diff --git a/include/budg.h b/include/budg.h
index d92f17b1..cf948c90 100644
--- a/include/budg.h
+++ b/include/budg.h
@@ -33,8 +33,8 @@
 
 void fill_update_array(int *bp, struct sctstr *sp);
 int *get_wp(int *bp, struct sctstr *sp, int cm);
-int gt_bg_nmbr(int *bp, struct sctstr *sp, int comm);
-void pt_bg_nmbr(int *bp, struct sctstr *sp, int comm, int amount);
+int gt_bg_nmbr(int *bp, struct sctstr *sp, i_type comm);
+void pt_bg_nmbr(int *bp, struct sctstr *sp, i_type comm, int amount);
 void get_materials(struct sctstr *sp, int *bp, int *mvec, int check);
 
 extern long money[MAXNOC];
diff --git a/include/commodity.h b/include/commodity.h
index a8741ba5..512f1d0f 100644
--- a/include/commodity.h
+++ b/include/commodity.h
@@ -40,7 +40,7 @@ struct comstr {
     short ef_type;
     natid com_owner;
     short com_uid;
-    int com_type;
+    i_type com_type;
     int com_amount;
     float com_price;
     int com_maxbidder;
diff --git a/include/item.h b/include/item.h
index 4b470516..c616d0b8 100644
--- a/include/item.h
+++ b/include/item.h
@@ -46,9 +46,28 @@ enum {
     NUMPKG = BPKG + 1
 };
 
+typedef enum {
+	I_NONE,
+	I_CIVIL,
+	I_MILIT,
+	I_SHELL,
+	I_GUN,
+	I_PETROL,
+	I_IRON,
+	I_DUST,
+	I_BAR,
+	I_FOOD,
+	I_OIL,
+	I_LCM,
+	I_HCM,
+	I_UW,
+	I_RAD,
+	I_MAX = I_RAD
+} ATTRIBUTE((packed)) i_type;
+
 struct ichrstr {
     int i_mnem;			/* usually the initial letter */
-    int i_vtype;		/* var type */
+    i_type i_vtype;		/* var type */
     int i_value;		/* mortgage value */
     int i_sell;			/* can this be sold? */
     int i_lbs;			/* how hard to move */
diff --git a/include/nsc.h b/include/nsc.h
index 545f23d7..d0e0bba2 100644
--- a/include/nsc.h
+++ b/include/nsc.h
@@ -65,6 +65,14 @@ typedef enum {
 } nsc_type;
 typedef char packed_nsc_type;
 
+/* Return nsc_type for a signed integer with the same size as TYPE.  */
+#define NSC_SITYPE(type)				\
+    (sizeof(type) == 1 ? NSC_CHAR			\
+     : sizeof(type) == sizeof(short) ? NSC_SHORT	\
+     : sizeof(type) == sizeof(int) ? NSC_INT		\
+     : sizeof(type) == sizeof(long) ? NSC_LONG		\
+     : 1/0)
+
 /* Value category */
 typedef enum {
     NSC_NOCAT,
diff --git a/include/product.h b/include/product.h
index 7934c7cf..381327e3 100644
--- a/include/product.h
+++ b/include/product.h
@@ -41,9 +41,9 @@
 enum { MAXPRCON = 3 };
 
 struct pchrstr {
-    u_char p_ctype[MAXPRCON];	/* constituent types */
+    i_type p_ctype[MAXPRCON];	/* constituent types */
     u_short p_camt[MAXPRCON];	/* constituent amounts */
-    int p_type;			/* product item type, or I_NONE if level */
+    i_type p_type;		/* product item type, or I_NONE if level */
     int p_level;		/* level index (NAT_?LEV), or -1 if item */
     int p_cost;			/* dollars / product unit */
     int p_nrndx;		/* index into sect of natural resource */
diff --git a/include/prototypes.h b/include/prototypes.h
index a7ea72a1..7c4fffb4 100644
--- a/include/prototypes.h
+++ b/include/prototypes.h
@@ -65,9 +65,9 @@ extern int check_market(void);
 extern void set_coastal(struct sctstr *);
 extern int sendmessage(struct natstr *, struct natstr *, char *, int);
 extern void gift(int, int, s_char *, int, s_char *);
-extern int display_mark(int, int);
-extern int want_to_abandon(struct sctstr *, int, int, struct lndstr *);
-extern int would_abandon(struct sctstr *, int, int, struct lndstr *);
+extern int display_mark(i_type, int);
+extern int want_to_abandon(struct sctstr *, i_type, int, struct lndstr *);
+extern int would_abandon(struct sctstr *, i_type, int, struct lndstr *);
 extern int nav_map(int, int, int);
 extern int count_pop(register int);
 extern int scuttle_tradeship(struct shpstr *, int);
@@ -102,7 +102,7 @@ extern void planedamage(struct plnstr *, int);
 extern int nukedamage(struct nchrstr *, int, int);
 extern int effdamage(register int, int);
 extern void item_damage(int, short *);
-extern int commdamage(register int, int, int);
+extern int commdamage(int, int, i_type);
 /* check.c */
 extern int check_sect_ok(struct sctstr *);
 extern int check_ship_ok(struct shpstr *);
@@ -511,9 +511,9 @@ extern int snxtitem(register struct nstr_item *, int, s_char *);
 extern int snxtsct(register struct nstr_sect *, s_char *);
 /* supply.c */
 extern void resupply_all(struct lndstr *);
-extern void resupply_commod(struct lndstr *, int);
-extern int supply_commod(int, int, int, int, int);
-extern int try_supply_commod(int, int, int, int, int);
+extern void resupply_commod(struct lndstr *, i_type);
+extern int supply_commod(int, int, int, i_type, int);
+extern int try_supply_commod(int, int, int, i_type, int);
 extern int has_supply(struct lndstr *);
 extern int use_supply(struct lndstr *);
 /* takeover.c */
@@ -578,10 +578,10 @@ extern void prod_nat(int);
 extern int nav_ship(register struct shpstr *);
 /* nav_util.c */
 extern int check_nav(struct sctstr *);
-extern int load_it(register struct shpstr *, register struct sctstr *,
+extern int load_it(struct shpstr *, struct sctstr *,
 		   int);
-extern void unload_it(register struct shpstr *);
-extern void auto_fuel_ship(register struct shpstr *);
+extern void unload_it(struct shpstr *);
+extern void auto_fuel_ship(struct shpstr *);
 /* nxtitemp.c */
 extern s_char *nxtitemp(struct nstr_item *, int);
 /* nxtsctp.c */
diff --git a/include/ship.h b/include/ship.h
index 227a0f84..9239b5c8 100644
--- a/include/ship.h
+++ b/include/ship.h
@@ -82,8 +82,8 @@ struct shpstr {
     short shp_glim;
     coord shp_destx[2];		/* location for ship destination */
     coord shp_desty[2];
-    s_char shp_tstart[TMAX];	/* what goods to pick up at start point */
-    s_char shp_tend[TMAX];	/* what goods to pick up at end point   */
+    i_type shp_tstart[TMAX];	/* what goods to pick up at start point */
+    i_type shp_tend[TMAX];	/* what goods to pick up at end point   */
     short shp_lstart[TMAX];	/* How much do we pick up at the start  */
     short shp_lend[TMAX];	/* How much do we pick up at the end    */
     u_char shp_autonav;		/* autonavigation flags */
diff --git a/include/var.h b/include/var.h
index e42fb531..28bfbffd 100644
--- a/include/var.h
+++ b/include/var.h
@@ -40,21 +40,4 @@
 #define	PLG_INCUBATE	3
 #define	PLG_EXPOSED	4
 
