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authorRoland McGrath <roland@gnu.org>1995-02-18 01:27:10 +0000
committerRoland McGrath <roland@gnu.org>1995-02-18 01:27:10 +0000
commit28f540f45bbacd939bfd07f213bcad2bf730b1bf (patch)
tree15f07c4c43d635959c6afee96bde71fb1b3614ee /sysdeps/vax/memmove.s
initial import
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diff --git a/sysdeps/vax/memmove.s b/sysdeps/vax/memmove.s
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+/*-
+ * Copyright (c) 1990 The Regents of the University of California.
+ * All rights reserved.
+ *
+ * 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. All advertising materials mentioning features or use of this software
+ * must display the following acknowledgement:
+ * This product includes software developed by the University of
+ * California, Berkeley and its contributors.
+ * 4. 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.
+ */
+
+#if defined(LIBC_SCCS) && !defined(lint)
+ .asciz "@(#)memmove.s 5.1 (Berkeley) 5/15/90"
+#endif /* LIBC_SCCS and not lint */
+
+/*
+ * void *memmove(dst, src, size)
+ * returns dst
+ *
+ * This optimises the usual case (count < 65536) at the expense
+ * of some extra memory references and branches when count >= 65536.
+ */
+
+#include "DEFS.h"
+
+ENTRY(memmove, 0)
+ movzwl $65535,r0 /* r0 = 64K (needed below) */
+ movq 8(ap),r1 /* r1 = src, r2 = length */
+ movl 4(ap),r3 /* r3 = dst */
+ cmpl r1,r3
+ bgtru 1f /* normal forward case */
+ beql 2f /* equal, nothing to do */
+ addl2 r2,r1 /* overlaps iff src<dst but src+len>dst */
+ cmpl r1,r3
+ bgtru 4f /* overlapping, must move backwards */
+ subl2 r2,r1
+
+1: /* move forward */
+ cmpl r2,r0
+ bgtru 3f /* stupid movc3 limitation */
+ movc3 r2,(r1),(r3) /* move it all */
+2:
+ movl 4(ap),r0 /* return original dst */
+ ret
+3:
+ subl2 r0,12(ap) /* adjust length by 64K */
+ movc3 r0,(r1),(r3) /* move 64K */
+ movl 12(ap),r2
+ decw r0 /* from 0 to 65535 */
+ brb 1b /* retry */
+
+4: /* move backward */
+ addl2 r2,r3
+5:
+ cmpl r2,r0
+ bgtru 6f /* stupid movc3 limitation */
+ subl2 r2,r1
+ subl2 r2,r3
+ movc3 r2,(r1),(r3) /* move it all */
+ movl 4(ap),r0 /* return original dst */
+ ret
+6:
+ subl2 r0,12(ap) /* adjust length by 64K */
+ subl2 r0,r1
+ subl2 r0,r3
+ movc3 r0,(r1),(r3) /* move 64K */
+ movl 12(ap),r2
+ decw r0
+ subl2 r0,r1
+ subl2 r0,r3
+ brb 5b