Map_Flat

include vmm.inc

mov     ah, SegOffset    ; client register containing the segment
mov     al, OffOffset    ; client register containing the offset
VMMCall Map_Flat

cmp     eax, -1         ; -1 if error
je      error
mov     [LinAddr], eax  ; ring-0 linear address
 

Converts the address contained in the specified client registers to a linear address. The given address is either a selector:offset or segment:offset address, depending on the execution mode of the current virtual machine. Uses EAX, Flags.

• Returns a ring-0 linear address in the EAX register if successful, – 1 if the specified selector is invalid.

SegOffset

Offset of the client register containing the segment address or selector.

OffOffset

Offset of the client register containing the offset address. Can be – 1, in which case the offset address is zero.

The SegOffset and OffOffset parameters specify offsets, in bytes, relative to the beginning of the Client_Reg_Struc structure for the current virtual machine.

Before converting an address, Map_Flat checks the current execution mode and, for protected-mode applications, the bitness of the DPMI client. If the virtual machine is running a 32-bit protected mode application, it uses 32-bit address offsets. For V86 and 16-bit protected-mode applications, it uses 16-bit address offsets and ignores the high word if the OffOffset parameter specifies a 32-bit register.

The following example converts the address Client_DS:Client_DX and returns the linear address in EAX:

mov     ax, (Client_DS SHL 8) + Client_DX
VMMCall Map_Flat
 

It is typically more convenient to use the Client_Ptr_Flat macro instead.

See Also

Client_Ptr_Flat