-#define I_NONE		0
-#define I_CIVIL		1
-#define I_MILIT		2
-#define I_SHELL		3
-#define	I_GUN		4
-#define	I_PETROL	5
-#define I_IRON		6
-#define I_DUST		7
-#define I_BAR		8
-#define I_FOOD		9
-#define I_OIL		10
-#define	I_LCM		11
-#define	I_HCM		12
-#define I_UW		13
-#define I_RAD		14
-#define I_MAX		14
-
 #endif /* _VAR_H_ */
diff --git a/src/lib/commands/bomb.c b/src/lib/commands/bomb.c
index 9c3738f1..f8d44741 100644
--- a/src/lib/commands/bomb.c
+++ b/src/lib/commands/bomb.c
@@ -65,7 +65,7 @@ static void plane_bomb(struct emp_qelem *list, struct sctstr *target);
 static void land_bomb(struct emp_qelem *list, struct sctstr *target);
 static void ship_bomb(struct emp_qelem *list, struct sctstr *target);
 
-static int bombcomm[] = {
+static i_type bombcomm[] = {
     I_CIVIL,
     I_MILIT,
     I_SHELL,
diff --git a/src/lib/commands/buy.c b/src/lib/commands/buy.c
index bcaba85e..59972e5e 100644
--- a/src/lib/commands/buy.c
+++ b/src/lib/commands/buy.c
@@ -237,7 +237,7 @@ check_market(void)
 	    tleft = 0;
 	if (tleft > 0.0)
 	    continue;
-	if (CANT_HAPPEN((unsigned)comm.com_type > I_MAX))
+	if (CANT_HAPPEN(comm.com_type <= I_NONE || comm.com_type > I_MAX))
 	    continue;
 	sect = getsectp(comm.com_x, comm.com_y);
 	m = sect->sct_item[comm.com_type];
diff --git a/src/lib/commands/coll.c b/src/lib/commands/coll.c
index c704b638..9ad041d1 100644
--- a/src/lib/commands/coll.c
+++ b/src/lib/commands/coll.c
@@ -101,7 +101,7 @@ coll(void)
     }
     pay = dchr[sect.sct_type].d_value * ((float)sect.sct_effic + 100.0);
     for (i = 0; ichr[i].i_name; i++) {
-	if (ichr[i].i_value == 0 || ichr[i].i_vtype == 0)
+	if (ichr[i].i_value == 0 || ichr[i].i_vtype == I_NONE)
 	    continue;
 	val = sect.sct_item[ichr[i].i_vtype];
 	pay += val * ichr[i].i_value;
diff --git a/src/lib/commands/expl.c b/src/lib/commands/expl.c
index af1ab6b7..38e7135d 100644
--- a/src/lib/commands/expl.c
+++ b/src/lib/commands/expl.c
@@ -56,7 +56,7 @@ explore(void)
     double weight;
     int mcost, dam;
     int infected;
-    int vtype;
+    i_type vtype;
     int amt_src;
     int amt_dst;
     struct ichrstr *ip;
diff --git a/src/lib/commands/load.c b/src/lib/commands/load.c
index c28d8da7..6cc8ae63 100644
--- a/src/lib/commands/load.c
+++ b/src/lib/commands/load.c
@@ -737,7 +737,7 @@ static int
 load_comm_ship(struct sctstr *sectp, struct shpstr *sp,
 	       struct ichrstr *ich, int load_unload, int *nshipsp)
 {
-    register int item = ich->i_vtype;
+    i_type item = ich->i_vtype;
     struct mchrstr *mcp = &mchr[(int)sp->shp_type];
     int ship_amt, ship_max, sect_amt, move_amt;
     int amount;
@@ -940,7 +940,7 @@ static int
 load_comm_land(struct sctstr *sectp, struct lndstr *lp,
 	       struct ichrstr *ich, int load_unload, int *nunitsp)
 {
-    register int item = ich->i_vtype;
+    i_type item = ich->i_vtype;
     struct lchrstr *lcp = &lchr[(int)lp->lnd_type];
     int land_amt, land_max, sect_amt, move_amt;
     int amount;
diff --git a/src/lib/commands/mark.c b/src/lib/commands/mark.c
index c723baa3..78ea9302 100644
--- a/src/lib/commands/mark.c
+++ b/src/lib/commands/mark.c
@@ -92,14 +92,14 @@ pr_mark(struct comstr *comm)
 }
 
