h8300.c

gcc-2.95.3 Linux下最常用的C编译器

	break;
      }

    default:
      output_addr_const (file, addr);
      break;
    }
}

/* Output all insn addresses and their sizes into the assembly language
   output file.  This is helpful for debugging whether the length attributes
   in the md file are correct.  This is not meant to be a user selectable
   option.  */

void
final_prescan_insn (insn, operand, num_operands)
     rtx insn, *operand;
     int num_operands;
{
  /* This holds the last insn address.  */
  static int last_insn_address = 0;

  int uid = INSN_UID (insn);

  if (TARGET_RTL_DUMP)
    {
      fprintf (asm_out_file, "\n****************");
      print_rtl (asm_out_file, PATTERN (insn));
      fprintf (asm_out_file, "\n");
    }

  if (TARGET_ADDRESSES)
    {
      fprintf (asm_out_file, "; 0x%x %d\n", insn_addresses[uid],
	       insn_addresses[uid] - last_insn_address);
      last_insn_address = insn_addresses[uid];
    }
}

/* Prepare for an SI sized move.  */

int
do_movsi (operands)
     rtx operands[];
{
  rtx src = operands[1];
  rtx dst = operands[0];
  if (!reload_in_progress && !reload_completed)
    {
      if (!register_operand (dst, GET_MODE (dst)))
	{
	  rtx tmp = gen_reg_rtx (GET_MODE (dst));
	  emit_move_insn (tmp, src);
	  operands[1] = tmp;
	}
    }
  return 0;
}

/* Function for INITIAL_ELIMINATION_OFFSET(FROM, TO, OFFSET).
   Define the offset between two registers, one to be eliminated, and the other
   its replacement, at the start of a routine.  */

int
initial_offset (from, to)
{
  int offset = 0;

  if (from == ARG_POINTER_REGNUM && to == FRAME_POINTER_REGNUM)
    offset = UNITS_PER_WORD + frame_pointer_needed * UNITS_PER_WORD;
  else
    {
      int regno;

      for (regno = 0; regno < FIRST_PSEUDO_REGISTER; regno++)
	if (WORD_REG_USED (regno))
	  offset += UNITS_PER_WORD;

      /* See the comments for get_frame_size.  We need to round it up to
	 STACK_BOUNDARY.  */

      offset += ((get_frame_size () + STACK_BOUNDARY / BITS_PER_UNIT - 1)
		 & ~(STACK_BOUNDARY / BITS_PER_UNIT - 1));

      if (from == ARG_POINTER_REGNUM && to == STACK_POINTER_REGNUM)
	offset += UNITS_PER_WORD;	/* Skip saved PC */
    }
  return offset;
}

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

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

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

    case CC_SET_ZN:
      /* Insn sets the Z,N flags of CC to recog_operand[0].
	 The V flag is unusable.  The C flag may or may not be known but
	 that's ok because alter_cond will change tests to use EQ/NE.  */
      CC_STATUS_INIT;
      cc_status.flags |= CC_OVERFLOW_UNUSABLE | CC_NO_CARRY;
      cc_status.value1 = recog_operand[0];
      break;

    case CC_SET_ZNV:
      /* Insn sets the Z,N,V flags of CC to recog_operand[0].
	 The C flag may or may not be known but that's ok because
	 alter_cond will change tests to use EQ/NE.  */
      CC_STATUS_INIT;
      cc_status.flags |= CC_NO_CARRY;
      cc_status.value1 = recog_operand[0];
      break;

    case CC_COMPARE:
      /* The insn is a compare instruction.  */
      CC_STATUS_INIT;
      cc_status.value1 = SET_SRC (body);
      break;

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

/* Recognize valid operators for bit instructions */

int
bit_operator (x, mode)
     rtx x;
     enum machine_mode mode;
{
  enum rtx_code code = GET_CODE (x);

  return (code == XOR
	  || code == AND
	  || code == IOR);
}

/* Shifts.

   We devote a fair bit of code to getting efficient shifts since we can only
   shift one bit at a time on the H8/300 and H8/300H and only one or two
   bits at a time on the H8/S.

