xnu-792.25.20.tar.gz

[apple/xnu.git] / osfmk / i386 / bcopy.s

diff --git a/osfmk/i386/bcopy.s b/osfmk/i386/bcopy.s
index 0061c2ed492d13cec7f92c44ab4548db4c62719e..fe9b9b883b4b7f874def98dea8d0d86a2dd9c0ce 100644 (file)
--- a/osfmk/i386/bcopy.s
+++ b/osfmk/i386/bcopy.s
@@ -3,22 +3,19 @@
  *
  * @APPLE_LICENSE_HEADER_START@
  * 
- * Copyright (c) 1999-2003 Apple Computer, Inc.  All Rights Reserved.
+ * The contents of this file constitute Original Code as defined in and
+ * are subject to the Apple Public Source License Version 1.1 (the
+ * "License").  You may not use this file except in compliance with the
+ * License.  Please obtain a copy of the License at
+ * http://www.apple.com/publicsource and read it before using this file.
  * 
- * This file contains Original Code and/or Modifications of Original Code
- * as defined in and that are subject to the Apple Public Source License
- * Version 2.0 (the 'License'). You may not use this file except in
- * compliance with the License. Please obtain a copy of the License at
- * http://www.opensource.apple.com/apsl/ and read it before using this
- * file.
- * 
- * The Original Code and all software distributed under the License are
- * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
+ * This Original Code and all software distributed under the License are
+ * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
- * Please see the License for the specific language governing rights and
- * limitations under the License.
+ * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
+ * License for the specific language governing rights and limitations
+ * under the License.
  * 
  * @APPLE_LICENSE_HEADER_END@
  */
@@ -112,3 +109,54 @@ ENTRY(bcopy16)
        popl    %edi
        ret     
 
+       
+ /*
+  * Based on NetBSD's bcopy.S from their libc.
+  * bcopy(src, dst, cnt)
+  *  ws@tools.de     (Wolfgang Solfrank, TooLs GmbH) +49-228-985800
+  */
+ENTRY(bcopy)
+               pushl   %esi
+               pushl   %edi
+               movl    12(%esp),%esi
+               movl    16(%esp),%edi
+               movl    20(%esp),%ecx
+
+               movl    %edi,%edx
+               subl    %esi,%edx
+               cmpl    %ecx,%edx                       /* overlapping && src < dst? */
+                       movl    %ecx,%edx
+               jb      1f
+
+               shrl    $2,%ecx                         /* copy by 32-bit words */
+               cld                                     /* nope, copy forwards */
+               rep
+               movsl
+               movl    %edx,%ecx
+               andl    $3,%ecx                         /* any bytes left? */
+               rep
+               movsb
+               popl    %edi
+               popl    %esi
+               ret
+
+
+1:
+               addl    %ecx,%edi                       /* copy backwards */
+               addl    %ecx,%esi
+               decl    %edi
+               decl    %esi
+               andl    $3,%ecx                         /* any fractional bytes? */
+               std
+               rep
+               movsb
+               movl    %edx,%ecx                   /* copy remainder by 32-bit words */
+               shrl    $2,%ecx
+               subl    $3,%esi
+               subl    $3,%edi
+               rep
+               movsl
+               popl    %edi
+               popl    %esi
+               cld
+               ret