Viewing file:  arith-rand.c (2.24 KB) -rw-r--r--
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long
simple_rand ()
{
static unsigned long seed = 47114711;
unsigned long this = seed * 1103515245 + 12345;
seed = this;
return this >> 8;
}
unsigned long int
random_bitstring ()
{
unsigned long int x;
int n_bits;
long ran;
int tot_bits = 0;
x = 0;
for (;;)
{
ran = simple_rand ();
n_bits = (ran >> 1) % 16;
tot_bits += n_bits;
if (n_bits == 0)
return x;
else
{
x <<= n_bits;
if (ran & 1)
x |= (1 << n_bits) - 1;
if (tot_bits > 8 * sizeof (long) + 6)
return x;
}
}
}
#define ABS(x) ((x) >= 0 ? (x) : -(x))
main ()
{
long int i;
for (i = 0; i < 1000; i++)
{
unsigned long x, y;
x = random_bitstring ();
y = random_bitstring ();
if (sizeof (int) == sizeof (long))
goto save_time;
{ unsigned long xx = x, yy = y, r1, r2;
if (yy == 0) continue;
r1 = xx / yy;
r2 = xx % yy;
if (r2 >= yy || r1 * yy + r2 != xx)
abort ();
}
{ signed long xx = x, yy = y, r1, r2;
if ((unsigned long) xx << 1 == 0 && yy == -1)
continue;
r1 = xx / yy;
r2 = xx % yy;
if (ABS (r2) >= (unsigned long) ABS (yy) || (signed long) (r1 * yy + r2) != xx)
abort ();
}
save_time:
{ unsigned int xx = x, yy = y, r1, r2;
if (yy == 0) continue;
r1 = xx / yy;
r2 = xx % yy;
if (r2 >= yy || r1 * yy + r2 != xx)
abort ();
}
{ signed int xx = x, yy = y, r1, r2;
if ((unsigned int) xx << 1 == 0 && yy == -1)
continue;
r1 = xx / yy;
r2 = xx % yy;
if (ABS (r2) >= (unsigned int) ABS (yy) || (signed int) (r1 * yy + r2) != xx)
abort ();
}
{ unsigned short xx = x, yy = y, r1, r2;
if (yy == 0) continue;
r1 = xx / yy;
r2 = xx % yy;
if (r2 >= yy || r1 * yy + r2 != xx)
abort ();
}
{ signed short xx = x, yy = y, r1, r2;
r1 = xx / yy;
r2 = xx % yy;
if (ABS (r2) >= (unsigned short) ABS (yy) || (signed short) (r1 * yy + r2) != xx)
abort ();
}
{ unsigned char xx = x, yy = y, r1, r2;
if (yy == 0) continue;
r1 = xx / yy;
r2 = xx % yy;
if (r2 >= yy || r1 * yy + r2 != xx)
abort ();
}
{ signed char xx = x, yy = y, r1, r2;
r1 = xx / yy;
r2 = xx % yy;
if (ABS (r2) >= (unsigned char) ABS (yy) || (signed char) (r1 * yy + r2) != xx)
abort ();
}
}
exit (0);
}
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