vax.c

早期freebsd实现

      reg = 1;
      break;
    case MULT:
      indexed = 1;	/* 2 on VAX 2 */
      break;
    case CONST_INT:
      /* byte offsets cost nothing (on a VAX 2, they cost 1 cycle) */
      if (offset == 0)
	offset = (unsigned)(INTVAL(addr)+128) > 256;
      break;
    case CONST:
    case SYMBOL_REF:
      offset = 1;	/* 2 on VAX 2 */
      break;
    case LABEL_REF:	/* this is probably a byte offset from the pc */
      if (offset == 0)
	offset = 1;
      break;
    case PLUS:
      if (plus_op0)
	plus_op1 = XEXP (addr, 0);
      else
	plus_op0 = XEXP (addr, 0);
      addr = XEXP (addr, 1);
      goto restart;
    case MEM:
      indir = 2;	/* 3 on VAX 2 */
      addr = XEXP (addr, 0);
      goto restart;
    }

  /* Up to 3 things can be added in an address.  They are stored in
     plus_op0, plus_op1, and addr.  */

  if (plus_op0)
    {
      addr = plus_op0;
      plus_op0 = 0;
      goto restart;
    }
  if (plus_op1)
    {
      addr = plus_op1;
      plus_op1 = 0;
      goto restart;
    }
  /* Indexing and register+offset can both be used (except on a VAX 2)
     without increasing execution time over either one alone. */
  if (reg && indexed && offset)
    return reg + indir + offset + predec;
  return reg + indexed + indir + offset + predec;
}


/* Cost of an expression on a VAX.  This version has costs tuned for the
   CVAX chip (found in the VAX 3 series) with comments for variations on
   other models.  */

int
vax_rtx_cost (x)
    register rtx x;
{
  register enum rtx_code code = GET_CODE (x);
  enum machine_mode mode = GET_MODE (x);
  register int c;
  int i = 0;				/* may be modified in switch */
  char *fmt = GET_RTX_FORMAT (code);	/* may be modified in switch */

  switch (code)
    {
    case POST_INC:
      return 2;
    case PRE_DEC:
      return 3;
    case MULT:
      switch (mode)
	{
	case DFmode:
	  c = 16;		/* 4 on VAX 9000 */
	  break;
	case SFmode:
	  c = 9;		/* 4 on VAX 9000, 12 on VAX 2 */
	  break;
	case DImode:
	  c = 16;		/* 6 on VAX 9000, 28 on VAX 2 */
	  break;
	case SImode:
	case HImode:
	case QImode:
	  c = 10;		/* 3-4 on VAX 9000, 20-28 on VAX 2 */
	  break;
	}
      break;
    case UDIV:
      c = 17;
      break;
    case DIV:
      if (mode == DImode)
	c = 30;	/* highly variable */
      else if (mode == DFmode)
	/* divide takes 28 cycles if the result is not zero, 13 otherwise */
	c = 24;
      else
	c = 11;			/* 25 on VAX 2 */
      break;
    case MOD:
      c = 23;
      break;
    case UMOD:
      c = 29;
      break;
    case FLOAT:
      c = 6 + (mode == DFmode) + (GET_MODE (XEXP (x, 0)) != SImode);
      /* 4 on VAX 9000 */
      break;
    case FIX:
      c = 7;			/* 17 on VAX 2 */
      break;
    case LSHIFT:
    case ASHIFT:
    case LSHIFTRT:
    case ASHIFTRT:
      if (mode == DImode)
	c = 12;
      else
	c = 10;			/* 6 on VAX 9000 */
      break;
    case ROTATE:
    case ROTATERT:
      c = 6;			/* 5 on VAX 2, 4 on VAX 9000 */
      if (GET_CODE (XEXP (x, 1)) == CONST_INT)
	fmt = "e";	/* all constant rotate counts are short */
      break;
    case PLUS:
      /* Check for small negative integer operand: subl2 can be used with
	 a short positive constant instead.  */
      if (GET_CODE (XEXP (x, 1)) == CONST_INT)
	if ((unsigned)(INTVAL (XEXP (x, 1)) + 63) < 127)
	  fmt = "e";
    case MINUS:
      c = (mode == DFmode) ? 13 : 8;	/* 6/8 on VAX 9000, 16/15 on VAX 2 */
    case IOR:
    case XOR:
      c = 3;
      break;
    case AND:
      /* AND is special because the first operand is complemented. */
      c = 3;
      if (GET_CODE (XEXP (x, 0)) == CONST_INT)
	{
	  if ((unsigned)~INTVAL (XEXP (x, 0)) > 63)
	    c = 4;
	  fmt = "e";
	  i = 1;
	}
      break;
    case NEG:
      if (mode == DFmode)
	return 9;
      else if (mode == SFmode)
	return 6;
      else if (mode == DImode)
	return 4;
    case NOT:
      return 2;
    case ZERO_EXTRACT:
    case SIGN_EXTRACT:
      c = 15;
      break;
    case MEM:
      if (mode == DImode || mode == DFmode)
	c = 5;				/* 7 on VAX 2 */
      else
	c = 3;				/* 4 on VAX 2 */
      x = XEXP (x, 0);
      if (GET_CODE (x) == REG || GET_CODE (x) == POST_INC)
	return c;
      return c + vax_address_cost (x);
    default:
      c = 3;
      break;
    }


  /* Now look inside the expression.  Operands which are not registers or
     short constants add to the cost.

