xref: /openbmc/u-boot/arch/nios2/lib/libgcc.c (revision 83d290c56fab2d38cd1ab4c4cc7099559c1d5046)

// SPDX-License-Identifier: GPL-2.0+
/*
 * This file is part of GNU CC.
 */

typedef unsigned int UWtype;
typedef unsigned int UHWtype;
typedef unsigned long long UDWtype;
#define W_TYPE_SIZE 32

typedef unsigned char UQItype;
typedef long SItype;
typedef unsigned long USItype;
typedef long long DItype;
typedef unsigned long long DSItype;

#include "longlong.h"


typedef int word_type;
typedef long Wtype;
typedef long long DWtype;

struct DWstruct { Wtype low, high;};

typedef union
{
  struct DWstruct s;
  DWtype ll;
} DWunion;

#define BITS_PER_UNIT 8

UDWtype
__udivmoddi4 (UDWtype n, UDWtype d, UDWtype *rp);

const UQItype __clz_tab[256] =
{
  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
};


DWtype
__ashldi3 (DWtype u, word_type b)
{
  if (b == 0)
    return u;

  const DWunion uu = {.ll = u};
  const word_type bm = (sizeof (Wtype) * BITS_PER_UNIT) - b;
  DWunion w;

  if (bm <= 0)
    {
      w.s.low = 0;
      w.s.high = (UWtype) uu.s.low << -bm;
    }
  else
    {
      const UWtype carries = (UWtype) uu.s.low >> bm;

      w.s.low = (UWtype) uu.s.low << b;
      w.s.high = ((UWtype) uu.s.high << b) | carries;
    }

  return w.ll;
}

DWtype
__ashrdi3 (DWtype u, word_type b)
{
  if (b == 0)
    return u;

  const DWunion uu = {.ll = u};
  const word_type bm = (sizeof (Wtype) * BITS_PER_UNIT) - b;
  DWunion w;

  if (bm <= 0)
    {
      /* w.s.high = 1..1 or 0..0 */
      w.s.high = uu.s.high >> (sizeof (Wtype) * BITS_PER_UNIT - 1);
      w.s.low = uu.s.high >> -bm;
    }
  else
    {
      const UWtype carries = (UWtype) uu.s.high << bm;

      w.s.high = uu.s.high >> b;
      w.s.low = ((UWtype) uu.s.low >> b) | carries;
    }

  return w.ll;
}

DWtype
__lshrdi3 (DWtype u, word_type b)
{
  if (b == 0)
    return u;

  const DWunion uu = {.ll = u};
  const word_type bm = (sizeof (Wtype) * BITS_PER_UNIT) - b;
  DWunion w;

  if (bm <= 0)
    {
      w.s.high = 0;
      w.s.low = (UWtype) uu.s.high >> -bm;
    }
  else
    {
      const UWtype carries = (UWtype) uu.s.high << bm;

      w.s.high = (UWtype) uu.s.high >> b;
      w.s.low = ((UWtype) uu.s.low >> b) | carries;
    }

  return w.ll;
}

word_type
__cmpdi2 (DWtype a, DWtype b)
{
  const DWunion au = {.ll = a};
  const DWunion bu = {.ll = b};

  if (au.s.high < bu.s.high)
    return 0;
  else if (au.s.high > bu.s.high)
    return 2;
  if ((UWtype) au.s.low < (UWtype) bu.s.low)
    return 0;
  else if ((UWtype) au.s.low > (UWtype) bu.s.low)
    return 2;
  return 1;
}

UDWtype
__udivmoddi4 (UDWtype n, UDWtype d, UDWtype *rp)
{
  const DWunion nn = {.ll = n};
  const DWunion dd = {.ll = d};
  DWunion rr;
  UWtype d0, d1, n0, n1, n2;
  UWtype q0, q1;
  UWtype b, bm;

  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 >> (W_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 W_TYPE_SIZE are undefined.)  */

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

	      b = W_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
	    {
	      UWtype m1, m0;
	      /* Normalize.  */

	      b = W_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--;
		  sub_ddmmss (m1, m0, m1, m0, d1, d0);
		}

	      q1 = 0;

