diff --git a/polymer/eduke32/source/lunatic/bitar.lua b/polymer/eduke32/source/lunatic/bitar.lua
index f92f521ea..454578981 100644
--- a/polymer/eduke32/source/lunatic/bitar.lua
+++ b/polymer/eduke32/source/lunatic/bitar.lua
@@ -1,83 +1,203 @@
 
 -- "Bit array" module based on LuaJIT's BitOp.
 
-local ffi = require "ffi"
 local bit = require "bit"
+local math = require "math"
+
+local ffi = require "ffi"
 
-local error = error
 local assert = assert
+local error = error
 local type = type
 
-local setmetatable=setmetatable
+local tostring = tostring
 
 
 module(...)
 
 
--- Is bit i set in bit array ar?
-function isset(ar, i)
-    return bit.band(ar[bit.rshift(i, 5)], bit.lshift(1, i)) ~= 0
+ffi.cdef[[
+struct bitar { const double maxbidx, maxidx; const intptr_t arptr; }
+]]
+
+local bitar_ct = ffi.typeof("struct bitar")
+local ptr_to_int = ffi.typeof("int32_t *")
+
+local anchor = {}
+
+-- population count of a nibble
+local nibpop = ffi.new("double [?]", 16,
+                       { 0, 1, 1, 2, 1, 2, 2, 3,
+                         1, 2, 2, 3, 2, 3, 3, 4 })
+-- ...and of a byte
+local bytepop = ffi.new("double [?]", 256)
+for i=0,255 do
+    bytepop[i] = nibpop[bit.band(i, 15)] + nibpop[bit.rshift(i, 4)]
+end
+nibpop = nil
+
+local function bitar_from_intar(maxbidx, maxidx, ar)
+    -- We need to have the int32_t[?] array be reachable so that it will not be
+    -- garbage collected
+    local ar_intptr = ffi.cast("intptr_t", ar)
+    anchor[tostring(ar_intptr)] = ar
+
+    -- Leaving the (potential) high trailing bits at 0 lets us not worry
+    -- about them in the population count calculation (__len metamethod).
+    -- Also, this is correct for maxbidx%32 == 0, since BitOp's shifts
+    -- mask the 5 lower bits of the counts.
+    local numremain = bit.band(maxbidx+1, 31)
+    ar[maxidx] = bit.band(ar[maxidx], bit.rshift(-1, 32-numremain))
+
+    return bitar_ct(maxbidx, maxidx, ar_intptr)
 end
 
--- Set bit j in bit array ar.
-function set0(ar, j)
-    local jx = bit.rshift(j, 5)
-    ar[jx] = bit.band(ar[jx], bit.rol(0xfffffffe, j))
+local function setop_common_rel(s1, s2)
+    if (s1.maxbidx ~= s2.maxbidx) then
+        error("bad arguments to bit array set op: must be of same length", 4)
+    end
+
+    local ar1 = ffi.cast(ptr_to_int, s1.arptr)
+    local ar2 = ffi.cast(ptr_to_int, s2.arptr)
+
+    return ar1, ar2
 end
 
--- Clear bit j in bit array ar.
-function set1(ar, j)
-    local jx = bit.rshift(j, 5)
-    ar[jx] = bit.bor(ar[jx], bit.rol(0x00000001, j))
+local function setop_common(s1, s2)
+    if (not ffi.istype(bitar_ct, s1) or not ffi.istype(bitar_ct, s2)) then
+        error("bad arguments to bit array set op: both must be 'bitar' types", 3)
+    end
+
+    local ar1, ar2 = setop_common_rel(s1, s2)
+    local ar = ffi.new("int32_t [?]", s1.maxidx+1)
+
+    return ar, ar1, ar2
 end
 
-local ops = { isset=isset, set0=set0, set1=set1 }
-local mt
-mt = {
-    __index=ops,
+local mt = {
+    --- Operational methods
 
-    -- set ops disguised as arithmetic ones...
-
-    __mul = function(ar1, ar2)  -- set intersection
-        assert(#ar1 == #ar2)
-        local p = {}
-        for i=0,#ar1 do
-            p[i] = bit.band(ar1[i], ar2[i])
+    __add = function(s1, s2)  -- set union
+        local ar, ar1, ar2 = setop_common(s1, s2)
+        for i=0,s1.maxidx do
+            ar[i] = bit.bor(ar1[i], ar2[i])
         end
-        return setmetatable(p, mt)
+        return bitar_from_intar(s1.maxbidx, s1.maxidx, ar)
     end,
 
