op-2.h

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/* Software floating-point emulation.
   Basic two-word fraction declaration and manipulation.
   Copyright (C) 1997,1998,1999 Free Software Foundation, Inc.
   This file is part of the GNU C Library.
   Contributed by Richard Henderson ([e-mail]),
		  Jakub Jelinek ([e-mail]),
		  David S. Miller ([e-mail]) and
		  Peter Maydell ([e-mail]).

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Library General Public License as
   published by the Free Software Foundation; either version 2 of the
   License, or (at your option) any later version.

   The GNU C Library 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
   Library General Public License for more details.

   You should have received a copy of the GNU Library General Public
   License along with the GNU C Library; see the file COPYING.LIB.  If
   not, write to the Free Software Foundation, Inc.,
   59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */

#ifndef __MATH_EMU_OP_2_H__
#define __MATH_EMU_OP_2_H__

#define _FP_FRAC_DECL_2(X)	_FP_W_TYPE X##_f0, X##_f1
#define _FP_FRAC_COPY_2(D,S)	(D##_f0 = S##_f0, D##_f1 = S##_f1)
#define _FP_FRAC_SET_2(X,I)	__FP_FRAC_SET_2(X, I)
#define _FP_FRAC_HIGH_2(X)	(X##_f1)
#define _FP_FRAC_LOW_2(X)	(X##_f0)
#define _FP_FRAC_WORD_2(X,w)	(X##_f##w)

#define _FP_FRAC_SLL_2(X,N)						\
  do {									\
    if ((N) < _FP_W_TYPE_SIZE)						\
      {									\
	if (__builtin_constant_p(N) && (N) == 1) 			\
	  {								\
	    X##_f1 = X##_f1 + X##_f1 + (((_FP_WS_TYPE)(X##_f0)) < 0);	\
	    X##_f0 += X##_f0;						\
	  }								\
	else								\
	  {								\
	    X##_f1 = X##_f1 << (N) | X##_f0 >> (_FP_W_TYPE_SIZE - (N));	\
	    X##_f0 <<= (N);						\
	  }								\
      }									\
    else								\
      {									\
	X##_f1 = X##_f0 << ((N) - _FP_W_TYPE_SIZE);			\
	X##_f0 = 0;							\
      }									\
  } while (0)

#define _FP_FRAC_SRL_2(X,N)						\
  do {									\
    if ((N) < _FP_W_TYPE_SIZE)						\
      {									\
	X##_f0 = X##_f0 >> (N) | X##_f1 << (_FP_W_TYPE_SIZE - (N));	\
	X##_f1 >>= (N);							\
      }									\
    else								\
      {									\
	X##_f0 = X##_f1 >> ((N) - _FP_W_TYPE_SIZE);			\
	X##_f1 = 0;							\
      }									\
  } while (0)

/* Right shift with sticky-lsb.  */
#define _FP_FRAC_SRS_2(X,N,sz)						\
  do {									\
    if ((N) < _FP_W_TYPE_SIZE)						\
      {									\
	X##_f0 = (X##_f1 << (_FP_W_TYPE_SIZE - (N)) | X##_f0 >> (N) |	\
		  (__builtin_constant_p(N) && (N) == 1			\
		   ? X##_f0 & 1						\
		   : (X##_f0 << (_FP_W_TYPE_SIZE - (N))) != 0));	\
	X##_f1 >>= (N);							\
      }									\
    else								\
      {									\
	X##_f0 = (X##_f1 >> ((N) - _FP_W_TYPE_SIZE) |			\
		(((X##_f1 << (2*_FP_W_TYPE_SIZE - (N))) | X##_f0) != 0)); \
	X##_f1 = 0;							\
      }									\
  } while (0)

#define _FP_FRAC_ADDI_2(X,I)	\
  __FP_FRAC_ADDI_2(X##_f1, X##_f0, I)

#define _FP_FRAC_ADD_2(R,X,Y)	\
  __FP_FRAC_ADD_2(R##_f1, R##_f0, X##_f1, X##_f0, Y##_f1, Y##_f0)

#define _FP_FRAC_SUB_2(R,X,Y)	\
  __FP_FRAC_SUB_2(R##_f1, R##_f0, X##_f1, X##_f0, Y##_f1, Y##_f0)

#define _FP_FRAC_DEC_2(X,Y)	\
  __FP_FRAC_DEC_2(X##_f1, X##_f0, Y##_f1, Y##_f0)

#define _FP_FRAC_CLZ_2(R,X)	\
  do {				\
    if (X##_f1)			\
      __FP_CLZ(R,X##_f1);	\
    else 			\
    {				\
      __FP_CLZ(R,X##_f0);	\
      R += _FP_W_TYPE_SIZE;	\
    }				\
  } while(0)

