<html><head><meta http-equiv="Content-Type" content="text/html charset=windows-1252"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;"><br><div><div>On Jul 17, 2013, at 9:13 AM, Tim Northover <<a href="mailto:t.p.northover@gmail.com">t.p.northover@gmail.com</a>> wrote:</div><br class="Apple-interchange-newline"><blockquote type="cite"><div style="font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px;">On Wed, Jul 17, 2013 at 4:54 PM, James Molloy <<a href="mailto:james@jamesmolloy.co.uk">james@jamesmolloy.co.uk</a>> wrote:<br><blockquote type="cite">Wouldn't this be a viable use of the third disassembler return value<br>"SoftFail"? The only difference between its use here and how it is used in<br>the ARM backend is that the Intel manuals explicitly define the behaviour in<br>the out of range case, but you could easily reappropriate SoftFail for the<br>x86 architecture to mean "It's defined, but I'm going to warn about it".<br></blockquote><br>I think that's going too far; these instructions appear to be<br>sanctioned in the manual unlike the ARM ones. But there's a<br>CommentStream available during disassembly. They could probably be<br>annotated as "non-standard encoding ..." or something more pithy if we<br>decide to go down that route.<br><br>I think this is the approach armasm takes to at least some of the<br>similar ARM issues.<br><br></div></blockquote><div dir="auto"><br></div><div dir="auto">A fair point. Also note that issuing a diagnostic doesn’t mean we have to reject the instruction. We could use a warning rather than a hard error.</div><div dir="auto"><br></div><div dir="auto">-Jim</div></div></body></html>