diff options
Diffstat (limited to 'lib/libc/amd64/string/bcopy.S')
| -rw-r--r-- | lib/libc/amd64/string/bcopy.S | 88 |
1 files changed, 88 insertions, 0 deletions
diff --git a/lib/libc/amd64/string/bcopy.S b/lib/libc/amd64/string/bcopy.S new file mode 100644 index 0000000..d58f591 --- /dev/null +++ b/lib/libc/amd64/string/bcopy.S @@ -0,0 +1,88 @@ +/*- + * 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 + cld /* nope, copy forwards. */ + shrq $3,%rcx /* copy by words */ + rep + movsq + movq %rdx,%rcx + andq $7,%rcx /* any bytes left? */ + rep + movsb + ret +1: + addq %rcx,%rdi /* copy backwards. */ + addq %rcx,%rsi + std + andq $7,%rcx /* any fractional bytes? */ + decq %rdi + decq %rsi + rep + movsb + movq %rdx,%rcx /* copy remainder by words */ + shrq $3,%rcx + subq $7,%rsi + subq $7,%rdi + rep + movsq + cld + ret |
