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/* Helper function for cshift functions.
Copyright (C) 2008-2018 Free Software Foundation, Inc.
Contributed by Thomas Koenig <tkoenig@gcc.gnu.org>
This file is part of the GNU Fortran runtime library (libgfortran).
Libgfortran 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 of the License, or (at your option) any later version.
Libgfortran 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/>. */
#include "libgfortran.h"
#include <string.h>
#if defined (HAVE_GFC_REAL_8)
void
cshift0_r8 (gfc_array_r8 *ret, const gfc_array_r8 *array, ptrdiff_t shift,
int which)
{
/* r.* indicates the return array. */
index_type rstride[GFC_MAX_DIMENSIONS];
index_type rstride0;
index_type roffset;
GFC_REAL_8 *rptr;
/* s.* indicates the source array. */
index_type sstride[GFC_MAX_DIMENSIONS];
index_type sstride0;
index_type soffset;
const GFC_REAL_8 *sptr;
index_type count[GFC_MAX_DIMENSIONS];
index_type extent[GFC_MAX_DIMENSIONS];
index_type dim;
index_type len;
index_type n;
bool do_blocked;
index_type r_ex, a_ex;
which = which - 1;
sstride[0] = 0;
rstride[0] = 0;
extent[0] = 1;
count[0] = 0;
n = 0;
/* Initialized for avoiding compiler warnings. */
roffset = 1;
soffset = 1;
len = 0;
r_ex = 1;
a_ex = 1;
if (which > 0)
{
/* Test if both ret and array are contiguous. */
do_blocked = true;
dim = GFC_DESCRIPTOR_RANK (array);
for (n = 0; n < dim; n ++)
{
index_type rs, as;
rs = GFC_DESCRIPTOR_STRIDE (ret, n);
if (rs != r_ex)
{
do_blocked = false;
break;
}
as = GFC_DESCRIPTOR_STRIDE (array, n);
if (as != a_ex)
{
do_blocked = false;
break;
}
r_ex *= GFC_DESCRIPTOR_EXTENT (ret, n);
a_ex *= GFC_DESCRIPTOR_EXTENT (array, n);
}
}
else
do_blocked = false;
n = 0;
if (do_blocked)
{
/* For contiguous arrays, use the relationship that
dimension(n1,n2,n3) :: a, b
b = cshift(a,sh,3)
can be dealt with as if
dimension(n1*n2*n3) :: an, bn
bn = cshift(a,sh*n1*n2,1)
we can used a more blocked algorithm for dim>1. */
sstride[0] = 1;
rstride[0] = 1;
roffset = 1;
soffset = 1;
len = GFC_DESCRIPTOR_STRIDE(array, which)
* GFC_DESCRIPTOR_EXTENT(array, which);
shift *= GFC_DESCRIPTOR_STRIDE(array, which);
for (dim = which + 1; dim < GFC_DESCRIPTOR_RANK (array); dim++)
{
count[n] = 0;
extent[n] = GFC_DESCRIPTOR_EXTENT(array,dim);
rstride[n] = GFC_DESCRIPTOR_STRIDE(ret,dim);
sstride[n] = GFC_DESCRIPTOR_STRIDE(array,dim);
n++;
}
dim = GFC_DESCRIPTOR_RANK (array) - which;
}
else
{
for (dim = 0; dim < GFC_DESCRIPTOR_RANK (array); dim++)
{
if (dim == which)
{
roffset = GFC_DESCRIPTOR_STRIDE(ret,dim);
if (roffset == 0)
roffset = 1;
soffset = GFC_DESCRIPTOR_STRIDE(array,dim);
if (soffset == 0)
soffset = 1;
len = GFC_DESCRIPTOR_EXTENT(array,dim);
}
else
{
count[n] = 0;
extent[n] = GFC_DESCRIPTOR_EXTENT(array,dim);
rstride[n] = GFC_DESCRIPTOR_STRIDE(ret,dim);
sstride[n] = GFC_DESCRIPTOR_STRIDE(array,dim);
n++;
}
}
if (sstride[0] == 0)
sstride[0] = 1;
if (rstride[0] == 0)
rstride[0] = 1;
dim = GFC_DESCRIPTOR_RANK (array);
}
rstride0 = rstride[0];
sstride0 = sstride[0];
rptr = ret->base_addr;
sptr = array->base_addr;
/* Avoid the costly modulo for trivially in-bound shifts. */
if (shift < 0 || shift >= len)
{
shift = len == 0 ? 0 : shift % (ptrdiff_t)len;
if (shift < 0)
shift += len;
}
while (rptr)
{
/* Do the shift for this dimension. */
/* If elements are contiguous, perform the operation
in two block moves. */
if (soffset == 1 && roffset == 1)
{
size_t len1 = shift * sizeof (GFC_REAL_8);
size_t len2 = (len - shift) * sizeof (GFC_REAL_8);
memcpy (rptr, sptr + shift, len2);
memcpy (rptr + (len - shift), sptr, len1);
}
else
{
/* Otherwise, we will have to perform the copy one element at
a time. */
GFC_REAL_8 *dest = rptr;
const GFC_REAL_8 *src = &sptr[shift * soffset];
for (n = 0; n < len - shift; n++)
{
*dest = *src;
dest += roffset;
src += soffset;
}
for (src = sptr, n = 0; n < shift; n++)
{
*dest = *src;
dest += roffset;
src += soffset;
}
}
/* Advance to the next section. */
rptr += rstride0;
sptr += sstride0;
count[0]++;
n = 0;
while (count[n] == extent[n])
{
/* When we get to the end of a dimension, reset it and increment
the next dimension. */
count[n] = 0;
/* We could precalculate these products, but this is a less
frequently used path so probably not worth it. */
rptr -= rstride[n] * extent[n];
sptr -= sstride[n] * extent[n];
n++;
if (n >= dim - 1)
{
/* Break out of the loop. */
rptr = NULL;
break;
}
else
{
count[n]++;
rptr += rstride[n];
sptr += sstride[n];
}
}
}
return;
}
#endif
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