1  /* Cray PVP/IEEE mpn_mul_basecase.
       2  
       3  Copyright 2000, 2001 Free Software Foundation, Inc.
       4  
       5  This file is part of the GNU MP Library.
       6  
       7  The GNU MP Library is free software; you can redistribute it and/or modify
       8  it under the terms of either:
       9  
      10    * the GNU Lesser General Public License as published by the Free
      11      Software Foundation; either version 3 of the License, or (at your
      12      option) any later version.
      13  
      14  or
      15  
      16    * the GNU General Public License as published by the Free Software
      17      Foundation; either version 2 of the License, or (at your option) any
      18      later version.
      19  
      20  or both in parallel, as here.
      21  
      22  The GNU MP Library is distributed in the hope that it will be useful, but
      23  WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
      24  or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
      25  for more details.
      26  
      27  You should have received copies of the GNU General Public License and the
      28  GNU Lesser General Public License along with the GNU MP Library.  If not,
      29  see https://www.gnu.org/licenses/.  */
      30  
      31  /* The most critical loop of this code runs at about 5 cycles/limb on a T90.
      32     That is not perfect, mainly due to vector register shortage.  */
      33  
      34  #include <intrinsics.h>
      35  #include "gmp-impl.h"
      36  
      37  void
      38  mpn_mul_basecase (mp_ptr rp,
      39  		  mp_srcptr up, mp_size_t un,
      40  		  mp_srcptr vp, mp_size_t vn)
      41  {
      42    mp_limb_t cy[un + vn];
      43    mp_limb_t vl;
      44    mp_limb_t a, b, r, s0, s1, c0, c1;
      45    mp_size_t i, j;
      46    int more_carries;
      47  
      48    for (i = 0; i < un + vn; i++)
      49      {
      50        rp[i] = 0;
      51        cy[i] = 0;
      52      }
      53  
      54  #pragma _CRI novector
      55    for (j = 0; j < vn; j++)
      56      {
      57        vl = vp[j];
      58  
      59        a = up[0] * vl;
      60        r = rp[j];
      61        s0 = a + r;
      62        rp[j] = s0;
      63        c0 = ((a & r) | ((a | r) & ~s0)) >> 63;
      64        cy[j] += c0;
      65  
      66  #pragma _CRI ivdep
      67        for (i = 1; i < un; i++)
      68  	{
      69  	  a = up[i] * vl;
      70  	  b = _int_mult_upper (up[i - 1], vl);
      71  	  s0 = a + b;
      72  	  c0 = ((a & b) | ((a | b) & ~s0)) >> 63;
      73  	  r = rp[j + i];
      74  	  s1 = s0 + r;
      75  	  rp[j + i] = s1;
      76  	  c1 = ((s0 & r) | ((s0 | r) & ~s1)) >> 63;
      77  	  cy[j + i] += c0 + c1;
      78  	}
      79        rp[j + un] = _int_mult_upper (up[un - 1], vl);
      80      }
      81  
      82    more_carries = 0;
      83  #pragma _CRI ivdep
      84    for (i = 1; i < un + vn; i++)
      85      {
      86        r = rp[i];
      87        c0 = cy[i - 1];
      88        s0 = r + c0;
      89        rp[i] = s0;
      90        c0 = (r & ~s0) >> 63;
      91        more_carries += c0;
      92      }
      93    /* If that second loop generated carry, handle that in scalar loop.  */
      94    if (more_carries)
      95      {
      96        mp_limb_t cyrec = 0;
      97        for (i = 1; i < un + vn; i++)
      98  	{
      99  	  r = rp[i];
     100  	  c0 = (r < cy[i - 1]);
     101  	  s0 = r + cyrec;
     102  	  rp[i] = s0;
     103  	  c1 = (r & ~s0) >> 63;
     104  	  cyrec = c0 | c1;
     105  	}
     106      }
     107  }