	      /* Remainder in (n1n0 - m1m0) >> bm.  */
	      if (rp != 0)
		{
		  sub_ddmmss (n1, n0, n1, n0, m1, m0);
		  rr.s.low = (n1 << b) | (n0 >> bm);
		  rr.s.high = n1 >> bm;
		  *rp = rr.ll;
		}
	    }
	}
    }

  const DWunion ww = {{.low = q0, .high = q1}};
  return ww.ll;
}

DWtype
__divdi3 (DWtype u, DWtype v)
{
  word_type c = 0;
  DWunion uu = {.ll = u};
  DWunion vv = {.ll = v};
  DWtype w;

  if (uu.s.high < 0)
    c = ~c,
    uu.ll = -uu.ll;
  if (vv.s.high < 0)
    c = ~c,
    vv.ll = -vv.ll;

  w = __udivmoddi4 (uu.ll, vv.ll, (UDWtype *) 0);
  if (c)
    w = -w;

  return w;
}

DWtype
__negdi2 (DWtype u)
{
  const DWunion uu = {.ll = u};
  const DWunion w = { {.low = -uu.s.low,
		       .high = -uu.s.high - ((UWtype) -uu.s.low > 0) } };

  return w.ll;
}


DWtype
__muldi3 (DWtype u, DWtype v)
{
  const DWunion uu = {.ll = u};
  const DWunion vv = {.ll = v};
  DWunion  w = {.ll = __umulsidi3 (uu.s.low, vv.s.low)};

  w.s.high += ((UWtype) uu.s.low * (UWtype) vv.s.high
  + (UWtype) uu.s.high * (UWtype) vv.s.low);

  return w.ll;
}

DWtype
__moddi3 (DWtype u, DWtype v)
{
  word_type c = 0;
  DWunion uu = {.ll = u};
  DWunion vv = {.ll = v};
  DWtype w;

  if (uu.s.high < 0)
    c = ~c,
    uu.ll = -uu.ll;
  if (vv.s.high < 0)
    vv.ll = -vv.ll;

  (void) __udivmoddi4 (uu.ll, vv.ll, (UDWtype*)&w);
  if (c)
    w = -w;

  return w;
}

word_type
__ucmpdi2 (DWtype a, DWtype b)
{
  const DWunion au = {.ll = a};
  const DWunion bu = {.ll = b};

  if ((UWtype) au.s.high < (UWtype) bu.s.high)
    return 0;
  else if ((UWtype) au.s.high > (UWtype) bu.s.high)
    return 2;
  if ((UWtype) au.s.low < (UWtype) bu.s.low)
    return 0;
  else if ((UWtype) au.s.low > (UWtype) bu.s.low)
    return 2;
  return 1;
}


UDWtype
__udivdi3 (UDWtype n, UDWtype d)
{
  return __udivmoddi4 (n, d, (UDWtype *) 0);
}

UDWtype
__umoddi3 (UDWtype u, UDWtype v)
{
  UDWtype w;
  (void) __udivmoddi4 (u, v, &w);

  return w;
}

static USItype
udivmodsi4(USItype num, USItype den, word_type modwanted)
{
  USItype bit = 1;
  USItype res = 0;

  while (den < num && bit && !(den & (1L<<31)))
    {
      den <<=1;
      bit <<=1;
    }
  while (bit)
    {
      if (num >= den)
	{
	  num -= den;
	  res |= bit;
	}
      bit >>=1;
      den >>=1;
    }
  if (modwanted) return num;
  return res;
}

SItype
__divsi3 (SItype a, SItype b)
{
  word_type neg = 0;
  SItype res;

  if (a < 0)
    {
      a = -a;
      neg = !neg;
    }

  if (b < 0)
    {
      b = -b;
      neg = !neg;
    }

  res = udivmodsi4 (a, b, 0);

  if (neg)
    res = -res;

  return res;
}


SItype
__udivsi3 (SItype a, SItype b)
{
  return udivmodsi4 (a, b, 0);
}


SItype
__modsi3 (SItype a, SItype b)
{
  word_type neg = 0;
  SItype res;

  if (a < 0)
    {
      a = -a;
      neg = 1;
    }

  if (b < 0)
    b = -b;

  res = udivmodsi4 (a, b, 1);

  if (neg)
    res = -res;

  return res;
}

SItype
__mulsi3 (SItype a, SItype b)
{
  SItype res = 0;
  USItype cnt = a;

  while (cnt)
    {
      if (cnt & 1)
	{
	  res += b;
	}
      b <<= 1;
      cnt >>= 1;
    }

  return res;
}

SItype
__umodsi3 (SItype a, SItype b)

{
  return udivmodsi4 (a, b, 1);
}

int
__gcc_bcmp (const unsigned char *s1, const unsigned char *s2, unsigned long size)
{
  while (size > 0)
    {
      const unsigned char c1 = *s1++, c2 = *s2++;
      if (c1 != c2)
	return c1 - c2;
      size--;
    }
  return 0;
}