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kernel/linux-imx6_3.14.28/arch/sh/lib/memmove.S 3.92 KB
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  /* $Id: memmove.S,v 1.2 2001/07/27 11:51:09 gniibe Exp $
   *
   * "memmove" implementation of SuperH
   *
   * Copyright (C) 1999  Niibe Yutaka
   *
   */
  
  /*
   * void *memmove(void *dst, const void *src, size_t n);
   * The memory areas may overlap.
   */
  
  #include <linux/linkage.h>
  ENTRY(memmove)
  	! if dest > src, call memcpy (it copies in decreasing order)
  	cmp/hi	r5,r4
  	bf	1f
  	mov.l	2f,r0
  	jmp	@r0
  	 nop
  	.balign 4
  2:	.long	memcpy
  1:
  	sub	r5,r4		! From here, r4 has the distance to r0
  	tst	r6,r6
  	bt/s	9f		! if n=0, do nothing
  	 mov	r5,r0
  	add	r6,r5
  	mov	#12,r1
  	cmp/gt	r6,r1
  	bt/s	8f		! if it's too small, copy a byte at once
  	 add	#-1,r4
  	add	#1,r4
  	!
  	!                [ ...  ] DST             [ ...  ] SRC
  	!	         [ ...  ]                 [ ...  ]
  	!	           :                        :
  	!      r0+r4-->  [ ...  ]       r0    --> [ ...  ]
  	!	           :                        :
  	!	         [ ...  ]                 [ ...  ]
  	!			        r5    -->
  	!
  	mov	r4,r1
  	mov	#3,r2
  	and	r2,r1
  	shll2	r1
  	mov	r0,r3		! Save the value on R0 to R3
  	mova	jmptable,r0
  	add	r1,r0
  	mov.l	@r0,r1
  	jmp	@r1
  	 mov	r3,r0		! and back to R0
  	.balign	4
  jmptable:
  	.long	case0
  	.long	case1
  	.long	case2
  	.long	case3
  
  	! copy a byte at once
  8:	mov.b	@r0+,r1
  	cmp/hs	r5,r0
  	bf/s	8b			! while (r0<r5)
  	 mov.b	r1,@(r0,r4)
  	add	#1,r4
  9:
  	add	r4,r0
  	rts
  	 sub	r6,r0
  
  case_none:
  	bra	8b
  	 add	#-1,r4
  
  case0:
  	!
  	!	GHIJ KLMN OPQR -->  GHIJ KLMN OPQR
  	!
  	! First, align to long word boundary
  	mov	r0,r3
  	and	r2,r3
  	tst	r3,r3
  	bt/s	2f
  	 add	#-1,r4
  	mov	#4,r2
  	sub	r3,r2
  1:	dt	r2
  	mov.b	@r0+,r1
  	bf/s	1b
  	 mov.b	r1,@(r0,r4)
  	!
  2:	! Second, copy a long word at once
  	add	#-3,r4
  	add	#-3,r5
  3:	mov.l	@r0+,r1
  	cmp/hs	r5,r0
  	bf/s	3b
  	 mov.l	r1,@(r0,r4)
  	add	#3,r5
  	!
  	! Third, copy a byte at once, if necessary
  	cmp/eq	r5,r0
  	bt/s	9b
  	 add	#4,r4
  	bra	8b
  	 add	#-1,r4
  
