/* Optimized version of the standard memmove() function.

   This file is part of the GNU C Library.

   Copyright (C) 2000-2018 Free Software Foundation, Inc.

   Contributed by Dan Pop <Dan.Pop@cern.ch>.

   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/>.  */

/* Return: dest

   Inputs:

        in0:    dest

        in1:    src

        in2:    byte count

   The core of the function is the memcpy implementation used in memcpy.S.

   When bytes have to be copied backwards, only the easy case, when

   all arguments are multiples of 8, is optimised.

   In this form, it assumes little endian mode.  For big endian mode,

   sh1 must be computed using an extra instruction: sub sh1 = 64, sh1

   or the UM.be bit should be cleared at the beginning and set at the end.  */

#include <sysdep.h>

#undef ret

#define OP_T_THRES 	16

#define OPSIZ 		 8

#define adest		r15

#define saved_pr	r17

#define saved_lc	r18

#define dest		r19

#define src		r20

#define len		r21

#define asrc		r22

#define tmp2		r23

#define tmp3		r24

#define	tmp4		r25

#define ptable		r26

#define ploop56		r27

#define	loopaddr	r28

#define	sh1		r29

#define loopcnt		r30

#define	value		r31

#ifdef GAS_ALIGN_BREAKS_UNWIND_INFO

# define ALIGN(n)	{ nop 0 }

#else

# define ALIGN(n)	.align n

#endif

#define LOOP(shift)							\

		ALIGN(32);						\

.loop##shift##:								\

(p[0])		ld8	r[0] = [asrc], 8 ;	/* w1 */		\

(p[MEMLAT+1])	st8	[dest] = value, 8 ;				\

(p[MEMLAT])	shrp	value = r[MEMLAT], r[MEMLAT+1], shift ;		\

		nop.b	0 ;						\

		nop.b	0 ;						\

		br.ctop.sptk .loop##shift ;				\

		br.cond.sptk .cpyfew ; /* deal with the remaining bytes */

#define MEMLAT	21

#define Nrot	(((2*MEMLAT+3) + 7) & ~7)

ENTRY(memmove)

	.prologue

	alloc 	r2 = ar.pfs, 3, Nrot - 3, 0, Nrot

	.rotr	r[MEMLAT + 2], q[MEMLAT + 1]

	.rotp	p[MEMLAT + 2]

	mov	ret0 = in0		// return value = dest

	.save pr, saved_pr

	mov	saved_pr = pr		// save the predicate registers

	.save ar.lc, saved_lc

        mov 	saved_lc = ar.lc	// save the loop counter

	.body

	or	tmp3 = in0, in1 ;;	// tmp3 = dest | src

	or	tmp3 = tmp3, in2	// tmp3 = dest | src | len

	mov 	dest = in0		// dest

	mov 	src = in1		// src

	mov	len = in2		// len

	sub	tmp2 = r0, in0		// tmp2 = -dest

	cmp.eq	p6, p0 = in2, r0	// if (len == 0)

(p6)	br.cond.spnt .restore_and_exit;;// 	return dest;

	and	tmp4 = 7, tmp3 		// tmp4 = (dest | src | len) & 7

	cmp.le	p6, p0 = dest, src	// if dest <= src it's always safe

(p6)	br.cond.spnt .forward		// to copy forward

	add	tmp3 = src, len;;

	cmp.lt	p6, p0 = dest, tmp3	// if dest > src && dest < src + len

(p6)	br.cond.spnt .backward		// we have to copy backward

.forward:

	shr.u	loopcnt = len, 4 ;;	// loopcnt = len / 16

	cmp.ne	p6, p0 = tmp4, r0	// if ((dest | src | len) & 7 != 0)

(p6)	br.cond.sptk .next		//	goto next;

// The optimal case, when dest, src and len are all multiples of 8

	and	tmp3 = 0xf, len

	mov	pr.rot = 1 << 16	// set rotating predicates

	mov	ar.ec = MEMLAT + 1 ;;	// set the epilog counter

	cmp.ne	p6, p0 = tmp3, r0	// do we have to copy an extra word?

	adds	loopcnt = -1, loopcnt;;	// --loopcnt

(p6)	ld8	value = [src], 8;;

(p6)	st8	[dest] = value, 8	// copy the "odd" word

	mov	ar.lc = loopcnt 	// set the loop counter

	cmp.eq	p6, p0 = 8, len

(p6)	br.cond.spnt .restore_and_exit;;// the one-word special case

	adds	adest = 8, dest		// set adest one word ahead of dest

	adds	asrc = 8, src ;;	// set asrc one word ahead of src

	nop.b	0			// get the "golden" alignment for

	nop.b	0			// the next loop

.l0:

