UNDI INITIALIZE

Op-Code:	`PXENV_UNDI_INITIALIZE`
Input:	ES:DI points to a `t_PXENV_UNDI_INITIALIZE` parameter structure that has been initialized by the caller.
Output:	`PXENV_EXIT_SUCCESS` or `PXENV_EXIT_FAILURE` will be returned in AX, with the CF set accordingly. The status field in the parameter structure will be set to one of the values represented by the `PXENV_STATUS_xxx` constants.
Description:	This call resets the adapter and programs it with default parameters. The default parameters used are those supplied to the most recent UNDI_STARTUP call. This routine does not enable the receive and transmit units of the network adapter to readily receive or transmit packets. The application must call `PXENV_UNDI_OPEN` to logically connect the network adapter to the network.
	This call must be made by an application to establish an interface to the network adapter driver. The parameter block to this call contains the pointer to the call-back routines that will be called when a packet is received or when any other interrupt occurs.
Note:	When a receive interrupt occurs, the network adapter driver queues the packet and calls the application&rsquo’s callback receive routine with a pointer to the packet received. Then, the callback routine can either copy the packet into its buffer or decide to delay the copy to a later time. The callback receive routine always gets the pointer to the first packet in the receive queue and not to the currently received packet that generated the interrupt.
	If the call-back routine decides not to copy the data from the buffer at this time, the packet will remain in the receive queue and, as a result, the later packets might be dropped when the receive queue is full. At a later time, when the application wants to copy the packet, it can call the `PXENV_UNDI_force_interrupt` routine to simulate the receive interrupt.
	When the preboot code makes this call to initialize the network adapter, it passes a NULL pointer for the `ProtocolIni` field in the parameter structure.