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[/] [or1k_soc_on_altera_embedded_dev_kit/] [trunk/] [linux-2.6/] [linux-2.6.24/] [arch/] [powerpc/] [math-emu/] [udivmodti4.c] - Blame information for rev 3

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1 3 xianfeng 
/* This has so very few changes over libgcc2's __udivmoddi4 it isn't funny.  */
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#include "soft-fp.h"
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#undef count_leading_zeros
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#define count_leading_zeros  __FP_CLZ
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void
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_fp_udivmodti4(_FP_W_TYPE q[2], _FP_W_TYPE r[2],
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               _FP_W_TYPE n1, _FP_W_TYPE n0,
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               _FP_W_TYPE d1, _FP_W_TYPE d0)
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{
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  _FP_W_TYPE q0, q1, r0, r1;
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  _FP_I_TYPE b, bm;
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  if (d1 == 0)
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    {
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#if !UDIV_NEEDS_NORMALIZATION
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      if (d0 > n1)
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        {
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          /* 0q = nn / 0D */
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          udiv_qrnnd (q0, n0, n1, n0, d0);
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          q1 = 0;
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          /* Remainder in n0.  */
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        }
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      else
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        {
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          /* qq = NN / 0d */
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          if (d0 == 0)
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            d0 = 1 / d0;        /* Divide intentionally by zero.  */
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          udiv_qrnnd (q1, n1, 0, n1, d0);
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          udiv_qrnnd (q0, n0, n1, n0, d0);
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          /* Remainder in n0.  */
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        }
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      r0 = n0;
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      r1 = 0;
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#else /* UDIV_NEEDS_NORMALIZATION */
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      if (d0 > n1)
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        {
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          /* 0q = nn / 0D */
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          count_leading_zeros (bm, d0);
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          if (bm != 0)
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            {
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              /* Normalize, i.e. make the most significant bit of the
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                 denominator set.  */
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              d0 = d0 << bm;
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              n1 = (n1 << bm) | (n0 >> (_FP_W_TYPE_SIZE - bm));
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              n0 = n0 << bm;
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            }
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          udiv_qrnnd (q0, n0, n1, n0, d0);
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          q1 = 0;
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          /* Remainder in n0 >> bm.  */
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        }
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      else
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        {
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          /* qq = NN / 0d */
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          if (d0 == 0)
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            d0 = 1 / d0;        /* Divide intentionally by zero.  */
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          count_leading_zeros (bm, d0);
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          if (bm == 0)
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            {
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              /* From (n1 >= d0) /\ (the most significant bit of d0 is set),
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                 conclude (the most significant bit of n1 is set) /\ (the
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                 leading quotient digit q1 = 1).
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                 This special case is necessary, not an optimization.
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                 (Shifts counts of SI_TYPE_SIZE are undefined.)  */
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              n1 -= d0;
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              q1 = 1;
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            }
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          else
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            {
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              _FP_W_TYPE n2;
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              /* Normalize.  */
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              b = _FP_W_TYPE_SIZE - bm;
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              d0 = d0 << bm;
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              n2 = n1 >> b;
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              n1 = (n1 << bm) | (n0 >> b);
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              n0 = n0 << bm;
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              udiv_qrnnd (q1, n1, n2, n1, d0);
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            }
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          /* n1 != d0...  */
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          udiv_qrnnd (q0, n0, n1, n0, d0);
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          /* Remainder in n0 >> bm.  */
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        }
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      r0 = n0 >> bm;
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      r1 = 0;
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#endif /* UDIV_NEEDS_NORMALIZATION */
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    }
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  else
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    {
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      if (d1 > n1)
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        {
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          /* 00 = nn / DD */
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          q0 = 0;
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          q1 = 0;
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          /* Remainder in n1n0.  */
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          r0 = n0;
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          r1 = n1;
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        }
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      else
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        {
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          /* 0q = NN / dd */
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          count_leading_zeros (bm, d1);
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          if (bm == 0)
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            {
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              /* From (n1 >= d1) /\ (the most significant bit of d1 is set),
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                 conclude (the most significant bit of n1 is set) /\ (the
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                 quotient digit q0 = 0 or 1).
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                 This special case is necessary, not an optimization.  */
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              /* The condition on the next line takes advantage of that
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                 n1 >= d1 (true due to program flow).  */
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              if (n1 > d1 || n0 >= d0)
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                {
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                  q0 = 1;
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                  sub_ddmmss (n1, n0, n1, n0, d1, d0);
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                }
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              else
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                q0 = 0;
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              q1 = 0;
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              r0 = n0;
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              r1 = n1;
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            }
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          else
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            {
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              _FP_W_TYPE m1, m0, n2;
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              /* Normalize.  */
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              b = _FP_W_TYPE_SIZE - bm;
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              d1 = (d1 << bm) | (d0 >> b);
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              d0 = d0 << bm;
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              n2 = n1 >> b;
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              n1 = (n1 << bm) | (n0 >> b);
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              n0 = n0 << bm;
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              udiv_qrnnd (q0, n1, n2, n1, d1);
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              umul_ppmm (m1, m0, q0, d0);
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              if (m1 > n1 || (m1 == n1 && m0 > n0))
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                {
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                  q0--;
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                  sub_ddmmss (m1, m0, m1, m0, d1, d0);
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                }
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              q1 = 0;
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              /* Remainder in (n1n0 - m1m0) >> bm.  */
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              sub_ddmmss (n1, n0, n1, n0, m1, m0);
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              r0 = (n1 << b) | (n0 >> bm);
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              r1 = n1 >> bm;
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            }
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        }
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    }
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  q[0] = q0; q[1] = q1;
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  r[0] = r0, r[1] = r1;
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}

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