(p[0])		ld8	r[0] = [src], 16

(p[0])		ld8	q[0] = [asrc], 16

(p[MEMLAT])	st8	[dest] = r[MEMLAT], 16

(p[MEMLAT])	st8	[adest] = q[MEMLAT], 16

		br.ctop.dptk .l0 ;;

	mov	pr = saved_pr, -1	// restore the predicate registers

	mov	ar.lc = saved_lc	// restore the loop counter

	br.ret.sptk.many b0

.next:

	cmp.ge	p6, p0 = OP_T_THRES, len	// is len <= OP_T_THRES

	and	loopcnt = 7, tmp2 		// loopcnt = -dest % 8

(p6)	br.cond.spnt	.cpyfew			// copy byte by byte

	;;

	cmp.eq	p6, p0 = loopcnt, r0

(p6)	br.cond.sptk	.dest_aligned

	sub	len = len, loopcnt	// len -= -dest % 8

	adds	loopcnt = -1, loopcnt	// --loopcnt

	;;

	mov	ar.lc = loopcnt

.l1:					// copy -dest % 8 bytes

	ld1	value = [src], 1	// value = *src++

	;;

	st1	[dest] = value, 1	// *dest++ = value

	br.cloop.dptk .l1

.dest_aligned:

	and	sh1 = 7, src 		// sh1 = src % 8

	and	tmp2 = -8, len   	// tmp2 = len & -OPSIZ

	and	asrc = -8, src		// asrc = src & -OPSIZ  -- align src

	shr.u	loopcnt = len, 3	// loopcnt = len / 8

	and	len = 7, len;;		// len = len % 8

	adds	loopcnt = -1, loopcnt	// --loopcnt

	addl	tmp4 = @ltoff(.table), gp

	addl	tmp3 = @ltoff(.loop56), gp

	mov     ar.ec = MEMLAT + 1	// set EC

	mov     pr.rot = 1 << 16;;	// set rotating predicates

	mov	ar.lc = loopcnt		// set LC

	cmp.eq  p6, p0 = sh1, r0 	// is the src aligned?

(p6)    br.cond.sptk .src_aligned

	add	src = src, tmp2		// src += len & -OPSIZ

	shl	sh1 = sh1, 3		// sh1 = 8 * (src % 8)

	ld8	ploop56 = [tmp3]	// ploop56 = &loop56

	ld8	ptable = [tmp4];;	// ptable = &table

	add	tmp3 = ptable, sh1;;	// tmp3 = &table + sh1

	mov	ar.ec = MEMLAT + 1 + 1 // one more pass needed

	ld8	tmp4 = [tmp3];;		// tmp4 = loop offset

	sub	loopaddr = ploop56,tmp4	// loopadd = &loop56 - loop offset

	ld8	r[1] = [asrc], 8;;	// w0

	mov	b6 = loopaddr;;

	br	b6			// jump to the appropriate loop

	LOOP(8)

	LOOP(16)

	LOOP(24)

	LOOP(32)

	LOOP(40)

	LOOP(48)

	LOOP(56)

.src_aligned:

.l3:

(p[0])		ld8	r[0] = [src], 8

(p[MEMLAT])	st8	[dest] = r[MEMLAT], 8

		br.ctop.dptk .l3

.cpyfew:

	cmp.eq	p6, p0 = len, r0	// is len == 0 ?

	adds	len = -1, len		// --len;

(p6)	br.cond.spnt	.restore_and_exit ;;

	mov	ar.lc = len

.l4:

	ld1	value = [src], 1

	;;

	st1	[dest] = value, 1

	br.cloop.dptk	.l4 ;;

.restore_and_exit:

	mov     pr = saved_pr, -1    	// restore the predicate registers

	mov 	ar.lc = saved_lc	// restore the loop counter

	br.ret.sptk.many b0

// In the case of a backward copy, optimise only the case when everything

// is a multiple of 8, otherwise copy byte by byte.  The backward copy is

// used only when the blocks are overlapping and dest > src.

.backward:

	shr.u	loopcnt = len, 3	// loopcnt = len / 8

	add	src = src, len		// src points one byte past the end

	add	dest = dest, len ;; 	// dest points one byte past the end

	mov	ar.ec = MEMLAT + 1	// set the epilog counter

	mov	pr.rot = 1 << 16	// set rotating predicates

	adds	loopcnt = -1, loopcnt	// --loopcnt

	cmp.ne	p6, p0 = tmp4, r0	// if ((dest | src | len) & 7 != 0)

(p6)	br.cond.sptk .bytecopy ;;	// copy byte by byte backward

	adds	src = -8, src		// src points to the last word

	adds	dest = -8, dest 	// dest points to the last word

	mov	ar.lc = loopcnt;;	// set the loop counter

.l5:

(p[0])		ld8	r[0] = [src], -8

(p[MEMLAT])	st8	[dest] = r[MEMLAT], -8

		br.ctop.dptk .l5

		br.cond.sptk .restore_and_exit

.bytecopy:

	adds	src = -1, src		// src points to the last byte

	adds	dest = -1, dest		// dest points to the last byte

	adds	loopcnt = -1, len;;	// loopcnt = len - 1

	mov	ar.lc = loopcnt;;	// set the loop counter

.l6:

(p[0])		ld1	r[0] = [src], -1

(p[MEMLAT])	st1	[dest] = r[MEMLAT], -1

		br.ctop.dptk .l6

		br.cond.sptk .restore_and_exit

END(memmove)

	.rodata

	.align 8

.table:

	data8	0			// dummy entry

	data8 	.loop56 - .loop8

	data8 	.loop56 - .loop16

	data8 	.loop56 - .loop24

	data8	.loop56 - .loop32

	data8	.loop56 - .loop40

	data8	.loop56 - .loop48

	data8	.loop56 - .loop56

libc_hidden_builtin_def (memmove)