MFSH PHYSTOVIRT: Difference between revisions
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{{DISPLAYTITLE:MFSH_PHYSTOVIRT}} | {{DISPLAYTITLE:MFSH_PHYSTOVIRT}} | ||
Translate the physical address of a data buffer into a virtual address. | Translate the physical address of a data buffer into a virtual address. | ||
==Syntax== | ==Syntax== | ||
int far pascal MFSH_PHYSTOVIRT(ulAddr, usLen, pusSel) | int far pascal MFSH_PHYSTOVIRT(ulAddr, usLen, pusSel) | ||
==Parameters== | ==Parameters== | ||
; ulAddr: is the physical address to be translated. | ;ulAddr: is the physical address to be translated. | ||
; usLen: is the length of the segment for the physical address. | ;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 . | ;pusSel: is a pointer to the word in which the selector or segment is returned. | ||
==Returns== | ==Returns== | ||
If an error is not detected, a zero error code is returned. If an error is detected, the following error is returned: | 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. | ;ERROR_PROTECTION_VIOLATION :the supplied address is invalid. | ||
==Sample== | ==Sample== | ||
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==Remarks== | ==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. | 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. | A caller must issue a corresponding UNPHYSTOVIRT before returning to its caller or using any other helpers. | ||
[[Category:IFS]] | [[Category:IFS Interfaces]] | ||
Latest revision as of 21:35, 20 November 2019
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.