/*
   * Copyright (C) 2009 Michal Simek <monstr@monstr.eu>
   * Copyright (C) 2009 PetaLogix
   * Copyright (C) 2007 LynuxWorks, Inc.
   *
   * This file is subject to the terms and conditions of the GNU General Public
   * License.  See the file "COPYING" in the main directory of this archive
   * for more details.
   */
  
  #include <linux/errno.h>
  #include <linux/linkage.h>

  #include <asm/page.h>

  
  /*
   * int __strncpy_user(char *to, char *from, int len);
   *
   * Returns:
   *  -EFAULT  for an exception
   *  len      if we hit the buffer limit
   *  bytes copied
   */
  
  	.text
  .globl __strncpy_user;

  .type  __strncpy_user, @function

  .align 4;
  __strncpy_user:
  
  	/*
  	 * r5 - to
  	 * r6 - from
  	 * r7 - len
  	 * r3 - temp count
  	 * r4 - temp val
  	 */

  	beqid	r7,3f

  	addik	r3,r7,0		/* temp_count = len */

  1:
  	lbu	r4,r6,r0
  	sb	r4,r5,r0
  
  	addik	r3,r3,-1
  	beqi	r3,2f		/* break on len */
  
  	addik	r5,r5,1
  	bneid	r4,1b
  	addik	r6,r6,1		/* delay slot */
  	addik	r3,r3,1		/* undo "temp_count--" */
  2:
  	rsubk	r3,r3,r7	/* temp_count = len - temp_count */
  3:
  	rtsd	r15,8
  	nop

  	.size   __strncpy_user, . - __strncpy_user

  	.section	.fixup, "ax"
  	.align	2
  4:
  	brid	3b
  	addik	r3,r0, -EFAULT
  
  	.section	__ex_table, "a"
  	.word	1b,4b
  
  /*
   * int __strnlen_user(char __user *str, int maxlen);
   *
   * Returns:
   *  0 on error
   *  maxlen + 1  if no NUL byte found within maxlen bytes
   *  size of the string (including NUL byte)
   */
  
  	.text
  .globl __strnlen_user;

  .type  __strnlen_user, @function

  .align 4;
  __strnlen_user:

  	beqid	r6,3f

  	addik	r3,r6,0

  1:
  	lbu	r4,r5,r0
  	beqid	r4,2f		/* break on NUL */
  	addik	r3,r3,-1	/* delay slot */
  
  	bneid	r3,1b
  	addik	r5,r5,1		/* delay slot */
  
  	addik	r3,r3,-1	/* for break on len */
  2:
  	rsubk	r3,r3,r6
  3:
  	rtsd	r15,8
  	nop

  	.size   __strnlen_user, . - __strnlen_user

  	.section	.fixup,"ax"
  4:
  	brid	3b
  	addk	r3,r0,r0
  
  	.section	__ex_table,"a"
  	.word	1b,4b

  /* Loop unrolling for __copy_tofrom_user */
  #define COPY(offset)	\
  1:	lwi	r4 , r6, 0x0000 + offset;	\
  2:	lwi	r19, r6, 0x0004 + offset;	\
  3:	lwi	r20, r6, 0x0008 + offset;	\
  4:	lwi	r21, r6, 0x000C + offset;	\
  5:	lwi	r22, r6, 0x0010 + offset;	\
  6:	lwi	r23, r6, 0x0014 + offset;	\
  7:	lwi	r24, r6, 0x0018 + offset;	\
  8:	lwi	r25, r6, 0x001C + offset;	\
  9:	swi	r4 , r5, 0x0000 + offset;	\
  10:	swi	r19, r5, 0x0004 + offset;	\
  11:	swi	r20, r5, 0x0008 + offset;	\
  12:	swi	r21, r5, 0x000C + offset;	\
  13:	swi	r22, r5, 0x0010 + offset;	\
  14:	swi	r23, r5, 0x0014 + offset;	\
  15:	swi	r24, r5, 0x0018 + offset;	\
  16:	swi	r25, r5, 0x001C + offset;	\
  	.section __ex_table,"a";		\
  	.word	1b, 0f;				\
  	.word	2b, 0f;				\
  	.word	3b, 0f;				\
  	.word	4b, 0f;				\
  	.word	5b, 0f;				\
  	.word	6b, 0f;				\
  	.word	7b, 0f;				\
  	.word	8b, 0f;				\
  	.word	9b, 0f;				\
  	.word	10b, 0f;			\
  	.word	11b, 0f;			\
  	.word	12b, 0f;			\
  	.word	13b, 0f;			\
  	.word	14b, 0f;			\
  	.word	15b, 0f;			\
  	.word	16b, 0f;			\
  	.text
  
