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include dosnet.inc VxDcall DOSNET_Do_PSP_Adjust |
The DOSNET_Do_PSP_Adjust service specifies whether the virtual device requires unique PSP addresses for each virtual machine. The virtual MS-DOS manager calls this service to determine whether it should adjust PSP addresses for the virtual machines.
This service has no parameters.
The carry flag is clear if the virtual MS-DOS manager should adjust the PSP. Otherwise, the carry flag is set to prevent the virtual MS-DOS manager from adjusting the PSP.
The EAX register contains zero if the virtual MS-DOS manager should check the SYSTEM.INI file to determine whether to override the action specified by the carry flag. Otherwise, the EAX register contains a nonzero value to prevent the virtual device from checking the file.
A network that uses the MS-DOS PSP addresses as part of an ID should clear the carry flag and return to direct the virtual MS-DOS manager to adjust PSP addresses. The manager adjusts PSP addresses by starting each virtual machine at a different paragraph address (using the virtual machine identifier as the basis of the adjustment). This technique does not guarantee unique PSP addresses. To ensure uniqueness, network software should always use the MS-DOS function Get Current Virtual Machine ID (Interrupt 2Fh, Function 1683h) to retrieve the virtual machine identifier, and use this identifier to create a unique network ID.
EAX, Flags