gcc/gcc/real.h

/* Front-end tree definitions for GNU compiler.
   Copyright (C) 1989, 1991 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, 675 Mass Ave, Cambridge, MA 02139, USA.  */

#ifndef REAL_H_INCLUDED
#define REAL_H_INCLUDED

/* Define codes for all the float formats that we know of.  */
#define UNKNOWN_FLOAT_FORMAT 0
#define IEEE_FLOAT_FORMAT 1
#define VAX_FLOAT_FORMAT 2

/* Default to IEEE float if not specified.  Nearly all machines use it.  */

#ifndef TARGET_FLOAT_FORMAT
#define	TARGET_FLOAT_FORMAT	IEEE_FLOAT_FORMAT
#endif

#ifndef HOST_FLOAT_FORMAT
#define	HOST_FLOAT_FORMAT	IEEE_FLOAT_FORMAT
#endif

#if TARGET_FLOAT_FORMAT == IEEE_FLOAT_FORMAT
#define REAL_INFINITY
#endif

#ifdef REAL_ARITHMETIC
/* Defining REAL_IS_NOT_DOUBLE breaks certain initializations
   when REAL_ARITHMETIC etc. are not defined.  */

/* Now see if the host and target machines use the same format. 
   If not, define REAL_IS_NOT_DOUBLE (even if we end up representing
   reals as doubles because we have no better way in this cross compiler.)
   This turns off various optimizations that can happen when we know the
   compiler's float format matches the target's float format.
   */
#if HOST_FLOAT_FORMAT != TARGET_FLOAT_FORMAT
#define	REAL_IS_NOT_DOUBLE
#ifndef REAL_VALUE_TYPE
#define REAL_VALUE_TYPE \
  struct real_value{ HOST_WIDE_INT i[sizeof (double)/sizeof (HOST_WIDE_INT)]; }
#endif /* no REAL_VALUE_TYPE */
#endif /* formats differ */
#endif /* 0 */

/* If we are not cross-compiling, use a `double' to represent the
   floating-point value.  Otherwise, use some other type
   (probably a struct containing an array of longs).  */
#ifndef REAL_VALUE_TYPE
#define REAL_VALUE_TYPE double
#else
#define REAL_IS_NOT_DOUBLE
#endif

#if HOST_FLOAT_FORMAT == TARGET_FLOAT_FORMAT

/* Convert a type `double' value in host format first to a type `float'
   value in host format and then to a single type `long' value which
   is the bitwise equivalent of the `float' value.  */
#define REAL_VALUE_TO_TARGET_SINGLE(IN, OUT)				\
do { float f = (float) (IN);						\
     (OUT) = *(long *) &f;						\
  } while (0)

/* Convert a type `double' value in host format to a pair of type `long'
   values which is its bitwise equivalent, but put the two words into
   proper word order for the target.  */
#if defined (HOST_WORDS_BIG_ENDIAN) == WORDS_BIG_ENDIAN
#define REAL_VALUE_TO_TARGET_DOUBLE(IN, OUT)				\
do { REAL_VALUE_TYPE in = (IN);  /* Make sure it's not in a register.  */\
     (OUT)[0] = ((long *) &in)[0];					\
     (OUT)[1] = ((long *) &in)[1];					\
   } while (0)
#else
#define REAL_VALUE_TO_TARGET_DOUBLE(IN, OUT)				\
do { REAL_VALUE_TYPE in = (IN);  /* Make sure it's not in a register.  */\
     (OUT)[1] = ((long *) &in)[0];					\
     (OUT)[0] = ((long *) &in)[1];					\
   } while (0)
#endif
#endif /* HOST_FLOAT_FORMAT == TARGET_FLOAT_FORMAT */

/* Compare two floating-point values for equality.  */
#ifndef REAL_VALUES_EQUAL
#define REAL_VALUES_EQUAL(x,y) ((x) == (y))
#endif

/* Compare two floating-point values for less than.  */
#ifndef REAL_VALUES_LESS
#define REAL_VALUES_LESS(x,y) ((x) < (y))
#endif

/* Convert a floating-point value to integer by truncating.  */
#ifndef REAL_VALUE_FIX_TRUNCATE
#define REAL_VALUE_FIX_TRUNCATE(x) ((int) (x))
#endif

/* Convert a floating-point value to unsigned integer by truncating.  */
#ifndef REAL_VALUE_UNSIGNED_FIX_TRUNCATE
#define REAL_VALUE_UNSIGNED_FIX_TRUNCATE(x) ((unsigned int) (x))
#endif

/* Convert a floating-point value to integer, using any rounding mode.  */
#ifndef REAL_VALUE_FIX
#define REAL_VALUE_FIX(x) ((int) (x))
#endif

