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NdisImmediateReadPortUchar function

Note   NDIS 5. x has been deprecated and is superseded by NDIS 6. x. For new NDIS driver development, see Network Drivers Starting with Windows Vista. For information about porting NDIS 5. x drivers to NDIS 6. x, see Porting NDIS 5.x Drivers to NDIS 6.0.

NdisImmediateReadPortUchar reads a byte from a given bus-relative I/O port.

Syntax


VOID NdisImmediateReadPortUchar(
  _In_   NDIS_HANDLE WrapperConfigurationContext,
  _In_   ULONG Port,
  _Out_  PUCHAR Data
);

Parameters

WrapperConfigurationContext [in]

Specifies the handle input to MiniportInitialize.

Port [in]

Specifies the bus-relative I/O port address.

Data [out]

Pointer to a caller-supplied variable in which this function returns the value read from the I/O port.

Return value

None

Remarks

NdisImmediateReadPortUchar determines how the host accesses the given I/O port, maps the bus-relative port address, and then reads a byte from the device.

A miniport driver can call NdisImmediateReadPortUchar during initialization to read data from a device I/O port when that driver has not yet called NdisMRegisterIoPortRange to obtain mapped device memory ranges. After its call to NdisMRegisterIoPortRange, the driver uses the faster NdisRawXxx functions to communicate with its NIC.

A miniport driver should not call NdisImmediateReadPortUchar in a Plug and Play environment.

Requirements

Version

Not supported for NDIS 6.0 drivers in Windows Vista. Supported for NDIS 5.1 drivers in Windows Vista and Windows XP. Windows XP supports this function for legacy drivers. However, the Windows XP DDK will not build an NDIS driver that calls this function. Drivers should call NdisReadPortUcharinstead.

Header

Ndis.h (include Ndis.h)

IRQL

PASSIVE_LEVEL

See also

MiniportInitialize
NdisImmediateReadPortUlong
NdisImmediateReadPortUshort
NdisImmediateWritePortUchar
NdisMRegisterIoPortRange
NdisRawReadPortUchar
NdisReadPortUchar

 

 

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