libgcc2.c

C++ 编写的EROS RTOS

/* More subroutines needed by GCC output code on some machines.  */
/* Compile this one with gcc.  */
/* Copyright (C) 1989, 1992, 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.  */

/* As a special exception, if you link this library with other files,
   some of which are compiled with GCC, to produce an executable,
   this library does not by itself cause the resulting executable
   to be covered by the GNU General Public License.
   This exception does not however invalidate any other reasons why
   the executable file might be covered by the GNU General Public License.  */

/* It is incorrect to include config.h here, because this file is being
   compiled for the target, and hence definitions concerning only the host
   do not apply.  */

#include "tconfig.h"
#include "machmode.h"
#include "defaults.h" 
#ifndef L_trampoline
#include <stddef.h>
#endif

/* Don't use `fancy_abort' here even if config.h says to use it.  */
#ifdef abort
#undef abort
#endif

#if (SUPPORTS_WEAK == 1) && defined (ASM_OUTPUT_DEF)
#define WEAK_ALIAS
#endif

/* Permit the tm.h file to select the endianness to use just for this
   file.  This is used when the endianness is determined when the
   compiler is run.  */

#ifndef LIBGCC2_WORDS_BIG_ENDIAN
#define LIBGCC2_WORDS_BIG_ENDIAN WORDS_BIG_ENDIAN
#endif

/* In the first part of this file, we are interfacing to calls generated
   by the compiler itself.  These calls pass values into these routines
   which have very specific modes (rather than very specific types), and
   these compiler-generated calls also expect any return values to have
   very specific modes (rather than very specific types).  Thus, we need
   to avoid using regular C language type names in this part of the file
   because the sizes for those types can be configured to be anything.
   Instead we use the following special type names.  */

typedef unsigned int UQItype	__attribute__ ((mode (QI)));
typedef 	 int SItype	__attribute__ ((mode (SI)));
typedef unsigned int USItype	__attribute__ ((mode (SI)));
typedef		 int DItype	__attribute__ ((mode (DI)));
typedef unsigned int UDItype	__attribute__ ((mode (DI)));

typedef 	float SFtype	__attribute__ ((mode (SF)));
typedef		float DFtype	__attribute__ ((mode (DF)));

#if LONG_DOUBLE_TYPE_SIZE == 96
typedef		float XFtype	__attribute__ ((mode (XF)));
#endif
#if LONG_DOUBLE_TYPE_SIZE == 128
typedef		float TFtype	__attribute__ ((mode (TF)));
#endif

typedef int word_type __attribute__ ((mode (__word__)));

/* Make sure that we don't accidentally use any normal C language built-in
   type names in the first part of this file.  Instead we want to use *only*
   the type names defined above.  The following macro definitions insure
   that if we *do* accidentally use some normal C language built-in type name,
   we will get a syntax error.  */

#define char bogus_type
#define short bogus_type
#define int bogus_type
#define long bogus_type
#define unsigned bogus_type
#define float bogus_type
#define double bogus_type

#define SI_TYPE_SIZE (sizeof (SItype) * BITS_PER_UNIT)

/* DIstructs are pairs of SItype values in the order determined by
   LIBGCC2_WORDS_BIG_ENDIAN.  */

#if LIBGCC2_WORDS_BIG_ENDIAN
  struct DIstruct {SItype high, low;};
#else
  struct DIstruct {SItype low, high;};
#endif

/* We need this union to unpack/pack DImode values, since we don't have
   any arithmetic yet.  Incoming DImode parameters are stored into the
   `ll' field, and the unpacked result is read from the struct `s'.  */

typedef union
{
  struct DIstruct s;
  DItype ll;
} DIunion;

#if (defined (L_udivmoddi4) || defined (L_muldi3) || defined (L_udiv_w_sdiv)\
     || defined (L_divdi3) || defined (L_udivdi3) \
     || defined (L_moddi3) || defined (L_umoddi3))

#include "longlong.h"

#endif /* udiv or mul */

extern DItype __fixunssfdi (SFtype a);
extern DItype __fixunsdfdi (DFtype a);
#if LONG_DOUBLE_TYPE_SIZE == 96
extern DItype __fixunsxfdi (XFtype a);
#endif
#if LONG_DOUBLE_TYPE_SIZE == 128
extern DItype __fixunstfdi (TFtype a);
#endif