 int
-display_mark(int only_itype, int only_cheapest)
+display_mark(i_type only_itype, int only_cheapest)
 {
     struct comstr comm;
     struct comstr comm2;
     int sellers = 0;
     int cnt = 0;
     int cheapest_items[I_MAX + 1];
-    int i;
+    i_type i;
 
     /* Execute trades so report lists only lots that are still available.  */
     check_market();
@@ -111,12 +111,13 @@ display_mark(int only_itype, int only_cheapest)
     pr(" ---  -------------  --  ---------  -----  ----  ------  ------\n");
 
     if (only_cheapest) {
-	for (i = 0; i < I_MAX + 1; i++)
+	for (i = I_NONE + 1; i <= I_MAX; i++)
 	    cheapest_items[i] = -1;
 	for (sellers = 0; getcomm(sellers, &comm); sellers++) {
 	    if (comm.com_owner == 0)
 		continue;
-	    if (CANT_HAPPEN((unsigned)comm.com_type > I_MAX))
+	    if (CANT_HAPPEN(comm.com_type <= I_NONE
+				|| comm.com_type > I_MAX))
 		continue;
 	    if (cheapest_items[comm.com_type] != -1) {
 		getcomm(cheapest_items[comm.com_type], &comm2);
@@ -128,7 +129,7 @@ display_mark(int only_itype, int only_cheapest)
 	    }
 	}
 	CANT_HAPPEN(only_itype != I_NONE); /* not implemented */
-	for (i = 0; i < I_MAX + 1; i++) {
+	for (i = I_NONE + 1; i <= I_MAX; i++) {
 	    if (cheapest_items[i] == -1)
 		continue;
 	    getcomm(cheapest_items[i], &comm);
diff --git a/src/lib/commands/move.c b/src/lib/commands/move.c
index 4fabbe9b..5a226841 100644
--- a/src/lib/commands/move.c
+++ b/src/lib/commands/move.c
@@ -61,7 +61,7 @@ move(void)
     int left;
     int mcost, dam;
     int infected;
-    int vtype;
+    i_type vtype;
     int amt_src;
     int amt_dst;
     struct ichrstr *ip;
@@ -347,7 +347,7 @@ cmd_move_map(s_char *what, coord curx, coord cury, s_char *arg)
 }
 
 int
-want_to_abandon(struct sctstr *sp, int vtype, int amnt, struct lndstr *lp)
+want_to_abandon(struct sctstr *sp, i_type vtype, int amnt, struct lndstr *lp)
 {
     char prompt[80];
 
@@ -368,7 +368,7 @@ want_to_abandon(struct sctstr *sp, int vtype, int amnt, struct lndstr *lp)
 }
 
 int
-would_abandon(struct sctstr *sp, int vtype, int amnt, struct lndstr *lp)
+would_abandon(struct sctstr *sp, i_type vtype, int amnt, struct lndstr *lp)
 {
     int mil, civs, loyalcivs;
 
diff --git a/src/lib/commands/orde.c b/src/lib/commands/orde.c
index 100de2e4..0a1e94b6 100644
--- a/src/lib/commands/orde.c
+++ b/src/lib/commands/orde.c
@@ -238,7 +238,7 @@ orde(void)
 			    level = 0;	/* prevent negatives. */
 			    pr("You must use positive number! Level set to 0.\n");
 			}
-			ship.shp_tstart[sub] = (s_char)i1->i_vtype;
+			ship.shp_tstart[sub] = i1->i_vtype;
 			ship.shp_lstart[sub] = level;
 			pr("Order Set \n");
 			break;
@@ -258,7 +258,7 @@ orde(void)
 			    level = 0;
 			    pr("You must use positive number! Level set to 0.\n");
 			}
-			ship.shp_tend[sub] = (s_char)i1->i_vtype;
+			ship.shp_tend[sub] = i1->i_vtype;
 			ship.shp_lend[sub] = level;
 			pr("Order Set \n");
 			break;
@@ -286,7 +286,7 @@ orde(void)
 		&& (ship.shp_lstart[1] != ' '))) {
 
 	    coord tcord;
-	    s_char tcomm;
+	    i_type tcomm;
 	    short lev[TMAX];
 	    int i;
 
@@ -354,10 +354,10 @@ eta_calc(struct shpstr *sp, s_char *path, int *len, int *nupdates)
 }
 
 static void
-prhold(int hold, int itype, int amt)
+prhold(int hold, i_type itype, int amt)
 {
     if (itype != I_NONE && amt != 0) {
-	if (CANT_HAPPEN((unsigned)itype > I_MAX))
+	if (CANT_HAPPEN(itype <= I_NONE || itype > I_MAX))
 	    return;
 	pr("%d-", hold + 1);
 	pr("%c", ichr[itype].i_mnem);
diff --git a/src/lib/commands/prod.c b/src/lib/commands/prod.c
index 22e0798a..d0641bf4 100644
--- a/src/lib/commands/prod.c
+++ b/src/lib/commands/prod.c
@@ -86,8 +86,8 @@ prod(void)
     int unit_work;		/* sum of component amounts */
     int used;			/* production w/infinite workforce */
     int wforce;
-    int it;
-    u_char vtype;
+    i_type it;
+    i_type vtype;
     s_char *resource;
     s_char maxc[MAXPRCON][10];
     s_char use[MAXPRCON][10];
@@ -249,7 +249,7 @@ prod(void)
 	real = dmin(999.0, (double)act * prodeff);
 	maxr = dmin(999.0, (double)max * prodeff);
 
