Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: notesfiles Path: utzoo!watmath!clyde!bonnie!akgua!whuxlm!whuxl!houxm!mtuxo!mtunh!mtung!mtunf!ariel!vax135!timeinc!phri!pesnta!hplabs!hp-pcd!hpfclg!larry From: larry@hpfclg.UUCP (larry) Newsgroups: net.puzzle Subject: Re: Orphaned Response Message-ID: <77300001@hpfclg.UUCP> Date: Fri, 21-Jun-85 19:03:00 EDT Article-I.D.: hpfclg.77300001 Posted: Fri Jun 21 19:03:00 1985 Date-Received: Wed, 3-Jul-85 07:05:49 EDT References: <3256@dartvax.UUCP> Organization: Hewlett-Packard - Fort Collins, CO Lines: 47 Nf-ID: #R:dartvax:3256:hpfclg:77300001:37777777600:1430 Nf-From: hpfclg!larry Jun 21 13:03:00 1985 /***** hpfclg:net.puzzle / dartvax!chuck / 12:24 am Jun 17, 1985*/ The following 5 instruction routine is written in 68000 code. What does it do? ; D0 and D1 are 32 bit registers. move.l d0,d1 ; d1 := d0 bra.s L2 ; goto L2 L1: sub.l d1,d0 ; L1: d0 := d0 - d1 L2: lsr.l #1,d1 ; L2: d1 := d1 div 2 bne.s L1 ; if d1 <> 0 then goto L1 Cheers, Chuck /* ---------- */ *** SPOILER *** (rot13) Gur cerprqvat pbqr frdhrapr jvyy pnyphyngr gur ahzore bs 1 ovgf va Q0. N ybbc vainevnag orgjrra Y1 & Y2 pbhyq or cuenfrq nf sbyybjf: Gur ahzore bs ovgf va Q1 cyhf gur qvssrerapr Q0-Q1 vf vainevnag. Ng gur ortvaavat Q0=Q1 fb gur inyhr bs gung vainevnag rkcerffvba vf jung jr jnag. Ng gur raq Q1=0 fb gur inyhr bs gur vainevnag rkcerffvba vf Q0. Rnpu gvzr guebhtu gur ybbc gurer vf 1 bs 2 pnfrf: Q1 vf bqq, be Q1 vf rira. Vs Q1 vf rira, fuvsgvat qbrfa'g punatr gur ahzore bs 1 ovgf va Q1 naq Q0-Q1 vf gur fnzr nsgre gur fhogenpgvba. Vs Q1 vf bqq, fuvsgvat erzbirf n 1 ovg va Q1 naq Q0-Q1 vapernfrf ol 1. Guvax bs Q0 nf orvat Q1+A. Vs Q1 vf bqq gura Q1=Q1/2+Q1/2+1 (vagrtre qvivfvba), fb Q1-Q1/2=Q1/2+1. Gur arj Q1 vf Q1/2 fb gur arj Q0 vf Q1+1+A, whfg nf jr jnag. V ernyvmr gur rkcynangvba vf n ovg whzoyrq, ohg V qvq vg zber sbe zlfrys guna sbe lbh. Yneel Srafxr {vuac4, ucynof}!ucspyn!yneel-s Larry Fenske {ihnp4, hplabs}!hpfcla!larry-f