diff --git a/include/jtag/instruction.h b/include/jtag/instruction.h
index 258f5bb7..c96d59f1 100644
--- a/include/jtag/instruction.h
+++ b/include/jtag/instruction.h
@@ -26,12 +26,14 @@
 #define	JTAG_INSTRUCTION_H
 
 #include <jtag/register.h>
+#include <jtag/data_register.h>
 
 typedef struct instruction instruction;
 
 struct instruction {
 	char *name;
 	tap_register *value;
+	data_register *data_register;
 	instruction *next;
 };
 
diff --git a/jtag/src/part/instruction.c b/jtag/src/part/instruction.c
index 3871564b..d6233656 100644
--- a/jtag/src/part/instruction.c
+++ b/jtag/src/part/instruction.c
@@ -53,6 +53,7 @@ instruction_alloc( const char *name, int len, const char *val )
 	}
 
 	register_init( i->value, val );
+	i->data_register = NULL;
 	i->next = NULL;
 
 	return i;