/* Predicates */
#define _FP_FRAC_NEGP_2(X)	((_FP_WS_TYPE)X##_f1 < 0)
#define _FP_FRAC_ZEROP_2(X)	((X##_f1 | X##_f0) == 0)
#define _FP_FRAC_OVERP_2(fs,X)	(_FP_FRAC_HIGH_##fs(X) & _FP_OVERFLOW_##fs)
#define _FP_FRAC_EQ_2(X, Y)	(X##_f1 == Y##_f1 && X##_f0 == Y##_f0)
#define _FP_FRAC_GT_2(X, Y)	\
  (X##_f1 > Y##_f1 || (X##_f1 == Y##_f1 && X##_f0 > Y##_f0))
#define _FP_FRAC_GE_2(X, Y)	\
  (X##_f1 > Y##_f1 || (X##_f1 == Y##_f1 && X##_f0 >= Y##_f0))

#define _FP_ZEROFRAC_2		0, 0
#define _FP_MINFRAC_2		0, 1
#define _FP_MAXFRAC_2		(~(_FP_WS_TYPE)0), (~(_FP_WS_TYPE)0)

/*
 * Internals 
 */

#define __FP_FRAC_SET_2(X,I1,I0)	(X##_f0 = I0, X##_f1 = I1)

#define __FP_CLZ_2(R, xh, xl)	\
  do {				\
    if (xh)			\
      __FP_CLZ(R,xh);		\
    else 			\
    {				\
      __FP_CLZ(R,xl);		\
      R += _FP_W_TYPE_SIZE;	\
    }				\
  } while(0)

#if 0

#ifndef __FP_FRAC_ADDI_2
#define __FP_FRAC_ADDI_2(xh, xl, i)	\
  (xh += ((xl += i) < i))
#endif
#ifndef __FP_FRAC_ADD_2
#define __FP_FRAC_ADD_2(rh, rl, xh, xl, yh, yl)	\
  (rh = xh + yh + ((rl = xl + yl) < xl))
#endif
#ifndef __FP_FRAC_SUB_2
#define __FP_FRAC_SUB_2(rh, rl, xh, xl, yh, yl)	\
  (rh = xh - yh - ((rl = xl - yl) > xl))
#endif
#ifndef __FP_FRAC_DEC_2
#define __FP_FRAC_DEC_2(xh, xl, yh, yl)	\
  do {					\
    UWtype _t = xl;			\
    xh -= yh + ((xl -= yl) > _t);	\
  } while (0)
#endif

#else

#undef __FP_FRAC_ADDI_2
#define __FP_FRAC_ADDI_2(xh, xl, i)	add_ssaaaa(xh, xl, xh, xl, 0, i)
#undef __FP_FRAC_ADD_2
#define __FP_FRAC_ADD_2			add_ssaaaa
#undef __FP_FRAC_SUB_2
#define __FP_FRAC_SUB_2			sub_ddmmss
#undef __FP_FRAC_DEC_2
#define __FP_FRAC_DEC_2(xh, xl, yh, yl)	sub_ddmmss(xh, xl, xh, xl, yh, yl)

#endif

/*
 * Unpack the raw bits of a native fp value.  Do not classify or
 * normalize the data.
 */

#define _FP_UNPACK_RAW_2(fs, X, val)			\
  do {							\
    union _FP_UNION_##fs _flo; _flo.flt = (val);	\
							\
    X##_f0 = _flo.bits.frac0;				\
    X##_f1 = _flo.bits.frac1;				\
    X##_e  = _flo.bits.exp;				\
    X##_s  = _flo.bits.sign;				\
  } while (0)

#define _FP_UNPACK_RAW_2_P(fs, X, val)			\
  do {							\
    union _FP_UNION_##fs *_flo =			\
      (union _FP_UNION_##fs *)(val);			\
							\
    X##_f0 = _flo->bits.frac0;				\
    X##_f1 = _flo->bits.frac1;				\
    X##_e  = _flo->bits.exp;				\
    X##_s  = _flo->bits.sign;				\
  } while (0)


/*
 * Repack the raw bits of a native fp value.
 */

#define _FP_PACK_RAW_2(fs, val, X)			\
  do {							\
    union _FP_UNION_##fs _flo;				\
							\
    _flo.bits.frac0 = X##_f0;				\
    _flo.bits.frac1 = X##_f1;				\
    _flo.bits.exp   = X##_e;				\
    _flo.bits.sign  = X##_s;				\
							\
    (val) = _flo.flt;					\
  } while (0)

#define _FP_PACK_RAW_2_P(fs, val, X)			\
  do {							\
    union _FP_UNION_##fs *_flo =			\
      (union _FP_UNION_##fs *)(val);			\
							\
    _flo->bits.frac0 = X##_f0;				\
    _flo->bits.frac1 = X##_f1;				\
    _flo->bits.exp   = X##_e;				\
    _flo->bits.sign  = X##_s;				\
  } while (0)