-    __add = function(ar1, ar2)  -- set union
-        assert(#ar1 == #ar2)
-        local p = {}
-        for i=0,#ar1 do
-            p[i] = bit.bor(ar1[i], ar2[i])
+    __mul = function(s1, s2)  -- set intersection
+        local ar, ar1, ar2 = setop_common(s1, s2)
+        for i=0,s1.maxidx do
+            ar[i] = bit.band(ar1[i], ar2[i])
         end
-        return setmetatable(p, mt)
+        return bitar_from_intar(s1.maxbidx, s1.maxidx, ar)
     end,
 
-    __sub = function(ar1, ar2)  -- set difference
-        assert(#ar1 == #ar2)
-        local p = {}
-        for i=0,#ar1 do
-            p[i] = bit.band(ar1[i], bit.bnot(ar2[i]))
+    __sub = function(s1, s2)  -- set difference
+        local ar, ar1, ar2 = setop_common(s1, s2)
+        for i=0,s1.maxidx do
+            ar[i] = bit.band(ar1[i], bit.bnot(ar2[i]))
         end
-        return setmetatable(p, mt)
+        return bitar_from_intar(s1.maxbidx, s1.maxidx, ar)
+    end,
+
+    __unm = function(s)  -- bitwise NOT
+        local newar = ffi.new("int32_t [?]", s.maxidx+1)
+        local oldar = ffi.cast(ptr_to_int, s.arptr)
+        for i=0,s.maxidx do
+            newar[i] = bit.bnot(oldar[i])
+        end
+        return bitar_from_intar(s.maxbidx, s.maxidx, newar)
+    end,
+
+
+    --- Additional operations
+
+    __index = {
+        -- Is bit i set?
+        isset = function(s, i)
+            if (not (i >= 0 and i<=s.maxbidx)) then
+                error("bad bit index for isset: must be in [0.."..s.maxbidx.."]", 2)
+            end
+            s = ffi.cast(ptr_to_int, s.arptr)
+            return (bit.band(s[bit.rshift(i, 5)], bit.lshift(1, i)) ~= 0)
+        end,
+
+        -- Clear bit i.
+        set0 = function(s, i)
+            if (not (i >= 0 and i<=s.maxbidx)) then
+                error("bad bit index for set0: must be in [0.."..s.maxbidx.."]", 2)
+            end
+            s = ffi.cast(ptr_to_int, s.arptr)
+            local jx = bit.rshift(i, 5)
+            s[jx] = bit.band(s[jx], bit.rol(0xfffffffe, i))
+        end,
+
+        -- Set bit i.
+        set1 = function(s, i)
+            if (not (i >= 0 and i<=s.maxbidx)) then
+                error("bad bit index for set1: must be in [0.."..s.maxbidx.."]", 2)
+            end
+            s = ffi.cast(ptr_to_int, s.arptr)
+            local jx = bit.rshift(i, 5)
+            s[jx] = bit.bor(s[jx], bit.rol(0x00000001, i))
+        end
+    },
+
+
+    --- Relational methods
+
+    __eq = function(s1, s2)  -- set identity
+        local ar1, ar2 = setop_common_rel(s1, s2)
+        for i=0,s1.maxidx do
+            if (bit.bxor(ar1[i], ar2[i]) ~= 0) then
+                return false
+            end
+        end
+        return true
+    end,
+
+    __le = function(s1, s2)
+        local ar1, ar2 = setop_common_rel(s1, s2)
+        for i=0,s1.maxidx do
+            if (bit.band(ar1[i], bit.bnot(ar2[i])) ~= 0) then
+                return false
+            end
+        end
+        return true
+    end,
+
+    __lt = function(s1, s2)
+        return s1 <= s2 and not (s2 == s1)
+    end,
+
+    -- The length operator gets the population count of the bit array, i.e. the
+    -- number of set bits.
+    __len = function(s)
+        local ar = ffi.cast(ptr_to_int, s.arptr)
+        local popcnt = 0
+        for i=0,s.maxidx do
+            popcnt = popcnt + bytepop[bit.band(ar[i], 255)] +
+                bytepop[bit.band(bit.rshift(ar[i], 8), 255)] +
+                bytepop[bit.band(bit.rshift(ar[i], 16), 255)] +
+                bytepop[bit.rshift(ar[i], 24)]
+        end
+        return popcnt
     end,
 
