rem: exi->flags = (exi->flags&~EXI_FLAG_ATTACH);
add: exi->flags &= ~EXI_FLAG_ATTACH;
context: void __ext_irq_handler(u32 nIrq,void *pCtx){	u32 chan,dev;	exibus_priv *exi = NULL;	const u32 fact = 0x55555556;	chan = ((fact*(nIrq-IRQ_EXI0_EXT))>>1)&0x0f;	dev = _SHIFTR((_exiReg[chan*5]&0x380),8,2);	__MaskIrq(IRQMASK(nIrq));	exi = &eximap[chan];	_exiReg[chan*5] = ((_exiReg[chan*5]&~(EXI_EXI_IRQ|EXI_TC_IRQ|EXI_EXT_IRQ))|EXI_EXT_IRQ);		exi->flags = (exi->flags&~EXI_FLAG_ATTACH);	if(exi->CallbackEXT) exi->CallbackEXT(chan,dev);#ifdef _EXI_DEBUG	printf("__ext_irq_handler(%p)\n",exi->CallbackEXT);#endif}