.if n .pH portguide.FS @(#)FS	40.1
.\" Copyright 1989 AT&T
..
.BK "Programmer's Guide: Porting the Kernel"
.CH "Directory - FS" 6
.H 2 "Directory - FS"
.IX FS directory
The following files/functions in the \f3fs\fP directory
have machine-specific functionality:
.BL
.LI
\f3proc/prmachdep.c  -  MD\f1
.br
The address of the u-area is known.
.br
.BL
.LI
\f4prgetregs()/prsetregs()\f1 
.br
These functions return/set general registers from u-area.
.LI
\f4prgetpc()\fP
.br
This returns the program counter and it is called from portable code.
.LI
\f4prhasfp()\fP
.br
This function checks for floating point hardware.
.LI
\f4prgetfpregs()/prsetfpregs()\fP
.br
The functions get/set floating point registers.
.LI
\f4prgetpsaddr()\fP
.br
This returns (aligned) page table address for u-area.
.LI
\f4prstep()\fP
.br
The \f4prstep\f1 function sets a \f4psw\f1 to single-step the process.
.LI
\f4prsvaddr()\fP
.br
This sets the program counter to the specified virtual address.
.LI
\f4prmapin()\fP
.br
This maps an address to a kernel virtual address.
.LI
\f4prmapout()\fP
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\f4prmapout\f1 unmaps an address.
This function is an inverse of \f4prmapin()\f1.
.LI
\f4prfastmapin()\f1
.br
This function short-cuts fast mapping-in of a processe's page.
.LI
\f4prfastmapout()\fP
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This is an inverse of \f4prfastmapin()\fP.
.LE
.LI
\f3rfs/rf_canon.h  -  MD\f1
.br
This header file contains machine-specific translations to XDR format.
.NE 10
.LI
\f3rfs/rfsr_subr.c  -  MD\f1
.BL
.LI
\f4rfsr_rawread()\f1
.br
This function uses a segment's worth of memory.
This may be machine-specific.
.LE 