#if defined (L_negdi2) || defined (L_divdi3) || defined (L_moddi3)
#if defined (L_divdi3) || defined (L_moddi3)
static inline
#endif
DItype
__negdi2 (u)
     DItype u;
{
  DIunion w;
  DIunion uu;

  uu.ll = u;

  w.s.low = -uu.s.low;
  w.s.high = -uu.s.high - ((USItype) w.s.low > 0);

  return w.ll;
}
#endif

#ifdef L_lshrdi3
DItype
__lshrdi3 (u, b)
     DItype u;
     word_type b;
{
  DIunion w;
  word_type bm;
  DIunion uu;

  if (b == 0)
    return u;

  uu.ll = u;

  bm = (sizeof (SItype) * BITS_PER_UNIT) - b;
  if (bm <= 0)
    {
      w.s.high = 0;
      w.s.low = (USItype)uu.s.high >> -bm;
    }
  else
    {
      USItype carries = (USItype)uu.s.high << bm;
      w.s.high = (USItype)uu.s.high >> b;
      w.s.low = ((USItype)uu.s.low >> b) | carries;
    }

  return w.ll;
}
#endif

#ifdef L_ashldi3
DItype
__ashldi3 (u, b)
     DItype u;
     word_type b;
{
  DIunion w;
  word_type bm;
  DIunion uu;

  if (b == 0)
    return u;

  uu.ll = u;

  bm = (sizeof (SItype) * BITS_PER_UNIT) - b;
  if (bm <= 0)
    {
      w.s.low = 0;
      w.s.high = (USItype)uu.s.low << -bm;
    }
  else
    {
      USItype carries = (USItype)uu.s.low >> bm;
      w.s.low = (USItype)uu.s.low << b;
      w.s.high = ((USItype)uu.s.high << b) | carries;
    }

  return w.ll;
}
#endif

#ifdef L_ashrdi3
DItype
__ashrdi3 (u, b)
     DItype u;
     word_type b;
{
  DIunion w;
  word_type bm;
  DIunion uu;

  if (b == 0)
    return u;

  uu.ll = u;

  bm = (sizeof (SItype) * BITS_PER_UNIT) - b;
  if (bm <= 0)
    {
      /* w.s.high = 1..1 or 0..0 */
      w.s.high = uu.s.high >> (sizeof (SItype) * BITS_PER_UNIT - 1);
      w.s.low = uu.s.high >> -bm;
    }
  else
    {
      USItype carries = (USItype)uu.s.high << bm;
      w.s.high = uu.s.high >> b;
      w.s.low = ((USItype)uu.s.low >> b) | carries;
    }

  return w.ll;
}
#endif

#ifdef L_ffsdi2
DItype
__ffsdi2 (u)
     DItype u;
{
  DIunion uu, w;
  uu.ll = u;
  w.s.high = 0;
  w.s.low = ffs (uu.s.low);
  if (w.s.low != 0)
    return w.ll;
  w.s.low = ffs (uu.s.high);
  if (w.s.low != 0)
    {
      w.s.low += BITS_PER_UNIT * sizeof (SItype);
      return w.ll;
    }
  return w.ll;
}
#endif

#ifdef L_muldi3
DItype
__muldi3 (u, v)
     DItype u, v;
{
  DIunion w;
  DIunion uu, vv;

  uu.ll = u,
  vv.ll = v;

  w.ll = __umulsidi3 (uu.s.low, vv.s.low);
  w.s.high += ((USItype) uu.s.low * (USItype) vv.s.high
	       + (USItype) uu.s.high * (USItype) vv.s.low);

  return w.ll;
}
#endif

#ifdef L_udiv_w_sdiv
#if defined (sdiv_qrnnd)
USItype
__udiv_w_sdiv (rp, a1, a0, d)
     USItype *rp, a1, a0, d;
{
  USItype q, r;
  USItype c0, c1, b1;