  case3:
  	!
  	!	GHIJ KLMN OPQR -->  ...G HIJK LMNO PQR.
  	!
  	! First, align to long word boundary
  	mov	r0,r3
  	and	r2,r3
  	tst	r3,r3
  	bt/s	2f
  	 add	#-1,r4
  	mov	#4,r2
  	sub	r3,r2
  1:	dt	r2
  	mov.b	@r0+,r1
  	bf/s	1b
  	 mov.b	r1,@(r0,r4)
  	!
  2:	! Second, read a long word and write a long word at once
  	add	#-2,r4
  	mov.l	@(r0,r4),r1
  	add	#-7,r5
  	add	#-4,r4
  	!
  #ifdef __LITTLE_ENDIAN__
  	shll8	r1
  3:	mov	r1,r3		! JIHG
  	shlr8	r3		! xJIH
  	mov.l	@r0+,r1		! NMLK
  	mov	r1,r2
  	shll16	r2
  	shll8	r2		! Kxxx
  	or	r2,r3		! KJIH
  	cmp/hs	r5,r0
  	bf/s	3b
  	 mov.l	r3,@(r0,r4)
  #else
  	shlr8	r1
  3:	mov	r1,r3		! GHIJ
  	shll8	r3		! HIJx
  	mov.l	@r0+,r1		! KLMN
  	mov	r1,r2
  	shlr16	r2
  	shlr8	r2		! xxxK
  	or	r2,r3		! HIJK
  	cmp/hs	r5,r0
  	bf/s	3b
  	 mov.l	r3,@(r0,r4)
  #endif
  	add	#7,r5
  	!
  	! Third, copy a byte at once, if necessary
  	cmp/eq	r5,r0
  	bt/s	9b
  	 add	#7,r4
  	add	#-3,r0
  	bra	8b
  	 add	#-1,r4
  
  case2:
  	!
  	!	GHIJ KLMN OPQR -->  ..GH IJKL MNOP QR..
  	!
  	! First, align to word boundary
  	tst	#1,r0
  	bt/s	2f
  	 add	#-1,r4
  	mov.b	@r0+,r1
  	mov.b	r1,@(r0,r4)
  	!
  2:	! Second, read a word and write a word at once
  	add	#-1,r4
  	add	#-1,r5
  	!
  3:	mov.w	@r0+,r1
  	cmp/hs	r5,r0
  	bf/s	3b
  	 mov.w	r1,@(r0,r4)
  	add	#1,r5
  	!
  	! Third, copy a byte at once, if necessary
  	cmp/eq	r5,r0
  	bt/s	9b
  	 add	#2,r4
  	mov.b	@r0,r1
  	mov.b	r1,@(r0,r4)
  	bra	9b
  	 add	#1,r0
  
  case1:
  	!
  	!	GHIJ KLMN OPQR -->  .GHI JKLM NOPQ R...
  	!
  	! First, align to long word boundary
  	mov	r0,r3
  	and	r2,r3
  	tst	r3,r3
  	bt/s	2f
  	 add	#-1,r4
  	mov	#4,r2
  	sub	r3,r2
  1:	dt	r2
  	mov.b	@r0+,r1
  	bf/s	1b
  	 mov.b	r1,@(r0,r4)
  	!
  2:	! Second, read a long word and write a long word at once
  	mov.l	@(r0,r4),r1
  	add	#-7,r5
  	add	#-4,r4
  	!
  #ifdef __LITTLE_ENDIAN__
  	shll16	r1
  	shll8	r1
  3:	mov	r1,r3		! JIHG
  	shlr16	r3
  	shlr8	r3		! xxxJ
  	mov.l	@r0+,r1		! NMLK
  	mov	r1,r2
  	shll8	r2		! MLKx
  	or	r2,r3		! MLKJ
  	cmp/hs	r5,r0
  	bf/s	3b
  	 mov.l	r3,@(r0,r4)
  #else
  	shlr16	r1
  	shlr8	r1
  3:	mov	r1,r3		! GHIJ
  	shll16	r3
  	shll8	r3		! Jxxx
  	mov.l	@r0+,r1		! KLMN
  	mov	r1,r2
  	shlr8	r2		! xKLM
  	or	r2,r3		! JKLM
  	cmp/hs	r5,r0
  	bf/s	3b		! while(r0<r5)
  	 mov.l	r3,@(r0,r4)
  #endif
  	add	#7,r5
  	!
  	! Third, copy a byte at once, if necessary
  	cmp/eq	r5,r0
  	bt/s	9b
  	 add	#5,r4
  	add	#-3,r0
  	bra	8b
  	 add	#-1,r4