#qi-hardware IRC log for Friday, 2016-05-27

kristianpaul:o http://sdrgps.blogspot.com.co/2016/04/paul-breed-rocket-flight-test-data-2.html01:30
DocScrutinizer05http://sdrgps.blogspot.de/search/label/gnss-sdr hmm03:55
DocScrutinizer05not bad, but the COCOM isn't spoiling stuff there even for the BRB(?) gps03:56
planasbI have 32 bit ripple two numbers adder. I need to add 32bit number with constant (say 4). How to do it not using full 32 bit adder chain?19:13
DocScrutinizer05tell me if you find a solution19:21
planasbDesign an incrementer circuit for adding 4 to the PC instead of using a regular 2-input adder. This is easy to do -- just think about an adder where the second input is the constant 4 (i.e., all but one of the input bits is zero!) and then eliminate/simplify the adder logic appropriately. This optimization will also help with speed.19:24
planasbahh, yes i need full 32 bit chain.. !19:24
whitequarkthats homework19:25
whitequarkyou should do your homework yourself19:25
planasbi now know how to do it19:25
planasbi need use constants (like zero) .. and not FA19:26
wpwrakthe most efficient solution is obviously to use a 30 x 1 G ROM. an adder is such a waste of gates.19:28
wpwrak32 x 4 G for non-standard arithmetic19:28
whitequarkone could perhaps use Peano numbers in hardware to implement this19:30
whitequarkadding becomes really easy and efficient.19:31
whitequarkactually, I do wonder how a 2**32 cycle long delay loop would fare19:31
DocScrutinizer05wpwrak: I already pondered to suggest a LUT, but... Wasn't aware it's already Friday ;-)19:36
wpwrakfriday, the weekend is beckoning, no time to waste - so we have to pick solutions that are simple and guaranteed to work19:37
DocScrutinizer05now!!! use fuzzy logic ;-)19:37
DocScrutinizer05or an analog calculator19:37
DocScrutinizer05adding 4 is simply done by some passive components then, 19:38
DocScrutinizer05D/A->Zener->A/D  ;-P19:38
wpwrakanother option is to add an "output valid" signal, then a suitably configured 32:1 LUT. VALID only is high when the result is ready. else, you have to wait.19:39
DocScrutinizer05btw, where was the definition of the base system? even if we use a discrete numbers system at all? use an analog system then adding 4 is extremely simple and with sufficient cooling you easily reach a valid value range that fits the requirement of "32bit precision"19:40
DocScrutinizer05https://en.wikipedia.org/wiki/Analog_computer19:41
larscif you only want to iterate through a list of number, but don't care about the order you can also use a lfsr19:46
wpwrakDocScrutinizer05: actually, he never said how accurate the result has to be. if we add a little bit of tolerance, say +/- 1 MSB, it gets a lot easier. and you can readily half the error interval.19:50
wpwrakor, rather, halve19:50
DocScrutinizer05:nod:19:51
DocScrutinizer05the approach with a counter instead a full adder is nifty though19:51
DocScrutinizer05not fast, but nifty19:52
DocScrutinizer05I'd grant full point rating at that solution19:53
planasbhttp://hyperphysics.phy-astr.gsu.edu/hbase/electronic/ietron/fulladd6.gif << just reduce this logic if B is 020:02
planasbI winner20:02
whitequarkI think it's even simpler20:19
whitequarkif you're adding 4, you don't need the *32-bit* adder chain, you can do with a 30-bit20:19
whitequarkadmittedly a literal reading of requirements20:21
planasbyes20:27
DocScrutinizer05huh?20:31
DocScrutinizer05silly riddles time?20:31
planasbyup20:31
DocScrutinizer05meh20:32
planasbwhich adder you recommend ?20:32
planasbi need 32 bit picture of it :P20:32
DocScrutinizer05obviously I don't recommend anything since I feel bored about that20:33
planasbDocScrutinizer05: it's friday, take long drink20:34
DocScrutinizer05here it's snolfday20:35
DocScrutinizer05and on snolfdays no longdrinks before 87:37620:35
DocScrutinizer05btw this doesn't sound like riddlers but actually like homework20:36
planasbhomework20:36
planasbbut i found answear20:36
planasbself20:36
DocScrutinizer05~ask20:37
infobotQuestions in the channel should be specific, informative, complete, concise, and on-topic.  Don't ask if you can ask a question first.  Don't ask if a person is there; just ask what you intended to ask them.  Better questions more frequently yield better answers.  We are all here voluntarily or against our will.20:37
DocScrutinizer05~question20:37
infobotquestion is, like, If you have a question and want people to give useful answers, make sure you have read this first: http://www.catb.org/~esr/faqs/smart-questions.html20:37
planasbok20:37
DocScrutinizer05http://www.catb.org/~esr/faqs/smart-questions.html#idm4583569181931220:38
DocScrutinizer05http://www.catb.org/~esr/faqs/smart-questions.html#homework even20:38
planasbok20:39
whitequark\20:53
--- Sat May 28 201600:00

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