VGET_USECOUNT
vs = VGET_USECOUNT;
vs = VGET_USECOUNT;
case VGET_USECOUNT:
VNPASS(vs == VGET_HOLDCNT || vs == VGET_USECOUNT, vp);
VNPASS(vs == VGET_HOLDCNT || vs == VGET_USECOUNT, vp);
if (vs == VGET_USECOUNT)