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/* Signed and unsigned multiplication and division and modulus for CRIS.

   Contributed by Axis Communications.

   Written by Hans-Peter Nilsson <hp@axis.se>, c:a 1992.

   Copyright (C) 1998, 1999, 2000, 2001, 2002,

   2005, 2009  Free Software Foundation, Inc.

This file is part of GCC.

GCC 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 3, or (at your option) any

later version.

This file 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.

Under Section 7 of GPL version 3, you are granted additional

permissions described in the GCC Runtime Library Exception, version

3.1, as published by the Free Software Foundation.

You should have received a copy of the GNU General Public License and

a copy of the GCC Runtime Library Exception along with this program;

see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see

<http://www.gnu.org/licenses/>.  */

/* Note that we provide prototypes for all "const" functions, to attach

   the const attribute.  This is necessary in 2.7.2 - adding the

   attribute to the function *definition* is a syntax error.

    This did not work with e.g. 2.1; back then, the return type had to

   be "const".  */

#include "config.h"

#if defined (__CRIS_arch_version) && __CRIS_arch_version >= 3

#define LZ(v) __builtin_clz (v)

#endif

#if defined (L_udivsi3) || defined (L_divsi3) || defined (L_umodsi3) \

    || defined (L_modsi3)

/* Result type of divmod worker function.  */

struct quot_rem

 {

   long quot;

   long rem;

 };

/* This is the worker function for div and mod.  It is inlined into the

   respective library function.  Parameter A must have bit 31 == 0.  */

static __inline__ struct quot_rem

do_31div (unsigned long a, unsigned long b)

     __attribute__ ((__const__, __always_inline__));

static __inline__ struct quot_rem

do_31div (unsigned long a, unsigned long b)

{

  /* Adjust operands and result if a is 31 bits.  */

  long extra = 0;

  int quot_digits = 0;

  if (b == 0)

    {

      struct quot_rem ret;

      ret.quot = 0xffffffff;

      ret.rem = 0xffffffff;

      return ret;

    }

  if (a < b)

    return (struct quot_rem) { 0, a };

#ifdef LZ

  if (b <= a)

    {

      quot_digits = LZ (b) - LZ (a);

      quot_digits += (a >= (b << quot_digits));

      b <<= quot_digits;

    }

#else

  while (b <= a)

    {

      b <<= 1;

      quot_digits++;

    }

#endif

  /* Is a 31 bits?  Note that bit 31 is handled by the caller.  */

  if (a & 0x40000000)

    {

      /* Then make b:s highest bit max 0x40000000, because it must have

         been 0x80000000 to be 1 bit higher than a.  */

      b >>= 1;

      /* Adjust a to be maximum 0x3fffffff, i.e. two upper bits zero.  */

      if (a >= b)

        {

          a -= b;

          extra = 1 << (quot_digits - 1);

        }

      else

        {

          a -= b >> 1;

          /* Remember that we adjusted a by subtracting b * 2 ** Something.  */

          extra = 1 << quot_digits;

        }

      /* The number of quotient digits will be one less, because

         we just adjusted b.  */

      quot_digits--;

    }

  /* Now do the division part.  */

  /* Subtract b and add ones to the right when a >= b

     i.e. "a - (b - 1) == (a - b) + 1".  */

  b--;

#define DS __asm__ ("dstep %2,%0" : "=r" (a) : "0" (a), "r" (b))

  switch (quot_digits)

    {

    case 32: DS; case 31: DS; case 30: DS; case 29: DS;

    case 28: DS; case 27: DS; case 26: DS; case 25: DS;

    case 24: DS; case 23: DS; case 22: DS; case 21: DS;

    case 20: DS; case 19: DS; case 18: DS; case 17: DS;

    case 16: DS; case 15: DS; case 14: DS; case 13: DS;

    case 12: DS; case 11: DS; case 10: DS; case 9: DS;

    case 8: DS; case 7: DS; case 6: DS; case 5: DS;

    case 4: DS; case 3: DS; case 2: DS; case 1: DS;

    case 0:;

    }

  {

    struct quot_rem ret;

    ret.quot = (a & ((1 << quot_digits) - 1)) + extra;

    ret.rem = a >> quot_digits;

    return ret;

