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Re: quad precision on PowerPC?
On 2011-05-16 02:15:57 +0200, Vincent Lefevre wrote:
> -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!
Unfortunately it's not usable in practice, at least under Debian:
at link time, I get errors like:
undefined reference to `_q_add'
--
Vincent Lefèvre <vincent@vinc17.net> - Web: <http://www.vinc17.net/>
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Work: CR INRIA - computer arithmetic / Arénaire project (LIP, ENS-Lyon)