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muldi3.c

/* muldi3.c extracted from gcc-2.7.2.3/libgcc2.c and 
                     gcc-2.7.2.3/longlong.h which is: */
/* Copyright (C) 1989, 1992, 1993, 1994, 1995 Free Software Foundation, Inc.

This file is part of GNU CC.

GNU CC 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 2, or (at your option)
any later version.

GNU CC 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.

You should have received a copy of the GNU General Public License
along with GNU CC; see the file COPYING.  If not, write to
the Free Software Foundation, 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA.  */

#define BITS_PER_UNIT 8
#define SI_TYPE_SIZE 32

#define __BITS4 (SI_TYPE_SIZE / 4)
#define __ll_B (1L << (SI_TYPE_SIZE / 2))
#define __ll_lowpart(t) ((USItype) (t) % __ll_B)
#define __ll_highpart(t) ((USItype) (t) / __ll_B)

#define umul_ppmm(w1, w0, u, v)                                   \
  do {                                                      \
    USItype __x0, __x1, __x2, __x3;                         \
    USItype __ul, __vl, __uh, __vh;                         \
                                                      \
    __ul = __ll_lowpart (u);                                \
    __uh = __ll_highpart (u);                               \
    __vl = __ll_lowpart (v);                                \
    __vh = __ll_highpart (v);                               \
                                                      \
    __x0 = (USItype) __ul * __vl;                           \
    __x1 = (USItype) __ul * __vh;                           \
    __x2 = (USItype) __uh * __vl;                           \
    __x3 = (USItype) __uh * __vh;                           \
                                                      \
    __x1 += __ll_highpart (__x0);/* this can't give carry */            \
    __x1 += __x2;       /* but this indeed can */           \
    if (__x1 < __x2)          /* did we get it? */                \
      __x3 += __ll_B;         /* yes, add it in the proper pos. */      \
                                                      \
    (w1) = __x3 + __ll_highpart (__x1);                           \
    (w0) = __ll_lowpart (__x1) * __ll_B + __ll_lowpart (__x0);          \
  } while (0)

#define __umulsidi3(u, v) \
  ({DIunion __w;                                      \
    umul_ppmm (__w.s.high, __w.s.low, u, v);                      \
    __w.ll; })

typedef      int SItype __attribute__ ((mode (SI)));
typedef unsigned int USItype  __attribute__ ((mode (SI)));
typedef            int DItype __attribute__ ((mode (DI)));
typedef int word_type __attribute__ ((mode (__word__)));

struct DIstruct {SItype high, low;};

typedef union
{
  struct DIstruct s;
  DItype ll;
} DIunion;

DItype
__muldi3 (DItype u, DItype v)
{
  DIunion w;
  DIunion uu, vv;

  uu.ll = u,
  vv.ll = v;

  w.ll = __umulsidi3 (uu.s.low, vv.s.low);
  w.s.high += ((USItype) uu.s.low * (USItype) vv.s.high
             + (USItype) uu.s.high * (USItype) vv.s.low);

  return w.ll;
}

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