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+/* Optimized version of the standard memmove() function.
+   This file is part of the GNU C Library.
+   Copyright (C) 2000, 2001, 2003 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)
generated by cgit-pink 1.4.1 (git 2.36.1) at 2024-06-12 04:20:38 +0000