  if ((SItype) d >= 0)
    {
      if (a1 < d - a1 - (a0 >> (SI_TYPE_SIZE - 1)))
	{
	  /* dividend, divisor, and quotient are nonnegative */
	  sdiv_qrnnd (q, r, a1, a0, d);
	}
      else
	{
	  /* Compute c1*2^32 + c0 = a1*2^32 + a0 - 2^31*d */
	  sub_ddmmss (c1, c0, a1, a0, d >> 1, d << (SI_TYPE_SIZE - 1));
	  /* Divide (c1*2^32 + c0) by d */
	  sdiv_qrnnd (q, r, c1, c0, d);
	  /* Add 2^31 to quotient */
	  q += (USItype) 1 << (SI_TYPE_SIZE - 1);
	}
    }
  else
    {
      b1 = d >> 1;			/* d/2, between 2^30 and 2^31 - 1 */
      c1 = a1 >> 1;			/* A/2 */
      c0 = (a1 << (SI_TYPE_SIZE - 1)) + (a0 >> 1);

      if (a1 < b1)			/* A < 2^32*b1, so A/2 < 2^31*b1 */
	{
	  sdiv_qrnnd (q, r, c1, c0, b1); /* (A/2) / (d/2) */

	  r = 2*r + (a0 & 1);		/* Remainder from A/(2*b1) */
	  if ((d & 1) != 0)
	    {
	      if (r >= q)
		r = r - q;
	      else if (q - r <= d)
		{
		  r = r - q + d;
		  q--;
		}
	      else
		{
		  r = r - q + 2*d;
		  q -= 2;
		}
	    }
	}
      else if (c1 < b1)			/* So 2^31 <= (A/2)/b1 < 2^32 */
	{
	  c1 = (b1 - 1) - c1;
	  c0 = ~c0;			/* logical NOT */

	  sdiv_qrnnd (q, r, c1, c0, b1); /* (A/2) / (d/2) */

	  q = ~q;			/* (A/2)/b1 */
	  r = (b1 - 1) - r;

	  r = 2*r + (a0 & 1);		/* A/(2*b1) */

	  if ((d & 1) != 0)
	    {
	      if (r >= q)
		r = r - q;
	      else if (q - r <= d)
		{
		  r = r - q + d;
		  q--;
		}
	      else
		{
		  r = r - q + 2*d;
		  q -= 2;
		}
	    }
	}
      else				/* Implies c1 = b1 */
	{				/* Hence a1 = d - 1 = 2*b1 - 1 */
	  if (a0 >= -d)
	    {
	      q = -1;
	      r = a0 + d;
	    }
	  else
	    {
	      q = -2;
	      r = a0 + 2*d;
	    }
	}
    }

  *rp = r;
  return q;
}
#else
/* If sdiv_qrnnd doesn't exist, define dummy __udiv_w_sdiv.  */
USItype
__udiv_w_sdiv (rp, a1, a0, d)
     USItype *rp, a1, a0, d;
{}
#endif
#endif

#if (defined (L_udivdi3) || defined (L_divdi3) || \
     defined (L_umoddi3) || defined (L_moddi3))
#define L_udivmoddi4
#endif

#ifdef L_udivmoddi4
static const UQItype __clz_tab[] =
{
  0,1,2,2,3,3,3,3,4,4,4,4,4,4,4,4,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,
  6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,
  7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,
  7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,
  8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,
  8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,
  8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,
  8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,
};

#if (defined (L_udivdi3) || defined (L_divdi3) || \
     defined (L_umoddi3) || defined (L_moddi3))
static inline
#endif
UDItype
__udivmoddi4 (n, d, rp)
     UDItype n, d;
     UDItype *rp;
{
  DIunion ww;
  DIunion nn, dd;
  DIunion rr;
  USItype d0, d1, n0, n1, n2;
  USItype q0, q1;
  USItype b, bm;

  nn.ll = n;
  dd.ll = d;

  d0 = dd.s.low;
  d1 = dd.s.high;
  n0 = nn.s.low;
  n1 = nn.s.high;

#if !UDIV_NEEDS_NORMALIZATION
  if (d1 == 0)
    {
      if (d0 > n1)
	{
	  /* 0q = nn / 0D */

	  udiv_qrnnd (q0, n0, n1, n0, d0);
	  q1 = 0;