  #define COPY_80(offset)	\
  	COPY(0x00 + offset);\
  	COPY(0x20 + offset);\
  	COPY(0x40 + offset);\
  	COPY(0x60 + offset);

  /*
   * int __copy_tofrom_user(char *to, char *from, int len)
   * Return:
   *   0 on success
   *   number of not copied bytes on error
   */
  	.text
  .globl __copy_tofrom_user;

  .type  __copy_tofrom_user, @function

  .align 4;
  __copy_tofrom_user:
  	/*
  	 * r5 - to
  	 * r6 - from
  	 * r7, r3 - count
  	 * r4 - tempval
  	 */

  	beqid	r7, 0f /* zero size is not likely */

  	or	r3, r5, r6 /* find if is any to/from unaligned */

  	or	r3, r3, r7 /* find if count is unaligned */
  	andi	r3, r3, 0x3 /* mask last 3 bits */
  	bneid	r3, bu1 /* if r3 is not zero then byte copying */

  	or	r3, r0, r0

  	rsubi	r3, r7, PAGE_SIZE /* detect PAGE_SIZE */
  	beqid	r3, page;
  	or	r3, r0, r0

  w1:	lw	r4, r6, r3 /* at least one 4 byte copy */
  w2:	sw	r4, r5, r3

  	addik	r7, r7, -4

  	bneid	r7, w1

  	addik	r3, r3, 4
  	addik	r3, r7, 0
  	rtsd	r15, 8
  	nop

  
  	.section	__ex_table,"a"

  	.word	w1, 0f;
  	.word	w2, 0f;

  	.text

  .align 4 /* Alignment is important to keep icache happy */
  page:	/* Create room on stack and save registers for storign values */
  	addik   r1, r1, -32
  	swi	r19, r1, 4
  	swi	r20, r1, 8
  	swi	r21, r1, 12
  	swi	r22, r1, 16
  	swi	r23, r1, 20
  	swi	r24, r1, 24
  	swi	r25, r1, 28
  loop:	/* r4, r19, r20, r21, r22, r23, r24, r25 are used for storing values */
  	/* Loop unrolling to get performance boost */
  	COPY_80(0x000);
  	COPY_80(0x080);
  	COPY_80(0x100);
  	COPY_80(0x180);
  	/* copy loop */
  	addik	r6, r6, 0x200
  	addik	r7, r7, -0x200
  	bneid	r7, loop
  	addik	r5, r5, 0x200
  	/* Restore register content */
  	lwi	r19, r1, 4
  	lwi	r20, r1, 8
  	lwi	r21, r1, 12
  	lwi	r22, r1, 16
  	lwi	r23, r1, 20
  	lwi	r24, r1, 24
  	lwi	r25, r1, 28
  	addik   r1, r1, 32
  	/* return back */
  	addik	r3, r7, 0
  	rtsd	r15, 8
  	nop
  
  .align 4 /* Alignment is important to keep icache happy */

  bu1:	lbu	r4,r6,r3
  bu2:	sb	r4,r5,r3

  	addik	r7,r7,-1

  	bneid	r7,bu1

  	addik	r3,r3,1		/* delay slot */

  0:

  	addik	r3,r7,0

  	rtsd	r15,8
  	nop

  	.size   __copy_tofrom_user, . - __copy_tofrom_user

  	.section	__ex_table,"a"

  	.word	bu1, 0b;
  	.word	bu2, 0b;

  	.text