SItype becomes explicit `long int'

[unix-history] / usr / src / lib / libc / quad / muldi3.c

/*-
* Copyright (c) 1992 The Regents of the University of California.
* All rights reserved.
*
* %sccs.include.redist.c%
*/

#if defined(LIBC_SCCS) && !defined(lint)
static char sccsid[] = "@(#)muldi3.c    5.3 (Berkeley) %G%";
#endif /* LIBC_SCCS and not lint */

#include "longlong.h"

static void bmul ();

long long 
__muldi3 (u, v)
    long long u, v;
{
 long a[2], b[2], c[2][2];
 long_long w;
 long_long uu, vv;

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

 a[HIGH] = uu.s.high;
 a[LOW] = uu.s.low;
 b[HIGH] = vv.s.high;
 b[LOW] = vv.s.low;

 bmul (a, b, c, sizeof a, sizeof b);

 w.s.high = c[LOW][HIGH];
 w.s.low = c[LOW][LOW];
 return w.ll;
}

static void 
bmul (a, b, c, m, n)
   unsigned short *a, *b, *c;
   size_t m, n;
{
 int i, j;
 unsigned short *d;
 unsigned long acc;

 m /= sizeof *a;
 n /= sizeof *b;

 for (i = m + n, d = c; i-- > 0; *d++ = 0)
   ;

 for (j = little_end (n); is_not_msd (j, n); j = next_msd (j))
   {
     unsigned short *c1 = c + j + little_end (2);
     acc = 0;
     for (i = little_end (m); is_not_msd (i, m); i = next_msd (i))
       {
         /* Widen before arithmetic to avoid loss of high bits.  */
         acc += (unsigned long) a[i] * b[j] + c1[i];
         c1[i] = acc & low16;
         acc = acc >> 16;
       }
     c1[i] = acc;
   }
}