diff --git a/Make.engine b/Make.engine
index 8dac7fe..93eea13 100644
--- a/Make.engine
+++ b/Make.engine
@@ -1,10 +1,14 @@
-OBJS=abCalc.o expr/abCExpr.o expr/abCExpReal.o expr/abCExprInt.o abCStack.o \
-    abCMode.o abCMain.o ops/abCOp.o abCError.o ops/abCOpAdd.o \
-    ops/abCOpSubtr.o ops/abCOpMult.o ops/abCOpDiv.o ops/abCOpPower.o \
-    ops/abCOpAnd.o ops/abCOpOr.o ops/abCOpXor.o ops/abCOpNot.o \
-    ops/abCOpBin.o ops/abCOpOct.o ops/abCOpDec.o ops/abCOpHex.o ops/abCOpStws.o \
-    ops/abCOpRcws.o ops/abCOpSl.o ops/abCOpRl.o ops/abCOpSr.o ops/abCOpRr.o \
-    ops/abCOpAsr.o
+CALC_OBJS=abCalc.o abCStack.o abCMode.o abCError.o
+
+EXPR_OBJS=expr/abCExpr.o expr/abCExpReal.o expr/abCExprInt.o
+
+OPS_OBJS=ops/abCOp.o ops/abCOpAdd.o ops/abCOpSubtr.o ops/abCOpMult.o \
+    ops/abCOpDiv.o ops/abCOpPower.o ops/abCOpAnd.o ops/abCOpOr.o ops/abCOpXor.o \
+    ops/abCOpNot.o ops/abCOpBin.o ops/abCOpOct.o ops/abCOpDec.o ops/abCOpHex.o \
+    ops/abCOpStws.o ops/abCOpRcws.o ops/abCOpSl.o ops/abCOpRl.o ops/abCOpSr.o \
+    ops/abCOpRr.o ops/abCOpAsr.o
+
+OBJS=abCMain.o $(CALC_OBJS) $(EXPR_OBJS) $(OPS_OBJS)
 
 abCMain.o: abCalc.h abCStack.h expr/abCExpr.h ops/abCOp.h abCError.h
 
diff --git a/Make.mac b/Make.mac
index f1bdf8f..343a9d0 100644
--- a/Make.mac
+++ b/Make.mac
@@ -1,6 +1,6 @@
 NAME=abCalc
 
-CFLAGS=-Iexpr -Iops -I.
+CFLAGS=-I.
 
 all: $(NAME)
 
diff --git a/Makefile b/Makefile
index 6df2b2f..970e990 100644
--- a/Makefile
+++ b/Makefile
@@ -9,7 +9,14 @@ $(NAME): $(OBJS)
 
 clean:
 	cp -p rm -f $(NAME) $(OBJS) $(NAME).r $(NAME).root
+	cp -p rm -f *.root
+	cp -p rm -f expr/*.root
+	cp -p rm -f ops/*.root
+
+fixtype:
+	chtyp -l CC *.c *.h
+	chtyp -l CC expr/*.c expr/*.h
+	chtyp -l CC ops/*.c ops/*.h
 
 %.o: %.c
-	chtyp -l CC $<
-	occ -c $<
+	occ $(CFLAGS) -c $<
diff --git a/abCMain.c b/abCMain.c
index 08f99fc..6d74347 100644
--- a/abCMain.c
+++ b/abCMain.c
@@ -9,11 +9,13 @@
 #include <stdlib.h>
 
 #include "abCalc.h"
-#include "abCExpr.h"
 #include "abCStack.h"
-#include "abCOp.h"
 #include "abCError.h"
 
+#include "expr/abCExpr.h"
+
+#include "ops/abCOp.h"
+
 
 char gBuffer[AB_CALC_EXPR_STRING_MAX];
 abCalcExpr gExpr;
diff --git a/abCMode.h b/abCMode.h
index 5a431ce..31aa46e 100644
--- a/abCMode.h
+++ b/abCMode.h
@@ -8,7 +8,7 @@
 #define ABCMODE_H
 
 
-#include "abCExpr.h"
+#include "expr/abCExpr.h"
 
 
 typedef enum abCalcModeIntBase
diff --git a/abCStack.h b/abCStack.h
index 54c4348..b7afa0a 100644
--- a/abCStack.h
+++ b/abCStack.h
@@ -8,7 +8,8 @@
 #define ABCSTACK_H
 
