OSS_IOCPARM_MASK
#define _OSS_IOCTL(w,x,y,z) ((uint)((w)|(((z)&OSS_IOCPARM_MASK)<<16)|((x)<<8)|(y)))
#define OSS_IOCTL_SIZE(x) (((x) >> 16) & OSS_IOCPARM_MASK)
