ NO_REGS, /* g */ NO_REGS, /* h */ NO_REGS,
  /* i */ NO_REGS, /* j */ NO_REGS, /* k */ NO_REGS, /* l */ PR_REGS,
  /* m */ NO_REGS, /* n */ NO_REGS, /* o */ NO_REGS, /* p */ NO_REGS,
  /* q */ NO_REGS, /* r */ NO_REGS, /* s */ NO_REGS, /* t */ T_REGS,
  /* u */ NO_REGS, /* v */ NO_REGS, /* w */ NO_REGS, /* x */ MAC_REGS,
  /* y */ NO_REGS, /* z */ R0_REGS
};

/* Print the operand address in x to the stream.  */

void
print_operand_address (stream, x)
     FILE *stream;
     rtx x;
{
  switch (GET_CODE (x))
    {
    case REG:
      fprintf (stream, "@%s", reg_names[REGNO (x)]);
      break;

    case PLUS:
      {
	rtx base = XEXP (x, 0);
	rtx index = XEXP (x, 1);

	switch (GET_CODE (index))
	  {
	  case CONST_INT:
	    fprintf (stream, "@(%d,%s)", INTVAL (index),
		     reg_names[REGNO (base)]);
	    break;

	  case REG:
	    fprintf (stream, "@(r0,%s)",
		     reg_names[MAX (REGNO (base), REGNO (index))]);
	    break;

	  default:
	    debug_rtx (x);
	    abort ();
	  }
      }
      break;

    case PRE_DEC:
      fprintf (stream, "@-%s", reg_names[REGNO (XEXP (x, 0))]);
      break;

    case POST_INC:
      fprintf (stream, "@%s+", reg_names[REGNO (XEXP (x, 0))]);
      break;

    default:
      output_addr_const (stream, x);
      break;
    }
}

/* Print operand x (an rtx) in assembler syntax to file stream
   according to modifier code.

   '.'  print a .s if insn needs delay slot
   '@'  print rte or rts depending upon pragma interruptness
   '#'  output a nop if there is nothing to put in the delay slot
   'O'  print a constant without the #
   'R'  print the LSW of a dp value - changes if in little endian
   'S'  print the MSW of a dp value - changes if in little endian
   'T'  print the next word of a dp value - same as 'R' in big endian mode.  */

void
print_operand (stream, x, code)
     FILE *stream;
     rtx x;
     int code;
{
  switch (code)
    {
    case '.':
      if (final_sequence
	  && ! INSN_ANNULLED_BRANCH_P (XVECEXP (final_sequence, 0, 0)))
	fprintf (stream, ".s");
      break;
    case '@':
      if (pragma_interrupt)
	fprintf (stream, "rte");
      else
	fprintf (stream, "rts");
      break;
    case '#':
      /* Output a nop if there's nothing in the delay slot.  */
      if (dbr_sequence_length () == 0)
	fprintf (stream, "\n\tnop");
      break;
    case 'O':
      output_addr_const (stream, x);
      break;
    case 'R':
      fputs (reg_names[REGNO (x) + LSW], (stream));
      break;
    case 'S':
      fputs (reg_names[REGNO (x) + MSW], (stream));
      break;
    case 'T':
      /* Next word of a double.  */
      switch (GET_CODE (x))
	{
	case REG:
	  fputs (reg_names[REGNO (x) + 1], (stream));
	  break;
	case MEM:
	  print_operand_address (stream,
				 XEXP (adj_offsettable_operand (x, 4), 0));
	  break;
	}
      break;
    default:
      switch (GET_CODE (x))
	{
	case REG:
	  fputs (reg_names[REGNO (x)], (stream));
	  break;
	case MEM:
	  output_address (XEXP (x, 0));
	  break;
	default:
	  fputc ('#', stream);
	  output_addr_const (stream, x);
	  break;
	}
      break;
    }
}

/* Emit code to perform a block move.  Choose the best method.

