[vcf-midatlantic] A little personal milestone

Mike Loewen mloewen at cpumagic.scol.pa.us
Sun Jun 18 22:12:59 EDT 2017


On Sun, 18 Jun 2017, Evan Koblentz via vcf-midatlantic wrote:

>>  Set the address switches to 100 (octal)
>
> It's like a light bulb has illuminated and is reflecting off my bald
head! 
> I've long been able to do the long-form math (on paper) for octal/hex, but 
> now I suddenly "get" what someone means by "set the address switches to 100 
> (octal). Off/off/on -- off/off/off -- off/off/off. Better late than never, 
> huh?

    It's all just ones and zeroes.  :-)

    All you really need to know is this:

 	8  4  2  1    Hex    Dec    Oct
 	-------------------------------
 	0  0  0  0     0      0      0
 	0  0  0  1     1      1      1
 	0  0  1  0     2      2      2
 	0  0  1  1     3      3      3
 	0  1  0  0     4      4      4
 	0  1  0  1     5      5      5
 	0  1  1  0     6      6      6
 	0  1  1  1     7      7      7
 	1  0  0  0     8      8     10
 	1  0  0  1     9      9     11
 	1  0  1  0     A     10     12
 	1  0  1  1     B     11     13
         1  1  0  0     C     12     14
 	1  1  0  1     D     13     15
 	1  1  1  0     E     14     16
 	1  1  1  1     F     15     17


    Want to convert a hex number to binary?  Just decode each hex digit (I 
know, it's not really a digit) to its 4-bit binary equivalent, left to 
right:

 	e.g. B5 hex => 10110101 binary

    Want to convert that to an octal number?  Just group the bits by 
threes, starting with the Least Significant Bits (LSB), then insert the 
octal equivalent for each group of three:

 	10 110 101 => 265 octal

    I was going to go over this with you last weekend, but didn't get 
around to it.  :-)


Mike Loewen				mloewen at cpumagic.scol.pa.us
Old Technology				http://q7.neurotica.com/Oldtech/



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