 
-#include "abCExpr.h"
+#include "expr/abCExpr.h"
+
 
 void abCalcStackInit(void);
 
diff --git a/abCalc.c b/abCalc.c
index e74b485..6083b42 100644
--- a/abCalc.c
+++ b/abCalc.c
@@ -4,14 +4,16 @@
  */
 
 
-#include "abCExpr.h"
-#include "abCExprInt.h"
-#include "abCExpReal.h"
 #include "abCMode.h"
 #include "abCStack.h"
-#include "abCOp.h"
 #include "abCError.h"
 
+#include "expr/abCExpr.h"
+#include "expr/abCExprInt.h"
+#include "expr/abCExpReal.h"
+
+#include "ops/abCOp.h"
+
 
 void abCalcInit(void)
 {
diff --git a/expr/abCExpReal.c b/expr/abCExpReal.c
index 1597d05..d6cf157 100644
--- a/expr/abCExpReal.c
+++ b/expr/abCExpReal.c
@@ -9,7 +9,7 @@
 #include <string.h>
 #include <stdlib.h>
 
-#include "abCExpr.h"
+#include "expr/abCExpr.h"
 
 
 static abCalcExpr *abCalcExprRealParse(abCalcExpr *expr, char *buffer);
diff --git a/expr/abCExpr.c b/expr/abCExpr.c
index d2847e8..495951b 100644
--- a/expr/abCExpr.c
+++ b/expr/abCExpr.c
@@ -6,7 +6,7 @@
 
 #include <stdlib.h>
 
-#include "abCExpr.h"
+#include "expr/abCExpr.h"
 
 
 static abCalcExprCallbacks *gCallbacks[abCalcExprTypeMax];
diff --git a/expr/abCExprInt.c b/expr/abCExprInt.c
index f0cbf71..c0cadbb 100644
--- a/expr/abCExprInt.c
+++ b/expr/abCExprInt.c
@@ -8,9 +8,10 @@
 #include <string.h>
 #include <stdlib.h>
 
-#include "abCExpr.h"
 #include "abCMode.h"
 
+#include "expr/abCExpr.h"
+
 
 static abCalcExpr *abCalcExprIntParse(abCalcExpr *expr, char *buffer);
 static char *abCalcExprIntFormat(abCalcExpr *expr, char *buffer);
diff --git a/ops/abCOp.c b/ops/abCOp.c
index cb725fb..6dd01b2 100644
--- a/ops/abCOp.c
+++ b/ops/abCOp.c
@@ -7,33 +7,35 @@
 #include <stdio.h>
 #include <string.h>
 
-#include "abCOp.h"
-#include "abCExpr.h"
 #include "abCError.h"
 #include "abCStack.h"
 
-#include "abCOpAdd.h"
-#include "abCOpSubtr.h"
-#include "abCOpMult.h"
-#include "abCOpDiv.h"
-#include "abCOpPower.h"
+#include "expr/abCExpr.h"
 
-#include "abCOpAnd.h"
-#include "abCOpOr.h"
-#include "abCOpXor.h"
-#include "abCOpNot.h"
-#include "abCOpSl.h"
-#include "abCOpRl.h"
-#include "abCOpSr.h"
-#include "abCOpRr.h"
-#include "abCOpAsr.h"
+#include "ops/abCOp.h"
 
-#include "abCOpBin.h"
-#include "abCOpOct.h"
-#include "abCOpDec.h"
-#include "abCOpHex.h"
-#include "abCOpStws.h"
-#include "abCOpRcws.h"
+#include "ops/abCOpAdd.h"
+#include "ops/abCOpSubtr.h"
+#include "ops/abCOpMult.h"
+#include "ops/abCOpDiv.h"
+#include "ops/abCOpPower.h"
+
+#include "ops/abCOpAnd.h"
+#include "ops/abCOpOr.h"
+#include "ops/abCOpXor.h"
+#include "ops/abCOpNot.h"
+#include "ops/abCOpSl.h"
+#include "ops/abCOpRl.h"
+#include "ops/abCOpSr.h"
+#include "ops/abCOpRr.h"
+#include "ops/abCOpAsr.h"
+
+#include "ops/abCOpBin.h"
+#include "ops/abCOpOct.h"
+#include "ops/abCOpDec.h"
+#include "ops/abCOpHex.h"
+#include "ops/abCOpStws.h"
+#include "ops/abCOpRcws.h"
 
 
 #define AB_CALC_MAX_OPS 128
diff --git a/ops/abCOpAdd.c b/ops/abCOpAdd.c
index ab987a5..4be5ec7 100644
--- a/ops/abCOpAdd.c
+++ b/ops/abCOpAdd.c
@@ -6,15 +6,17 @@
 
