2 * Empire - A multi-player, client/server Internet based war game.
3 * Copyright (C) 1986-2014, Dave Pare, Jeff Bailey, Thomas Ruschak,
4 * Ken Stevens, Steve McClure, Markus Armbruster
6 * Empire is free software: you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation, either version 3 of the License, or
9 * (at your option) any later version.
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
16 * You should have received a copy of the GNU General Public License
17 * along with this program. If not, see <http://www.gnu.org/licenses/>.
21 * See files README, COPYING and CREDITS in the root of the source
22 * tree for related information and legal notices. It is expected
23 * that future projects/authors will amend these files as needed.
27 * shpsub.c: Ship subroutine stuff
29 * Known contributors to this file:
31 * Steve McClure, 1996-2000
32 * Markus Armbruster, 2006-2014
50 #include "prototypes.h"
56 static void shp_nav_put_one(struct ulist *);
57 static int shp_check_one_mines(struct ulist *);
58 static int shp_hit_mine(struct shpstr *);
59 static void shp_stays(natid, char *, struct ulist *);
62 shp_sel(struct nstr_item *ni, struct emp_qelem *list)
67 while (nxtitem(ni, &ship)) {
69 * It would be nice to let deities navigate foreign ships, but
70 * much of the code assumes that only the ship's owner can
73 if (!ship.shp_own || ship.shp_own != player->cnum)
76 if (ontradingblock(EF_SHIP, &ship)) {
77 pr("ship #%d inelligible - it's for sale.\n",
84 memset(ship.shp_rpath, 0, sizeof(ship.shp_rpath));
85 putship(ship.shp_uid, &ship);
86 shp_insque(&ship, list);
92 * Return the new list link.
95 shp_insque(struct shpstr *sp, struct emp_qelem *list)
97 struct ulist *mlp = malloc(sizeof(struct ulist));
99 mlp->chrp = (struct empobj_chr *)&mchr[sp->shp_type];
100 mlp->unit.ship = *sp;
101 mlp->mobil = sp->shp_mobil;
102 emp_insque(&mlp->queue, list);
106 /* This function assumes that the list was created by shp_sel */
108 shp_nav(struct emp_qelem *list, double *minmobp, double *maxmobp,
109 int *togetherp, natid actor)
111 struct emp_qelem *qp;
112 struct emp_qelem *next;
123 for (qp = list->q_back; qp != list; qp = next) {
125 mlp = (struct ulist *)qp;
126 sp = &mlp->unit.ship;
127 getship(sp->shp_uid, sp);
128 if (sp->shp_own != actor) {
129 mpr(actor, "%s was sunk at %s\n",
130 prship(sp), xyas(sp->shp_x, sp->shp_y, actor));
131 emp_remque(&mlp->queue);
136 if (*sp->shp_path && !update_running) {
137 shp_stays(actor, "has a sail path", mlp);
138 mpr(actor, "Use `sail <#> -' to reset\n");
142 /* check crew - uws don't count */
143 if (sp->shp_item[I_MILIT] == 0 && sp->shp_item[I_CIVIL] == 0) {
144 shp_stays(actor, "is crewless", mlp);
147 if (!getsect(sp->shp_x, sp->shp_y, §)) {
148 shp_stays(actor, "was sucked into the sky by a strange looking spaceship", mlp); /* heh -KHS */
151 switch (shp_check_nav(sp, §)) {
154 shp_stays(actor, "is caught in a construction zone", mlp);
158 shp_stays(actor, "is landlocked", mlp);
164 shp_stays(actor, "was just swallowed by a big green worm", mlp);
172 if (sp->shp_x != allx || sp->shp_y != ally)
174 if (sp->shp_mobil + 1 < (int)mlp->mobil) {
175 mlp->mobil = sp->shp_mobil;
