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kernel/linux-imx6_3.14.28/arch/sh/lib/memset.S 828 Bytes
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  /* $Id: memset.S,v 1.1 2000/04/14 16:49:01 mjd Exp $
   *
   * "memset" implementation of SuperH
   *
   * Copyright (C) 1999  Niibe Yutaka
   *
   */
  
  /*
   *            void *memset(void *s, int c, size_t n);
   */
  
  #include <linux/linkage.h>
  
  ENTRY(memset)
  	tst	r6,r6
  	bt/s	5f		! if n=0, do nothing
  	 add	r6,r4
  	mov	#12,r0
  	cmp/gt	r6,r0
  	bt/s	4f		! if it's too small, set a byte at once
  	 mov	r4,r0
  	and	#3,r0
  	cmp/eq	#0,r0
  	bt/s	2f		! It's aligned
  	 sub	r0,r6
  1:
  	dt	r0
  	bf/s	1b
  	 mov.b	r5,@-r4
  2:				! make VVVV
  	extu.b	r5,r5
  	swap.b	r5,r0		!   V0
  	or	r0,r5		!   VV
  	swap.w	r5,r0		! VV00
  	or	r0,r5		! VVVV
  	!
  	mov	r6,r0
  	shlr2	r0
  	shlr	r0		! r0 = r6 >> 3
  3:
  	dt	r0
  	mov.l	r5,@-r4		! set 8-byte at once
  	bf/s	3b
  	 mov.l	r5,@-r4
  	!
  	mov	#7,r0
  	and	r0,r6
  	tst	r6,r6
  	bt	5f
  	! fill bytes
  4:
  	dt	r6
  	bf/s	4b
  	 mov.b	r5,@-r4
  5:
  	rts
  	 mov	r4,r0