     -- serialization
-    __tostring = function(ar)
-        local maxidx=#ar
-        local size=maxidx+1
+    __tostring = function(s)
+        local size=s.maxidx+1
+        local ar = ffi.cast(ptr_to_int, s.arptr)
 
-        local hdr = "bitar.new('"
+        local hdr = "bitar.new("..s.maxbidx..", '"
         local ofs = #hdr
         local totalstrlen = ofs+8*size+2
         local str = ffi.new("char [?]", totalstrlen)
 
         ffi.copy(str, hdr, ofs)
 
-        for i=0,maxidx do
+        for i=0,s.maxidx do
             -- 'a' is ASCII 97
             for nib=0,7 do
                 str[ofs + 8*i + nib] = 97 + bit.band(bit.rshift(ar[i], 4*nib), 0x0000000f)
@@ -88,51 +208,69 @@ mt = {
 
         return ffi.string(str, totalstrlen)
     end,
+
+    -- On garbage collection of the bitar, clear the array's anchor so that it
+    -- can be collected too.
+    __gc = function(s)
+        anchor[tostring(s.arptr)] = nil
+    end,
 }
 
--- Create new bit array.
--- Returns a table p in which entries p[0] through p[floor((maxbidx+31)/32)]
--- are set to an initialization value: 0 if 0 has been passed, -1 if 1
--- has been passed.
--- Storage: 4 bits/bit + O(1)? (per 32 bits: 64 bits key, 64 bits value)
-function new(maxbidx, initval)
-    local p = {}
+local bitar = ffi.metatype("struct bitar", mt)
 
-    if (type(maxbidx)=="string") then
-        -- string containing hex digits (a..p) given, internal
-        local lstr = maxbidx
+-- Create new bit array.
+function new(maxbidx, initval)
+    if (type(maxbidx) ~= "number" or not (maxbidx >= 0 and maxbidx <= (2^31)-2)) then
+        error("bad argument #1 to bitar.new (must be a number in [0..(2^31)-2])", 2)
+    end
+
+    if (math.floor(maxbidx) ~= maxbidx) then
+        error("bad argument #1 to bitar.new (must be an integral number)")
+    end
+
+    if (type(initval)=="string") then
+        -- string containing hex digits (a..p) given, for INTERNAL use
+
+        local lstr = initval
 
         local numnibs = #lstr
         assert(numnibs%8 == 0)
 
         local size = numnibs/8
         local maxidx = size-1
+        local ar = ffi.new("int32_t [?]", size)
 
         local str = ffi.new("char [?]", numnibs)
         ffi.copy(str, lstr, numnibs)
 
         for i=0,maxidx do
-            p[i] = 0
+            ar[i] = 0
 
             for nib=0,7 do
                 local hexdig = str[8*i + nib]
                 assert(hexdig >= 97 and hexdig < 97+16)
-                p[i] = bit.bor(p[i], bit.lshift(hexdig-97, 4*nib))
+                ar[i] = bit.bor(ar[i], bit.lshift(hexdig-97, 4*nib))
             end
         end
+
+        return bitar_from_intar(maxbidx, maxidx, ar)
+
     else
-        if (type(maxbidx) ~= "number" or not (maxbidx >= 0)) then
-            error("bad argument #1 to newarray (must be a nonnegative number)", 2)
-        end
+        -- User-requested bitar creation.
 
         if (initval ~= 0 and initval ~= 1) then
-            error("bad argument #2 to newarray (must be either 0 or 1)", 2)
+            error("bad argument #2 to bitar.new (must be either 0 or 1)", 2)
         end
 
-        for i=0,maxbidx/32 do
-            p[i] = -initval
+        local maxidx = math.floor(maxbidx/32)
+        local size = maxidx+1
+
+        local ar = ffi.new("int32_t [?]", size)
+
+        if (initval==1) then
+            ffi.fill(ar, size*4, -1)
         end
+
+        return bitar_from_intar(maxbidx, maxidx, ar)
     end
-
-    return setmetatable(p, mt)
 end
diff --git a/polymer/eduke32/source/lunatic/bittest.lua b/polymer/eduke32/source/lunatic/bittest.lua
index 0130c4541..9fa6a2af9 100755
--- a/polymer/eduke32/source/lunatic/bittest.lua
+++ b/polymer/eduke32/source/lunatic/bittest.lua
@@ -3,8 +3,8 @@
 -- Usage: luajit bittest.lua <number or "x"> [-ffi] [-bchk]
 
 local string = require "string"
+local math = require "math"
 
