libgfortran/generated/cshift0_r8.c

   1 /* Helper function for cshift functions.
   2    Copyright (C) 2008-2018 Free Software Foundation, Inc.
   3    Contributed by Thomas Koenig <tkoenig@gcc.gnu.org>
   4
   5 This file is part of the GNU Fortran runtime library (libgfortran).
   6
   7 Libgfortran is free software; you can redistribute it and/or
   8 modify it under the terms of the GNU General Public
   9 License as published by the Free Software Foundation; either
  10 version 3 of the License, or (at your option) any later version.
  11
  12 Libgfortran is distributed in the hope that it will be useful,
  13 but WITHOUT ANY WARRANTY; without even the implied warranty of
  14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15 GNU General Public License for more details.
  16
  17 Under Section 7 of GPL version 3, you are granted additional
  18 permissions described in the GCC Runtime Library Exception, version
  19 3.1, as published by the Free Software Foundation.
  20
  21 You should have received a copy of the GNU General Public License and
  22 a copy of the GCC Runtime Library Exception along with this program;
  23 see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
  24 <http://www.gnu.org/licenses/>.  */
  25
  26 #include "libgfortran.h"
  27 #include <string.h>
  28
  29
  30 #if defined (HAVE_GFC_REAL_8)
  31
  32 void
  33 cshift0_r8 (gfc_array_r8 *ret, const gfc_array_r8 *array, ptrdiff_t shift,
  34                      int which)
  35 {
  36   /* r.* indicates the return array.  */
  37   index_type rstride[GFC_MAX_DIMENSIONS];
  38   index_type rstride0;
  39   index_type roffset;
  40   GFC_REAL_8 *rptr;
  41
  42   /* s.* indicates the source array.  */
  43   index_type sstride[GFC_MAX_DIMENSIONS];
  44   index_type sstride0;
  45   index_type soffset;
  46   const GFC_REAL_8 *sptr;
  47
  48   index_type count[GFC_MAX_DIMENSIONS];
  49   index_type extent[GFC_MAX_DIMENSIONS];
  50   index_type dim;
  51   index_type len;
  52   index_type n;
  53
  54   bool do_blocked;
  55   index_type r_ex, a_ex;
  56
  57   which = which - 1;
  58   sstride[0] = 0;
  59   rstride[0] = 0;
  60
  61   extent[0] = 1;
  62   count[0] = 0;
  63   n = 0;
  64   /* Initialized for avoiding compiler warnings.  */
  65   roffset = 1;
  66   soffset = 1;
  67   len = 0;
  68
  69   r_ex = 1;
  70   a_ex = 1;
  71
  72   if (which > 0)
  73     {
  74       /* Test if both ret and array are contiguous.  */
  75       do_blocked = true;
  76       dim = GFC_DESCRIPTOR_RANK (array);
  77       for (n = 0; n < dim; n ++)
  78         {
  79           index_type rs, as;
  80           rs = GFC_DESCRIPTOR_STRIDE (ret, n);
  81           if (rs != r_ex)
  82             {
  83               do_blocked = false;
  84               break;
  85             }
  86           as = GFC_DESCRIPTOR_STRIDE (array, n);
  87           if (as != a_ex)
  88             {
  89               do_blocked = false;
  90               break;
  91             }
  92           r_ex *= GFC_DESCRIPTOR_EXTENT (ret, n);
  93           a_ex *= GFC_DESCRIPTOR_EXTENT (array, n);
  94         }
  95     }
  96   else
  97     do_blocked = false;
  98
  99   n = 0;
 100
 101   if (do_blocked)
 102     {
 103       /* For contiguous arrays, use the relationship that
 104
 105          dimension(n1,n2,n3) :: a, b
 106          b = cshift(a,sh,3)
 107
 108          can be dealt with as if
 109
 110          dimension(n1*n2*n3) :: an, bn
 111          bn = cshift(a,sh*n1*n2,1)
 112
 113          we can used a more blocked algorithm for dim>1.  */
 114       sstride[0] = 1;
 115       rstride[0] = 1;
 116       roffset = 1;
 117       soffset = 1;
 118       len = GFC_DESCRIPTOR_STRIDE(array, which)
 119         * GFC_DESCRIPTOR_EXTENT(array, which);
 120       shift *= GFC_DESCRIPTOR_STRIDE(array, which);
 121       for (dim = which + 1; dim < GFC_DESCRIPTOR_RANK (array); dim++)