   The basic shift methods:

     * loop shifts -- emit a loop using one (or two on H8/S) bit shifts;
     this is the default.  SHIFT_LOOP

     * inlined shifts -- emit straight line code for the shift; this is
     used when a straight line shift is about the same size or smaller
     than a loop.  We allow the inline version to be slightly longer in
     some cases as it saves a register.  SHIFT_INLINE

     * rotate + and -- rotate the value the opposite direction, then
     mask off the values we don't need.  This is used when only a few
     of the bits in the original value will survive in the shifted value.
     Again, this is used when it's about the same size or smaller than
     a loop.  We allow this version to be slightly longer as it is usually
     much faster than a loop.  SHIFT_ROT_AND

     * swap (+ shifts) -- often it's possible to swap bytes/words to
     simulate a shift by 8/16.  Once swapped a few inline shifts can be
     added if the shift count is slightly more than 8 or 16.  This is used
     when it's about the same size or smaller than a loop.  We allow this
     version to be slightly longer as it is usually much faster than a loop.
     SHIFT_SPECIAL

     * There other oddballs.  Not worth explaining.  SHIFT_SPECIAL


   Here are some thoughts on what the absolutely positively best code is.
   "Best" here means some rational trade-off between code size and speed,
   where speed is more preferred but not at the expense of generating 20 insns.

   A trailing '*' after the shift count indicates the "best" mode isn't
   implemented.
   
   H8/300 QImode shifts
   1-4    - do them inline
   5-6    - ASHIFT | LSHIFTRT: rotate, mask off other bits
            ASHIFTRT: loop
   7      - ASHIFT | LSHIFTRT: rotate, mask off other bits
            ASHIFTRT: shll, subx (propagate carry bit to all bits)

   H8/300 HImode shifts
   1-4    - do them inline
   5-6    - loop
   7      - shift 2nd half other way into carry.
	    copy 1st half into 2nd half
	    rotate 2nd half other way with carry
	    rotate 1st half other way (no carry)
	    mask off bits in 1st half (ASHIFT | LSHIFTRT).
	    sign extend 1st half (ASHIFTRT)
   8      - move byte, zero (ASHIFT | LSHIFTRT) or sign extend other (ASHIFTRT)
   9-12   - do shift by 8, inline remaining shifts
   13-14* - ASHIFT | LSHIFTRT: rotate 3/2, mask, move byte, set other byte to 0
          - ASHIFTRT: loop
   15     - ASHIFT | LSHIFTRT: rotate 1, mask, move byte, set other byte to 0
          - ASHIFTRT: shll, subx, set other byte

   H8/300 SImode shifts
   1-2    - do them inline
   3-6    - loop
   7*     - shift other way once, move bytes into place,
            move carry into place (possibly with sign extension)
   8      - move bytes into place, zero or sign extend other
   9-14   - loop
   15*    - shift other way once, move word into place, move carry into place
   16     - move word, zero or sign extend other
   17-23  - loop
   24*    - move bytes into place, zero or sign extend other
   25-27  - loop
   28-30* - ASHIFT | LSHIFTRT: rotate top byte, mask, move byte into place,
                               zero others
            ASHIFTRT: loop
   31     - ASHIFT | LSHIFTRT: rotate top byte, mask, move byte into place,
                               zero others
            ASHIFTRT: shll top byte, subx, copy to other bytes

   H8/300H QImode shifts (same as H8/300 QImode shifts)
   1-4    - do them inline
   5-6    - ASHIFT | LSHIFTRT: rotate, mask off other bits
            ASHIFTRT: loop
   7      - ASHIFT | LSHIFTRT: rotate, mask off other bits
            ASHIFTRT: shll, subx (propagate carry bit to all bits)


   H8/300H HImode shifts
   1-4    - do them inline
   5-6    - loop
   7      - shift 2nd half other way into carry.
	    copy 1st half into 2nd half
	    rotate entire word other way using carry
	    mask off remaining bits  (ASHIFT | LSHIFTRT)
	    sign extend remaining bits (ASHIFTRT)
   8      - move byte, zero (ASHIFT | LSHIFTRT) or sign extend other (ASHIFTRT)
   9-12   - do shift by 8, inline remaining shifts
   13-14  - ASHIFT | LSHIFTRT: rotate 3/2, mask, move byte, set other byte to 0
          - ASHIFTRT: loop
   15     - ASHIFT | LSHIFTRT: rotate 1, mask, move byte, set other byte to 0
          - ASHIFTRT: shll, subx, set other byte