177 if (mlp->mobil < *minmobp)
178 *minmobp = mlp->mobil;
179 if (mlp->mobil > *maxmobp)
180 *maxmobp = mlp->mobil;
185 shp_nav_put(struct emp_qelem *list, natid actor)
187 struct emp_qelem *qp, *next;
191 for (qp = list->q_back; qp != list; qp = next) {
193 mlp = (struct ulist *)qp;
194 sp = &mlp->unit.ship;
195 mpr(actor, "%s stopped at %s\n",
196 prship(sp), xyas(sp->shp_x, sp->shp_y, actor));
197 shp_nav_put_one(mlp);
202 shp_nav_put_one(struct ulist *mlp)
204 mlp->unit.ship.shp_mobil = (int)mlp->mobil;
205 putship(mlp->unit.ship.shp_uid, &mlp->unit.ship);
206 emp_remque(&mlp->queue);
211 shp_sweep(struct emp_qelem *ship_list, int verbose, int takemob, natid actor)
213 struct emp_qelem *qp;
214 struct emp_qelem *next;
217 int mines, m, max, shells;
221 for (qp = ship_list->q_back; qp != ship_list; qp = next) {
223 mlp = (struct ulist *)qp;
224 if (!(((struct mchrstr *)mlp->chrp)->m_flags & M_SWEEP)) {
226 mpr(actor, "%s doesn't have minesweeping capability!\n",
227 prship(&mlp->unit.ship));
230 if (takemob && mlp->mobil <= 0.0) {
232 mpr(actor, "%s is out of mobility!\n",
233 prship(&mlp->unit.ship));
236 getsect(mlp->unit.ship.shp_x, mlp->unit.ship.shp_y, §);
237 if (sect.sct_type != SCT_WATER) {
239 mpr(actor, "%s is not at sea. No mines there!\n",
240 prship(&mlp->unit.ship));
244 mlp->mobil -= shp_mobcost(&mlp->unit.ship);
245 mlp->unit.ship.shp_mobil = (int)mlp->mobil;
247 putship(mlp->unit.ship.shp_uid, &mlp->unit.ship);
248 if (!(mines = sect.sct_mines))
250 max = ((struct mchrstr *)mlp->chrp)->m_item[I_SHELL];
251 shells = mlp->unit.ship.shp_item[I_SHELL];
252 for (m = 0; mines > 0 && m < 5; m++) {
254 mpr(actor, "Sweep...\n");
256 shells = MIN(max, shells + 1);
257 changed |= map_set(actor, sect.sct_x, sect.sct_y, 'X', 0);
260 sect.sct_mines = mines;
261 mlp->unit.ship.shp_item[I_SHELL] = shells;
262 putship(mlp->unit.ship.shp_uid, &mlp->unit.ship);
264 if (shp_check_one_mines(mlp)) {
276 shp_check_one_mines(struct ulist *mlp)
281 getsect(mlp->unit.ship.shp_x, mlp->unit.ship.shp_y, §);
282 if (sect.sct_type != SCT_WATER)
286 if (chance(DMINE_HITCHANCE(sect.sct_mines))) {
287 actor = mlp->unit.ship.shp_own;
288 shp_hit_mine(&mlp->unit.ship);
290 if (map_set(actor, sect.sct_x, sect.sct_y, 'X', 0))
293 putship(mlp->unit.ship.shp_uid, &mlp->unit.ship);
294 if (!mlp->unit.ship.shp_own)
301 shp_check_mines(struct emp_qelem *ship_list)
303 struct emp_qelem *qp;
304 struct emp_qelem *next;
308 for (qp = ship_list->q_back; qp != ship_list; qp = next) {
310 mlp = (struct ulist *)qp;
311 if (shp_check_one_mines(mlp)) {
322 shp_stays(natid actor, char *str, struct ulist *mlp)
324 mpr(actor, "%s %s & stays in %s\n",
325 prship(&mlp->unit.ship), str,
326 xyas(mlp->unit.ship.shp_x, mlp->unit.ship.shp_y, actor));
327 shp_nav_put_one(mlp);
331 * Can SP navigate in SECTP?
332 * Sector ownership is *not* considered!
333 * Return NAVOK when yes.
334 * Return NAV_02 when it could if the sector was at least 2% efficient.
335 * Return NAV_60 when it could if the sector was at least 60% efficient.
336 * Return NAV_CANAL when it lacks capability M_CANAL.
337 * Return NAV_NONE when this sector type isn't navigable at all.
