Re: [Jprogramming] A bit-twisting puzzle

['lindaalvord' via Programming]

Is this am answer? ]c=:#:i.40 00 11 01 1   ]a=:0{"1 c0 0 1 1   ]b=:1{"1 c      
]b=:1{"1 c0 1 0 1   {:a*b1   LindaSent from my Verizon, Samsung Galaxy 
smartphone
-------- Original message --------From: Henry Rich <henryhr...@gmail.com> Date: 
7/28/19  8:51 PM  (GMT-05:00) To: programm...@jsoftware.com Subject: 
[Jprogramming] A bit-twisting puzzle Many of the members of this Forum will 
remember the days of assembler language   ...and who could less than merry be   
when writing out BXLE?AND, OR, XOR were our meat.  Those days are returning.You 
have two integer variables a and b and you want to do something if one or both 
of them are 0.  In C, you might write   if(a==0 || b==0)stmt;but that will 
generate the code   cmp a,0   bz stmt   cmp b,0   bnz 
notstmtstmt:...notstmt:Here's the problem: your machine is very slow at branch 
instructions.  Each branch takes 30 times as long as a regular instruction.  (I 
am describing a state-of-the-art Intel CPU when it cannot predict the branches 
effectively, perhaps because the data is... unpredictable).Obviously, you want 
to use only one branch instruction.  You may use as many arithmetic and logic 
instructions as you like, but only one branch.  The usual condition codes, 
ZNCV, are available. How tight can you make the code?Example: suppose the 
problem were to execute stmt if one or both of a and b is NOT zero.  Then you 
would simply write   or a,b   bnz notstmt...Checking for zero seems to be 
harder.No hurry.  I have pondered this problem for over a year, and just today 
I found a solution I consider acceptable.Henry Rich---This email has been 
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