 122         {
 123           count[n] = 0;
 124           extent[n] = GFC_DESCRIPTOR_EXTENT(array,dim);
 125           rstride[n] = GFC_DESCRIPTOR_STRIDE(ret,dim);
 126           sstride[n] = GFC_DESCRIPTOR_STRIDE(array,dim);
 127           n++;
 128         }
 129       dim = GFC_DESCRIPTOR_RANK (array) - which;
 130     }
 131   else
 132     {
 133       for (dim = 0; dim < GFC_DESCRIPTOR_RANK (array); dim++)
 134         {
 135           if (dim == which)
 136             {
 137               roffset = GFC_DESCRIPTOR_STRIDE(ret,dim);
 138               if (roffset == 0)
 139                 roffset = 1;
 140               soffset = GFC_DESCRIPTOR_STRIDE(array,dim);
 141               if (soffset == 0)
 142                 soffset = 1;
 143               len = GFC_DESCRIPTOR_EXTENT(array,dim);
 144             }
 145           else
 146             {
 147               count[n] = 0;
 148               extent[n] = GFC_DESCRIPTOR_EXTENT(array,dim);
 149               rstride[n] = GFC_DESCRIPTOR_STRIDE(ret,dim);
 150               sstride[n] = GFC_DESCRIPTOR_STRIDE(array,dim);
 151               n++;
 152             }
 153         }
 154       if (sstride[0] == 0)
 155         sstride[0] = 1;
 156       if (rstride[0] == 0)
 157         rstride[0] = 1;
 158
 159       dim = GFC_DESCRIPTOR_RANK (array);
 160     }
 161
 162   rstride0 = rstride[0];
 163   sstride0 = sstride[0];
 164   rptr = ret->base_addr;
 165   sptr = array->base_addr;
 166
 167   /* Avoid the costly modulo for trivially in-bound shifts.  */
 168   if (shift < 0 || shift >= len)
 169     {
 170       shift = len == 0 ? 0 : shift % (ptrdiff_t)len;
 171       if (shift < 0)
 172         shift += len;
 173     }
 174
 175   while (rptr)
 176     {
 177       /* Do the shift for this dimension.  */
 178
 179       /* If elements are contiguous, perform the operation
 180          in two block moves.  */
 181       if (soffset == 1 && roffset == 1)
 182         {
 183           size_t len1 = shift * sizeof (GFC_REAL_8);
 184           size_t len2 = (len - shift) * sizeof (GFC_REAL_8);
 185           memcpy (rptr, sptr + shift, len2);
 186           memcpy (rptr + (len - shift), sptr, len1);
 187         }
 188       else
 189         {
 190           /* Otherwise, we will have to perform the copy one element at
 191              a time.  */
 192           GFC_REAL_8 *dest = rptr;
 193           const GFC_REAL_8 *src = &sptr[shift * soffset];
 194
 195           for (n = 0; n < len - shift; n++)
 196             {
 197               *dest = *src;
 198               dest += roffset;
 199               src += soffset;
 200             }
 201           for (src = sptr, n = 0; n < shift; n++)
 202             {
 203               *dest = *src;
 204               dest += roffset;
 205               src += soffset;
 206             }
 207         }
 208
 209       /* Advance to the next section.  */
 210       rptr += rstride0;
 211       sptr += sstride0;
 212       count[0]++;
 213       n = 0;
 214       while (count[n] == extent[n])
 215         {
 216           /* When we get to the end of a dimension, reset it and increment
 217              the next dimension.  */
 218           count[n] = 0;
 219           /* We could precalculate these products, but this is a less
 220              frequently used path so probably not worth it.  */
 221           rptr -= rstride[n] * extent[n];
 222           sptr -= sstride[n] * extent[n];
 223           n++;
 224           if (n >= dim - 1)
 225             {
 226               /* Break out of the loop.  */
 227               rptr = NULL;
 228               break;
 229             }
 230           else
 231             {
 232               count[n]++;
 233               rptr += rstride[n];
 234               sptr += sstride[n];
 235             }
 236         }
 237     }
 238
 239   return;
 240 }
 241
 242 #endif