-	if (vtype != 0) {
+	if (vtype != I_NONE) {
 	    if (real < 0.0)
 		real = 0.0;
 	    /* production backlog? */
@@ -305,7 +305,7 @@ prod(void)
 	pr(" %3.0f%%", p_e * 100.0);
 
 	pr(" %4d", wforce);
-	if (vtype != 0) {
+	if (vtype != I_NONE) {
 	    pr(" %4d", (int)(real + 0.5));
 	} else if (type != SCT_ENLIST) {
 	    switch (pp->p_level) {
@@ -369,7 +369,7 @@ prod(void)
 	    max = 0;
 	    maxr = 0;
 	}
-	if (vtype != 0 || pp->p_level == NAT_ELEV
+	if (vtype != I_NONE || pp->p_level == NAT_ELEV
 	    || pp->p_level == NAT_HLEV)
 	    pr(" %4d\n", min(999, (int)(max * prodeff + 0.05)));
 	else
diff --git a/src/lib/commands/rese.c b/src/lib/commands/rese.c
index abe96531..1eceec2a 100644
--- a/src/lib/commands/rese.c
+++ b/src/lib/commands/rese.c
@@ -116,7 +116,7 @@ rese(void)
 	    pr("The destination sector must be at least 60%% efficient.\n");
 	    return RET_OK;
 	}
-	if (CANT_HAPPEN((unsigned)comm.com_type > I_MAX)) {
+	if (CANT_HAPPEN(comm.com_type <= I_NONE || comm.com_type > I_MAX)) {
 	    pr("The goods have been eaten by a grue.");
 	    return RET_OK;
 	}
diff --git a/src/lib/commands/rout.c b/src/lib/commands/rout.c
index 0c0d276f..755359f1 100644
--- a/src/lib/commands/rout.c
+++ b/src/lib/commands/rout.c
@@ -58,7 +58,7 @@ rout(void)
     int row;
     int y;
     int ry;
-    int i_del;
+    i_type i_del;
     int dir;
     s_char *p;
     s_char what[64];
diff --git a/src/lib/commands/scra.c b/src/lib/commands/scra.c
index b1d700e9..28949986 100644
--- a/src/lib/commands/scra.c
+++ b/src/lib/commands/scra.c
@@ -63,7 +63,7 @@ scra(void)
     struct plchrstr *pp;
     struct lchrstr *lp;
     s_char *p;
-    int i;
+    i_type i;
     struct nstr_item ni2;
     struct plnstr plane;
     struct lndstr land;
@@ -187,7 +187,7 @@ scra(void)
 	    }
 	    pr("%s", prship(&item.ship));
 	    /* FIXME obey ITEM_MAX */
-	    for (i = 1; i <= I_MAX; i++) {
+	    for (i = I_NONE + 1; i <= I_MAX; i++) {
 		sect.sct_item[i] += item.ship.shp_item[i];
 	    }
 	    sect.sct_item[I_LCM] += mp->m_lcm * 2 / 3 * eff;
@@ -254,7 +254,7 @@ scra(void)
 	    lp = &lchr[(int)item.land.lnd_type];
 	    pr("%s", prland(&item.land));
 	    /* FIXME obey ITEM_MAX */
-	    for (i = 1; i <= I_MAX; i++) {
+	    for (i = I_NONE + 1; i <= I_MAX; i++) {
 		sect.sct_item[i] += item.land.lnd_item[i];
 	    }
 	    sect.sct_item[I_LCM] += lp->l_lcm * 2 / 3 * eff;
diff --git a/src/lib/commands/shoo.c b/src/lib/commands/shoo.c
index 0ee78620..780d35ca 100644
--- a/src/lib/commands/shoo.c
+++ b/src/lib/commands/shoo.c
@@ -54,7 +54,7 @@ shoo(void)
     int nshot;
     int mob_cost;
     double m;
-    int item;
+    i_type item;
     struct ichrstr *ip;
     struct lndstr land;
     int targets;
diff --git a/src/lib/commands/thre.c b/src/lib/commands/thre.c
index 38119389..a042d58e 100644
--- a/src/lib/commands/thre.c
+++ b/src/lib/commands/thre.c
@@ -55,7 +55,7 @@ thre(void)
     struct ichrstr *ip;
     s_char *p;
     int thresh;
-    int type;
+    i_type type;
     s_char prompt[128];
     s_char buf[128];
 
diff --git a/src/lib/commands/xdump.c b/src/lib/commands/xdump.c
index a4b6308e..957de34a 100644
--- a/src/lib/commands/xdump.c
+++ b/src/lib/commands/xdump.c
@@ -82,14 +82,6 @@
 /* Selector descriptors for characteristics tables */
 /* FIXME belongs into src/lib/global/ */
 
