On Dec 9, 2007, at 11:25 PM, Liu Yu wrote: > > > > > >> -----Original Message----- >> From: David Gibson [mailto:[EMAIL PROTECTED] >> Sent: Monday, December 10, 2007 12:56 PM >> To: Liu Yu >> Cc: linuxppc-dev@ozlabs.org >> Subject: Re: [PATCH] Fix rounding bug in emulation for double >> floatoperating >> >> >> On Mon, Dec 10, 2007 at 01:00:52PM +0800, Liu Yu wrote: >>> >>> This patch fixes rounding bug in emulation for double float >> operating on PowerPC platform. >>> >>> When pack double float operand, it need to truncate the >> tail due to the limited precision. >>> If the truncated part is not zero, the last bit of work bit >> (totally 3 bits) need to '|' 1. >>> >>> This patch is completed in _FP_FRAC_SRS_2(X,N,sz) >> (arch/powerpc/math-emu/op-2.h). >>> Originally the code leftwards rotates the operand to just keep the >>> truncated part, then check whether it is zero. However, the >> number it >>> rotates is not correct when N is not smaller than >> _FP_W_TYPE_SIZE, and it will cause the work bit '|' 1 in the >> improper case. >>> >>> This patch fixes this issue. >>> >>> Signed-off-by: Liu Yu <[EMAIL PROTECTED]> >> >> Wow someone deciphered the hideous macro hell of the math >> emulation code enough to fix a bug. I don't suppose you'd >> care to fix the millions of warnings that the math-emu code >> generates...? > > Oh, I don't like macro define either. But it's really a bug...
how did you find this? - k _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@ozlabs.org https://ozlabs.org/mailman/listinfo/linuxppc-dev