 #include <stdio.h>
 
-#include "abCOpAdd.h"
 
-#include "abCOp.h"
 #include "abCError.h"
-#include "abCExpr.h"
-#include "abCExpReal.h"
-#include "abCExprInt.h"
 #include "abCStack.h"
 
+#include "expr/abCExpr.h"
+#include "expr/abCExpReal.h"
+#include "expr/abCExprInt.h"
+
+#include "ops/abCOp.h"
+#include "ops/abCOpAdd.h"
+
 
 #define OP_NAME "+"
 
diff --git a/ops/abCOpAnd.c b/ops/abCOpAnd.c
index 46270b8..f92632a 100644
--- a/ops/abCOpAnd.c
+++ b/ops/abCOpAnd.c
@@ -6,14 +6,15 @@
 
 #include <stdio.h>
 
-#include "abCOpAnd.h"
-
-#include "abCOp.h"
 #include "abCError.h"
-#include "abCExpr.h"
-#include "abCExprInt.h"
 #include "abCStack.h"
 
+#include "expr/abCExpr.h"
+#include "expr/abCExprInt.h"
+
+#include "ops/abCOp.h"
+#include "ops/abCOpAnd.h"
+
 
 #define OP_NAME "AND"
 
diff --git a/ops/abCOpAsr.c b/ops/abCOpAsr.c
index d75681f..736164c 100644
--- a/ops/abCOpAsr.c
+++ b/ops/abCOpAsr.c
@@ -6,15 +6,16 @@
 
 #include <stdio.h>
 
-#include "abCOpAsr.h"
-
-#include "abCOp.h"
 #include "abCError.h"
-#include "abCExpr.h"
-#include "abCExprInt.h"
 #include "abCMode.h"
 #include "abCStack.h"
 
+#include "expr/abCExpr.h"
+#include "expr/abCExprInt.h"
+
+#include "ops/abCOp.h"
+#include "ops/abCOpAsr.h"
+
 
 #define OP_NAME "ASR"
 
diff --git a/ops/abCOpBin.c b/ops/abCOpBin.c
index f78b11f..142d6e1 100644
--- a/ops/abCOpBin.c
+++ b/ops/abCOpBin.c
@@ -6,11 +6,11 @@
 
 #include <stdio.h>
 
-#include "abCOpBin.h"
-
-#include "abCOp.h"
 #include "abCMode.h"
 
+#include "ops/abCOp.h"
+#include "ops/abCOpBin.h"
+
 
 #define OP_NAME "BIN"
 
diff --git a/ops/abCOpDec.c b/ops/abCOpDec.c
index a6a5ee0..018547d 100644
--- a/ops/abCOpDec.c
+++ b/ops/abCOpDec.c
@@ -6,11 +6,11 @@
 
 #include <stdio.h>
 
-#include "abCOpDec.h"
-
-#include "abCOp.h"
 #include "abCMode.h"
 
+#include "ops/abCOp.h"
+#include "ops/abCOpDec.h"
+
 
 #define OP_NAME "DEC"
 
diff --git a/ops/abCOpDiv.c b/ops/abCOpDiv.c
index f30bf82..f3d1a70 100644
--- a/ops/abCOpDiv.c
+++ b/ops/abCOpDiv.c
@@ -6,15 +6,16 @@
 
 #include <stdio.h>
 
-#include "abCOpDiv.h"
-
-#include "abCOp.h"
 #include "abCError.h"
-#include "abCExpr.h"
-#include "abCExpReal.h"
-#include "abCExprInt.h"
 #include "abCStack.h"
 
+#include "expr/abCExpr.h"
+#include "expr/abCExpReal.h"
+#include "expr/abCExprInt.h"
+
+#include "ops/abCOp.h"
+#include "ops/abCOpDiv.h"
+
 
 #define OP_NAME "/"
 
diff --git a/ops/abCOpHex.c b/ops/abCOpHex.c
index e9898ac..9343cb4 100644
--- a/ops/abCOpHex.c
+++ b/ops/abCOpHex.c
@@ -6,11 +6,11 @@
 
 #include <stdio.h>
 
-#include "abCOpHex.h"
-
-#include "abCOp.h"
 #include "abCMode.h"
 
+#include "ops/abCOp.h"
+#include "ops/abCOpHex.h"
+
 
 #define OP_NAME "HEX"
 
diff --git a/ops/abCOpMult.c b/ops/abCOpMult.c
index 5385db1..c5729b3 100644
--- a/ops/abCOpMult.c
+++ b/ops/abCOpMult.c
@@ -6,15 +6,16 @@
 
