1 files changed, 36 insertions, 0 deletions
diff --git a/usr/klibc/memmove.c b/usr/klibc/memmove.c
new file mode 100644
index 0000000..a398cd8
--- /dev/null
+++ b/usr/klibc/memmove.c
@@ -0,0 +1,36 @@
+/*
+ * memmove.c
+ */
+
+#include <string.h>
+
+void *memmove(void *dst, const void *src, size_t n)
+{
+	const char *p = src;
+	char *q = dst;
+#if defined(__i386__) || defined(__x86_64__)
+	if (q < p) {
+		asm volatile("cld; rep; movsb"
+			     : "+c" (n), "+S"(p), "+D"(q));
+	} else {
+		p += (n - 1);
+		q += (n - 1);
+		asm volatile("std; rep; movsb; cld"
+			     : "+c" (n), "+S"(p), "+D"(q));
+	}
+#else
+	if (q < p) {
+		while (n--) {
+			*q++ = *p++;
+		}
+	} else {
+		p += n;
+		q += n;
+		while (n--) {
+			*--q = *--p;
+		}
+	}
+#endif
+
+	return dst;
+}