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kernel/linux-imx6_3.14.28/arch/arc/lib/strcpy-700.S 1.52 KB
6b13f685e   김민수   BSP 최초 추가
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  /*
   * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
   *
   * 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.
   */
  
  /* If dst and src are 4 byte aligned, copy 8 bytes at a time.
     If the src is 4, but not 8 byte aligned, we first read 4 bytes to get
     it 8 byte aligned.  Thus, we can do a little read-ahead, without
     dereferencing a cache line that we should not touch.
     Note that short and long instructions have been scheduled to avoid
     branch stalls.
     The beq_s to r3z could be made unaligned & long to avoid a stall
     there, but the it is not likely to be taken often, and it
     would also be likey to cost an unaligned mispredict at the next call.  */
  
  #include <asm/linkage.h>
  
  ARC_ENTRY strcpy
  	or	r2,r0,r1
  	bmsk_s	r2,r2,1
  	brne.d	r2,0,charloop
  	mov_s	r10,r0
  	ld_s	r3,[r1,0]
  	mov	r8,0x01010101
  	bbit0.d	r1,2,loop_start
  	ror	r12,r8
  	sub	r2,r3,r8
  	bic_s	r2,r2,r3
  	tst_s	r2,r12
  	bne	r3z
  	mov_s	r4,r3
  	.balign 4
  loop:
  	ld.a	r3,[r1,4]
  	st.ab	r4,[r10,4]
  loop_start:
  	ld.a	r4,[r1,4]
  	sub	r2,r3,r8
  	bic_s	r2,r2,r3
  	tst_s	r2,r12
  	bne_s	r3z
  	st.ab	r3,[r10,4]
  	sub	r2,r4,r8
  	bic	r2,r2,r4
  	tst	r2,r12
  	beq	loop
  	mov_s	r3,r4
  #ifdef __LITTLE_ENDIAN__
  r3z:	bmsk.f	r1,r3,7
  	lsr_s	r3,r3,8
  #else
  r3z:	lsr.f	r1,r3,24
  	asl_s	r3,r3,8
  #endif
  	bne.d	r3z
  	stb.ab	r1,[r10,1]
  	j_s	[blink]
  
  	.balign	4
  charloop:
  	ldb.ab	r3,[r1,1]
  
  
  	brne.d	r3,0,charloop
  	stb.ab	r3,[r10,1]
  	j	[blink]
  ARC_EXIT strcpy