diff options
Diffstat (limited to 'src/llimits.h')
| -rw-r--r-- | src/llimits.h | 92 |
1 files changed, 91 insertions, 1 deletions
diff --git a/src/llimits.h b/src/llimits.h index 4b75a84e..f8ede143 100644 --- a/src/llimits.h +++ b/src/llimits.h @@ -1,5 +1,5 @@ /* -** $Id: llimits.h,v 1.82 2010/05/31 16:08:55 roberto Exp $ +** $Id: llimits.h,v 1.84 2010/11/08 16:33:20 roberto Exp $ ** Limits, basic types, and some other `installation-dependent' definitions ** See Copyright Notice in lua.h */ @@ -168,6 +168,96 @@ typedef lu_int32 Instruction; #define luai_userstateyield(L,n) ((void)L) #endif +/* +** lua_number2int is a macro to convert lua_Number to int. +** lua_number2integer is a macro to convert lua_Number to lua_Integer. +** lua_number2unsigned is a macro to convert a lua_Number to a lua_Unsigned. +** lua_unsigned2number is a macro to convert a lua_Unsigned to a lua_Number. +*/ + +#if defined(MS_ASMTRICK) /* { */ +/* trick with Microsoft assembler for X86 */ + +#define lua_number2int(i,n) __asm {__asm fld n __asm fistp i} +#define lua_number2integer(i,n) lua_number2int(i, n) +#define lua_number2unsigned(i,n) \ + {__int64 l; __asm {__asm fld n __asm fistp l} i = (unsigned int)l;} + + +#elif defined(LUA_IEEE754TRICK) /* }{ */ +/* the next trick should work on any machine using IEEE754 with + a 32-bit integer type */ + +union luai_Cast { double l_d; LUA_INT32 l_p[2]; }; + +#if !defined(LUA_IEEEENDIAN) /* { */ +#define LUAI_EXTRAIEEE \ + static const union luai_Cast ieeeendian = {-(33.0 + 6755399441055744.0)}; +#define LUA_IEEEENDIAN (ieeeendian.l_p[1] == 33) +#else +#define LUAI_EXTRAIEEE /* empty */ +#endif /* } */ + +#define lua_number2int32(i,n,t) \ + { LUAI_EXTRAIEEE \ + volatile union luai_Cast u; u.l_d = (n) + 6755399441055744.0; \ + (i) = (t)u.l_p[LUA_IEEEENDIAN]; } + +#define lua_number2int(i,n) lua_number2int32(i, n, int) +#define lua_number2integer(i,n) lua_number2int32(i, n, lua_Integer) +#define lua_number2unsigned(i,n) lua_number2int32(i, n, lua_Unsigned) + +#endif /* } */ + + +/* the following definitions always work, but may be slow */ + +#if !defined(lua_number2int) +#define lua_number2int(i,n) ((i)=(int)(n)) +#endif + +#if !defined(lua_number2integer) +#define lua_number2integer(i,n) ((i)=(lua_Integer)(n)) +#endif + +#if !defined(lua_number2unsigned) /* { */ +/* the following definition assures proper modulo behavior */ +#if defined(LUA_NUMBER_DOUBLE) +#include <math.h> +#define SUPUNSIGNED ((lua_Number)(~(lua_Unsigned)0) + 1) +#define lua_number2unsigned(i,n) \ + ((i)=(lua_Unsigned)((n) - floor((n)/SUPUNSIGNED)*SUPUNSIGNED)) +#else +#define lua_number2unsigned(i,n) ((i)=(lua_Unsigned)(n)) +#endif +#endif /* } */ + + +#if !defined(lua_unsigned2number) +/* on several machines, coercion from unsigned to double is slow, + so it may be worth to avoid */ +#define lua_unsigned2number(u) \ + (((u) <= (lua_Unsigned)INT_MAX) ? (lua_Number)(int)(u) : (lua_Number)(u)) +#endif + + +/* +** luai_hashnum is a macro do hash a lua_Number value into an integer. +** The hash must be deterministic and give reasonable values for +** both small and large values (outside the range of integers). +** It is used only in ltable.c. +*/ + +#if !defined(luai_hashnum) /* { */ + +#include <float.h> +#include <math.h> + +#define luai_hashnum(i,n) { int e; \ + n = frexp(n, &e) * (lua_Number)(INT_MAX - DBL_MAX_EXP); \ + lua_number2int(i, n); i += e; } + +#endif /* } */ |