On 2004-03-12 20:50:20 +0900, GOTO Masanori wrote: > Thanks for your detailed explanation, I understand this is about > manipulating wrapper function of x87 precious control field. The > similar symbol is already defined in fpu_control.h like _FPU_EXTENDED > and so, on i386/adm64/m68k/sparc.
/usr/include/fpu_control.h on x86 defines: /* precision control */ #define _FPU_EXTENDED 0x300 /* libm requires double extended precision. */ #define _FPU_DOUBLE 0x200 #define _FPU_SINGLE 0x0 but these macros are not defined on PPC since it doesn't support dynamic precision control. So, one should probably have things like #ifdef _FPU_EXTENDED #define FE_LDBLPREC whatever #endif > I understand this is sometimes useful when a user want to change the > precision of FPU. But, the problem is it's extended function, not > standard. soft-fp in glibc uses EXTENDED, and don't recommend SINGLE. > I found recent Solaris on x86 only defines it. Is this function > future-rock? Well, one never knows. Perhaps this needs discussions with other C library developers (e.g. from *BSD) to agree on a de facto standard. But the one from the C99 draft would probably be the most logical one. I think that these should be defined only if __USE_GNU is defined (just like the exp10 function, which is a GNU extension, but may also be available with other C libraries, e.g. under Solaris). Also note that if the user changes the rounding precision (with either these functions or with the existing fpu_control.h macros or another method), functions from the libm may fail, but anyway this would be a libm bug (and I'd regard it as a part of bug 153022). -- Vincent Lef�vre <[EMAIL PROTECTED]> - Web: <http://www.vinc17.org/> - 100% validated (X)HTML - Acorn Risc PC, Yellow Pig 17, Championnat International des Jeux Math�matiques et Logiques, TETRHEX, etc. Work: CR INRIA - computer arithmetic / SPACES project at LORIA -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of "unsubscribe". Trouble? Contact [EMAIL PROTECTED]
