diff -urN lua-5.1.4-orig/src/lmathlib.c lua-5.1.4/src/lmathlib.c
--- lua-5.1.4-orig/src/lmathlib.c	2007-12-27 22:02:25 +0900
+++ lua-5.1.4/src/lmathlib.c	2010-06-09 10:57:16 +0900
@@ -17,10 +17,66 @@
 #include "lualib.h"
 
 
+#ifdef LUA_NUMBER_FLOAT
+
+#undef PI
+#define PI (3.14159265f)
+#define RADIANS_PER_DEGREE (PI/180.0f)
+
+#undef acos
+#undef asin
+#undef atan
+#undef atan2
+#undef ceil
+#undef cos
+#undef cosh
+#undef exp
+#undef fabs
+#undef floor
+#undef fmod
+#undef frexp
+#undef ldexp
+#undef log
+#undef log10
+#undef modf
+#undef pow
+#undef sin
+#undef sinh
+#undef sqrt
+#undef tan
+#undef tanh
+
+#define acos acosf
+#define asin asinf
+#define atan atanf
+#define atan2 atan2f
+#define ceil ceilf
+#define cos cosf
+#define cosh coshf
+#define exp expf
+#define fabs fabsf
+#define floor floorf
+#define fmod fmodf
+#define frexp frexpf
+#define ldexp ldexpf
+#define log logf
+#define log10 log10f
+#define modf modff
+#define pow powf
+#define sin sinf
+#define sinh sinhf
+#define sqrt sqrtf
+#define tan tanf
+#define tanh tanhf
+
+#else  // !LUA_NUMBER_FLOAT
+
 #undef PI
 #define PI (3.14159265358979323846)
 #define RADIANS_PER_DEGREE (PI/180.0)
 
+#endif  // LUA_NUMBER_FLOAT
+
 
 
 static int math_abs (lua_State *L) {
@@ -94,8 +150,13 @@
 }
 
 static int math_modf (lua_State *L) {
+#ifdef LUA_NUMBER_FLOAT
+  float ip;
+  float fp = modff(luaL_checknumber(L, 1), &ip);
+#else
   double ip;
   double fp = modf(luaL_checknumber(L, 1), &ip);
+#endif
   lua_pushnumber(L, ip);
   lua_pushnumber(L, fp);
   return 2;
diff -urN lua-5.1.4-orig/src/luaconf.h lua-5.1.4/src/luaconf.h
--- lua-5.1.4-orig/src/luaconf.h	2008-02-12 01:25:08 +0900
+++ lua-5.1.4/src/luaconf.h	2010-06-09 10:56:19 +0900
@@ -501,8 +501,9 @@
 ** ===================================================================
 */
 
-#define LUA_NUMBER_DOUBLE
-#define LUA_NUMBER	double
+/* #define LUA_NUMBER_DOUBLE */
+#define LUA_NUMBER_FLOAT
+#define LUA_NUMBER	float
 
 /*
 @@ LUAI_UACNUMBER is the result of an 'usual argument conversion'
@@ -518,11 +519,11 @@
 @@ LUAI_MAXNUMBER2STR is maximum size of previous conversion.
 @@ lua_str2number converts a string to a number.
 */
-#define LUA_NUMBER_SCAN		"%lf"
-#define LUA_NUMBER_FMT		"%.14g"
+#define LUA_NUMBER_SCAN		"%f"
+#define LUA_NUMBER_FMT		"%g"
 #define lua_number2str(s,n)	sprintf((s), LUA_NUMBER_FMT, (n))
 #define LUAI_MAXNUMBER2STR	32 /* 16 digits, sign, point, and \0 */
-#define lua_str2number(s,p)	strtod((s), (p))
+#define lua_str2number(s,p)	strtof((s), (p))
 
 
 /*
@@ -534,8 +535,8 @@
 #define luai_numsub(a,b)	((a)-(b))
 #define luai_nummul(a,b)	((a)*(b))
 #define luai_numdiv(a,b)	((a)/(b))
-#define luai_nummod(a,b)	((a) - floor((a)/(b))*(b))
-#define luai_numpow(a,b)	(pow(a,b))
+#define luai_nummod(a,b)	((a) - floorf((a)/(b))*(b))
+#define luai_numpow(a,b)	(powf(a,b))
 #define luai_numunm(a)		(-(a))
 #define luai_numeq(a,b)		((a)==(b))
 #define luai_numlt(a,b)		((a)<(b))