Книга: Microsoft Windows Embedded CE 6.0 Exam Preparation Kit
Mapping Noncontiguous Physical Memory
Mapping Noncontiguous Physical Memory
As mentioned in Chapter 2, "Building and Deploying a Run-Time Image," you must define a single contiguous region in the RAMIMAGE memory region for the operating system in the MEMORY section of the Config.bib file. The system uses this definition to load the kernel image and any modules you specified in the MODULES and FILES sections. You cannot define multiple RAMIMAGE regions, yet the OAL can extend the RAMIMAGE region and provide additional noncontiguous memory sections at runtime.
Table 5-11 summarizes important variables and functions to extend the RAM region.
Table 5-11 Variables and functions to extend the RAM region
| Variable/Function | Description |
|---|---|
| MainMemoryEndAddress | This variable indicates the end of the RAM region. The kernel sets this variable initially according to the size reserved for the operating system in the Config.bib file. The OAL OEMInit function can update this variable if additional contiguous memory is available. |
| OEMGetExtensionDRAM | The OAL can use this function to report the presence of an additional region of noncontiguous memory to the kernel. OEMGetExtensionDRAM returns the start address and length of the second region of memory. |
| pNKEnumExtensionDRAM | The OAL can use this function pointer to report the presence of more than one additional region of memory to the kernel. This mechanism supports up to 15 different noncontiguous memory regions. If you implement the pNKEnumExtensionDRAM function pointer, then OEMGetExtensionDRAM is not called during the startup process |
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