 #include <stdio.h>
 
-#include "abCOpMult.h"
-
-#include "abCOp.h"
 #include "abCError.h"
-#include "abCExpr.h"
-#include "abCExpReal.h"
-#include "abCExprInt.h"
 #include "abCStack.h"
 
+#include "expr/abCExpr.h"
+#include "expr/abCExpReal.h"
+#include "expr/abCExprInt.h"
+
+#include "ops/abCOp.h"
+#include "ops/abCOpMult.h"
+
 
 #define OP_NAME "*"
 
diff --git a/ops/abCOpNot.c b/ops/abCOpNot.c
index ce8d484..df0d929 100644
--- a/ops/abCOpNot.c
+++ b/ops/abCOpNot.c
@@ -6,14 +6,15 @@
 
 #include <stdio.h>
 
-#include "abCOpNot.h"
-
-#include "abCOp.h"
 #include "abCError.h"
-#include "abCExpr.h"
-#include "abCExprInt.h"
 #include "abCStack.h"
 
+#include "expr/abCExpr.h"
+#include "expr/abCExprInt.h"
+
+#include "ops/abCOp.h"
+#include "ops/abCOpNot.h"
+
 
 #define OP_NAME "NOT"
 
diff --git a/ops/abCOpOct.c b/ops/abCOpOct.c
index da058a8..475c6b7 100644
--- a/ops/abCOpOct.c
+++ b/ops/abCOpOct.c
@@ -6,11 +6,11 @@
 
 #include <stdio.h>
 
-#include "abCOpOct.h"
-
-#include "abCOp.h"
 #include "abCMode.h"
 
+#include "ops/abCOp.h"
+#include "ops/abCOpOct.h"
+
 
 #define OP_NAME "OCT"
 
diff --git a/ops/abCOpOr.c b/ops/abCOpOr.c
index a83cf34..4a413d9 100644
--- a/ops/abCOpOr.c
+++ b/ops/abCOpOr.c
@@ -6,14 +6,15 @@
 
 #include <stdio.h>
 
-#include "abCOpOr.h"
-
-#include "abCOp.h"
 #include "abCError.h"
-#include "abCExpr.h"
-#include "abCExprInt.h"
 #include "abCStack.h"
 
+#include "expr/abCExpr.h"
+#include "expr/abCExprInt.h"
+
+#include "ops/abCOp.h"
+#include "ops/abCOpOr.h"
+
 
 #define OP_NAME "OR"
 
diff --git a/ops/abCOpPower.c b/ops/abCOpPower.c
index 3347ef8..19f63a6 100644
--- a/ops/abCOpPower.c
+++ b/ops/abCOpPower.c
@@ -7,14 +7,15 @@
 #include <math.h>
 #include <stdio.h>
 
-#include "abCOpPower.h"
-
-#include "abCOp.h"
 #include "abCError.h"
-#include "abCExpr.h"
-#include "abCExpReal.h"
 #include "abCStack.h"
 
+#include "expr/abCExpr.h"
+#include "expr/abCExpReal.h"
+
+#include "ops/abCOp.h"
+#include "ops/abCOpPower.h"
+
 
 #define OP_NAME "^"
 
diff --git a/ops/abCOpRcws.c b/ops/abCOpRcws.c
index 6052b6c..e3d3902 100644
--- a/ops/abCOpRcws.c
+++ b/ops/abCOpRcws.c
@@ -6,14 +6,15 @@
 
 #include <stdio.h>
 
-#include "abCOpRcws.h"
-
-#include "abCOp.h"
-#include "abCExpr.h"
-#include "abCExpReal.h"
 #include "abCStack.h"
 #include "abCMode.h"
 
+#include "expr/abCExpr.h"
+#include "expr/abCExpReal.h"
+
+#include "ops/abCOp.h"
+#include "ops/abCOpRcws.h"
+
 
 #define OP_NAME "RCWS"
 
diff --git a/ops/abCOpRl.c b/ops/abCOpRl.c
index 175e7c6..9a0ac99 100644
--- a/ops/abCOpRl.c
+++ b/ops/abCOpRl.c
@@ -6,15 +6,16 @@
 
 #include <stdio.h>
 
-#include "abCOpRl.h"
-
-#include "abCOp.h"
 #include "abCError.h"
-#include "abCExpr.h"
-#include "abCExprInt.h"
 #include "abCMode.h"
 #include "abCStack.h"
 
