On 2011-05-16 02:07:15 +0200, Vincent Lefevre wrote:
> ay:~> gcc -dM -E -xc /dev/null | grep LDBL
> #define __LDBL_MAX__ 1.79769313486231580793728971405301e+308L
> #define __LDBL_MAX_EXP__ 1024
> #define __LDBL_HAS_INFINITY__ 1
> #define __LDBL_MIN__ 2.00416836000897277799610805135016e-292L
> #define __LDBL_HAS_QUIET_NAN__ 1
> #define __LDBL_HAS_DENORM__ 1
> #define __LDBL_EPSILON__ 4.94065645841246544176568792868221e-324L
> #define __LDBL_MANT_DIG__ 106
> #define __LDBL_MIN_EXP__ (-968)
> #define __LDBL_MAX_10_EXP__ 308
> #define __LDBL_DENORM_MIN__ 4.94065645841246544176568792868221e-324L
> #define __LDBL_MIN_10_EXP__ (-291)
> #define __LDBL_DIG__ 31
>
> ay:~> gcc -dM -E -xc /dev/null -mlong-double-128 | grep LDBL
> #define __LDBL_MAX__ 1.79769313486231580793728971405301e+308L
> #define __LDBL_MAX_EXP__ 1024
> #define __LDBL_HAS_INFINITY__ 1
> #define __LDBL_MIN__ 2.00416836000897277799610805135016e-292L
> #define __LDBL_HAS_QUIET_NAN__ 1
> #define __LDBL_HAS_DENORM__ 1
> #define __LDBL_EPSILON__ 4.94065645841246544176568792868221e-324L
> #define __LDBL_MANT_DIG__ 106
> #define __LDBL_MIN_EXP__ (-968)
> #define __LDBL_MAX_10_EXP__ 308
> #define __LDBL_DENORM_MIN__ 4.94065645841246544176568792868221e-324L
> #define __LDBL_MIN_10_EXP__ (-291)
> #define __LDBL_DIG__ 31
-mabi=ieeelongdouble seems to be the solution:
ay:~> gcc -dM -E -xc /dev/null -mabi=ieeelongdouble | grep LDBL
cc1: warning: Using IEEE extended precision long double
#define __LDBL_MAX__ 1.18973149535723176508575932662800702e+4932L
#define __LDBL_MAX_EXP__ 16384
#define __LDBL_HAS_INFINITY__ 1
#define __LDBL_MIN__ 3.36210314311209350626267781732175260e-4932L
#define __LDBL_HAS_QUIET_NAN__ 1
#define __LDBL_HAS_DENORM__ 1
#define __LDBL_EPSILON__ 1.92592994438723585305597794258492732e-34L
#define __LDBL_MANT_DIG__ 113
#define __LDBL_MIN_EXP__ (-16381)
#define __LDBL_MAX_10_EXP__ 4932
#define __LDBL_DENORM_MIN__ 6.47517511943802511092443895822764655e-4966L
#define __LDBL_MIN_10_EXP__ (-4931)
#define __LDBL_DIG__ 33
113-bit precision, that's quadruple precision!
But it's badly documented:
`-mabi=ieeelongdouble'
Change the current ABI to use IEEE extended precision long double.
This is a PowerPC 32-bit Linux ABI option.
"IEEE extended precision" doesn't give much information: it can be
any precision and range at least those of Intel's x87. This notion
has even been removed from the IEEE 754 standard in its current
version (2008).
--
Vincent Lefèvre <vincent@xxxxxxxxxx> - Web: <http://www.vinc17.net/>
100% accessible validated (X)HTML - Blog: <http://www.vinc17.net/blog/>
Work: CR INRIA - computer arithmetic / Arénaire project (LIP, ENS-Lyon)
