On Sat, Jan 07, 2023 at 01:42:20PM -0500, Greg Wooledge wrote:
> Or should the code do the multiplications with unsigned
> values, store them in unsigned variables, and then replace the subtraction
> with some kind of conditional that checks which of the two is greater?
Here's a version that does just that:
static u_bits32_t
intrand32 (last)
u_bits32_t last;
{
u_bits32_t h, l, t1, t2, ret;
ret = (last == 0) ? 123459876 : last;
h = ret / 127773;
l = ret - (127773 * h);
t1 = 16807 * l;
t2 = 2836 * h;
if (t1 < t2)
ret = 0x7fffffff - t2 + t1;
else
ret = t1 - t2;
return ret;
}
It passes the implementation test in the paper (checking the seed
after 10000 iterations), and I believe it's free from any kind of
overflow.
Do with it as you like. Feel free to replace the if/else with a
ternary ?: operator if that's your preference.