-local bit = require("bit")
 local bitar = require "bitar"
 
 local print = print
@@ -28,6 +28,7 @@ end
 -- based on example from http://bitop.luajit.org/api.html
 
 local m = string.dump and tonumber(arg[1]) or 1e7
+local maxidx = math.floor(m/32)
 
 local ffiar_p, boundchk_p = false, false
 
@@ -46,24 +47,23 @@ function sieve()
     local p = {}
 
     if (ffiar_p) then
-        -- stand-alone using unchecked int32_t array instead of table:
-        -- on x86_64 approx. 100 vs. 160 ms for m = 1e7
-        -- (enabling bound checking makes it be around 170 ms)
+        -- stand-alone using unchecked int32_t array: on x86_64 approx. 80 ms
+        -- for m = 1e7 (enabling bound checking makes it be around 100 ms)
         local ffi = require "ffi"
-        local pp = ffi.new("int32_t [?]", (m+31)/32 + 1)
+        local pp = ffi.new("int32_t [?]", maxidx + 1)
 
         p = pp
 
         if (boundchk_p) then
             local mt = {
                 __index = function(tab,idx)
-                    if (idx >= 0 and idx <= (m+31)/32) then
+                    if (idx >= 0 and idx <= maxidx) then
                         return pp[idx]
                     end
                 end,
 
                 __newindex = function(tab,idx,val)
-                    if (idx >= 0 and idx <= (m+31)/32) then
+                    if (idx >= 0 and idx <= maxidx) then
                         pp[idx] = val
                     end
                 end,
@@ -72,43 +72,73 @@ function sieve()
             p = setmetatable({}, mt)
         end
 
-        for i=0,(m+31)/32 do p[i] = -1; end
+        for i=0,maxidx do p[i] = -1; end
     else
         p = bitar.new(m, 1)
     end
 
     local t = getticks()
 
-    for i=2,m do
-        if (p:isset(i)) then
-            count = count + 1
-            for j=i+i,m,i do p:set0(j); end
+    if (ffiar_p) then
+        local bit = require "bit"
+
+        for i=2,m do
+            if (bit.band(p[bit.rshift(i, 5)], bit.lshift(1, i)) ~= 0) then
+                count = count + 1
+                for j=i+i,m,i do
+                    local jx = bit.rshift(j, 5)
+                    p[jx] = bit.band(p[jx], bit.rol(0xfffffffe, j));
+                end
+            end
+        end
+    else
+        for i=2,m do
+            if (p:isset(i)) then
+                count = count + 1
+                for j=i+i,m,i do p:set0(j); end
+            end
         end
     end
 
+    -- When using bitar module: x86_64: approx. 110 ms
     print(string.format("[%s] Found %d primes up to %d (%.02f ms)",
                         ffiar_p and "ffi-ar"..(boundchk_p and ", bchk" or "") or "tab-ar",
                         count, m, getticks()-t))
 
-    return p
+    return p, count
 end
 
 if (string.dump) then
-    local p = sieve()
+    local function printf(fmt, ...) print(string.format(fmt, ...)) end
+
+    local p, count = sieve()
     local t = getticks()
 
+    if (ffiar_p) then
+        return
+    end
+
     -- test serialization
-    local p2 = bitar.new(string.match(tostring(p), "'(.*)'"))
-    print(getticks()-t)
+    local ser = tostring(p)
+    local maxbidx_str = string.match(ser, '%(([0-9]+),')
+    local p2 = bitar.new(tonumber(maxbidx_str), string.match(ser, "'(.*)'"))
+    printf("serialization + new: %.02f ms", tostring(getticks()-t))
 
-    for i=0,#p do
-        assert(p[i]==p2[i])
+    assert(p==p2)
+    if (m >= 2) then
+        assert(#p == count+2)  -- +2 is because 0 and 1 are set even though they're not primes
     end
 
-    for i = 3,#p do
-        p[i] = nil
+    if (not ffiar_p) then
+        math.randomseed(os.time())
+        local maxbidx = math.random(0, 65536)
+        local p3 = bitar.new(maxbidx, 1)
+        assert(#p3 == maxbidx+1)  -- bits 0 to maxbidx inclusive are set
     end
-
+--[[
     print(p)
     print(p-p)  -- test set difference
+    print(-p)
+--]]
+    assert(p-p == p*(-p))
 end
diff --git a/polymer/eduke32/source/lunatic/defs.ilua b/polymer/eduke32/source/lunatic/defs.ilua
index c56a36293..9b8555a03 100644
--- a/polymer/eduke32/source/lunatic/defs.ilua
+++ b/polymer/eduke32/source/lunatic/defs.ilua
@@ -592,12 +592,17 @@ local function check_literal_am(am)
     end
 end
 