-/* Return nsc_type for a signed integer with the same size as TYPE.  */
-#define NSC_SITYPE(type)				\
-    (sizeof(type) == 1 ? NSC_CHAR			\
-     : sizeof(type) == sizeof(short) ? NSC_SHORT	\
-     : sizeof(type) == sizeof(int) ? NSC_INT		\
-     : sizeof(type) == sizeof(long) ? NSC_LONG		\
-     : 1/0)
-
 static struct castr dchr_ca[] = {
     {NSC_STRING, 0, 0, offsetof(struct dchrstr, d_name), "name"},
     {NSC_INT, 0, 0, offsetof(struct dchrstr, d_mnem), "mnem"},
@@ -110,7 +102,7 @@ static struct castr dchr_ca[] = {
 static struct castr ichr_ca[] = {
     {NSC_STRING, 0, 0, offsetof(struct ichrstr, i_name), "name"},
     {NSC_INT, 0, 0, offsetof(struct ichrstr, i_mnem), "mnem"},
-    {NSC_INT, 0, 0, offsetof(struct ichrstr, i_vtype), "vtype"},
+    {NSC_SITYPE(i_type), 0, 0, offsetof(struct ichrstr, i_vtype), "vtype"},
     {NSC_INT, 0, 0, offsetof(struct ichrstr, i_value), "value"},
     {NSC_INT, 0, 0, offsetof(struct ichrstr, i_sell), "sell"},
     {NSC_INT, 0, 0, offsetof(struct ichrstr, i_lbs), "lbs"},
@@ -166,9 +158,9 @@ static struct castr mchr_ca[] = {
 static struct castr pchr_ca[] = {
     {NSC_STRING, 0, 0, offsetof(struct pchrstr, p_name), "name"},
     {NSC_STRING, 0, 0, offsetof(struct pchrstr, p_sname), "sname"},
-    {NSC_UCHAR, 0, MAXPRCON, offsetof(struct pchrstr, p_ctype), "ctype"},
+    {NSC_SITYPE(i_type), 0, MAXPRCON, offsetof(struct pchrstr, p_ctype), "ctype"},
     {NSC_USHORT, 0, MAXPRCON, offsetof(struct pchrstr, p_camt), "camt"},
-    {NSC_INT, 0, 0, offsetof(struct pchrstr, p_type), "type"},
+    {NSC_SITYPE(i_type), 0, 0, offsetof(struct pchrstr, p_type), "type"},
     {NSC_INT, 0, 0, offsetof(struct pchrstr, p_level), "level"},
     {NSC_INT, 0, 0, offsetof(struct pchrstr, p_cost), "cost"},
     {NSC_INT, 0, 0, offsetof(struct pchrstr, p_nrndx), "nrndx"},
diff --git a/src/lib/common/damage.c b/src/lib/common/damage.c
index 0071cfab..ce876d79 100644
--- a/src/lib/common/damage.c
+++ b/src/lib/common/damage.c
@@ -52,9 +52,10 @@
 void
 item_damage(int pct, short *item)
 {
-    int i, lose;
+    int lose;
+    i_type i;
 
-    for (i = 1; i <= I_MAX; ++i) {
+    for (i = I_NONE + 1; i <= I_MAX; ++i) {
 	if (opt_SUPER_BARS && i == I_BAR)
 	    continue;
 	lose = roundavg((double)item[i] * pct * 0.01);
@@ -192,7 +193,7 @@ effdamage(register int amt, int dam)
 }
 
 int
-commdamage(register int amt, int dam, int vtype)
+commdamage(int amt, int dam, i_type vtype)
 {
     int lost;
 
diff --git a/src/lib/global/nsc.c b/src/lib/global/nsc.c
index e6e2bcb3..1a9ac5db 100644
--- a/src/lib/global/nsc.c
+++ b/src/lib/global/nsc.c
@@ -141,8 +141,8 @@ struct castr ship_ca[] = {
     {NSC_XCOORD, 0, 0, fldoff(shpstr, shp_destx[1]), "xend"},
     {NSC_YCOORD, 0, 0, fldoff(shpstr, shp_desty[0]), "ystart"},
     {NSC_YCOORD, 0, 0, fldoff(shpstr, shp_desty[1]), "yend"},
-    {NSC_CHAR, 0, TMAX, fldoff(shpstr, shp_tstart), "cargostart"},
-    {NSC_CHAR, 0, TMAX, fldoff(shpstr, shp_tend), "cargoend"},
+    {NSC_SITYPE(i_type), 0, TMAX, fldoff(shpstr, shp_tstart), "cargostart"},
+    {NSC_SITYPE(i_type), 0, TMAX, fldoff(shpstr, shp_tend), "cargoend"},
     {NSC_SHORT, 0, TMAX, fldoff(shpstr, shp_lstart), "amtstart"},
     {NSC_SHORT, 0, TMAX, fldoff(shpstr, shp_lend), "amtend"},
     {NSC_UCHAR, 0, 0, fldoff(shpstr, shp_autonav), "autonav"},
@@ -279,7 +279,7 @@ struct castr lost_ca[] = {
 struct castr commodity_ca[] = {
     {NSC_NATID, 0, 0, fldoff(comstr, com_owner), "owner"},
     {NSC_SHORT, 0, 0, fldoff(comstr, com_uid), "uid"},
-    {NSC_INT, 0, 0, fldoff(comstr, com_type), "type"},
+    {NSC_SITYPE(i_type), 0, 0, fldoff(comstr, com_type), "type"},
     {NSC_INT, 0, 0, fldoff(comstr, com_amount), "amount"},
     {NSC_INT, 0, 0, fldoff(comstr, com_maxbidder), "maxbidder"},
     {NSC_TIME, 0, 0, fldoff(comstr, com_markettime), "markettime"},
diff --git a/src/lib/subs/mission.c b/src/lib/subs/mission.c
index 69665d32..dd52c01e 100644
--- a/src/lib/subs/mission.c
+++ b/src/lib/subs/mission.c
@@ -1264,7 +1264,7 @@ mission_pln_equip(struct plist *plp, struct ichrstr *ip, int flags,
     struct lndstr land;
     struct shpstr ship;
     struct sctstr sect;
-    int itype;
+    i_type itype;
     int rval;
     short *item;
 
