Lunatic: add 'randgen' module, implementing an encapsulated JKISS PRNG.

Also fix error handling path in our_require(), i.e. when loadstring fails.

git-svn-id: https://svn.eduke32.com/eduke32@2857 1a8010ca-5511-0410-912e-c29ae57300e0

polymer/eduke32/Makefile

@@ -166,7 +166,8 @@ ifneq (0,$(LUNATIC))
     GAMEOBJS+= $(OBJ)/../lpeg.$o  # TEMP
     GAMEOBJS+= $(OBJ)/luaJIT_BC_con_lang.$o \
                $(OBJ)/luaJIT_BC_lunacon.$o \
-               $(OBJ)/luaJIT_BC_geom.$o
+               $(OBJ)/luaJIT_BC_geom.$o \
+               $(OBJ)/luaJIT_BC_randgen.$o
 
     # now, take care of having the necessary symbols (sector, wall, etc.) in the
     # executable no matter what the debugging level

polymer/eduke32/source/lunatic/defs.ilua

@@ -482,6 +482,19 @@ void kclose(int32_t handle);
 int32_t kread(int32_t handle, void *buffer, int32_t leng);
 ]]
 
+-- JKISS PRNG state struct and functions, see randgen module
+ffi.cdef[[
+typedef struct {
+    uint32_t x, y, z, c;
+} rng_jkiss_t;
+]]
+decl[[
+uint32_t rand_jkiss_u32(rng_jkiss_t *s);
+double rand_jkiss_dbl(rng_jkiss_t *s);
+
+void md4once(const unsigned char *block, unsigned int len, unsigned char digest[16]);
+]]
+
 ffi.cdef[[
 int32_t ksqrt(uint32_t num);
 ]]
@@ -523,6 +536,8 @@ local string_dump = string.dump
 string.dump = nil
 
 
+gv_tmp = gv_  -- required by randgen
+
 local allowed_modules = {
     coroutine=coroutine, bit=bit, table=table, math=math, string=string,
 
@@ -530,6 +545,7 @@ local allowed_modules = {
         clock = function() return gv_.gethitickms()/1000 end,
     },
 
+    randgen = require("randgen"),
     geom = require("geom"),
 }
 
@@ -620,7 +636,7 @@ local function our_require(modname)
 
     local modfunc, errmsg = loadstring(str)
     if (modfunc == nil) then
-        errorf(ERRLEV-1, "Couldn't load \"%s\": %s", fn, errmsg)
+        errorf(ERRLEV-1, "Couldn't load \"%s\": %s", modname, errmsg)
     end
 
     local modtab = modfunc(modname)

polymer/eduke32/source/lunatic/dynsymlist

@@ -41,6 +41,11 @@ g_player;
 luaJIT_BC_lunacon;
 luaJIT_BC_con_lang;
 luaJIT_BC_geom;
+luaJIT_BC_randgen;
+
+rand_jkiss_u32;
+rand_jkiss_dbl;
+md4once;
 
 gethitickms;
 };

polymer/eduke32/source/lunatic/lunatic.c

@@ -35,6 +35,35 @@ static int32_t SetActor_luacf(lua_State *L);
 // in lpeg.o
 extern int luaopen_lpeg(lua_State *L);
 
+
+typedef struct {
+    uint32_t x, y, z, c;
+} rng_jkiss_t;
+
+// See: Good Practice in (Pseudo) Random Number Generation for
+//      Bioinformatics Applications, by David Jones
+ATTRIBUTE((optimize("O2")))
+uint32_t rand_jkiss_u32(rng_jkiss_t *s)
+{
+    uint64_t t;
+    s->x = 314527869 * s->x + 1234567;
+    s->y ^= s->y << 5; s->y ^= s->y >> 7; s->y ^= s->y << 22;
+    t = 4294584393ULL * s->z + s->c; s->c = t >> 32; s->z = t;
+    return s->x + s->y + s->z;
+}
+
+ATTRIBUTE((optimize("O2")))
+double rand_jkiss_dbl(rng_jkiss_t *s)
+{
+    double x;
+    unsigned int a, b;
+    a = rand_jkiss_u32(s) >> 6; /* Upper 26 bits */
+    b = rand_jkiss_u32(s) >> 5; /* Upper 27 bits */
+    x = (a * 134217728.0 + b) / 9007199254740992.0;
+    return x;
+}
+
+
 void El_PrintTimes(void)
 {
     int32_t i;

