Initial Contribution
diff --git a/libc/string/bcopy.c b/libc/string/bcopy.c
new file mode 100644
index 0000000..4308c64
--- /dev/null
+++ b/libc/string/bcopy.c
@@ -0,0 +1,128 @@
+/* $OpenBSD: bcopy.c,v 1.5 2005/08/08 08:05:37 espie Exp $ */
+/*-
+ * Copyright (c) 1990 The Regents of the University of California.
+ * All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Chris Torek.
+ *
+ * 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 <string.h>
+
+/*
+ * sizeof(word) MUST BE A POWER OF TWO
+ * SO THAT wmask BELOW IS ALL ONES
+ */
+typedef long word; /* "word" used for optimal copy speed */
+
+#define wsize sizeof(word)
+#define wmask (wsize - 1)
+
+/*
+ * Copy a block of memory, handling overlap.
+ * This is the routine that actually implements
+ * (the portable versions of) bcopy, memcpy, and memmove.
+ */
+#ifdef MEMCOPY
+void *
+memcpy(void *dst0, const void *src0, size_t length)
+#else
+#ifdef MEMMOVE
+void *
+memmove(void *dst0, const void *src0, size_t length)
+#else
+void
+bcopy(const void *src0, void *dst0, size_t length)
+#endif
+#endif
+{
+ char *dst = dst0;
+ const char *src = src0;
+ size_t t;
+
+ if (length == 0 || dst == src) /* nothing to do */
+ goto done;
+
+ /*
+ * Macros: loop-t-times; and loop-t-times, t>0
+ */
+#define TLOOP(s) if (t) TLOOP1(s)
+#define TLOOP1(s) do { s; } while (--t)
+
+ if ((unsigned long)dst < (unsigned long)src) {
+ /*
+ * Copy forward.
+ */
+ t = (long)src; /* only need low bits */
+ if ((t | (long)dst) & wmask) {
+ /*
+ * Try to align operands. This cannot be done
+ * unless the low bits match.
+ */
+ if ((t ^ (long)dst) & wmask || length < wsize)
+ t = length;
+ else
+ t = wsize - (t & wmask);
+ length -= t;
+ TLOOP1(*dst++ = *src++);
+ }
+ /*
+ * Copy whole words, then mop up any trailing bytes.
+ */
+ t = length / wsize;
+ TLOOP(*(word *)dst = *(word *)src; src += wsize; dst += wsize);
+ t = length & wmask;
+ TLOOP(*dst++ = *src++);
+ } else {
+ /*
+ * Copy backwards. Otherwise essentially the same.
+ * Alignment works as before, except that it takes
+ * (t&wmask) bytes to align, not wsize-(t&wmask).
+ */
+ src += length;
+ dst += length;
+ t = (long)src;
+ if ((t | (long)dst) & wmask) {
+ if ((t ^ (long)dst) & wmask || length <= wsize)
+ t = length;
+ else
+ t &= wmask;
+ length -= t;
+ TLOOP1(*--dst = *--src);
+ }
+ t = length / wsize;
+ TLOOP(src -= wsize; dst -= wsize; *(word *)dst = *(word *)src);
+ t = length & wmask;
+ TLOOP(*--dst = *--src);
+ }
+done:
+#if defined(MEMCOPY) || defined(MEMMOVE)
+ return (dst0);
+#else
+ return;
+#endif
+}