diff --git a/src/lib/subs/plnsub.c b/src/lib/subs/plnsub.c
index c02ebd6a..08e43430 100644
--- a/src/lib/subs/plnsub.c
+++ b/src/lib/subs/plnsub.c
@@ -567,7 +567,7 @@ pln_equip(struct plist *plp, struct ichrstr *ip, int flags, s_char mission)
     struct lndstr land;
     struct shpstr ship;
     struct sctstr sect;
-    int itype;
+    i_type itype;
     int rval;
     short *item;
     int own;
diff --git a/src/lib/subs/show.c b/src/lib/subs/show.c
index df4142fb..6172a418 100644
--- a/src/lib/subs/show.c
+++ b/src/lib/subs/show.c
@@ -419,8 +419,9 @@ show_ship_stats(int tlev)
 void
 show_ship_capab(int tlev)
 {
-    register struct mchrstr *mp;
-    register int i;
+    struct mchrstr *mp;
+    i_type i;
+    int j;
     int scount;
     int n;
     s_char *p;
@@ -436,14 +437,14 @@ show_ship_capab(int tlev)
 
 	pr("%-25.25s ", mp->m_name);
 
-	for (i = 0; i <= I_MAX; ++i)
+	for (i = I_NONE + 1; i <= I_MAX; ++i)
 	    if (mp->m_item[i])
 		pr(" %d%c", mp->m_item[i], ichr[i].i_mnem);
 	pr(" ");
-	for (i = n = 0; i < 32; i++) {
-	    if (!(mp->m_flags & bit(i)))
+	for (j = n = 0; j < 32; j++) {
+	    if (!(mp->m_flags & bit(j)))
 		continue;
-	    if (NULL != (p = lookup(bit(i), ship_flags))) {
+	    if (NULL != (p = lookup(bit(j), ship_flags))) {
 		if (n++ > 0)
 		    pr(" ");
 		pr(p);
@@ -546,8 +547,9 @@ show_land_capab(int tlev)
 {
     struct lchrstr *lcp;
     int lcount;
-    register int i, n;
-    register s_char *p;
+    i_type i;
+    int j, n;
+    s_char *p;
 
     pr("%25s capabilities\n", "");
 
@@ -559,14 +561,14 @@ show_land_capab(int tlev)
 
 	pr("%-25s ", lcp->l_name);
 
-	for (i = 0; i <= I_MAX; ++i)
+	for (i = I_NONE + 1; i <= I_MAX; ++i)
 	    if (lcp->l_item[i])
 		pr(" %d%c", lcp->l_item[i], ichr[i].i_mnem);
 	pr(" ");
-	for (i = n = 0; i < 32; i++) {
-	    if (!(lcp->l_flags & bit(i)))
+	for (j = n = 0; j < 32; j++) {
+	    if (!(lcp->l_flags & bit(j)))
 		continue;
-	    if (NULL != (p = lookup(bit(i), land_flags))) {
+	    if (NULL != (p = lookup(bit(j), land_flags))) {
 		if (n++ > 0)
 		    pr(" ");
 		pr(p);
diff --git a/src/lib/subs/supply.c b/src/lib/subs/supply.c
index 3739dcf3..ec6b2077 100644
--- a/src/lib/subs/supply.c
+++ b/src/lib/subs/supply.c
@@ -49,8 +49,8 @@
 #include "player.h"
 #include "prototypes.h"
 
-static int get_minimum(struct lndstr *, int);
-static int s_commod(int, int, int, int, int, int);
+static int get_minimum(struct lndstr *, i_type);
+static int s_commod(int, int, int, i_type, int, int);
 
 /*
  * We want to get enough guns to be maxed out, enough shells to
@@ -84,7 +84,7 @@ resupply_all(struct lndstr *lp)
  */
 
 void
-resupply_commod(struct lndstr *lp, int type)
+resupply_commod(struct lndstr *lp, i_type type)
 {
     int amt;
     struct lchrstr *lcp;
@@ -131,7 +131,7 @@ resupply_commod(struct lndstr *lp, int type)
  * Actually get the commod
  */
 int
-supply_commod(int own, int x, int y, int type, int total_wanted)
+supply_commod(int own, int x, int y, i_type type, int total_wanted)
 {
     if (total_wanted < 0)
 	return 0;
@@ -142,7 +142,7 @@ supply_commod(int own, int x, int y, int type, int total_wanted)
  * Just return the number you COULD get, without doing it
  */
 int
-try_supply_commod(int own, int x, int y, int type, int total_wanted)
+try_supply_commod(int own, int x, int y, i_type type, int total_wanted)
 {
     if (total_wanted < 0)
 	return 0;
@@ -152,7 +152,7 @@ try_supply_commod(int own, int x, int y, int type, int total_wanted)
 