   H8/300H SImode shifts
   (These are complicated by the fact that we don't have byte level access to
   the top word.)
   A word is: bytes 3,2,1,0 (msb -> lsb), word 1,0 (msw -> lsw)
   1-4    - do them inline
   5-14   - loop
   15*    - shift other way once, move word into place, move carry into place
            (with sign extension for ASHIFTRT)
   16     - move word into place, zero or sign extend other
   17-20  - do 16bit shift, then inline remaining shifts
   20-23  - loop
   24*    - ASHIFT: move byte 0(msb) to byte 1, zero byte 0,
                    move word 0 to word 1, zero word 0
            LSHIFTRT: move word 1 to word 0, move byte 1 to byte 0,
                      zero word 1, zero byte 1
            ASHIFTRT: move word 1 to word 0, move byte 1 to byte 0,
                      sign extend byte 0, sign extend word 0
   25-27* - either loop, or
            do 24 bit shift, inline rest
   28-30  - ASHIFT: rotate 4/3/2, mask
            LSHIFTRT: rotate 4/3/2, mask
            ASHIFTRT: loop
   31     - shll, subx byte 0, sign extend byte 0, sign extend word 0

   H8/S QImode shifts
   1-6    - do them inline
   7      - ASHIFT | LSHIFTRT: rotate, mask off other bits
            ASHIFTRT: shll, subx (propagate carry bit to all bits)

   H8/S HImode shifts
   1-7	  - do them inline
   8      - move byte, zero (ASHIFT | LSHIFTRT) or sign extend other (ASHIFTRT)
   9-12   - do shift by 8, inline remaining shifts
   13-14  - ASHIFT | LSHIFTRT: rotate 3/2, mask, move byte, set other byte to 0
          - ASHIFTRT: loop
   15     - ASHIFT | LSHIFTRT: rotate 1, mask, move byte, set other byte to 0
          - ASHIFTRT: shll, subx, set other byte

   H8/S SImode shifts
   (These are complicated by the fact that we don't have byte level access to
   the top word.)
   A word is: bytes 3,2,1,0 (msb -> lsb), word 1,0 (msw -> lsw)
   1-10   - do them inline
   11-14  - loop
   15*    - shift other way once, move word into place, move carry into place
            (with sign extension for ASHIFTRT)
   16     - move word into place, zero or sign extend other
   17-20  - do 16bit shift, then inline remaining shifts
   20-23  - loop
   24*    - ASHIFT: move byte 0(msb) to byte 1, zero byte 0,
                    move word 0 to word 1, zero word 0
            LSHIFTRT: move word 1 to word 0, move byte 1 to byte 0,
                      zero word 1, zero byte 1
            ASHIFTRT: move word 1 to word 0, move byte 1 to byte 0,
                      sign extend byte 0, sign extend word 0
   25-27* - either loop, or
            do 24 bit shift, inline rest
   28-30  - ASHIFT: rotate 4/3/2, mask
            LSHIFTRT: rotate 4/3/2, mask
            ASHIFTRT: loop
   31     - shll, subx byte 0, sign extend byte 0, sign extend word 0

   Panic!!!  */

int
nshift_operator (x, mode)
     rtx x;
     enum machine_mode mode;
{
  switch (GET_CODE (x))
    {
    case ASHIFTRT:
    case LSHIFTRT:
    case ASHIFT:
      return 1;

    default:
      return 0;
    }
}

/* Called from the .md file to emit code to do shifts.
   Returns a boolean indicating success
   (currently this is always TRUE).  */

int
expand_a_shift (mode, code, operands)
     enum machine_mode mode;
     int code;
     rtx operands[];
{
  emit_move_insn (operands[0], operands[1]);

  /* need a loop to get all the bits we want  - we generate the
     code at emit time, but need to allocate a scratch reg now  */

  emit_insn (gen_rtx
	     (PARALLEL, VOIDmode,
	      gen_rtvec (2,
			 gen_rtx (SET, VOIDmode, operands[0],
				  gen_rtx (code, mode, operands[0], operands[2])),
			 gen_rtx (CLOBBER, VOIDmode, gen_rtx (SCRATCH, QImode, 0)))));

  return 1;
}

/* Shift algorithm determination.

