Someone asked off-list for a C translation of the PDP-11 assembly code. I
believe the equivalent modern C would be:

unsigned int ranx;

void
srand(unsigned int seed)
{
    ranx = seed;
}

int
rand(void)
{
    ranx = 13077*ranx + 6925;
    return ranx & 32767;
}

Best,
Russ