NBL_READWRITE
op == NBL_REMOVE || op == NBL_READWRITE);
op == NBL_REMOVE || op == NBL_READWRITE);
ASSERT(op == NBL_READ || op == NBL_WRITE || op == NBL_READWRITE ||
op = NBL_READWRITE;
ASSERT(op == NBL_READ || op == NBL_WRITE || op == NBL_READWRITE);
nop = NBL_READWRITE;
case NBL_READWRITE: