xref: /netbsd-src/external/lgpl3/gmp/dist/mpn/cray/mulww.f (revision 413d532bcc3f62d122e56d92e13ac64825a40baf)
1c     Helper for mpn_mul_1, mpn_addmul_1, and mpn_submul_1 for Cray PVP.
2
3c     Copyright 1996, 2000 Free Software Foundation, Inc.
4
5c     This file is part of the GNU MP Library.
6
7c     The GNU MP Library is free software; you can redistribute it and/or
8c     modify it under the terms of the GNU Lesser General Public License as
9c     published by the Free Software Foundation; either version 3 of the
10c     License, or (at your option) any later version.
11
12c     The GNU MP Library is distributed in the hope that it will be useful,
13c     but WITHOUT ANY WARRANTY; without even the implied warranty of
14c     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
15c     Lesser General Public License for more details.
16
17c     You should have received a copy of the GNU Lesser General Public License
18c     along with the GNU MP Library.  If not, see http://www.gnu.org/licenses/.
19
20c     p1[] = hi(a[]*s); the upper limbs of each product
21c     p0[] = low(a[]*s); the corresponding lower limbs
22c     n is number of limbs in the vectors
23
24      subroutine gmpn_mulww(p1,p0,a,n,s)
25      integer*8 p1(0:*),p0(0:*),a(0:*),s
26      integer n
27
28      integer*8 a0,a1,a2,s0,s1,s2,c
29      integer*8 ai,t0,t1,t2,t3,t4
30
31      s0 = shiftl(and(s,4194303),24)
32      s1 = shiftl(and(shiftr(s,22),4194303),24)
33      s2 = shiftl(and(shiftr(s,44),4194303),24)
34
35      do i = 0,n-1
36         ai = a(i)
37         a0 = shiftl(and(ai,4194303),24)
38         a1 = shiftl(and(shiftr(ai,22),4194303),24)
39         a2 = shiftl(and(shiftr(ai,44),4194303),24)
40
41         t0 = i24mult(a0,s0)
42         t1 = i24mult(a0,s1)+i24mult(a1,s0)
43         t2 = i24mult(a0,s2)+i24mult(a1,s1)+i24mult(a2,s0)
44         t3 = i24mult(a1,s2)+i24mult(a2,s1)
45         t4 = i24mult(a2,s2)
46
47         p0(i)=shiftl(t2,44)+shiftl(t1,22)+t0
48         c=shiftr(shiftr(t0,22)+and(t1,4398046511103)+
49     $        shiftl(and(t2,1048575),22),42)
50         p1(i)=shiftl(t4,24)+shiftl(t3,2)+shiftr(t2,20)+shiftr(t1,42)+c
51      end do
52      end
53