+#include "expr/abCExpr.h"
+#include "expr/abCExprInt.h"
+
+#include "ops/abCOp.h"
+#include "ops/abCOpRl.h"
+
 
 #define OP_NAME "RL"
 
diff --git a/ops/abCOpRr.c b/ops/abCOpRr.c
index 5b55209..e8bd541 100644
--- a/ops/abCOpRr.c
+++ b/ops/abCOpRr.c
@@ -6,15 +6,16 @@
 
 #include <stdio.h>
 
-#include "abCOpRr.h"
-
-#include "abCOp.h"
 #include "abCError.h"
-#include "abCExpr.h"
-#include "abCExprInt.h"
 #include "abCMode.h"
 #include "abCStack.h"
 
+#include "expr/abCExpr.h"
+#include "expr/abCExprInt.h"
+
+#include "ops/abCOp.h"
+#include "ops/abCOpRr.h"
+
 
 #define OP_NAME "RR"
 
diff --git a/ops/abCOpSl.c b/ops/abCOpSl.c
index 1c7d7a7..c78feb3 100644
--- a/ops/abCOpSl.c
+++ b/ops/abCOpSl.c
@@ -6,14 +6,15 @@
 
 #include <stdio.h>
 
-#include "abCOpSl.h"
-
-#include "abCOp.h"
 #include "abCError.h"
-#include "abCExpr.h"
-#include "abCExprInt.h"
 #include "abCStack.h"
 
+#include "expr/abCExpr.h"
+#include "expr/abCExprInt.h"
+
+#include "ops/abCOp.h"
+#include "ops/abCOpSl.h"
+
 
 #define OP_NAME "SL"
 
diff --git a/ops/abCOpSr.c b/ops/abCOpSr.c
index 6788346..b132580 100644
--- a/ops/abCOpSr.c
+++ b/ops/abCOpSr.c
@@ -6,14 +6,15 @@
 
 #include <stdio.h>
 
-#include "abCOpSr.h"
-
-#include "abCOp.h"
 #include "abCError.h"
-#include "abCExpr.h"
-#include "abCExprInt.h"
 #include "abCStack.h"
 
+#include "expr/abCExpr.h"
+#include "expr/abCExprInt.h"
+
+#include "ops/abCOp.h"
+#include "ops/abCOpSr.h"
+
 
 #define OP_NAME "SR"
 
diff --git a/ops/abCOpStws.c b/ops/abCOpStws.c
index 1646e86..6cd3bf1 100644
--- a/ops/abCOpStws.c
+++ b/ops/abCOpStws.c
@@ -6,14 +6,15 @@
 
 #include <stdio.h>
 
-#include "abCOpStws.h"
-
-#include "abCOp.h"
-#include "abCExpr.h"
 #include "abCError.h"
 #include "abCStack.h"
 #include "abCMode.h"
 
+#include "expr/abCExpr.h"
+
+#include "ops/abCOp.h"
+#include "ops/abCOpStws.h"
+
 
 #define OP_NAME "STWS"
 
diff --git a/ops/abCOpSubtr.c b/ops/abCOpSubtr.c
index 7c264de..b4ad8e0 100644
--- a/ops/abCOpSubtr.c
+++ b/ops/abCOpSubtr.c
@@ -6,15 +6,16 @@
 
 #include <stdio.h>
 
-#include "abCOpSubtr.h"
-
-#include "abCOp.h"
 #include "abCError.h"
-#include "abCExpr.h"
-#include "abCExpReal.h"
-#include "abCExprInt.h"
 #include "abCStack.h"
 
+#include "expr/abCExpr.h"
+#include "expr/abCExpReal.h"
+#include "expr/abCExprInt.h"
+
+#include "ops/abCOp.h"
+#include "ops/abCOpSubtr.h"
+
 
 #define OP_NAME "-"
 
diff --git a/ops/abCOpXor.c b/ops/abCOpXor.c
index a273a83..3c6b9b6 100644
--- a/ops/abCOpXor.c
+++ b/ops/abCOpXor.c
@@ -6,14 +6,15 @@
 
 #include <stdio.h>
 
-#include "abCOpXor.h"
-
-#include "abCOp.h"
 #include "abCError.h"
-#include "abCExpr.h"
-#include "abCExprInt.h"
 #include "abCStack.h"
 
+#include "expr/abCExpr.h"
+#include "expr/abCExprInt.h"
+
+#include "ops/abCOp.h"
+#include "ops/abCOpXor.h"
+
 
 #define OP_NAME "XOR"