Allocatepages() – Intel Extensible Firmware Interface User Manual

Page 119

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Services — Boot Services

Version 1.10

12/01/02

5-21

AllocatePages()

Summary

Allocates memory pages from the system.

Prototype

EFI_STATUS
AllocatePages(

IN EFI_ALLOCATE_TYPE

Type,

IN EFI_MEMORY_TYPE

MemoryType,

IN UINTN

Pages,

IN OUT EFI_PHYSICAL_ADDRESS

*Memory

);

Parameters

Type

The type of allocation to perform. See “Related Definitions.”

MemoryType

The type of memory to allocate. The type

EFI_MEMORY_TYPE

is

defined in “Related Definitions” below. These memory types are also
described in more detail in Table 5-5 and Table 5-6. Normal allocations
(that is, allocations by any EFI application) are of type

EfiLoaderData

.

MemoryType

values in the range

0x80000000..0xFFFFFFFF are reserved for use by EFI OS loaders that
are provided by operating system vendors. The only illegal memory type
values are those in the range

EfiMaxMemoryType

..0x7FFFFFFF.

Pages

The number of contiguous 4 KB pages to allocate.

Memory

Pointer to a physical address. On input, the way in which the address is
used depends on the value of

Type

. See “Description” for more

information. On output the address is set to the base of the page range
that was allocated. See “Related Definitions.”

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