340 shp_check_nav(struct shpstr *sp, struct sctstr *sectp)
342 switch (dchr[sectp->sct_type].d_nav) {
346 if (mchr[sp->shp_type].m_flags & M_CANAL) {
347 if (sectp->sct_effic < 2)
353 if (sectp->sct_effic < 2)
357 if (sectp->sct_effic < 60)
369 sect_has_dock(struct sctstr *sect)
371 switch (dchr[sect->sct_type].d_nav) {
381 shp_count(struct emp_qelem *list, int wantflags, int nowantflags,
384 struct emp_qelem *qp;
385 struct emp_qelem *next;
389 for (qp = list->q_back; qp != list; qp = next) {
391 mlp = (struct ulist *)qp;
392 if (mlp->unit.ship.shp_x != x || mlp->unit.ship.shp_y != y)
395 (((struct mchrstr *)mlp->chrp)->m_flags & wantflags) != wantflags)
398 ((struct mchrstr *)mlp->chrp)->m_flags & nowantflags)
406 shp_damage_one(struct ulist *mlp, int dam)
408 /* ship might have changed (launched interceptors, missile defense) */
409 getship(mlp->unit.ship.shp_uid, &mlp->unit.ship);
410 shipdamage(&mlp->unit.ship, dam);
411 putship(mlp->unit.ship.shp_uid, &mlp->unit.ship);
412 if (!mlp->unit.ship.shp_own) {
413 emp_remque(&mlp->queue);
419 shp_damage(struct emp_qelem *list, int totdam, int wantflags,
420 int nowantflags, int x, int y)
422 struct emp_qelem *qp;
423 struct emp_qelem *next;
429 || !(count = shp_count(list, wantflags, nowantflags, x, y)))
431 dam = ldround((double)totdam / count, 1);
432 for (qp = list->q_back; qp != list; qp = next) {
434 mlp = (struct ulist *)qp;
435 if (mlp->unit.ship.shp_x != x || mlp->unit.ship.shp_y != y)
438 (((struct mchrstr *)mlp->chrp)->m_flags & wantflags) != wantflags)
441 ((struct mchrstr *)mlp->chrp)->m_flags & nowantflags)
443 shp_damage_one(mlp, dam);
449 shp_contains(struct emp_qelem *list, int newx, int newy, int wantflags,
452 struct emp_qelem *qp;
453 struct emp_qelem *next;
456 for (qp = list->q_back; qp != list; qp = next) {
458 mlp = (struct ulist *)qp;
459 /* If the ship isn't in the requested sector, then continue */
460 if (newx != mlp->unit.ship.shp_x || newy != mlp->unit.ship.shp_y)
463 (((struct mchrstr *)mlp->chrp)->m_flags & wantflags) != wantflags)
466 ((struct mchrstr *)mlp->chrp)->m_flags & nowantflags)
473 static struct ulist *
474 most_valuable_ship(struct emp_qelem *list, coord x, coord y)
476 struct emp_qelem *qp;
477 struct emp_qelem *next;
479 struct ulist *mvs = NULL;
481 for (qp = list->q_back; qp != list; qp = next) {
483 mlp = (struct ulist *)qp;
484 if (mlp->unit.ship.shp_x != x || mlp->unit.ship.shp_y != y)
486 if (((struct mchrstr *)mlp->chrp)->m_flags & M_SUB)
488 if (!((struct mchrstr *)mlp->chrp)->m_nxlight &&
489 !((struct mchrstr *)mlp->chrp)->m_nchoppers &&
490 ((struct mchrstr *)mlp->chrp)->m_cost < 1000 &&
491 !((struct mchrstr *)mlp->chrp)->m_nplanes &&
492 !((struct mchrstr *)mlp->chrp)->m_nland)
498 if (((struct mchrstr *)mlp->chrp)->m_cost * mlp->unit.ship.shp_effic >
499 ((struct mchrstr *)mvs->chrp)->m_cost * mvs->unit.ship.shp_effic)
506 shp_easiest_target(struct emp_qelem *list, int wantflags, int nowantflags)
508 struct emp_qelem *qp;
509 struct emp_qelem *next;
512 int easiest = 9876; /* things start great for victim */
515 for (qp = list->q_back; qp != list; qp = next) {
517 mlp = (struct ulist *)qp;
519 (((struct mchrstr *)mlp->chrp)->m_flags & wantflags) != wantflags)
522 ((struct mchrstr *)mlp->chrp)->m_flags & nowantflags)
524 hard = shp_hardtarget(&mlp->unit.ship);
526 easiest = hard; /* things get worse for victim */
529 return easiest - count;
533 shp_missile_interdiction(struct emp_qelem *list, coord newx, coord newy,