polymer/eduke32/source/lunatic/randgen.lua

@@ -0,0 +1,78 @@
+-- Pseudo random number generation module for Lunatic
+
+local ffi = require("ffi")
+local ffiC = ffi.C
+
+local rawset = rawset
+
+local type = type
+local gv = gv_tmp  -- temporarily set in defs.c
+
+local print = print  -- for commented out debug block in new() below
+
+module(...)
+
+
+-- NOTE: PRNG state struct and functions are declared in defs.ilua
+
+ffi.cdef[[
+typedef union { unsigned char u[16]; double d[2]; } uchar_double_u_t;
+typedef union { unsigned char u[16]; uint32_t i[4]; } uchar_uint_u_t;
+]]
+
+local mt = {
+    __tostring = function(s)
+        return "rand.new("..s.x..","..s.y..","..s.z..","..s.c..")"
+    end,
+
+    __index = {
+        getu32 = ffiC.rand_jkiss_u32,
+        getdbl = ffiC.rand_jkiss_dbl,
+
+        -- Initialize the JKISS PRNG using the MD4 of the lower bits of the
+        -- profiling timer
+        init_time_md4 = function(s)
+            local tin = ffi.new("uchar_double_u_t")
+            local tout = ffi.new("uchar_uint_u_t")
+
+            repeat
+                tin.d[0] = gv.gethitickms() % 1
+                tin.d[1] = gv.gethitickms() % 1
+
+                ffiC.md4once(tin.u, 16, tout.u)
+
+                s.y = tout.u[1]
+            until (s.y ~= 0)  -- y must not be zero!
+
+            s.x = tout.u[0]
+            s.z = tout.u[2]
+            s.c = tout.u[3] % 698769068 + 1  -- Should be less than 698769069
+        end,
+    },
+}
+local jkiss = ffi.metatype("rng_jkiss_t", mt)
+
+function new(x,y,z,c)
+    local s
+    if (x == nil or type(x)=="boolean") then
+        s = jkiss(0,0,0,0)  -- invalid state, must be initialized first
+        if (x) then
+            s:init_time_md4()
+        end
+    else
+        s = jkiss(x,y,z,c)
+    end
+--[[
+    print("TEST")
+    local r=ffi.new("rng_jkiss_t")
+    r.x = 123456789; r.y = 987654321; r.z = 43219876; r.c = 6543217;
+
+    t=gv.gethitickms()
+    for i=1,4*2*1e6 do
+        ffiC.rand_jkiss_dbl(r)
+    end
+    print("TIME: "..gv.gethitickms()-t)  -- x86_64: approx. 100 ms
+--]]
+
+    return s
+end

polymer/eduke32/source/lunatic/test/test_geom.lua

@@ -1,22 +1,49 @@
 #!/usr/bin/env luajit
 
-local math = require("math")
 local os = require("os")
 
 local geom = require("geom")
 
 
-local N = os.exit and tostring(arg[1]) or 1e6
+local N = os.exit and (arg[1] and tostring(arg[1])) or 1e6
 
 local A,B = {}, {}
 local V,W = {}, {}
 
-local function randvec()
-    return geom.vec2(math.random(), math.random())
+local randvec
+
+if (os.exit) then
+    local math = require("math")
+
+    randvec = function()
+        return geom.vec2(math.random(), math.random())
+    end
+else
+    local randgen = require("randgen")
+    local s = randgen.new(true)
+
+    -- NOTE: factoring out the inner s:getdbl() into a separate function
+    -- reduces performance seriously (about an order of magnitude!)
+    randvec = function()
+        return geom.vec2(s:getdbl(), s:getdbl())
+    end
 end
 
 local t1 = os.clock()
 
+if (os.exit == nil) then
+    local randgen = require("randgen")
+    local r = randgen.new(true)
+
+    for i=1,4*2*N do
+        -- This is to test the performance compared to a direct
+        -- ffiC.rand_jkiss_dbl() call in randgen.lua
+        r:getdbl()
+    end
+end
+
+local t2 = os.clock()
+
 -- init random points and vectors
 for i=1,N do
     A[i] = randvec()
@@ -25,17 +52,20 @@ for i=1,N do
     W[i] = randvec()
 end
 
-local t2 = os.clock()
+local t3 = os.clock()
 
 local v = geom.vec2(0, 0)
 for i=1,N do
     v = v + geom.intersect(A[i],V[i], B[i],W[i], true)
 end
 
-local t3 = os.clock()
+local t4 = os.clock()
 
+-- x86_64 (embedded): approx. 200 ms (vs. the 100 ms of direct
+-- ffiC.rand_jkiss_dbl()):
 print(1000*(t2-t1))
-print(1000*(t3-t2))
+print(1000*(t3-t2))  -- x86_64: approx. 500 ms
+print(1000*(t4-t3))  -- x86_64: approx. 35 ms
 print(v)
 
 return {}  -- appease Lunatic's require