SIMPLE_RB_LINK_HEAD
case SIMPLE_RB_LINK_HEAD:
#define SIMPLE_RB_LINK_MASK ~(SIMPLE_RB_LINK_HEAD | SIMPLE_RB_LINK_HEAD_MOVING)
link |= SIMPLE_RB_LINK_HEAD;
unsigned long old = (*link & SIMPLE_RB_LINK_MASK) | SIMPLE_RB_LINK_HEAD;