/* Convert a floating-point value to unsigned integer, using any rounding
   mode.  */
#ifndef REAL_VALUE_UNSIGNED_FIX
#define REAL_VALUE_UNSIGNED_FIX(x) ((unsigned int) (x))
#endif

/* Scale X by Y powers of 2.  */
#ifndef REAL_VALUE_LDEXP
#define REAL_VALUE_LDEXP(x,y) ldexp (x, y)
extern double ldexp ();
#endif

/* Convert the string X to a floating-point value.  */
#ifndef REAL_VALUE_ATOF
#define REAL_VALUE_ATOF(x) atof (x)
#if defined (MIPSEL) || defined (MIPSEB)
/* MIPS compiler can't handle parens around the function name.
   This problem *does not* appear to be connected with any
   macro definition for atof.  It does not seem there is one.  */
extern double atof ();
#else
extern double (atof) ();
#endif
#endif

/* Negate the floating-point value X.  */
#ifndef REAL_VALUE_NEGATE
#define REAL_VALUE_NEGATE(x) (- (x))
#endif

/* Truncate the floating-point value X to mode MODE.  This is correct only
   for the most common case where the host and target have objects of the same
   size and where `float' is SFmode.  */

/* Don't use REAL_VALUE_TRUNCATE directly--always call real_value_truncate.  */
extern REAL_VALUE_TYPE real_value_truncate ();

#ifndef REAL_VALUE_TRUNCATE
#define REAL_VALUE_TRUNCATE(mode, x) \
 (GET_MODE_BITSIZE (mode) == sizeof (float) * HOST_BITS_PER_CHAR	\
  ? (float) (x) : (x))
#endif

/* Determine whether a floating-point value X is infinite. */
#ifndef REAL_VALUE_ISINF
#define REAL_VALUE_ISINF(x) (target_isinf (x))
#endif

/* Determine whether a floating-point value X is a NaN. */
#ifndef REAL_VALUE_ISNAN
#define REAL_VALUE_ISNAN(x) (target_isnan (x))
#endif

/* Determine whether a floating-point value X is negative. */
#ifndef REAL_VALUE_NEGATIVE
#define REAL_VALUE_NEGATIVE(x) (target_negative (x))
#endif

/* Determine whether a floating-point value X is minus 0. */
#ifndef REAL_VALUE_MINUS_ZERO
#define REAL_VALUE_MINUS_ZERO(x) ((x) == 0 && REAL_VALUE_NEGATIVE (x))
#endif

/* Constant real values 0, 1, 2, and -1.  */

extern REAL_VALUE_TYPE dconst0;
extern REAL_VALUE_TYPE dconst1;
extern REAL_VALUE_TYPE dconst2;
extern REAL_VALUE_TYPE dconstm1;

/* Union type used for extracting real values from CONST_DOUBLEs
   or putting them in.  */

union real_extract 
{
  REAL_VALUE_TYPE d;
  HOST_WIDE_INT i[sizeof (REAL_VALUE_TYPE) / sizeof (HOST_WIDE_INT)];
};

/* For a CONST_DOUBLE:
   The usual two ints that hold the value.
   For a DImode, that is all there are;
    and CONST_DOUBLE_LOW is the low-order word and ..._HIGH the high-order.
   For a float, the number of ints varies,
    and CONST_DOUBLE_LOW is the one that should come first *in memory*.
    So use &CONST_DOUBLE_LOW(r) as the address of an array of ints.  */
#define CONST_DOUBLE_LOW(r) XWINT (r, 2)
#define CONST_DOUBLE_HIGH(r) XWINT (r, 3)

/* Link for chain of all CONST_DOUBLEs in use in current function.  */
#define CONST_DOUBLE_CHAIN(r) XEXP (r, 1)
/* The MEM which represents this CONST_DOUBLE's value in memory,
   or const0_rtx if no MEM has been made for it yet,
   or cc0_rtx if it is not on the chain.  */
#define CONST_DOUBLE_MEM(r) XEXP (r, 0)

/* Function to return a real value (not a tree node)
   from a given integer constant.  */
REAL_VALUE_TYPE real_value_from_int_cst ();

/* Given a CONST_DOUBLE in FROM, store into TO the value it represents.  */

#define REAL_VALUE_FROM_CONST_DOUBLE(to, from)		\
do { union real_extract u;				\
     bcopy (&CONST_DOUBLE_LOW ((from)), &u, sizeof u);	\
     to = u.d; } while (0)

/* Return a CONST_DOUBLE with value R and mode M.  */

#define CONST_DOUBLE_FROM_REAL_VALUE(r,m) immed_real_const_1 (r, m)

#endif /* Not REAL_H_INCLUDED */