Function dos_ioctl

sys/msdos/msdos.c:511–523

}

static unsigned int
dos_ioctl(int handle, int mode, unsigned setvalue)
{
    union REGS regs;

    regs.h.ah = IOCTL;
    regs.h.al = mode;
    regs.x.bx = handle;
    regs.h.dl = setvalue;
    regs.h.dh = 0; /* Zero out dh */
    intdos(&regs, &regs);
    return (regs.x.dx);
}

unsigned long
sys_random_seed(void)