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I'll see what I can figure out.<div><br></div><div><br></div><div>I considered pushings pairs of operands in m3x86.m3 but I think</div><div>that won't work.</div><div><br></div><div><br></div><div>Noticing how integer vs. floating point is handled</div><div>is perhaps useful, as this is another way in which m3cg</div><div>is "homogenous" but backends have to act differently</div><div>based on type.</div><div><br></div><div><br></div><div> - Jay<br><br><br><br><hr id="stopSpelling">From: hosking@cs.purdue.edu<br>Date: Fri, 22 Jan 2010 09:49:28 -0500<br>To: jay.krell@cornell.edu<br>CC: m3devel@elegosoft.com<br>Subject: Re: [M3devel] thoughts on NT386/LONGINT?<br><br>
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<div>That's a very good question. I suspect allocating register pairs as needed would make for a fairly difficult implementation. I would err on the side of simplicity for LONGINT code generation rather than complexity. You might easily just push/pop operands and return values on the stack, on the grounds that modern x86 hardware will do a good job renaming stack locations to registers. i.e., worry about correctness first and performance later.</div><div><br></div><div><div>On 22 Jan 2010, at 07:39, Jay K wrote:</div><br class="ecxApple-interchange-newline"><blockquote><span class="ecxApple-style-span" style="border-collapse:separate;font-family:Helvetica;font-size:medium;font-style:normal;font-variant:normal;font-weight:normal;letter-spacing:normal;line-height:normal;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px"><div class="ecxhmmessage" style="font-size:10pt;font-family:Verdana">Anyone have any thoughts on how to implement LONGINT on NT386?<br> <br><br>The code is setup to do pretty good constant folding and enregistration.<br> <br><br>I did the work so that constant folding should work for LONGINT.<br> <br><br>However I think doing good enregistration is maybe still<br>too much work. In particular, I think every LONGINT<br>operation will do a load, operation, store.<br>Typical of unoptimized code, but not typical<br>of the Modula-3/NT386 quality.</div></span></blockquote><blockquote><span class="ecxApple-style-span" style="border-collapse:separate;font-family:Helvetica;font-size:medium;font-style:normal;font-variant:normal;font-weight:normal;letter-spacing:normal;line-height:normal;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px"><div class="ecxhmmessage" style="font-size:10pt;font-family:Verdana"><br> <br>In particular, there is still this notion of an "operand"<br>that might be held in one register.<br><br> <br>I'd have to make it a register pair, or array of registers,<br>or invent "psuedo registers" that are register pairs.<br>An array of registers is the obvious best choice, but<br>none of these are a small change.<br> <br><br>96 occurences of "reg" in Stackx86.m3, 58 in M3x86.m3,<br>would probably all have to change.<br>63 in Codex86.m3 unsure.<br> It is the lowest level and might need to only deal with single<br> registers.<br><br> <br>Returning LONGINT from a function also needs separate attention.<br>Maybe I really should go ahead and use an array of registers?<br> <br><br> - Jay<br><br></div></span></blockquote></div><br></div> </body>
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