From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Edelsohn To: Sam Lantinga Cc: egcs@egcs.cygnus.com Subject: Re: Rounding errors using doubles? Date: Thu, 18 Mar 1999 16:57:00 -0000 Message-id: <9903190057.AA48806@marc.watson.ibm.com> In-reply-to: Message from Sam Lantinga of "Thu, 18 Mar 1999 16:45:12 PST." < E10NnPU-0006Cc-00@roboto.devolution.com > References: X-SW-Source: 1999-03/msg00635.html >>>>> Sam Lantinga writes: Sam> BTW, does anyone know what precision is used on the PPC and Alpha Sam> architectures? Are you referring to wordsize or significand bits? I think that the following table will be useful: /* The number of useful digits depends upon the size of the */ /* hardware floating point word. Several word sizes */ /* and the corresponding digits are: */ /* Word size Significand bits Decimal digits */ /* 32 24 9 */ /* 64 53 17 */ /* 80 64 21 */ /* 128 106 33 */ /* 128 113 36 */ PowerPC supports 32-bit wordsize floats and 64-bit wordsize doubles. I assume that your reference to 53-bits describes significand bits in which case PowerPC supports that with its 64-bit wordsize. David From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Edelsohn To: Sam Lantinga Cc: egcs@egcs.cygnus.com Subject: Re: Rounding errors using doubles? Date: Wed, 31 Mar 1999 23:46:00 -0000 Message-ID: <9903190057.AA48806@marc.watson.ibm.com> References: X-SW-Source: 1999-03n/msg00640.html Message-ID: <19990331234600.ARkSGeMZ-Fo1lrd1mQqC1mi5Rmb9qkFZKrsQ3Mvj-t0@z> >>>>> Sam Lantinga writes: Sam> BTW, does anyone know what precision is used on the PPC and Alpha Sam> architectures? Are you referring to wordsize or significand bits? I think that the following table will be useful: /* The number of useful digits depends upon the size of the */ /* hardware floating point word. Several word sizes */ /* and the corresponding digits are: */ /* Word size Significand bits Decimal digits */ /* 32 24 9 */ /* 64 53 17 */ /* 80 64 21 */ /* 128 106 33 */ /* 128 113 36 */ PowerPC supports 32-bit wordsize floats and 64-bit wordsize doubles. I assume that your reference to 53-bits describes significand bits in which case PowerPC supports that with its 64-bit wordsize. David