source/libs/gmp/gmp-src/mpn/cray/mulww.f

   1 c    Helper for mpn_mul_1, mpn_addmul_1, and mpn_submul_1 for Cray PVP.
   2
   3 c    Copyright 1996, 2000 Free Software Foundation, Inc.
   4
   5 c    This file is part of the GNU MP Library.
   6 c
   7 c    The GNU MP Library is free software; you can redistribute it and/or modify
   8 c    it under the terms of either:
   9 c
  10 c      * the GNU Lesser General Public License as published by the Free
  11 c        Software Foundation; either version 3 of the License, or (at your
  12 c        option) any later version.
  13 c
  14 c    or
  15 c
  16 c      * the GNU General Public License as published by the Free Software
  17 c        Foundation; either version 2 of the License, or (at your option) any
  18 c        later version.
  19 c
  20 c    or both in parallel, as here.
  21 c
  22 c    The GNU MP Library is distributed in the hope that it will be useful, but
  23 c    WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
  24 c    or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  25 c    for more details.
  26 c
  27 c    You should have received copies of the GNU General Public License and the
  28 c    GNU Lesser General Public License along with the GNU MP Library.  If not,
  29 c    see https://www.gnu.org/licenses/.
  30
  31 c    p1[] = hi(a[]*s); the upper limbs of each product
  32 c    p0[] = low(a[]*s); the corresponding lower limbs
  33 c    n is number of limbs in the vectors
  34
  35       subroutine gmpn_mulww(p1,p0,a,n,s)
  36       integer*8 p1(0:*),p0(0:*),a(0:*),s
  37       integer n
  38
  39       integer*8 a0,a1,a2,s0,s1,s2,c
  40       integer*8 ai,t0,t1,t2,t3,t4
  41
  42       s0 = shiftl(and(s,4194303),24)
  43       s1 = shiftl(and(shiftr(s,22),4194303),24)
  44       s2 = shiftl(and(shiftr(s,44),4194303),24)
  45
  46       do i = 0,n-1
  47          ai = a(i)
  48          a0 = shiftl(and(ai,4194303),24)
  49          a1 = shiftl(and(shiftr(ai,22),4194303),24)
  50          a2 = shiftl(and(shiftr(ai,44),4194303),24)
  51
  52          t0 = i24mult(a0,s0)
  53          t1 = i24mult(a0,s1)+i24mult(a1,s0)
  54          t2 = i24mult(a0,s2)+i24mult(a1,s1)+i24mult(a2,s0)
  55          t3 = i24mult(a1,s2)+i24mult(a2,s1)
  56          t4 = i24mult(a2,s2)
  57
  58          p0(i)=shiftl(t2,44)+shiftl(t1,22)+t0
  59          c=shiftr(shiftr(t0,22)+and(t1,4398046511103)+
  60      $        shiftl(and(t2,1048575),22),42)
  61          p1(i)=shiftl(t4,24)+shiftl(t3,2)+shiftr(t2,20)+shiftr(t1,42)+c
  62       end do
  63       end