 /* Get supplies of a certain type */
 static int
-s_commod(int own, int x, int y, int type, int total_wanted,
+s_commod(int own, int x, int y, i_type type, int total_wanted,
 	 int actually_doit)
 {
     int wanted = total_wanted;
@@ -433,7 +433,7 @@ s_commod(int own, int x, int y, int type, int total_wanted,
  */
 
 static int
-get_minimum(struct lndstr *lp, int type)
+get_minimum(struct lndstr *lp, i_type type)
 {
     struct lchrstr *lcp;
     int max, want = 0;
diff --git a/src/lib/subs/trdsub.c b/src/lib/subs/trdsub.c
index c860a2aa..0f27a73b 100644
--- a/src/lib/subs/trdsub.c
+++ b/src/lib/subs/trdsub.c
@@ -133,7 +133,7 @@ trade_desc(struct trdstr *tp, union trdgenstr *tgp)
 	pr("(%3d)  tech %d %d%% %s [",
 	   tp->trd_owner, sp->shp_tech, sp->shp_effic, prship(sp));
 
-	for (i = 1; i <= I_MAX; ++i) {
+	for (i = I_NONE + 1; i <= I_MAX; ++i) {
 	    if (sp->shp_item[i])
 		pr("%c:%d ", ichr[i].i_mnem, sp->shp_item[i]);
 	}
@@ -191,7 +191,7 @@ trade_desc(struct trdstr *tp, union trdgenstr *tgp)
 	pr("(%3d)  tech %d %d%% %s [",
 	   tp->trd_owner,
 	   lp->lnd_tech, lp->lnd_effic, lchr[(int)lp->lnd_type].l_name);
-	for (i = 1; i <= I_MAX; ++i) {
+	for (i = I_NONE + 1; i <= I_MAX; ++i) {
 	    if (lp->lnd_item[i])
 		pr("%c:%d ", ichr[i].i_mnem, lp->lnd_item[i]);
 	}
@@ -252,7 +252,7 @@ get_couval(int cnum)
 	secttot += (long)(dchr[sp->sct_type].d_value *
 			  ((float)sp->sct_effic + 100.0));
 	for (k = 0; ichr[k].i_name; k++) {
-	    if (ichr[k].i_value == 0 || ichr[k].i_vtype == 0)
+	    if (ichr[k].i_value == 0 || ichr[k].i_vtype == I_NONE)
 		continue;
 	    val = sp->sct_item[ichr[k].i_vtype];
 	    secttot += val * ichr[k].i_value;
diff --git a/src/lib/update/bp.c b/src/lib/update/bp.c
index 7dfa6485..8d32c32d 100644
--- a/src/lib/update/bp.c
+++ b/src/lib/update/bp.c
@@ -52,7 +52,7 @@ get_wp(int *bp, struct sctstr *sp, int cm)
 }
 
 int
-gt_bg_nmbr(int *bp, struct sctstr *sp, int comm)
+gt_bg_nmbr(int *bp, struct sctstr *sp, i_type comm)
 {
     int *wp;
     int cm;
@@ -66,7 +66,7 @@ gt_bg_nmbr(int *bp, struct sctstr *sp, int comm)
 }
 
 void
-pt_bg_nmbr(int *bp, struct sctstr *sp, int comm, int amount)
+pt_bg_nmbr(int *bp, struct sctstr *sp, i_type comm, int amount)
 {
     int *wp;
     int cm;
@@ -80,10 +80,11 @@ pt_bg_nmbr(int *bp, struct sctstr *sp, int comm, int amount)
 void
 fill_update_array(int *bp, struct sctstr *sp)
 {
-    int i, k;
+    int k;
     int *wp;
+    i_type i;
 
-    for (i = 1; i <= I_MAX; i++)
+    for (i = I_NONE + 1; i <= I_MAX; i++)
 	if ((k = bud_key[i]) != 0) {
 	    wp = get_wp(bp, sp, k);
 	    *wp = sp->sct_item[i];
diff --git a/src/lib/update/deliver.c b/src/lib/update/deliver.c
index 400bbf0d..5829e6e9 100644
--- a/src/lib/update/deliver.c
+++ b/src/lib/update/deliver.c
@@ -45,11 +45,11 @@
 #define DELIVER_BONUS 4.0
 
 static int
-deliver(register struct sctstr *from, struct ichrstr *ip, int dir,
+deliver(struct sctstr *from, struct ichrstr *ip, int dir,
 	int thresh, int amt_src, int plague, i_packing packing)
 {
-    register struct sctstr *to;
-    int vtype;			/* item vartype */
+    struct sctstr *to;
+    i_type vtype;			/* item vartype */
     int amt_moved;
     int amt_dst;
     int mobility;
@@ -119,7 +119,7 @@ deliver(register struct sctstr *from, struct ichrstr *ip, int dir,
 void
 dodeliver(struct sctstr *sp)
 {
-    register int i;
+    i_type i;
     int thresh;
     int dir;
     int plague;
@@ -130,7 +130,7 @@ dodeliver(struct sctstr *sp)
 	return;
     plague = sp->sct_pstage;
     packing = sp->sct_effic >= 60 ? dchr[sp->sct_type].d_pkg : IPKG;
-    for (i = 1; i <= I_MAX; i++) {
+    for (i = I_NONE + 1; i <= I_MAX; i++) {
 	if (sp->sct_del[i] == 0)
 	    continue;
 	thresh = sp->sct_del[i] & ~0x7;
diff --git a/src/lib/update/distribute.c b/src/lib/update/distribute.c
index fba6ec5e..1e60a57e 100644
--- a/src/lib/update/distribute.c
+++ b/src/lib/update/distribute.c
@@ -69,7 +69,7 @@ dodistribute(struct sctstr *sp, int imex, s_char *path, double dist_i_cost,
     int pack;
     double mcost;
     int diff;
-    int item;
+    i_type item;
     int changed;
     int rplague;
     int lplague;
@@ -91,7 +91,7 @@ dodistribute(struct sctstr *sp, int imex, s_char *path, double dist_i_cost,
     sect_packing = sp->sct_effic   >= 60 ? dchr[sp->sct_type].d_pkg : IPKG;
 
     lplague = rplague = changed = 0;
-    for (item = 1; item < I_MAX + 1; item++) {
+    for (item = I_NONE + 1; item <= I_MAX; item++) {
 	if (sp->sct_dist[item] == 0)
 	    continue;
 	ip = &ichr[item];
diff --git a/src/lib/update/material.c b/src/lib/update/material.c
index b45c7b79..7b5f2dea 100644
--- a/src/lib/update/material.c
+++ b/src/lib/update/material.c
@@ -53,7 +53,7 @@ get_materials(struct sctstr *sp, int *bp, int *mvec, int check)
     int i;
     int still_left;
 
