/*
   *    User Space Access Routines
   *
   *    Copyright (C) 2000-2002 Hewlett-Packard (John Marvin)
   *    Copyright (C) 2000 Richard Hirst <rhirst with parisc-linux.org>
   *    Copyright (C) 2001 Matthieu Delahaye <delahaym at esiee.fr>
   *    Copyright (C) 2003 Randolph Chung <tausq with parisc-linux.org>
   *
   *
   *    This program is free software; you can redistribute it and/or modify
   *    it under the terms of the GNU General Public License as published by
   *    the Free Software Foundation; either version 2, or (at your option)
   *    any later version.
   *
   *    This program is distributed in the hope that it will be useful,
   *    but WITHOUT ANY WARRANTY; without even the implied warranty of
   *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   *    GNU General Public License for more details.
   *
   *    You should have received a copy of the GNU General Public License
   *    along with this program; if not, write to the Free Software
   *    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
   */
  
  /*
   * These routines still have plenty of room for optimization
   * (word & doubleword load/store, dual issue, store hints, etc.).
   */
  
  /*
   * The following routines assume that space register 3 (sr3) contains
   * the space id associated with the current users address space.
   */
  
  
  	.text
  	
  #include <asm/assembly.h>
  #include <asm/errno.h>
  #include <linux/linkage.h>
  
  	/*
  	 * get_sr gets the appropriate space value into
  	 * sr1 for kernel/user space access, depending
  	 * on the flag stored in the task structure.
  	 */
  
  	.macro  get_sr
  	mfctl       %cr30,%r1
  	ldw         TI_SEGMENT(%r1),%r22
  	mfsp        %sr3,%r1
  	or,<>       %r22,%r0,%r0
  	copy        %r0,%r1
  	mtsp        %r1,%sr1
  	.endm
  
  	.macro fixup_branch lbl
  	ldil	    L%\lbl, %r1
  	ldo	    R%\lbl(%r1), %r1
  	bv          %r0(%r1)
  	.endm
  
  	/*
  	 * unsigned long lclear_user(void *to, unsigned long n)
  	 *
  	 * Returns 0 for success.
  	 * otherwise, returns number of bytes not transferred.
  	 */
  
  ENTRY(lclear_user)
  	.proc
  	.callinfo NO_CALLS
  	.entry
  	comib,=,n   0,%r25,$lclu_done
  	get_sr
  $lclu_loop:
  	addib,<>    -1,%r25,$lclu_loop
  1:      stbs,ma     %r0,1(%sr1,%r26)
  
  $lclu_done:
  	bv          %r0(%r2)
  	copy        %r25,%r28
  	.exit
  ENDPROC(lclear_user)
  
  	.section .fixup,"ax"
  2:      fixup_branch $lclu_done
  	ldo        1(%r25),%r25
  	.previous
  
  	ASM_EXCEPTIONTABLE_ENTRY(1b,2b)
  
  	.procend
  
  	/*
  	 * long lstrnlen_user(char *s, long n)
  	 *
  	 * Returns 0 if exception before zero byte or reaching N,
  	 *         N+1 if N would be exceeded,
  	 *         else strlen + 1 (i.e. includes zero byte).
  	 */
  
  ENTRY(lstrnlen_user)
  	.proc
  	.callinfo NO_CALLS
  	.entry
  	comib,=     0,%r25,$lslen_nzero
  	copy	    %r26,%r24
  	get_sr
  1:      ldbs,ma     1(%sr1,%r26),%r1
  $lslen_loop:
  	comib,=,n   0,%r1,$lslen_done
  	addib,<>    -1,%r25,$lslen_loop
  2:      ldbs,ma     1(%sr1,%r26),%r1
  $lslen_done:
  	bv          %r0(%r2)
  	sub	    %r26,%r24,%r28
  	.exit
  
  $lslen_nzero:
  	b           $lslen_done
  	ldo         1(%r26),%r26 /* special case for N == 0 */
  ENDPROC(lstrnlen_user)
  
  	.section .fixup,"ax"
  3:      fixup_branch $lslen_done
  	copy        %r24,%r26    /* reset r26 so 0 is returned on fault */
  	.previous
  
  	ASM_EXCEPTIONTABLE_ENTRY(1b,3b)
  	ASM_EXCEPTIONTABLE_ENTRY(2b,3b)
  
  	.procend
  
  	.end