   There are various ways of doing a shift:
   SHIFT_INLINE: If the amount is small enough, just generate as many one-bit
                 shifts as we need.
   SHIFT_ROT_AND: If the amount is large but close to either end, rotate the
                  necessary bits into position and then set the rest to zero.
   SHIFT_SPECIAL: Hand crafted assembler.
   SHIFT_LOOP:    If the above methods fail, just loop.  */

enum shift_alg
{
  SHIFT_INLINE,
  SHIFT_ROT_AND,
  SHIFT_SPECIAL,
  SHIFT_LOOP,
  SHIFT_MAX
};

/* Symbols of the various shifts which can be used as indices.  */

enum shift_type
  {
    SHIFT_ASHIFT, SHIFT_LSHIFTRT, SHIFT_ASHIFTRT
  };

/* Symbols of the various modes which can be used as indices.  */

enum shift_mode
  {
    QIshift, HIshift, SIshift
  };

/* For single bit shift insns, record assembler and what bits of the
   condition code are valid afterwards (represented as various CC_FOO
   bits, 0 means CC isn't left in a usable state).  */

struct shift_insn
{
  char *assembler;
  int cc_valid;
};

/* Assembler instruction shift table.

   These tables are used to look up the basic shifts.
   They are indexed by cpu, shift_type, and mode.
*/

static const struct shift_insn shift_one[2][3][3] =
{
/* H8/300 */
  {
/* SHIFT_ASHIFT */
    {
      { "shll\t%X0", CC_NO_CARRY },
      { "add.w\t%T0,%T0", CC_OVERFLOW_UNUSABLE | CC_NO_CARRY },
      { "add.w\t%f0,%f0\n\taddx\t%y0,%y0\n\taddx\t%z0,%z0", 0 }
    },
/* SHIFT_LSHIFTRT */
    {
      { "shlr\t%X0", CC_NO_CARRY },
      { "shlr\t%t0\n\trotxr\t%s0", 0 },
      { "shlr\t%z0\n\trotxr\t%y0\n\trotxr\t%x0\n\trotxr\t%w0", 0 }
    },
/* SHIFT_ASHIFTRT */
    {
      { "shar\t%X0", CC_OVERFLOW_UNUSABLE | CC_NO_CARRY },
      { "shar\t%t0\n\trotxr\t%s0", 0 },
      { "shar\t%z0\n\trotxr\t%y0\n\trotxr\t%x0\n\trotxr\t%w0", 0 }
    }
  },
/* H8/300H */
  {
/* SHIFT_ASHIFT */
    {
      { "shll.b\t%X0", CC_NO_CARRY },
      { "shll.w\t%T0", CC_NO_CARRY },
      { "shll.l\t%S0", CC_NO_CARRY }
    },
/* SHIFT_LSHIFTRT */
    {
      { "shlr.b\t%X0", CC_NO_CARRY },
      { "shlr.w\t%T0", CC_NO_CARRY },
      { "shlr.l\t%S0", CC_NO_CARRY }
    },
/* SHIFT_ASHIFTRT */
    {
      { "shar.b\t%X0", CC_OVERFLOW_UNUSABLE | CC_NO_CARRY },
      { "shar.w\t%T0", CC_OVERFLOW_UNUSABLE | CC_NO_CARRY },
      { "shar.l\t%S0", CC_OVERFLOW_UNUSABLE | CC_NO_CARRY }
    }
  }
};

static const struct shift_insn shift_two[3][3] =
{
/* SHIFT_ASHIFT */
    {
      { "shll.b\t#2,%X0", CC_NO_CARRY },
      { "shll.w\t#2,%T0", CC_NO_CARRY },
      { "shll.l\t#2,%S0", CC_NO_CARRY }
    },
/* SHIFT_LSHIFTRT */
    {
      { "shlr.b\t#2,%X0", CC_NO_CARRY },
      { "shlr.w\t#2,%T0", CC_NO_CARRY },
      { "shlr.l\t#2,%S0", CC_NO_CARRY }
    },
/* SHIFT_ASHIFTRT */
    {
      { "shar.b\t#2,%X0", CC_OVERFLOW_UNUSABLE | CC_NO_CARRY },
      { "shar.w\t#2,%T0", CC_OVERFLOW_UNUSABLE | CC_NO_CARRY },
      { "shar.l\t#2,%S0", CC_OVERFLOW_UNUSABLE | CC_NO_CARRY }
    }
};

/* Rotates are organized by which shift they'll be used in implementing.
   There's no need to record whether the cc is valid afterwards because
   it is the AND insn that will decide this.  */

static const char *const rotate_one[2][3][3] =
{
/* H8/300 */
  {
/* SHIFT_ASHIFT */
    {
      "rotr\t%X0",
      "shlr\t%t0\n\trotxr\t%s0\n\tbst\t#7,%t0",
      0
    },
/* SHIFT_LSHIFTRT */
    {
      "rotl\t%X0",
      "shll\t%s0\n\trotxl\t%t0\n\tbst\t#0,%s0",