github.com/aergoio/aergo@v1.3.1/libtool/src/gmp-6.1.2/mpn/cray/mulww.f (about)

     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