1 files changed, 41 insertions, 0 deletions
diff --git a/unix/boot/bootlib/_bytmov.c b/unix/boot/bootlib/_bytmov.c
new file mode 100644
index 00000000..849d8e52
--- /dev/null
+++ b/unix/boot/bootlib/_bytmov.c
@@ -0,0 +1,41 @@
+/* Copyright(c) 1986 Association of Universities for Research in Astronomy Inc.
+ */
+
+#define	import_spp
+#define import_knames
+#include <iraf.h>
+
+/* BYTMOV -- Byte move from array "a" to array "b".  The move must be
+ * nondestructive, allowing a byte array to be shifted left or right a
+ * few bytes, hence comparison of the addresses of the arrays is necessary
+ * to determine if they overlap.
+ */
+void
+BYTMOV (
+  XCHAR	*a,			/* input byte array			*/
+  XINT	*aoff,			/* first byte in A to be moved		*/
+  XCHAR	*b,			/* output byte array			*/
+  XINT	*boff,			/* first byte in B to be written	*/
+  XINT	*nbytes 		/* number of bytes to move		*/
+)
+{
+	register char	*ip, *op;
+	register int	n = *nbytes;
+	char	*ap, *bp;
+
+	ap = (char *)a + (*aoff - 1);
+	bp = (char *)b + (*boff - 1);
+
+	/* If the two arrays are the same return immediately.  If the move is
+	 * to the left then copy left to right, else copy right to left.
+	 */
+	if (ap == bp) {
+	    return;
+	} else if (bp < ap) {
+	    for (ip=ap, op=bp;  --n >= 0;  )
+		*op++ = *ip++;
+	} else {
+	    for (ip = &ap[n], op = &bp[n];  --n >=  0;  )
+		*--op = *--ip;
+	}
+}