+local actor_ptr_ct = ffi.typeof("actor_u_t *")  -- an unrestricted actor_t pointer
+local con_action_ct = ffi.typeof("con_action_t")
+local con_move_ct = ffi.typeof("con_move_t")
+local con_ai_ct = ffi.typeof("con_ai_t")
+
 local actor_mt = {
     __index = {
         -- action
         set_action = function(a, act)
-            a = ffi.cast("actor_u_t *", a)
-            if (ffi.istype("con_action_t", act)) then
+            a = ffi.cast(actor_ptr_ct, a)
+            if (ffi.istype(con_action_ct, act)) then
                 a.t_data[4] = act.id
                 a.ac = act.ac
             else
@@ -611,8 +616,8 @@ local actor_mt = {
         end,
 
         has_action = function(a, act)
-            a = ffi.cast("actor_u_t *", a)
-            if (ffi.istype("con_action_t", act)) then
+            a = ffi.cast(actor_ptr_ct, a)
+            if (ffi.istype(con_action_ct, act)) then
                 return (a.t_data[4]==act.id)
             else
                 check_literal_am(act)
@@ -622,26 +627,26 @@ local actor_mt = {
 
         -- count
         set_count = function(a)
-            ffi.cast("actor_u_t *", a).t_data[0] = 0
+            ffi.cast(actor_ptr_ct, a).t_data[0] = 0
         end,
 
         get_count = function(a)
-            return ffi.cast("actor_u_t *", a).t_data[0]
+            return ffi.cast(actor_ptr_ct, a).t_data[0]
         end,
 
         -- action count
         reset_acount = function(a)
-            ffi.cast("actor_u_t *", a).t_data[2] = 0
+            ffi.cast(actor_ptr_ct, a).t_data[2] = 0
         end,
 
         get_acount = function(a)
-            return ffi.cast("actor_u_t *", a).t_data[2]
+            return ffi.cast(actor_ptr_ct, a).t_data[2]
         end,
 
         -- move
         set_move = function(a, mov, movflags)
-            a = ffi.cast("actor_u_t *", a)
-            if (ffi.istype("con_move_t", mov)) then
+            a = ffi.cast(actor_ptr_ct, a)
+            if (ffi.istype(con_move_ct, mov)) then
                 a.t_data[1] = mov.id
                 a.mv = mov.mv
             else
@@ -651,15 +656,15 @@ local actor_mt = {
             end
 
             a.t_data[0] = 0
-            local i = a-ffi.cast("actor_u_t *", ffiC.actor[0])
+            local i = a-ffi.cast(actor_ptr_ct, ffiC.actor[0])
             ffiC.sprite[i].hitag = movflags or 0
 
             -- TODO: random angle moveflag
         end,
 
         has_move = function(a, mov)
-            a = ffi.cast("actor_u_t *", a)
-            if (ffi.istype("con_move_t", mov)) then
+            a = ffi.cast(actor_ptr_ct, a)
+            if (ffi.istype(con_move_ct, mov)) then
                 return (a.t_data[1]==mov.id)
             else
                 check_literal_am(mov)
@@ -670,10 +675,10 @@ local actor_mt = {
         -- ai
         set_ai = function(a, ai)
             local oa = a
-            a = ffi.cast("actor_u_t *", a)
+            a = ffi.cast(actor_ptr_ct, a)
 
             -- TODO: literal number AIs?
-            assert(ffi.istype("con_ai_t", ai))
+            assert(ffi.istype(con_ai_ct, ai))
 
             -- NOTE: compare with gameexec.c
             a.t_data[5] = ai.id
@@ -685,9 +690,9 @@ local actor_mt = {
         end,
 
         has_ai = function(a, ai)
-            a = ffi.cast("actor_u_t *", a)
+            a = ffi.cast(actor_ptr_ct, a)
 
-            if (ffi.istype("con_ai_t", ai)) then
+            if (ffi.istype(con_ai_ct, ai)) then
                 return (a.t_data[5]==ai.id)
             else
                 check_literal_am(ai)