[syslinux] [PATCH 07/21] lua: use integer arithmetic
Ferenc Wágner
wferi at niif.hu
Tue Oct 15 11:03:35 PDT 2013
---
com32/lua/src/linit.c | 2 ++
com32/lua/src/lmathlib.c | 2 ++
com32/lua/src/loslib.c | 4 +++
com32/lua/src/ltable.c | 15 +++++------
com32/lua/src/luaconf.h | 62 +++++++++++++++++++++++++++++++++++++++++++---
com32/lua/src/lvm.c | 20 +++++++++++++++
6 files changed, 94 insertions(+), 11 deletions(-)
diff --git a/com32/lua/src/linit.c b/com32/lua/src/linit.c
index 8d3aa65..a2ca186 100644
--- a/com32/lua/src/linit.c
+++ b/com32/lua/src/linit.c
@@ -35,7 +35,9 @@ static const luaL_Reg loadedlibs[] = {
{LUA_OSLIBNAME, luaopen_os},
{LUA_STRLIBNAME, luaopen_string},
{LUA_BITLIBNAME, luaopen_bit32},
+#ifndef LUA_NUMBER_INTEGRAL
{LUA_MATHLIBNAME, luaopen_math},
+#endif
{LUA_DBLIBNAME, luaopen_debug},
{NULL, NULL}
};
diff --git a/com32/lua/src/lmathlib.c b/com32/lua/src/lmathlib.c
index a49f1fd..97b935a 100644
--- a/com32/lua/src/lmathlib.c
+++ b/com32/lua/src/lmathlib.c
@@ -272,8 +272,10 @@ LUAMOD_API int luaopen_math (lua_State *L) {
luaL_newlib(L, mathlib);
lua_pushnumber(L, PI);
lua_setfield(L, -2, "pi");
+#ifndef LUA_NUMBER_INTEGRAL
lua_pushnumber(L, HUGE_VAL);
lua_setfield(L, -2, "huge");
+#endif
return 1;
}
diff --git a/com32/lua/src/loslib.c b/com32/lua/src/loslib.c
index 5170fd0..04f8f9c 100644
--- a/com32/lua/src/loslib.c
+++ b/com32/lua/src/loslib.c
@@ -263,11 +263,13 @@ static int os_time (lua_State *L) {
}
+#ifndef LUA_NUMBER_INTEGRAL
static int os_difftime (lua_State *L) {
lua_pushnumber(L, difftime((time_t)(luaL_checknumber(L, 1)),
(time_t)(luaL_optnumber(L, 2, 0))));
return 1;
}
+#endif
/* }====================================================== */
@@ -300,7 +302,9 @@ static int os_exit (lua_State *L) {
static const luaL_Reg syslib[] = {
{"clock", os_clock},
{"date", os_date},
+#ifndef LUA_NUMBER_INTEGRAL
{"difftime", os_difftime},
+#endif
{"execute", os_execute},
{"exit", os_exit},
{"getenv", os_getenv},
diff --git a/com32/lua/src/ltable.c b/com32/lua/src/ltable.c
index 420391f..fca20a8 100644
--- a/com32/lua/src/ltable.c
+++ b/com32/lua/src/ltable.c
@@ -77,15 +77,16 @@ static const Node dummynode_ = {
/*
** hash for lua_Numbers
*/
+/* Taken from Lua 5.1 to avoid frexp() */
+#define numints cast_int(sizeof(lua_Number)/sizeof(int))
static Node *hashnum (const Table *t, lua_Number n) {
+ unsigned int a[numints];
int i;
- luai_hashnum(i, n);
- if (i < 0) {
- if (cast(unsigned int, i) == 0u - i) /* use unsigned to avoid overflows */
- i = 0; /* handle INT_MIN */
- i = -i; /* must be a positive value */
- }
- return hashmod(t, i);
+ if (luai_numeq(n, 0)) /* avoid problems with -0 */
+ return gnode(t, 0);
+ memcpy(a, &n, sizeof(a));
+ for (i = 1; i < numints; i++) a[0] += a[i];
+ return hashmod(t, a[0]);
}
diff --git a/com32/lua/src/luaconf.h b/com32/lua/src/luaconf.h
index df802c9..fa6546b 100644
--- a/com32/lua/src/luaconf.h
+++ b/com32/lua/src/luaconf.h
@@ -383,14 +383,31 @@
** ===================================================================
*/
+/* Define LUA_NUMBER_INTEGRAL to produce a system that uses no
+ floating point operations by changing the type of Lua numbers from
+ double to long. It implements division and modulus so that
+
+ x == (x / y) * y + x % y.
