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include vmm.inc
 
VMMcall _AddInstanceItem, <<OFFSET32 InstStruc>, flags>
 
or      eax, eax        ; nonzero if added, zero if error
jz      not_added
 
The _AddInstanceItem service identifies a region of instance data in the V86
address space.
 
Parameter  Description
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InstStruc  Points to an InstDataStruc structure containing information about
           the block of memory to instance.
 
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.
 
Comments
 
To prevent errors, a virtual device must not change the location and content
of any InstDataStruc structures until after the system has completed its
initialization. To achieve this, a virtual can either staticly allocate the
structures in its INIT data segment or dynamically allocate the structures
on the system heap using the _HeapAllocate service. If the structures are in
the INIT data segment, the system automatically frees the structure when it
reclaims the INIT segment space. If the structures are in the system heap,
the virtual device must free the structures using the _HeapFree service
while processing the Sys_VM_Init message.
 
If a virtual device the structures on the system heap, it must not attempt
to reallocate the structure before system initialization has completed since
this invalidates the structure address.
 
Only one, contiguous region of instance data can be identified with each
structure. The virtual device can cut down the call overhead and data space
requirements by coalescing adjacent blocks of instance data and identifying
the coalesced blocks as a single instance item.
 
Uses
 
EAX
 
See Also
 
InstDataStruc
 
 
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