View source for MFSH PHYSTOVIRT

{{DISPLAYTITLE:MFSH_PHYSTOVIRT}}
Translate the physical address of a data buffer into a virtual address.

==Syntax==
 int far pascal MFSH_PHYSTOVIRT(ulAddr, usLen, pusSel)

==Parameters==
;ulAddr: is the physical address to be translated.
;usLen: is the length of the segment for the physical address.
;pusSel: is a pointer to the word in which the selector or segment is returned.

==Returns==
If an error is not detected, a zero error code is returned. If an error is detected, the following error is returned:
;ERROR_PROTECTION_VIOLATION :the supplied address is invalid.

==Sample==
 unsigned long ulAddr;
 unsigned short usLen;
 unsigned short far * pusSel;
 
 int far pascal MFSH_PHYSTOVIRT(ulAddr, usLen, pusSel)

==Remarks==
This helper is for use by a mini-FSD with an imbedded device driver. It is the same as the standard device driver helper PHYSTOVIRT. A segment/offset pair is returned in real mode for addresses below the 1-Meg boundary. Else a selector/offset pair is returned.

A caller must issue a corresponding UNPHYSTOVIRT before returning to its caller or using any other helpers.