/* Copy memory to memory until the specified number of bytes
   has been copied.  Overlap is handled correctly.
   For SPARC V9.
   Copyright (C) 2017 Free Software Foundation, Inc.
   This file is part of the GNU C Library.

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library 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
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public
   License along with the GNU C Library; if not, see
   <http://www.gnu.org/licenses/>.  */

#include <sysdep.h>

#ifndef XCC
# define XCC    xcc
	.register	%g2, #scratch
#endif

ENTRY(memmove)
	mov	%o0, %g2	/* Save pointer to destination  */
	cmp	%o1, %o0	/* if from address is >= to use forward copy  */
	bgeu,a	%XCC, 2f	/* else use backward if ...  */
	 cmp	%o2, 17		/* delay slot, for small counts copy bytes  */

	sub	%o0, %o1, %o4	/* get difference of two addresses  */
	cmp	%o2, %o4	/* compare size and difference of addresses  */
	bgu	%XCC, .Lovbc	/* if size is bigger, have to do overlapped copy  */
	 cmp	%o2, 17		/* delay slot, for small counts copy bytes  */
/*
 * normal, copy forwards
 */
2:	ble	%XCC, .Ldbytecp
	 andcc	%o1, 3, %o5	/* is src word aligned  */
	bz,pn	%icc, .Laldst
	 cmp	%o5, 2		/* is src half-word aligned  */
	be,pn	%icc, .Ls2alg
	 cmp	%o5, 3		/* src is byte aligned  */
	ldub	[%o1], %o3	/* move 1 or 3 bytes to align it  */
	inc	1, %o1
	stb	%o3, [%o0]	/* move a byte to align src  */
	inc	1, %o0
	bne,pn	%icc, .Ls2alg
	 dec	%o2
	b	.Lald		/* now go align dest  */
	 andcc	%o0, 3, %o5

.Ls2alg:
	lduh	[%o1], %o3	/* know src is 2 byte aligned  */
	inc	2, %o1
	srl	%o3, 8, %o4
	stb	%o4, [%o0]	/* have to do bytes,  */
	stb	%o3, [%o0 + 1]	/* don't know dst alingment  */
	inc	2, %o0
	dec	2, %o2

.Laldst:
	andcc	%o0, 3, %o5	/* align the destination address  */
.Lald:	bz,pn	%icc, .Lw4cp
	 cmp	%o5, 2
	bz,pn	%icc, .Lw2cp
	 cmp	%o5, 3
.Lw3cp:
	lduw	[%o1], %o4
	inc	4, %o1
	srl	%o4, 24, %o5
	stb	%o5, [%o0]
	bne,pt	%icc, .Lw1cp
	 inc	%o0
	dec	1, %o2
	andn	%o2, 3, %o3	/* i3 is aligned word count  */
	dec	4, %o3		/* avoid reading beyond tail of src  */
	sub	%o1, %o0, %o1	/* i1 gets the difference  */

1:	sll	%o4, 8, %g1	/* save residual bytes  */
	lduw	[%o1+%o0], %o4
	deccc	4, %o3
	srl	%o4, 24, %o5	/* merge with residual  */
	or	%o5, %g1, %g1
	st	%g1, [%o0]
	bnz,pt	%XCC, 1b
	 inc	4, %o0
	sub	%o1, 3, %o1	/* used one byte of last word read  */
	and	%o2, 3, %o2
	b	7f
	 inc	4, %o2

.Lw1cp:
	srl	%o4, 8, %o5
	sth	%o5, [%o0]
	inc	2, %o0
	dec	3, %o2
	andn	%o2, 3, %o3
	dec	4, %o3		/* avoid reading beyond tail of src  */
	sub	%o1, %o0, %o1	/* i1 gets the difference  */

2:	sll	%o4, 24, %g1	/* save residual bytes  */
	lduw	[%o1+%o0], %o4
	deccc	4, %o3
	srl	%o4, 8, %o5	/* merge with residual  */
	or	%o5, %g1, %g1
	st	%g1, [%o0]
	bnz,pt	%XCC, 2b
	 inc	4, %o0
	sub	%o1, 1, %o1	/* used three bytes of last word read  */
	and	%o2, 3, %o2
	b	7f
	inc	4, %o2

.Lw2cp:
	lduw	[%o1], %o4
	inc	4, %o1
	srl	%o4, 16, %o5
	sth	%o5, [%o0]
	inc	2, %o0
	dec	2, %o2
	andn	%o2, 3, %o3	/* i3 is aligned word count  */
	dec	4, %o3		/* avoid reading beyond tail of src  */
	sub	%o1, %o0, %o1	/* i1 gets the difference  */

3:	sll	%o4, 16, %g1	/* save residual bytes  */
	lduw	[%o1+%o0], %o4
	deccc	4, %o3
	srl	%o4, 16, %o5	/* merge with residual  */
	or	%o5, %g1, %g1
	st	%g1, [%o0]
	bnz,pt	%XCC, 3b
	 inc	4, %o0
	sub	%o1, 2, %o1	/* used two bytes of last word read  */
	and	%o2, 3, %o2
	b	7f
	 inc	4, %o2

.Lw4cp:
	andn	%o2, 3, %o3	/* i3 is aligned word count  */
	sub	%o1, %o0, %o1	/* i1 gets the difference  */

1:	lduw	[%o1+%o0], %o4	/* read from address  */
	deccc	4, %o3		/* decrement count  */
	st	%o4, [%o0]	/* write at destination address  */
	bg,pt	%XCC, 1b
	 inc	4, %o0		/* increment to address  */
	b	7f
	 and	%o2, 3, %o2	/* number of leftover bytes, if any  */

/*
 * differenced byte copy, works with any alignment
 */
.Ldbytecp:
	b	7f
	 sub	%o1, %o0, %o1	/* i1 gets the difference  */

4:	stb	%o4, [%o0]	/* write to address  */
	inc	%o0		/* inc to address  */
7:	deccc	%o2		/* decrement count  */
	bge,a	%XCC, 4b	/* loop till done  */
	 ldub	[%o1+%o0], %o4	/* read from address  */
	retl
	 mov	%g2, %o0	/* return pointer to destination  */

/*
 * an overlapped copy that must be done "backwards"
 */
.Lovbc:
	add	%o1, %o2, %o1	/* get to end of source space  */
	add	%o0, %o2, %o0	/* get to end of destination space  */
	sub	%o1, %o0, %o1	/* i1 gets the difference  */

5:	dec	%o0		/* decrement to address  */
	ldub	[%o1+%o0], %o3	/* read a byte  */
	deccc	%o2		/* decrement count  */
	bg,pt	%XCC, 5b 	/* loop until done  */
	 stb	%o3, [%o0]	/* write byte  */
	retl
	 mov	%g2, %o0	/* return pointer to destination  */
END(memmove)

libc_hidden_builtin_def (memmove)