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include vmm.inc
 
VMMcall _UnmapFreePhysReg, <LinPgNum, nPages, flags>
 
or      eax, eax            ; nonzero if unmapped, zero if error
jz      not_unmapped
 
The _UnmapFreePhysReg service unmaps a page in a free physical region and
places the physical memory back on the free list.
 
Parameter  Description
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LinPgNum   Specifies the linear page number of the first page to unmap. A
           linear page number is a linear address shifted right by 12 bits.
 
nPages     Specifies the number of pages in the region to unmap. This region
           must lie within the boundaries of a free physical region
           previously allocated using the _PageAllocate service.
 
flags      Specifies the operation flags. This parameter must be set to 0.
 
Return Value
 
The EAX register contains a nonzero value if the service is successful.
Otherwise, EAX contains zero to indicate an error, such as an invalid linear
page number, an invalid range of pages, or part of the range already not
present.
 
Comments
 
This service is intended to be used in a free-physical-region callback
procedure installed using the _SetFreePhysRegCalBk service. Virtual devices
should not call this service until after the Sys_VM_Init message or the
Init_Complete message has been received.
 
If a virtual device maps pages using the PageFixed value with the
_MapFreePhysReg service, it must not attempt to unmap the pages using the
_UnmapFreePhysReg service.
 
Uses
 
EAX
 
See Also
 
_MapFreePhysReg, _PageAllocate
 
 
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