538 struct emp_qelem msl_list, *qp, *newqp;
542 mvs = most_valuable_ship(list, newx, newy);
546 msl_sel(&msl_list, newx, newy, victim, P_T | P_MAR, 0, MI_INTERDICT);
548 for (qp = msl_list.q_back; qp != &msl_list; qp = newqp) {
550 plp = (struct plist *)qp;
552 if (mvs && mission_pln_equip(plp, NULL, 'p') >= 0) {
553 if (msl_launch(&plp->plane, EF_SHIP, prship(&mvs->unit.ship),
554 newx, newy, victim, &sublaunch) < 0)
557 if (msl_hit(&plp->plane,
558 shp_hardtarget(&mvs->unit.ship), EF_SHIP,
559 N_SHP_MISS, N_SHP_SMISS, sublaunch, victim)) {
560 dam = pln_damage(&plp->plane, 'p', 1);
562 "missile interdiction mission does %d damage to %s!\n",
563 dam, prship(&mvs->unit.ship));
564 shp_damage_one(mvs, dam);
566 dam = pln_damage(&plp->plane, 'p', 0);
567 collateral_damage(newx, newy, dam);
569 mvs = most_valuable_ship(list, newx, newy);
571 plp->plane.pln_effic = 0;
572 putplane(plp->plane.pln_uid, &plp->plane);
581 /* Note that this function has a side effect - it uses coastwatch
582 * ranges to see if it should fire upon a ship. So, this function
583 * is expected to return positive if a ship is in range, and 0 if a
584 * ship is not in range. */
586 notify_coastguard(struct emp_qelem *list, int trange, struct sctstr *sectp)
588 struct emp_qelem *qp;
589 struct emp_qelem *next;
594 natp = getnatp(sectp->sct_own);
596 vrange = sectp->sct_type == SCT_RADAR ? 14 : 4;
597 vrange *= tfact(sectp->sct_own, 1.0) * sectp->sct_effic / 100.0;
605 for (qp = list->q_back; qp != list; qp = next) {
607 mlp = (struct ulist *)qp;
608 if (((struct mchrstr *)mlp->chrp)->m_flags & M_SUB)
610 if (natp->nat_flags & NF_COASTWATCH)
611 wu(0, sectp->sct_own,
612 "%s %s sighted at %s\n",
613 cname(mlp->unit.ship.shp_own),
614 prship(&mlp->unit.ship),
615 xyas(mlp->unit.ship.shp_x, mlp->unit.ship.shp_y,
618 setcont(sectp->sct_own, mlp->unit.ship.shp_own, FOUND_COAST);
625 shp_fort_interdiction(struct emp_qelem *list, coord newx, coord newy,
634 signed char notified[MAXNOC];
637 /* Inform neutral and worse */
638 for (i = 0; i < MAXNOC; ++i) {
639 if (relations_with(i, victim) <= NEUTRAL)
645 snxtsct_dist(&ns, newx, newy, fort_max_interdiction_range);
646 while (nxtsct(&ns, &fsect)) {
649 if (fsect.sct_own == victim)
651 if (notified[fsect.sct_own])
653 trange = mapdist(newx, newy, fsect.sct_x, fsect.sct_y);
654 if (notify_coastguard(list, trange, &fsect))
655 notified[fsect.sct_own] = 1;
657 if (opt_NO_FORT_FIRE)
658 return 0; /* Only coastwatch notify in nofortfire */
659 /* Only fire at Hostile ships */
660 for (i = 0; i < MAXNOC; ++i) {
661 if (relations_with(i, victim) >= NEUTRAL)
664 snxtsct_dist(&ns, newx, newy, fort_max_interdiction_range);
665 while (nxtsct(&ns, &fsect)) {
666 if (!notified[fsect.sct_own])
668 range = roundrange(fortrange(&fsect));
669 trange = mapdist(newx, newy, fsect.sct_x, fsect.sct_y);
672 dam = fort_fire(&fsect);
678 mpr(victim, "Incoming fire does %d damage!\n", dam);
680 mpr(victim, "%s fires at you for %d!\n",
681 xyas(fsect.sct_x, fsect.sct_y, victim), dam);
684 "%s fires at %s ships in %s for %d!\n",
685 xyas(fsect.sct_x, fsect.sct_y,
687 cname(victim), xyas(newx, newy, fsect.sct_own), dam);
688 nreport(fsect.sct_own, N_SHP_SHELL, victim, 1);
691 shp_damage(list, totdam, 0, M_SUB, newx, newy);
696 shp_mission_interdiction(struct emp_qelem *list, coord x, coord y,
697 natid victim, int subs)
699 char *what = subs ? "subs" : "ships";