     FMT and I may have been adjusted in the switch above for instructions
     which require special handling */

  while (*fmt++ == 'e')
    {
      register rtx op = XEXP (x, i++);
      code = GET_CODE (op);

      /* A NOT is likely to be found as the first operand of an AND
	 (in which case the relevant cost is of the operand inside
	 the not) and not likely to be found anywhere else.  */
      if (code == NOT)
	op = XEXP (op, 0), code = GET_CODE (op);

      switch (code)
	{
	case CONST_INT:
	  if ((unsigned)INTVAL (op) > 63 && GET_MODE (x) != QImode)
	    c += 1;		/* 2 on VAX 2 */
	  break;
	case CONST:
	case LABEL_REF:
	case SYMBOL_REF:
	  c += 1;		/* 2 on VAX 2 */
	  break;
	case CONST_DOUBLE:
	  if (GET_MODE_CLASS (GET_MODE (op)) == MODE_FLOAT)
	    {
	      /* Registers are faster than floating point constants -- even
		 those constants which can be encoded in a single byte.  */
	      if (vax_float_literal (op))
		c++;
	      else
		c += (GET_MODE (x) == DFmode) ? 3 : 2;
	    }
	  else
	    {
	      if (CONST_DOUBLE_HIGH (op) != 0
		  || (unsigned)CONST_DOUBLE_LOW (op) > 63)
		c += 2;
	    }
	  break;
	case MEM:
	  c += 1;		/* 2 on VAX 2 */
	  if (GET_CODE (XEXP (op, 0)) != REG)
	    c += vax_address_cost (XEXP (op, 0));
	  break;
	case REG:
	case SUBREG:
	  break;
	default:
	  c += 1;
	  break;
	}
    }
  return c;
}

#ifdef VMS
/* Additional support code for VMS. */

#ifdef QSORT_WORKAROUND
  /*
	Do not use VAXCRTL's qsort() due to a severe bug:  once you've
	sorted something which has a size that's an exact multiple of 4
	and is longword aligned, you cannot safely sort anything which
	is either not a multiple of 4 in size or not longword aligned.
	A static "move-by-longword" optimization flag inside qsort() is
	never reset.  This is known of affect VMS V4.6 through VMS V5.5-1.

	In this work-around an insertion sort is used for simplicity.
	The qsort code from glibc should probably be used instead.
   */
void
not_qsort (array, count, size, compare)
     void *array;
     unsigned count, size;
     int (*compare)();
{

  if (size == sizeof (short))
    {
      register int i;
      register short *next, *prev;
      short tmp, *base = array;

      for (next = base, i = count - 1; i > 0; i--)
	{
	  prev = next++;
	  if ((*compare)(next, prev) < 0)
	    {
	      tmp = *next;
	      do  *(prev + 1) = *prev;
		while (--prev >= base ? (*compare)(&tmp, prev) < 0 : 0);
	      *(prev + 1) = tmp;
	    }
	}
    }
  else if (size == sizeof (long))
    {
      register int i;
      register long *next, *prev;
      long tmp, *base = array;

      for (next = base, i = count - 1; i > 0; i--)
	{
	  prev = next++;
	  if ((*compare)(next, prev) < 0)
	    {
	      tmp = *next;
	      do  *(prev + 1) = *prev;
		while (--prev >= base ? (*compare)(&tmp, prev) < 0 : 0);
	      *(prev + 1) = tmp;
	    }
	}
    }
  else  /* arbitrary size */
    {
#ifdef USE_C_ALLOCA
      extern void *alloca ();
#endif
      register int i;
      register char *next, *prev, *tmp = alloca (size), *base = array;

      for (next = base, i = count - 1; i > 0; i--)
	{   /* count-1 forward iterations */
	  prev = next,  next += size;		/* increment front pointer */
	  if ((*compare)(next, prev) < 0)
	    {	/* found element out of order; move others up then re-insert */
	      memcpy (tmp, next, size);		/* save smaller element */
	      do { memcpy (prev + size, prev, size); /* move larger elem. up */
		   prev -= size;		/* decrement back pointer */
		 } while (prev >= base ? (*compare)(tmp, prev) < 0 : 0);
	      memcpy (prev + size, tmp, size);	/* restore small element */
	    }
	}
#ifdef USE_C_ALLOCA
      alloca (0);
#endif
    }

  return;
}
#endif /* QSORT_WORKAROUND */

#endif /* VMS */