amd64: convert libc bcopy to a C func to avoid future bloat

The function is of limited use and is an almost a direct clone of
memmove/memcpy (with arguments swapped). Introduction of ERMS variants
of string routines would mean avoidable growth of libc.

bcopy will get redefined to a __builtin_memmove later on with this
symbol only left for compatibility.

Reviewed by:	kib
Approved by:	re (gjb)
Sponsored by:	The FreeBSD Foundation
Differential Revision:	https://reviews.freebsd.org/D17539

lib/libc/amd64/string/Makefile.inc

@@ -2,7 +2,6 @@
 
 MDSRCS+= \
 	bcmp.S \
-	bcopy.S \
 	bzero.S \
 	memcmp.S \
 	memcpy.S \

lib/libc/amd64/string/bcopy.S

@@ -1,103 +0,0 @@
-/*-
- * Copyright (c) 1990 The Regents of the University of California.
- * All rights reserved.
- *
- * This code is derived from locore.s.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions
- * are met:
- * 1. Redistributions of source code must retain the above copyright
- *    notice, this list of conditions and the following disclaimer.
- * 2. Redistributions in binary form must reproduce the above copyright
- *    notice, this list of conditions and the following disclaimer in the
- *    documentation and/or other materials provided with the distribution.
- * 3. Neither the name of the University nor the names of its contributors
- *    may be used to endorse or promote products derived from this software
- *    without specific prior written permission.
- *
- * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
- * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
- * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
- * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
- * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
- * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
- * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
- * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
- * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
- * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
- * SUCH DAMAGE.
- */
-
-#include <machine/asm.h>
-__FBSDID("$FreeBSD$");
-
-#if 0
-	RCSID("$NetBSD: bcopy.S,v 1.2 2003/08/07 16:42:36 agc Exp $")
-#endif
-
-	/*
-	 * (ov)bcopy (src,dst,cnt)
-	 *  ws@tools.de     (Wolfgang Solfrank, TooLs GmbH) +49-228-985800
-	 */
-
-#ifdef MEMCOPY
-ENTRY(memcpy)
-#else
-#ifdef MEMMOVE
-ENTRY(memmove)
-#else
-ENTRY(bcopy)
-#endif
-#endif
-#if defined(MEMCOPY) || defined(MEMMOVE)
-	movq	%rdi,%rax	/* return dst */
-#else
-	xchgq	%rdi,%rsi
-#endif
-	movq	%rdx,%rcx
-	movq	%rdi,%r8
-	subq	%rsi,%r8
-	cmpq	%rcx,%r8	/* overlapping? */
-	jb	1f
-	shrq	$3,%rcx		/* copy by words */
-	rep
-	movsq
-	movq	%rdx,%rcx
-	andq	$7,%rcx		/* any bytes left? */
-	jne	2f
-	ret
-2:
-	rep
-	movsb
-	ret
-1:
-	addq	%rcx,%rdi	/* copy backwards. */
-	addq	%rcx,%rsi
-	std
-	decq	%rdi
-	decq	%rsi
-	andq	$7,%rcx		/* any fractional bytes? */
-	je	3f
-	rep
-	movsb
-3:
-	movq	%rdx,%rcx	/* copy remainder by words */
-	shrq	$3,%rcx
-	subq	$7,%rsi
-	subq	$7,%rdi
-	rep
-	movsq
-	cld
-	ret
-#ifdef MEMCOPY
-END(memcpy)
-#else
-#ifdef MEMMOVE
-END(memmove)
-#else
-END(bcopy)
-#endif
-#endif
-
-	.section .note.GNU-stack,"",%progbits

lib/libc/amd64/string/bcopy.c

@@ -0,0 +1,15 @@
+/*-
+ * Public domain.
+ */
+
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD$");
+
+#include <string.h>
+
+void
+bcopy(const void *src, void *dst, size_t len)
+{
+
+	memmove(dst, src, len);
+}