700 int wantflags = subs ? M_SUB : 0;
701 int nowantflags = subs ? 0 : M_SUB;
702 int mission = subs ? MI_SINTERDICT : MI_INTERDICT;
705 dam = unit_interdict(x, y, victim, what,
706 shp_easiest_target(list, wantflags, nowantflags),
709 shp_damage(list, dam, wantflags, nowantflags, x, y);
714 shp_interdict(struct emp_qelem *list, coord newx, coord newy, natid victim)
718 if (shp_contains(list, newx, newy, 0, M_SUB)) {
719 stopping |= shp_fort_interdiction(list, newx, newy, victim);
721 if (shp_contains(list, newx, newy, 0, M_SUB)) {
722 stopping |= shp_mission_interdiction(list, newx, newy, victim, 0);
723 stopping |= shp_missile_interdiction(list, newx, newy, victim);
726 if (shp_contains(list, newx, newy, M_SUB, 0))
727 stopping |= shp_mission_interdiction(list, newx, newy, victim, 1);
731 /* high value of hardtarget is harder to hit */
733 shp_hardtarget(struct shpstr *sp)
737 struct mchrstr *mcp = mchr + sp->shp_type;
740 getsect(sp->shp_x, sp->shp_y, §);
741 onsea = sect.sct_type == SCT_WATER;
742 if (mcp->m_flags & M_SUB)
744 return (int)((sp->shp_effic / 100.0) *
745 (20 + shp_speed(sp) * onsea / 2.0 - vis));
749 shp_hit_mine(struct shpstr *sp)
753 mpr(sp->shp_own, "Kawhomp! Mine detected in %s!\n",
754 xyas(sp->shp_x, sp->shp_y, sp->shp_own));
756 nreport(sp->shp_own, N_HIT_MINE, 0, 1);
759 if (mchr[sp->shp_type].m_flags & M_SWEEP)
762 shipdamage(sp, ldround(m, 1));
768 shp_nav_one_sector(struct emp_qelem *list, int dir, natid actor,
772 struct emp_qelem *qp;
773 struct emp_qelem *next;
775 struct emp_qelem done;
785 if (dir <= DIR_STOP || dir >= DIR_VIEW) {
786 shp_nav_put(list, actor);
791 for (qp = list->q_back; qp != list; qp = next) {
793 mlp = (struct ulist *)qp;
794 newx = xnorm(mlp->unit.ship.shp_x + dx);
795 newy = ynorm(mlp->unit.ship.shp_y + dy);
796 getsect(newx, newy, §);
797 navigate = shp_check_nav(&mlp->unit.ship, §);
798 if (navigate != NAVOK ||
800 && relations_with(sect.sct_own, actor) < FRIENDLY)) {
801 if (navigate == NAV_CANAL)
803 "is too large to fit into the canal system at %s",
804 xyas(newx, newy, actor));
806 sprintf(dp, "can't go to %s", xyas(newx, newy, actor));
808 mpr(actor, "%s\n", dp);
811 shp_stays(actor, dp, mlp);
816 if (mlp->mobil <= 0.0) {
817 shp_stays(actor, "is out of mobility", mlp);
820 mobcost = shp_mobcost(&mlp->unit.ship);
821 mlp->unit.ship.shp_x = newx;
822 mlp->unit.ship.shp_y = newy;
823 if (mlp->mobil - mobcost < -127) {
826 mlp->mobil -= mobcost;
828 mlp->unit.ship.shp_mobil = (int)mlp->mobil;
829 putship(mlp->unit.ship.shp_uid, &mlp->unit.ship);
831 /* Now update the map for this ship */
832 rad_map_set(mlp->unit.ship.shp_own,
833 mlp->unit.ship.shp_x, mlp->unit.ship.shp_y,
834 mlp->unit.ship.shp_effic, mlp->unit.ship.shp_tech,
835 ((struct mchrstr *)mlp->chrp)->m_vrnge);
839 stopping |= shp_sweep(list, 0, 0, actor);
842 stopping |= shp_check_mines(list);
846 /* interdict ships sector by sector */
848 while (!QEMPTY(list)) {
849 mlp = (struct ulist *)list->q_back;
850 newx = mlp->unit.ship.shp_x;
851 newy = mlp->unit.ship.shp_y;
852 stopping |= shp_interdict(list, newx, newy, actor);
853 /* move survivors in this sector to done */
854 for (qp = list->q_back; qp != list; qp = next) {
856 mlp = (struct ulist *)qp;
857 if (mlp->unit.ship.shp_x == newx &&
858 mlp->unit.ship.shp_y == newy) {
860 emp_insque(qp, &done);
864 /* assign surviving ships back to list */
865 emp_insque(list, &done);
873 * Check for incoming missiles with a P_MAR flag.
