Re: Lua and numbers

[ramsdell@... (John D. Ramsdell)]

> From: Gavin Wraith <gavin@wra1th.plus.com>
> Subject: Re: Lua and numbers
>
> > My use of "integer patch" name was probably misleading, it really is
> > either "non-FPU optimization 
> > patch" or "integer optimization patch".

Yeah, all I want is to avoid using all floating point operations.  I
have enclosed the patch I use.  You must define LUA_NUMBER_INTEGRAL,
or you'll get the original behavior of LUA_NUMBER as a double.

John

diff -ur olua-5.1/src/lmathlib.c lua-5.1/src/lmathlib.c
--- olua-5.1/src/lmathlib.c	2005-08-26 13:36:32.000000000 -0400
+++ lua-5.1/src/lmathlib.c	2006-04-10 08:36:30.000000000 -0400
@@ -252,8 +252,10 @@
   luaL_register(L, LUA_MATHLIBNAME, mathlib);
   lua_pushnumber(L, PI);
   lua_setfield(L, -2, "pi");
+#if !defined(LUA_NUMBER_INTEGRAL)
   lua_pushnumber(L, HUGE_VAL);
   lua_setfield(L, -2, "huge");
+#endif
 #if defined(LUA_COMPAT_MOD)
   lua_getfield(L, -1, "fmod");
   lua_setfield(L, -2, "mod");
diff -ur olua-5.1/src/luaconf.h lua-5.1/src/luaconf.h
--- olua-5.1/src/luaconf.h	2006-02-10 12:44:06.000000000 -0500
+++ lua-5.1/src/luaconf.h	2006-04-10 08:43:24.000000000 -0400
@@ -488,14 +488,18 @@
 ** ===================================================================
 */
 
+#if defined LUA_NUMBER_INTEGRAL
+#define LUA_NUMBER	long
+#else
 #define LUA_NUMBER_DOUBLE
 #define LUA_NUMBER	double
+#endif
 
 /*
 @@ LUAI_UACNUMBER is the result of an 'usual argument conversion'
 @* over a number.
 */
-#define LUAI_UACNUMBER	double
+#define LUAI_UACNUMBER	LUA_NUMBER
 
 
 /*
@@ -505,11 +509,20 @@
 @@ LUAI_MAXNUMBER2STR is maximum size of previous conversion.
 @@ lua_str2number converts a string to a number.
 */
+#if defined LUA_NUMBER_INTEGRAL
+#define LUA_NUMBER_SCAN		"%ld"
+#define LUA_NUMBER_FMT		"%ld"
+#else
 #define LUA_NUMBER_SCAN		"%lf"
 #define LUA_NUMBER_FMT		"%.14g"
+#endif
 #define lua_number2str(s,n)	sprintf((s), LUA_NUMBER_FMT, (n))
 #define LUAI_MAXNUMBER2STR	32 /* 16 digits, sign, point, and \0 */
+#if defined LUA_NUMBER_INTEGRAL
+#define lua_str2number(s,p)	strtol((s), (p), 10)
+#else
 #define lua_str2number(s,p)	strtod((s), (p))
+#endif
 
 
 /*
@@ -521,8 +534,14 @@
 #define luai_numsub(a,b)	((a)-(b))
 #define luai_nummul(a,b)	((a)*(b))
 #define luai_numdiv(a,b)	((a)/(b))
+#if defined LUA_NUMBER_INTEGRAL
+#define luai_nummod(a,b)	((a)%(b))
+LUA_NUMBER luai_ipow(LUA_NUMBER, LUA_NUMBER);
+#define luai_numpow(a,b)	(luai_ipow(a,b))
+#else
 #define luai_nummod(a,b)	((a) - floor((a)/(b))*(b))
 #define luai_numpow(a,b)	(pow(a,b))
+#endif
 #define luai_numunm(a)		(-(a))
 #define luai_numeq(a,b)		((a)==(b))
 #define luai_numlt(a,b)		((a)<(b))
diff -ur olua-5.1/src/lvm.c lua-5.1/src/lvm.c
--- olua-5.1/src/lvm.c	2006-01-23 14:51:43.000000000 -0500
+++ lua-5.1/src/lvm.c	2006-04-10 08:44:41.000000000 -0400
@@ -27,6 +27,25 @@
 #include "lvm.h"
 
 
+#if defined LUA_NUMBER_INTEGRAL
+LUA_NUMBER luai_ipow(LUA_NUMBER a, LUA_NUMBER b) {
+  if (b < 0)
+    return 0;
+  else if (b == 0)
+    return 1;
+  else {
+    LUA_NUMBER c = 1;
+    for (;;) {
+      if (b & 1)
+	c *= a;
+      b = b >> 1;
+      if (b == 0)
+	return c;
+      a *= a;
+    }
+  }
+}
+#endif
 
 /* limit for table tag-method chains (to avoid loops) */
 #define MAXTAGLOOP	100