diff --git a/src/Makefile b/src/Makefile
index 24a0b53..663a286 100644
--- a/src/Makefile
+++ b/src/Makefile
@@ -1,9 +1,11 @@
-OBJS=rk65c02.o bus.o instruction.o 65c02isa.o
+OBJS=rk65c02.o bus.o instruction.o
 LIB_SO=librk65c02.so
 LIB_STATIC=librk65c02.a
 LDFLAGS=-shared
 CFLAGS=-Wall -fpic
 
+65C02ISA=65c02isa
+
 all : $(LIB_SO) $(LIB_STATIC)
 
 $(LIB_SO) : $(OBJS)
@@ -12,10 +14,15 @@ $(LIB_SO) : $(OBJS)
 $(LIB_STATIC) : $(OBJS)
 	$(AR) rcs $(LIB_STATIC) $(OBJS)
 
-%.o : %.c %.h
+$(65C02ISA).h : $(65C02ISA).csv $(65C02ISA).awk
+	awk -f $(65C02ISA).awk $(65C02ISA).csv > $(65C02ISA).h 
+
+# XXX: dependency on 65c02isa.h is only for instruction.c 
+%.o : %.c %.h $(65C02ISA).h
 	$(CC) $(CFLAGS) -c $<
 
 clean :
+	rm -f $(65C02ISA).h
 	rm -f $(OBJS)
 	rm -f $(LIB_SO) $(LIB_STATIC)
 
diff --git a/src/instruction.c b/src/instruction.c
index 0c54676..643fac9 100644
--- a/src/instruction.c
+++ b/src/instruction.c
@@ -114,3 +114,13 @@ disassemble(bus_t *b, uint16_t addr)
 	printf("\n");
 }
 
+instrdef_t
+instrdef_get(uint8_t opcode)
+{
+	instrdef_t id;
+
+	id = instrs[opcode];
+
+	return id;
+}
+
diff --git a/src/instruction.h b/src/instruction.h
index fabbced..e227d84 100644
--- a/src/instruction.h
+++ b/src/instruction.h
@@ -39,5 +39,6 @@ typedef struct instruction instruction_t;
 instruction_t instruction_fetch(bus_t *, uint16_t);
 void instruction_print(instruction_t *);
 void disassemble(bus_t *, uint16_t);
+instrdef_t instrdef_get(uint8_t);
 
 #endif /* _INSTRUCTION_H_ */