-    for (i = 1; i <= I_MAX; i++) {
+    for (i = I_NONE + 1; i <= I_MAX; i++) {
 	if (mvec[i] == 0)
 	    continue;
 
diff --git a/src/lib/update/nav_ship.c b/src/lib/update/nav_ship.c
index 1473f4de..c786e798 100644
--- a/src/lib/update/nav_ship.c
+++ b/src/lib/update/nav_ship.c
@@ -52,7 +52,7 @@
 #include "common.h"
 #include <stdlib.h>
 
-static void swap(register struct shpstr *);
+static void swap(struct shpstr *);
 
 static void
 scuttle_it(register struct shpstr *sp)
@@ -116,10 +116,10 @@ nav_check_atdest(register struct shpstr *sp)
 /* CZ 6/1/94					      */
 
 static void
-swap(register struct shpstr *sp)
+swap(struct shpstr *sp)
 {
     coord tcord;
-    s_char tcomm[TMAX];
+    i_type tcomm[TMAX];
     short lev[TMAX];
     int i;
 
diff --git a/src/lib/update/nav_util.c b/src/lib/update/nav_util.c
index 3e0ab507..4842468f 100644
--- a/src/lib/update/nav_util.c
+++ b/src/lib/update/nav_util.c
@@ -82,16 +82,17 @@ check_nav(struct sctstr *sect)
  * Chad Zabel 6/1/94 
  */
 int
-load_it(register struct shpstr *sp, register struct sctstr *psect, int i)
+load_it(struct shpstr *sp, struct sctstr *psect, int i)
 {
-    int comm, shipown, amount, ship_amt, sect_amt;
+    int shipown, amount, ship_amt, sect_amt;
     int abs_max, max_amt, transfer;
+    i_type comm;
     struct mchrstr *vship;
 
     amount = sp->shp_lend[i];
     shipown = sp->shp_own;
     comm = sp->shp_tend[i];
-    if (CANT_HAPPEN((unsigned)comm > I_MAX))
+    if (CANT_HAPPEN(comm <= I_NONE || comm > I_MAX))
 	return 0;
 
     ship_amt = sp->shp_item[comm];
@@ -157,13 +158,13 @@ load_it(register struct shpstr *sp, register struct sctstr *psect, int i)
  * Chad Zabel 6/1/94  
  */
 void
-unload_it(register struct shpstr *sp)
+unload_it(struct shpstr *sp)
 {
     struct sctstr *sectp;
     int i;
     int landowner;
     int shipown;
-    int comm;
+    i_type comm;
     int sect_amt;
     int ship_amt;
     int max_amt;
@@ -182,7 +183,7 @@ unload_it(register struct shpstr *sp)
 	    continue;
 
 	comm = sp->shp_tend[i];
-	if (CANT_HAPPEN((unsigned)comm > I_MAX))
+	if (CANT_HAPPEN(comm <= I_NONE || comm > I_MAX))
 	    continue;
 	ship_amt = sp->shp_item[comm];
 	sect_amt = sectp->sct_item[comm];
@@ -221,7 +222,7 @@ unload_it(register struct shpstr *sp)
  */
 
 void
-auto_fuel_ship(register struct shpstr *sp)
+auto_fuel_ship(struct shpstr *sp)
 {
     double d;
     int totalfuel = 0;
diff --git a/src/lib/update/produce.c b/src/lib/update/produce.c
index fe4b359c..dc36cf1c 100644
--- a/src/lib/update/produce.c
+++ b/src/lib/update/produce.c
@@ -63,7 +63,7 @@ produce(struct natstr *np, struct sctstr *sp, short *vec, int work,
     double output;
     int actual;
     int unit_work;
-    int item;
+    i_type item;
     int worker_limit;
     int material_limit;
     int material_consume;
@@ -199,7 +199,8 @@ materials_cost(struct pchrstr *pp, short *vec, int *costp)
 static void
 materials_charge(struct pchrstr *pp, short *vec, int count)
 {
-    int i, item, n;
+    int i, n;
+    i_type item;
 
     for (i = 0; i < MAXPRCON; ++i) {
 	item = pp->p_ctype[i];
diff --git a/src/lib/update/sect.c b/src/lib/update/sect.c
index 36e36284..af3f026d 100644
--- a/src/lib/update/sect.c
+++ b/src/lib/update/sect.c
@@ -167,13 +167,13 @@ enlist(short *vec, int etu, int *cost)
 /* Fallout is calculated here. */
 
 static void
-meltitems(int etus, int fallout, int own, short *vec, int type, int x, int y,
+meltitems(int etus, int fallout, int own, short *vec, i_type type, int x, int y,
 	  int uid)
 {
-    int n;
+    i_type n;
     int melt;
 
-    for (n = 1; n <= I_MAX; n++) {
+    for (n = I_NONE + 1; n <= I_MAX; n++) {
 	melt = roundavg(vec[n] * etus * (long)fallout
 			/ (1000.0 * melt_item_denom[n]));
 	if (melt > vec[n])