+
+ The exponentiation function returns zero for negative exponents.
+ Defining LUA_NUMBER_INTEGRAL also removes the difftime function,
+ and the math module should not be used. The string.format function
+ no longer handles the floating point directives %e, %E, %f, %g, and
+ %G. */
+
+#define LUA_NUMBER_INTEGRAL
+#ifdef 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
/*
@@ -399,8 +416,13 @@
@@ lua_number2str converts a number to a string.
@@ LUAI_MAXNUMBER2STR is maximum size of previous conversion.
*/
+#ifdef 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 */
@@ -419,10 +441,14 @@
** systems, you can leave 'lua_strx2number' undefined and Lua will
** provide its own implementation.
*/
+#ifdef LUA_NUMBER_INTEGRAL
+#define lua_str2number(s,p) strtol((s), (p), 10)
+#else
#define lua_str2number(s,p) strtod((s), (p))
+#endif
-#if defined(LUA_USE_STRTODHEX)
-#define lua_strx2number(s,p) strtod((s), (p))
+#ifdef SYSLINUX
+#define lua_strx2number(s,p) strtol((s), (p), 16)
#endif
@@ -430,19 +456,46 @@
@@ The luai_num* macros define the primitive operations over numbers.
*/
+#ifndef LUA_NUMBER_INTEGRAL
/* the following operations need the math library */
#if defined(lobject_c) || defined(lvm_c)
#include <math.h>
#define luai_nummod(L,a,b) ((a) - l_mathop(floor)((a)/(b))*(b))
#define luai_numpow(L,a,b) (l_mathop(pow)(a,b))
#endif
+#endif
/* these are quite standard operations */
#if defined(LUA_CORE)
#define luai_numadd(L,a,b) ((a)+(b))
#define luai_numsub(L,a,b) ((a)-(b))
#define luai_nummul(L,a,b) ((a)*(b))
+#ifdef LUA_NUMBER_INTEGRAL
+#define luai_numdiv(L,a,b) \
+ (-1/2? \
+ (a)/(b): \
+ (((a)<0)==((b)<0)||(a)%(b)==0? \
+ (a)/(b): \
+ (a)/(b)-1))
+#define luai_nummod(L,a,b) \
+ (-1/2? \
+ (a)%(b): \
+ (((a)<0)==((b)<0)||(a)%(b)==0? \
+ (a)%(b): \
+ (a)%(b)+(b)))
+#define luai_lnumdiv(L,a,b) \
+ ((b)==0? \
+ (luaG_runerror(L,"divide by zero"),0): \
+ luai_numdiv(a,b))
+#define luai_lnummod(L,a,b) \
+ ((b)==0? \
+ (luaG_runerror(L,"modulo by zero"),0): \
+ luai_nummod(a,b))
+LUA_NUMBER luai_ipow(void *L, LUA_NUMBER, LUA_NUMBER);
+#define luai_numpow(L,a,b) (luai_ipow(L,a,b))
+#else
#define luai_numdiv(L,a,b) ((a)/(b))
+#endif
#define luai_numunm(L,a) (-(a))
#define luai_numeq(a,b) ((a)==(b))
#define luai_numlt(L,a,b) ((a)<(b))
@@ -457,7 +510,8 @@
** CHANGE that if ptrdiff_t is not adequate on your machine. (On most
** machines, ptrdiff_t gives a good choice between int or long.)
*/
-#define LUA_INTEGER ptrdiff_t
+#define LUA_INTEGER long
+/* Changed to long for use with integral Lua numbers. */
/*
@@ LUA_UNSIGNED is the integral type used by lua_pushunsigned/lua_tounsigned.
diff --git a/com32/lua/src/lvm.c b/com32/lua/src/lvm.c
index 657d5c4..9cb7571 100644
--- a/com32/lua/src/lvm.c
+++ b/com32/lua/src/lvm.c
@@ -27,6 +27,26 @@
#include "lvm.h"
+#ifdef LUA_NUMBER_INTEGRAL
+LUA_NUMBER luai_ipow(void *L, LUA_NUMBER a, LUA_NUMBER b) {
+ (void)L;
+ 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
--
1.7.10.4
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