<html><head><meta http-equiv="Content-Type" content="text/html charset=us-ascii"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><br><div><br><div>Begin forwarded message:</div><br class="Apple-interchange-newline"><blockquote type="cite"><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px;"><span style="font-family:'Helvetica'; font-size:medium; color:rgba(0, 0, 0, 1.0);"><b>From: </b></span><span style="font-family:'Helvetica'; font-size:medium;">"Joseph S. Myers" <<a href="mailto:jsm@polyomino.org.uk">jsm@polyomino.org.uk</a>><br></span></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px;"><span style="font-family:'Helvetica'; font-size:medium; color:rgba(0, 0, 0, 1.0);"><b>Subject: </b></span><span style="font-family:'Helvetica'; font-size:medium;"><b>(SC22WG14.13013) RE: Reset for TS 18661 Part 3?</b><br></span></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px;"><span style="font-family:'Helvetica'; font-size:medium; color:rgba(0, 0, 0, 1.0);"><b>Date: </b></span><span style="font-family:'Helvetica'; font-size:medium;">June 4, 2013 12:41:33 PM PDT<br></span></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px;"><span style="font-family:'Helvetica'; font-size:medium; color:rgba(0, 0, 0, 1.0);"><b>To: </b></span><span style="font-family:'Helvetica'; font-size:medium;">"Nelson, Clark" <<a href="mailto:clark.nelson@intel.com">clark.nelson@intel.com</a>><br></span></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px;"><span style="font-family:'Helvetica'; font-size:medium; color:rgba(0, 0, 0, 1.0);"><b>Cc: </b></span><span style="font-family:'Helvetica'; font-size:medium;">SC22 WG14 <<a href="mailto:sc22wg14@open-std.org">sc22wg14@open-std.org</a>><br></span></div><br><div>On Tue, 4 Jun 2013, Nelson, Clark wrote:<br><br><blockquote type="cite">Only after the Delft meeting ended, I realized that the FP standard is <br>using that word in a way that's somewhat idiosyncratic, but nevertheless <br>reasonable. They're not really talking about the ability to move binary <br>data between implementations, with meaningful results (which is the <br>usual sense of "interchange" in my experience). Instead I think they're <br>talking only about the ability to move floating-point algorithms and <br>calculations between implementations, with consistent results. That <br>seems to be implied by the fact that the FP standard doesn't talk about <br>byte ordering.<br></blockquote><br>The relevant wording in IEEE 754-2008 is in 3.1.2, "A conforming <br>implementation of a supported interchange format shall provide means to <br>read and write that format using a specific encoding defined in this <br>clause, for that format.". Encodings are defined as bit-strings while C <br>works in units of bytes (the floating-point standard never mentions <br>bytes); I think a C binding needs to say how the C bytes relate to the <br>bit-strings for the standard encodings, just as it needs to say what C <br>operators and functions correspond to what standard floating-point <br>operations.<br><br>That goes together with 3.1.1, "These interchange formats are identified <br>by their size (see 3.6) and can be used for the exchange of floating-point <br>data between implementations." and 3.6, "Interchange formats support the <br>exchange of floating-point data between implementations.".<br><br>-- <br>Joseph S. Myers<br><a href="mailto:joseph@codesourcery.com">joseph@codesourcery.com</a><br></div></blockquote></div><br></body></html>