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kernel/linux-imx6_3.14.28/arch/arm64/lib/strchr.S 1.06 KB
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  /*
   * Based on arch/arm/lib/strchr.S
   *
   * Copyright (C) 1995-2000 Russell King
   * Copyright (C) 2013 ARM Ltd.
   *
   * This program is free software; you can redistribute it and/or modify
   * it under the terms of the GNU General Public License version 2 as
   * published by the Free Software Foundation.
   *
   * 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, see <http://www.gnu.org/licenses/>.
   */
  
  #include <linux/linkage.h>
  #include <asm/assembler.h>
  
  /*
   * Find the first occurrence of a character in a string.
   *
   * Parameters:
   *	x0 - str
   *	x1 - c
   * Returns:
   *	x0 - address of first occurrence of 'c' or 0
   */
  ENTRY(strchr)
  	and	w1, w1, #0xff
  1:	ldrb	w2, [x0], #1
  	cmp	w2, w1
  	ccmp	w2, wzr, #4, ne
  	b.ne	1b
  	sub	x0, x0, #1
  	cmp	w2, w1
  	csel	x0, x0, xzr, eq
  	ret
  ENDPROC(strchr)