874 * Return True=1 if the missile was shotdown.
877 * Chad Zabel, July 95
881 shp_missile_defense(coord dx, coord dy, natid bombown, int hardtarget)
886 double gun, eff, teff;
888 snxtitem_dist(&ni, EF_SHIP, dx, dy, 1);
890 while (nxtitem(&ni, &ship)) {
894 if (!(mchr[(int)ship.shp_type].m_flags & M_ANTIMISSILE))
897 if (relations_with(ship.shp_own, bombown) >= NEUTRAL)
900 if (ship.shp_effic < 60)
903 if (ship.shp_item[I_MILIT] < 1) /* do we have mil? */
905 if (ship.shp_item[I_GUN] < 1) /* we need at least 1 gun */
907 if (!shp_supply(&ship, I_SHELL, 2))
909 ship.shp_item[I_SHELL] -= 2;
910 putship(ship.shp_uid, &ship);
912 /* now calculate the odds */
913 gun = shp_usable_guns(&ship);
914 eff = ship.shp_effic / 100.0;
915 teff = ship.shp_tech / (ship.shp_tech + 200.0);
916 /* raise 4.5 for better interception -KHS */
917 hitchance = (int)(gun * eff * teff * 4.5) - hardtarget;
918 hitchance = LIMIT_TO(hitchance, 0, 100);
919 hit = pct_chance(hitchance);
921 mpr(bombown, "%s anti-missile system activated...%s\n",
923 hit ? "KABOOOM!! Missile destroyed\n"
924 : "SWOOSH!! anti-missile system failed!!");
925 mpr(ship.shp_own, "Ship #%i anti-missile system activated!\n",
927 mpr(ship.shp_own, "%d%% hitchance...%s\n", hitchance,
928 hit ? "KABOOOM!! Incoming missile destroyed!\n"
929 : "SWOOSH!! Missile evades anti-missile systems\n");
934 return 0; /* all attempts failed */
938 /* Fire missiles at a ship which has fired shells */
940 shp_missdef(struct shpstr *sp, natid victim)
942 struct emp_qelem list;
948 mlp = shp_insque(sp, &list);
949 sprintf(buf, "%s", prship(&mlp->unit.ship));
952 shp_missile_interdiction(&list, sp->shp_x, sp->shp_y, sp->shp_own);
953 getship(sp->shp_uid, sp);
957 "missiles launched in defense did 100%% damage to %s\n",
959 wu(0, victim, "%s sunk!\n", buf);
960 } else if (eff > 0 && sp->shp_effic < eff) {
962 "missiles launched in defense did %d%% damage to %s\n",
963 100 * (eff - sp->shp_effic) / eff, buf);
970 shp_mobcost(struct shpstr *sp)
972 return speed_factor(sp->shp_effic * 0.01 * shp_speed(sp),
977 * Set SP's tech to TLEV along with everything else that depends on it.
980 shp_set_tech(struct shpstr *sp, int tlev)
982 struct mchrstr *mcp = mchr + sp->shp_type;
984 if (CANT_HAPPEN(tlev < mcp->m_tech))