  }

}

#ifdef L_udivsi3

unsigned long

__Udiv (unsigned long a, unsigned long b) __attribute__ ((__const__));

unsigned long

__Udiv (unsigned long a, unsigned long b)

{

  long extra = 0;

  /* Adjust operands and result, if a and/or b is 32 bits.  */

  /* Effectively: b & 0x80000000.  */

  if ((long) b < 0)

    return a >= b;

  /* Effectively: a & 0x80000000.  */

  if ((long) a < 0)

    {

      int tmp = 0;

      if (b == 0)

        return 0xffffffff;

#ifdef LZ

      tmp = LZ (b);

#else

      for (tmp = 31; (((long) b & (1 << tmp)) == 0); tmp--)

        ;

      tmp = 31 - tmp;

#endif

      if ((b << tmp) > a)

        {

          extra = 1 << (tmp-1);

          a -= b << (tmp - 1);

        }

      else

        {

          extra = 1 << tmp;

          a -= b << tmp;

        }

    }

  return do_31div (a, b).quot+extra;

}

#endif /* L_udivsi3 */

#ifdef L_divsi3

long

__Div (long a, long b) __attribute__ ((__const__));

long

__Div (long a, long b)

{

  long extra = 0;

  long sign = (b < 0) ? -1 : 1;

  /* We need to handle a == -2147483648 as expected and must while

     doing that avoid producing a sequence like "abs (a) < 0" as GCC

     may optimize out the test.  That sequence may not be obvious as

     we call inline functions.  Testing for a being negative and

     handling (presumably much rarer than positive) enables us to get

     a bit of optimization for an (accumulated) reduction of the

     penalty of the 0x80000000 special-case.  */

  if (a < 0)

    {

      sign = -sign;

      if ((a & 0x7fffffff) == 0)

        {

          /* We're at 0x80000000.  Tread carefully.  */

          a -= b * sign;

          extra = sign;

        }

      a = -a;

    }

  /* We knowingly penalize pre-v10 models by multiplication with the

     sign.  */

  return sign * do_31div (a, __builtin_labs (b)).quot + extra;

}

#endif /* L_divsi3 */

#ifdef L_umodsi3

unsigned long

__Umod (unsigned long a, unsigned long b) __attribute__ ((__const__));

unsigned long

__Umod (unsigned long a, unsigned long b)

{

  /* Adjust operands and result if a and/or b is 32 bits.  */

  if ((long) b < 0)

    return a >= b ? a - b : a;

  if ((long) a < 0)

    {

      int tmp = 0;

      if (b == 0)

        return a;

#ifdef LZ

      tmp = LZ (b);

#else

      for (tmp = 31; (((long) b & (1 << tmp)) == 0); tmp--)

        ;

      tmp = 31 - tmp;

#endif

      if ((b << tmp) > a)

        {

          a -= b << (tmp - 1);

        }

      else

        {

          a -= b << tmp;

        }

    }

  return do_31div (a, b).rem;

}

#endif /* L_umodsi3 */

#ifdef L_modsi3

long

__Mod (long a, long b) __attribute__ ((__const__));

long

__Mod (long a, long b)

{

  long sign = 1;

  /* We need to handle a == -2147483648 as expected and must while

     doing that avoid producing a sequence like "abs (a) < 0" as GCC

     may optimize out the test.  That sequence may not be obvious as

     we call inline functions.  Testing for a being negative and

     handling (presumably much rarer than positive) enables us to get

     a bit of optimization for an (accumulated) reduction of the

     penalty of the 0x80000000 special-case.  */

  if (a < 0)

    {

      sign = -1;

      if ((a & 0x7fffffff) == 0)

        /* We're at 0x80000000.  Tread carefully.  */

        a += __builtin_labs (b);

      a = -a;

    }

  return sign * do_31div (a, __builtin_labs (b)).rem;

}

#endif /* L_modsi3 */

#endif /* L_udivsi3 || L_divsi3 || L_umodsi3 || L_modsi3 */

/*

 * Local variables:

 * eval: (c-set-style "gnu")

 * indent-tabs-mode: t

 * End:

 */