<html xmlns:o="urn:schemas-microsoft-com:office:office" xmlns:w="urn:schemas-microsoft-com:office:word" xmlns:m="http://schemas.microsoft.com/office/2004/12/omml" xmlns="http://www.w3.org/TR/REC-html40"><head><meta http-equiv=Content-Type content="text/html; charset=utf-8"><meta name=Generator content="Microsoft Word 15 (filtered medium)"><style><!--
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--></style></head><body lang=DE-CH link=blue vlink="#954F72"><div class=WordSection1><p class=MsoNormal>Personally, I would use C22 in fix().</p><p class=MsoNormal>And «MOD maxCode» in FixLinx..()</p><p class=MsoNormal>And try to make ORG.maxCode a power of two for efficiency reasons.</p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>But feel free to take C22 everywhere.</p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>br</p><p class=MsoNormal>Jörg</p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Gesendet von <a href="https://go.microsoft.com/fwlink/?LinkId=550986">Mail</a> für Windows 10</p><p class=MsoNormal><o:p> </o:p></p><div style='mso-element:para-border-div;border:none;border-top:solid #E1E1E1 1.0pt;padding:3.0pt 0cm 0cm 0cm'><p class=MsoNormal style='border:none;padding:0cm'><b>Von: </b><a href="mailto:andreas_pirklbauer@yahoo.com">Andreas Pirklbauer</a><br><b>Gesendet: </b>Sonntag, 23. September 2018 17:46<br><b>An: </b><a href="mailto:oberon@lists.inf.ethz.ch">ETH Oberon and related systems</a><br><b>Betreff: </b>[Oberon] FJump and FixLink</p></div><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal> > The RISC5 processor has an addressbus of 24 bits («adr» in RISC5.v = 16 MB possible).</p><p class=MsoNormal> > The PC and branch displacements are on word boundary, they have 22 bits («disp» in RISC5.v)</p><p class=MsoNormal> ></p><p class=MsoNormal> > In short, I would have coded the procedures as follows:</p><p class=MsoNormal> ></p><p class=MsoNormal> > PROCEDURE FixLink*(L: LONGINT);</p><p class=MsoNormal> > VAR L1: LONGINT;</p><p class=MsoNormal> > BEGIN</p><p class=MsoNormal> > WHILE L # 0 DO L1 := code[L] MOD 2000H; FixOne(L); L := L1 END</p><p class=MsoNormal> > END FixLink;</p><p class=MsoNormal> ></p><p class=MsoNormal> > PROCEDURE FixLinkWith(L0, dst: LONGINT); (* used for «UNTIL» *)</p><p class=MsoNormal> > VAR L1: LONGINT;</p><p class=MsoNormal> > BEGIN</p><p class=MsoNormal> > WHILE L0 # 0 DO</p><p class=MsoNormal> > L1 := code[L0] MOD 2000H; fix(L0, dst - L0 - 1); L0 := L1</p><p class=MsoNormal> > END</p><p class=MsoNormal> > END FixLinkWith;</p><p class=MsoNormal> ></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Ok. Got it. This makes more sense. But it works only for ORG.maxCode = 8000,</p><p class=MsoNormal>since 2000H = 8196. In my compilers ORG.maxCode usually is 12000 or</p><p class=MsoNormal>even 16000. So with the above approach, I’d end up having to use 4000H</p><p class=MsoNormal>= 16’384, i.e. the next higher power of 2 (for efficiency) anyway..</p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>How about using C22 = 400000H (with FIVE zeros, not four!) = 4’194’304</p><p class=MsoNormal>= 2^22 instead of 2000H? That way, one would be...</p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>a) correct (max displacement = 22 bits), and </p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>b) “safe” even for all potential values of ORG.maxCode</p><p class=MsoNormal> up 4’194’304 = 4M words = 16MB RAM.</p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>once and for good?</p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>-ap</p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>--</p><p class=MsoNormal>Oberon@lists.inf.ethz.ch mailing list for ETH Oberon and related systems</p><p class=MsoNormal>https://lists.inf.ethz.ch/mailman/listinfo/oberon</p><p class=MsoNormal><o:p> </o:p></p></div></body></html>