/*
 * Multiplication algorithms:
 */

/* Given a 1W * 1W => 2W primitive, do the extended multiplication.  */

#define _FP_MUL_MEAT_2_wide(wfracbits, R, X, Y, doit)			\
  do {									\
    _FP_FRAC_DECL_4(_z); _FP_FRAC_DECL_2(_b); _FP_FRAC_DECL_2(_c);	\
									\
    doit(_FP_FRAC_WORD_4(_z,1), _FP_FRAC_WORD_4(_z,0), X##_f0, Y##_f0);	\
    doit(_b_f1, _b_f0, X##_f0, Y##_f1);					\
    doit(_c_f1, _c_f0, X##_f1, Y##_f0);					\
    doit(_FP_FRAC_WORD_4(_z,3), _FP_FRAC_WORD_4(_z,2), X##_f1, Y##_f1);	\
									\
    __FP_FRAC_ADD_3(_FP_FRAC_WORD_4(_z,3),_FP_FRAC_WORD_4(_z,2),	\
		    _FP_FRAC_WORD_4(_z,1), 0, _b_f1, _b_f0,		\
		    _FP_FRAC_WORD_4(_z,3),_FP_FRAC_WORD_4(_z,2),	\
		    _FP_FRAC_WORD_4(_z,1));				\
    __FP_FRAC_ADD_3(_FP_FRAC_WORD_4(_z,3),_FP_FRAC_WORD_4(_z,2),	\
		    _FP_FRAC_WORD_4(_z,1), 0, _c_f1, _c_f0,		\
		    _FP_FRAC_WORD_4(_z,3),_FP_FRAC_WORD_4(_z,2),	\
		    _FP_FRAC_WORD_4(_z,1));				\
									\
    /* Normalize since we know where the msb of the multiplicands	\
       were (bit B), we know that the msb of the of the product is	\
       at either 2B or 2B-1.  */					\
    _FP_FRAC_SRS_4(_z, wfracbits-1, 2*wfracbits);			\
    R##_f0 = _FP_FRAC_WORD_4(_z,0);					\
    R##_f1 = _FP_FRAC_WORD_4(_z,1);					\
  } while (0)

/* Given a 1W * 1W => 2W primitive, do the extended multiplication.
   Do only 3 multiplications instead of four. This one is for machines
   where multiplication is much more expensive than subtraction.  */

#define _FP_MUL_MEAT_2_wide_3mul(wfracbits, R, X, Y, doit)		\
  do {									\
    _FP_FRAC_DECL_4(_z); _FP_FRAC_DECL_2(_b); _FP_FRAC_DECL_2(_c);	\
    _FP_W_TYPE _d;							\
    int _c1, _c2;							\
									\
    _b_f0 = X##_f0 + X##_f1;						\
    _c1 = _b_f0 < X##_f0;						\
    _b_f1 = Y##_f0 + Y##_f1;						\
    _c2 = _b_f1 < Y##_f0;						\
    doit(_d, _FP_FRAC_WORD_4(_z,0), X##_f0, Y##_f0);			\
    doit(_FP_FRAC_WORD_4(_z,2), _FP_FRAC_WORD_4(_z,1), _b_f0, _b_f1);	\
    doit(_c_f1, _c_f0, X##_f1, Y##_f1);					\
									\
    _b_f0 &= -_c2;							\
    _b_f1 &= -_c1;							\
    __FP_FRAC_ADD_3(_FP_FRAC_WORD_4(_z,3),_FP_FRAC_WORD_4(_z,2),	\
		    _FP_FRAC_WORD_4(_z,1), (_c1 & _c2), 0, _d,		\
		    0, _FP_FRAC_WORD_4(_z,2), _FP_FRAC_WORD_4(_z,1));	\
    __FP_FRAC_ADDI_2(_FP_FRAC_WORD_4(_z,3),_FP_FRAC_WORD_4(_z,2),	\
		     _b_f0);						\
    __FP_FRAC_ADDI_2(_FP_FRAC_WORD_4(_z,3),_FP_FRAC_WORD_4(_z,2),	\
		     _b_f1);						\
    __FP_FRAC_DEC_3(_FP_FRAC_WORD_4(_z,3),_FP_FRAC_WORD_4(_z,2),	\
		    _FP_FRAC_WORD_4(_z,1),				\
		    0, _d, _FP_FRAC_WORD_4(_z,0));			\
    __FP_FRAC_DEC_3(_FP_FRAC_WORD_4(_z,3),_FP_FRAC_WORD_4(_z,2),	\
		    _FP_FRAC_WORD_4(_z,1), 0, _c_f1, _c_f0);		\
    __FP_FRAC_ADD_2(_FP_FRAC_WORD_4(_z,3), _FP_FRAC_WORD_4(_z,2),	\
		    _c_f1, _c_f0,					\
		    _FP_FRAC_WORD_4(_z,3), _FP_FRAC_WORD_4(_z,2));	\
									\
    /* Normalize since we know where the msb of the multiplicands	\
       were (bit B), we know that the msb of the of the product is	\
       at either 2B or 2B-1.  */					\
    _FP_FRAC_SRS_4(_z, wfracbits-1, 2*wfracbits);			\
    R##_f0 = _FP_FRAC_WORD_4(_z,0);					\
    R##_f1 = _FP_FRAC_WORD_4(_z,1);					\