MEM_DES structure (cfgmgr32.h)
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.
Flag | Definition | |
---|---|---|
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
Requirement | Value |
---|---|
Header | cfgmgr32.h (include Cfgmgr32.h) |