   OPERANDS[0] is the destination.
   OPERANDS[1] is the source.
   OPERANDS[2] is the size.
   OPERANDS[3] is the alignment safe to use.  */

int
expand_block_move (operands)
     rtx *operands;
{
  int align = INTVAL (operands[3]);
  int constp = (GET_CODE (operands[2]) == CONST_INT);
  int bytes = (constp ? INTVAL (operands[2]) : 0);

  /* If it isn't a constant number of bytes, or if it doesn't have 4 byte
     alignment, or if it isn't a multiple of 4 bytes, then fail.  */
  if (! constp || align < 4 || (bytes % 4 != 0))
    return 0;

  if (bytes < 64)
    {
      char entry[30];
      tree entry_name;
      rtx func_addr_rtx;
      rtx r4 = gen_rtx (REG, SImode, 4);
      rtx r5 = gen_rtx (REG, SImode, 5);

      sprintf (entry, "__movstrSI%d", bytes);
      entry_name = get_identifier (entry);

      func_addr_rtx
	= copy_to_mode_reg (Pmode,
			    gen_rtx (SYMBOL_REF, Pmode,
				     IDENTIFIER_POINTER (entry_name)));
      emit_insn (gen_move_insn (r4, XEXP (operands[0], 0)));
      emit_insn (gen_move_insn (r5, XEXP (operands[1], 0)));
      emit_insn (gen_block_move_real (func_addr_rtx));
      return 1;
    }

  /* This is the same number of bytes as a memcpy call, but to a different
     less common function name, so this will occasionally use more space.  */
  if (! TARGET_SMALLCODE)
    {
      tree entry_name;
      rtx func_addr_rtx;
      int final_switch, while_loop;
      rtx r4 = gen_rtx (REG, SImode, 4);
      rtx r5 = gen_rtx (REG, SImode, 5);
      rtx r6 = gen_rtx (REG, SImode, 6);

      entry_name = get_identifier ("__movstr");
      func_addr_rtx
	= copy_to_mode_reg (Pmode,
			    gen_rtx (SYMBOL_REF, Pmode,
				     IDENTIFIER_POINTER (entry_name)));
      emit_insn (gen_move_insn (r4, XEXP (operands[0], 0)));
      emit_insn (gen_move_insn (r5, XEXP (operands[1], 0)));

      /* r6 controls the size of the move.  16 is decremented from it
	 for each 64 bytes moved.  Then the negative bit left over is used
	 as an index into a list of move instructions.  e.g., a 72 byte move
	 would be set up with size(r6) = 14, for one iteration through the
	 big while loop, and a switch of -2 for the last part.  */

      final_switch = 16 - ((bytes / 4) % 16);
      while_loop = ((bytes / 4) / 16 - 1) * 16;
      emit_insn (gen_move_insn (r6, GEN_INT (while_loop + final_switch)));
      emit_insn (gen_block_lump_real (func_addr_rtx));
      return 1;
    }

  return 0;
}

/* Prepare operands for a move define_expand; specifically, one of the
   operands must be in a register.  */

int
prepare_move_operands (operands, mode)
     rtx operands[];
     enum machine_mode mode;
{
  /* Copy the source to a register if both operands aren't registers.  */
  if (! reload_in_progress && ! reload_completed
      && ! register_operand (operands[0], mode)
      && ! register_operand (operands[1], mode))
    operands[1] = copy_to_mode_reg (mode, operands[1]);

  return 0;
}

/* Prepare the operands for an scc instruction; make sure that the
   compare has been done.  */
rtx
prepare_scc_operands (code)
     enum rtx_code code;
{
  rtx t_reg = gen_rtx (REG, SImode, T_REG);
  enum rtx_code oldcode = code;
  enum machine_mode mode;

  /* First need a compare insn.  */
  switch (code)
    {
    case NE:
      /* It isn't possible to handle this case.  */
      abort ();
    case LT:
      code = GT;
      break;
    case LE:
      code = GE;
      break;
    case LTU:
      code = GTU;
      break;
    case LEU:
      code = GEU;
      break;
    }
  if (code != oldcode)
    {
      rtx tmp = sh_compare_op0;
      sh_compare_op0 = sh_compare_op1;
      sh_compare_op1 = tmp;
    }

  mode = GET_MODE (sh_compare_op0);
  if (mode == VOIDmode)
    mode = GET_MODE (sh_compare_op1);

  sh_compare_op0 = force_reg (mode, sh_compare_op0);
  if (code != EQ && code != NE
      && (sh_compare_op1 != const0_rtx
	  || code == GTU  || code == GEU || code == LTU || code == LEU))
    sh_compare_op1 = force_reg (mode, sh_compare_op1);

  emit_insn (gen_rtx (SET, VOIDmode, t_reg,
		      gen_rtx (code, SImode, sh_compare_op0,
			       sh_compare_op1)));

  return t_reg;
}

/* Called from the md file, set up the operands of a compare instruction.  */

void
from_compare (operands, code)
     rtx *operands;
     int code;
{
  if (code != EQ && code != NE)
    {
      /* Force args into regs, since we can't use constants here.  */
      sh_compare_op0 = force_reg (SImode, sh_compare_op0);
      if (sh_compare_op1 != const0_rtx
	  || code == GTU  || code == GEU || code == LTU || code == LEU)
	sh_compare_op1 = force_reg (SImode, sh_compare_op1);
    }
  operands[1] = sh_compare_op0;
  operands[2] = sh_compare_op1;
}

