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kernel/linux-imx6_3.14.28/arch/openrisc/lib/string.S 2.02 KB
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  /*
   * OpenRISC string.S
   *
   * Linux architectural port borrowing liberally from similar works of
   * others.  All original copyrights apply as per the original source
   * declaration.
   *
   * Modifications for the OpenRISC architecture:
   * Copyright (C) 2003 Matjaz Breskvar <phoenix@bsemi.com>
   * Copyright (C) 2010-2011 Jonas Bonn <jonas@southpole.se>
   *
   *      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 of the License, or (at your option) any later version.
   */
  
  #include <linux/linkage.h>
  #include <asm/errno.h>
  
  	/*
  	 * this can be optimized by doing gcc inline assemlby with
  	 * proper constraints (no need to save args registers...)
  	 *
  	 */
  
  
  /*
   *
   * int __copy_tofrom_user(void *to, const void *from, unsigned long size);
   *
   * NOTE: it returns number of bytes NOT copied !!!
   *
   */
  	.global	__copy_tofrom_user
  __copy_tofrom_user:
  	l.addi  r1,r1,-12
  	l.sw    0(r1),r6
  	l.sw    4(r1),r4
  	l.sw    8(r1),r3
  
  	l.addi  r11,r5,0
  2:  	l.sfeq  r11,r0
  	l.bf    1f
  	l.addi  r11,r11,-1
  8:    	l.lbz   r6,0(r4)
  9:    	l.sb    0(r3),r6
  	l.addi  r3,r3,1
  	l.j     2b
  	l.addi  r4,r4,1
  1:
  	l.addi  r11,r11,1               // r11 holds the return value
  
  	l.lwz   r6,0(r1)
  	l.lwz   r4,4(r1)
  	l.lwz   r3,8(r1)
  	l.jr    r9
  	l.addi  r1,r1,12
  
  	.section .fixup, "ax"
  99:
  		l.j     1b
  		l.nop
  	.previous
  
  	.section __ex_table, "a"
  		.long 8b, 99b		// read fault
  		.long 9b, 99b		// write fault
  	.previous
  
  /*
   * unsigned long clear_user(void *addr, unsigned long size) ;
   *
   * NOTE: it returns number of bytes NOT cleared !!!
   */
  	.global	__clear_user
  __clear_user:
  	l.addi  r1,r1,-8
  	l.sw    0(r1),r4
  	l.sw    4(r1),r3
  
  2:	l.sfeq	r4,r0
  	l.bf	1f
  	l.addi	r4,r4,-1
  9:	l.sb	0(r3),r0
  	l.j	2b
  	l.addi  r3,r3,1
  
  1:
  	l.addi  r11,r4,1
  
  	l.lwz	r4,0(r1)
  	l.lwz	r3,4(r1)
  	l.jr	r9
  	l.addi	r1,r1,8
  
  	.section .fixup, "ax"
  99:
  		l.j     1b
  		l.nop
  	.previous
  
  	.section __ex_table, "a"
  		.long 9b, 99b		// write fault
  	.previous