	  /* Remainder in n0.  */
	}
      else
	{
	  /* qq = NN / 0d */

	  if (d0 == 0)
	    d0 = 1 / d0;	/* Divide intentionally by zero.  */

	  udiv_qrnnd (q1, n1, 0, n1, d0);
	  udiv_qrnnd (q0, n0, n1, n0, d0);

	  /* Remainder in n0.  */
	}

      if (rp != 0)
	{
	  rr.s.low = n0;
	  rr.s.high = 0;
	  *rp = rr.ll;
	}
    }

#else /* UDIV_NEEDS_NORMALIZATION */

  if (d1 == 0)
    {
      if (d0 > n1)
	{
	  /* 0q = nn / 0D */

	  count_leading_zeros (bm, d0);

	  if (bm != 0)
	    {
	      /* Normalize, i.e. make the most significant bit of the
		 denominator set.  */

	      d0 = d0 << bm;
	      n1 = (n1 << bm) | (n0 >> (SI_TYPE_SIZE - bm));
	      n0 = n0 << bm;
	    }

	  udiv_qrnnd (q0, n0, n1, n0, d0);
	  q1 = 0;

	  /* Remainder in n0 >> bm.  */
	}
      else
	{
	  /* qq = NN / 0d */

	  if (d0 == 0)
	    d0 = 1 / d0;	/* Divide intentionally by zero.  */

	  count_leading_zeros (bm, d0);

	  if (bm == 0)
	    {
	      /* From (n1 >= d0) /\ (the most significant bit of d0 is set),
		 conclude (the most significant bit of n1 is set) /\ (the
		 leading quotient digit q1 = 1).

		 This special case is necessary, not an optimization.
		 (Shifts counts of SI_TYPE_SIZE are undefined.)  */

	      n1 -= d0;
	      q1 = 1;
	    }
	  else
	    {
	      /* Normalize.  */

	      b = SI_TYPE_SIZE - bm;

	      d0 = d0 << bm;
	      n2 = n1 >> b;
	      n1 = (n1 << bm) | (n0 >> b);
	      n0 = n0 << bm;

	      udiv_qrnnd (q1, n1, n2, n1, d0);
	    }

	  /* n1 != d0... */

	  udiv_qrnnd (q0, n0, n1, n0, d0);

	  /* Remainder in n0 >> bm.  */
	}

      if (rp != 0)
	{
	  rr.s.low = n0 >> bm;
	  rr.s.high = 0;
	  *rp = rr.ll;
	}
    }
#endif /* UDIV_NEEDS_NORMALIZATION */

  else
    {
      if (d1 > n1)
	{
	  /* 00 = nn / DD */

	  q0 = 0;
	  q1 = 0;

	  /* Remainder in n1n0.  */
	  if (rp != 0)
	    {
	      rr.s.low = n0;
	      rr.s.high = n1;
	      *rp = rr.ll;
	    }
	}
      else
	{
	  /* 0q = NN / dd */

	  count_leading_zeros (bm, d1);
	  if (bm == 0)
	    {
	      /* From (n1 >= d1) /\ (the most significant bit of d1 is set),
		 conclude (the most significant bit of n1 is set) /\ (the
		 quotient digit q0 = 0 or 1).

		 This special case is necessary, not an optimization.  */

	      /* The condition on the next line takes advantage of that
		 n1 >= d1 (true due to program flow).  */
	      if (n1 > d1 || n0 >= d0)
		{
		  q0 = 1;
		  sub_ddmmss (n1, n0, n1, n0, d1, d0);
		}
	      else
		q0 = 0;

	      q1 = 0;

	      if (rp != 0)
		{
		  rr.s.low = n0;
		  rr.s.high = n1;
		  *rp = rr.ll;
		}
	    }
	  else
	    {
	      USItype m1, m0;
	      /* Normalize.  */

	      b = SI_TYPE_SIZE - bm;

	      d1 = (d1 << bm) | (d0 >> b);
	      d0 = d0 << bm;
	      n2 = n1 >> b;
	      n1 = (n1 << bm) | (n0 >> b);
	      n0 = n0 << bm;

	      udiv_qrnnd (q0, n1, n2, n1, d1);
	      umul_ppmm (m1, m0, q0, d0);

	      if (m1 > n1 || (m1 == n1 && m0 > n0))
		{
		  q0--;