MEM_DES structure

The MEM_DES structure is used for specifying either a resource list or a resource requirements list that describes memory usage for a device instance. For more information about resource lists and resource requirements lists, see Hardware Resources.

Syntax


typedef struct Mem_Des_s {
  DWORD     MD_Count;
  DWORD     MD_Type;
  DWORDLONG MD_Alloc_Base;
  DWORDLONG MD_Alloc_End;
  DWORD     MD_Flags;
  DWORD     MD_Reserved;
} MEM_DES, *PMEM_DES;

Members

MD_Count

For a resource list:

Zero.

For a resource requirements list:

The number of elements in the MEM_RANGE array that is included in the MEM_RESOURCE structure.

MD_Type

Must be set to the constant value MType_Range.

MD_Alloc_Base

For a resource list:

The lowest-numbered of a range of contiguous physical memory addresses allocated to the device.

For a resource requirements list:

Zero.

MD_Alloc_End

For a resource list:

The highest-numbered of a range of contiguous physical memory addresses allocated to the device.

For a resource requirements list:

Zero.

MD_Flags

One bit flag from each of the flag sets described in the following table.

FlagDefinition

Read-Only Flags

fMD_ROM

The specified memory range is read-only.

fMD_RAM

The specified memory range is not read-only.

mMD_MemoryType

Bitmask for the bit within MD_Flags that specifies the read-only attribute.

Write-Only Flags

fMD_ReadDisallowed

The specified memory range is write-only.

fMD_ReadAllowed

The specified memory range is not write-only.

mMD_Readable

Bitmask for the bit within MD_Flags that specifies the write-only attribute.

Address Size Flags

fMD_24

24-bit addressing (not used).

fMD_32

32-bit addressing.

mMD_32_24

Bitmask for the bit within MD_Flags that specifies the address size.

Prefetch Flags

fMD_PrefetchAllowed

The specified memory range can be prefetched.

fMD_PrefetchDisallowed

The specified memory range cannot be prefetched.

mMD_Prefetchable

Bitmask for the bit within MD_Flags that specifies the prefetch ability.

Caching Flags

fMD_Cacheable

The specified memory range can be cached.

fMD_NonCacheable

The specified memory range cannot be cached.

mMD_Cacheable

Bitmask for the bit within MD_Flags that specifies the caching ability.

Combined-Write Caching Flags

fMD_CombinedWriteAllowed

Combined-write caching is allowed.

fMD_CombinedWriteDisallowed

Combined-write caching is not allowed.

mMD_CombinedWrite

Bitmask for the bit within MD_Flags that specifies the combine-write caching ability.

 

MD_Reserved

For internal use only.

Requirements

Header

Cfgmgr32.h (include Cfgmgr32.h)

See also

MEM_RANGE
MEM_RESOURCE

 

 

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