/* Functions to output assembly code.  */

/* Return a sequence of instructions to perform DI or DF move.

   Since the SH cannot move a DI or DF in one instruction, we have
   to take care when we see overlapping source and dest registers.  */

char *
output_movedouble (insn, operands, mode)
     rtx insn;
     rtx operands[];
     enum machine_mode mode;
{
  rtx dst = operands[0];
  rtx src = operands[1];

  if (GET_CODE (dst) == MEM
      && GET_CODE (XEXP (dst, 0)) == PRE_DEC)
    return "mov.l	%T1,%0\n\tmov.l	%1,%0";

  if (register_operand (dst, mode)
      && register_operand (src, mode))
    {
      if (REGNO (src) == MACH_REG)
	return "sts	mach,%S0\n\tsts	macl,%R0";

      /* When mov.d r1,r2 do r2->r3 then r1->r2;
         when mov.d r1,r0 do r1->r0 then r2->r1.  */

      if (REGNO (src) + 1 == REGNO (dst))
	return "mov	%T1,%T0\n\tmov	%1,%0";
      else
	return "mov	%1,%0\n\tmov	%T1,%T0";
    }
  else if (GET_CODE (src) == CONST_INT)
    {
      if (INTVAL (src) < 0)
	output_asm_insn ("mov	#-1,%S0", operands);
      else
	output_asm_insn ("mov	#0,%S0", operands);

      return "mov	%1,%R0";
    }
  else if (GET_CODE (src) == MEM)
    {
      int ptrreg = -1;
      int dreg = REGNO (dst);
      rtx inside = XEXP (src, 0);

      if (GET_CODE (inside) == REG)
	ptrreg = REGNO (inside);
      else if (GET_CODE (inside) == SUBREG)
	ptrreg = REGNO (SUBREG_REG (inside)) + SUBREG_WORD (inside);
      else if (GET_CODE (inside) == PLUS)
	{
	  ptrreg = REGNO (XEXP (inside, 0));
	  /* ??? A r0+REG address shouldn't be possible here, because it isn't
	     an offsettable address.  Unfortunately, offsettable addresses use
	     QImode to check the offset, and a QImode offsettable address
	     requires r0 for the other operand, which is not currently
	     supported, so we can't use the 'o' constraint.
	     Thus we must check for and handle r0+REG addresses here.
	     We punt for now, since this is likely very rare.  */
	  if (GET_CODE (XEXP (inside, 1)) == REG)
	    abort ();
	}
      else if (GET_CODE (inside) == LABEL_REF)
	return "mov.l	%1,%0\n\tmov.l	%1+4,%T0";
      else if (GET_CODE (inside) == POST_INC)
	return "mov.l	%1,%0\n\tmov.l	%1,%T0";
      else
	abort ();

      /* Work out the safe way to copy.  Copy into the second half first.  */
      if (dreg == ptrreg)
	return "mov.l	%T1,%T0\n\tmov.l	%1,%0";
    }

  return "mov.l	%1,%0\n\tmov.l	%T1,%T0";
}

/* Print an instruction which would have gone into a delay slot after
   another instruction, but couldn't because the other instruction expanded
   into a sequence where putting the slot insn at the end wouldn't work.  */

static void
print_slot (insn)
     rtx insn;
{
  final_scan_insn (XVECEXP (insn, 0, 1), asm_out_file, optimize, 0, 1);

  INSN_DELETED_P (XVECEXP (insn, 0, 1)) = 1;
}

/* We can't tell if we need a register as a scratch for the jump
   until after branch shortening, and then it's too late to allocate a
   register the 'proper' way.  These instruction sequences are rare
   anyway, so to avoid always using a reg up from our limited set, we'll
   grab one when we need one on output.  */

/* ??? Should fix compiler so that using a clobber scratch in jump
   instructions works, and then this will be unnecessary.  */

char *