diff options
Diffstat (limited to 'rts/gmp/mpn/cray/sub_n.c')
-rw-r--r-- | rts/gmp/mpn/cray/sub_n.c | 97 |
1 files changed, 97 insertions, 0 deletions
diff --git a/rts/gmp/mpn/cray/sub_n.c b/rts/gmp/mpn/cray/sub_n.c new file mode 100644 index 0000000000..902e07a727 --- /dev/null +++ b/rts/gmp/mpn/cray/sub_n.c @@ -0,0 +1,97 @@ +/* mpn_sub_n -- Subtract two limb vectors of equal, non-zero length. + For Cray vector processors. + + Copyright (C) 1996, 2000 Free Software Foundation, Inc. + + This file is part of the GNU MP Library. + + The GNU MP Library is free software; you can redistribute it and/or modify + it under the terms of the GNU Lesser General Public License as published by + the Free Software Foundation; either version 2.1 of the License, or (at your + option) any later version. + + The GNU MP Library 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 Lesser General Public + License for more details. + + You should have received a copy of the GNU Lesser General Public License + along with the GNU MP Library; see the file COPYING.LIB. If not, write to + the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, + MA 02111-1307, USA. */ + +#include "gmp.h" +#include "gmp-impl.h" + +mp_limb_t +mpn_sub_n (c, a, b, n) + mp_ptr c; + mp_srcptr a, b; + mp_size_t n; +{ + mp_size_t i; + mp_size_t nm1 = n - 1; + int more_carries = 0; + int carry_out; + + /* For small operands the non-vector code is faster. */ + if (n < 16) + goto sequential; + + if (a == c || b == c) + { + TMP_DECL (marker); + TMP_MARK (marker); + if (c == a) + { + /* allocate temp space for a */ + mp_ptr ax = (mp_ptr) TMP_ALLOC (n * BYTES_PER_MP_LIMB); + MPN_COPY (ax, a, n); + a = (mp_srcptr) ax; + } + if (c == b) + { + /* allocate temp space for b */ + mp_ptr bx = (mp_ptr) TMP_ALLOC (n * BYTES_PER_MP_LIMB); + MPN_COPY (bx, b, n); + b = (mp_srcptr) bx; + } + carry_out = mpn_sub_n (c, a, b, n); + TMP_FREE (marker); + return carry_out; + } + + carry_out = a[nm1] < b[nm1]; + +#pragma _CRI ivdep /* Cray PVP systems */ + for (i = nm1; i > 0; i--) + { + int cy_in; mp_limb_t t; + cy_in = a[i - 1] < b[i - 1]; + t = a[i] - b[i]; + more_carries += t < cy_in; + c[i] = t - cy_in; + } + c[0] = a[0] - b[0]; + + if (more_carries) + { + /* This won't vectorize, but we should come here rarely. */ + int cy; + sequential: + cy = 0; + for (i = 0; i < n; i++) + { + mp_limb_t ai, ci, t; + ai = a[i]; + t = b[i] + cy; + cy = t < cy; + ci = ai - t; + cy += ci > ai; + c[i] = ci; + } + carry_out = cy; + } + + return carry_out; +} |