Really stupid PDP assembler question

From: David V. Corbin <dvcorbin_at_optonline.net>
Date: Fri Jun 25 18:47:40 2004

While this question ask been well answered, it does bring to mind a good old
trivia question....

"What significant advantage did octal have over hex notation (especially in
the late '60s timeframe)?"


>>> -----Original Message-----
>>> From: cctalk-bounces_at_classiccmp.org
>>> [mailto:cctalk-bounces_at_classiccmp.org] On Behalf Of Paul Koning
>>> Sent: Friday, June 25, 2004 6:03 PM
>>> To: cctalk_at_classiccmp.org
>>> Subject: Re: Really stupid PDP assembler question
>>>
>>> >>>>> "wai-sun" == wai-sun chia <squidster_at_techie.com> writes:
>>>
>>> wai-sun> *WARNING: NEWBIE ALERT* Ok. I must be an idiot.
>>> I for the wai-sun> life of me cannot figure out why is it
>>> when I say:
>>>
>>> wai-sun> 1000: .ASCIZ /HELLO WORLD!/
>>>
>>> wai-sun> After assembling and linking it turns out that:
>>>
>>> wai-sun> 1000: 042510 ;H=110, E=105 ...
>>>
>>> wai-sun> Why is the octal ASCII code and the content of
>>> the addresses wai-sun> different?
>>>
>>> They aren't.
>>>
>>> Remember that bytes are 8 bits and octal gives you 3 bits per digit.
>>> So (unlike hex) the boundary between the two bytes is "in
>>> the middle"
>>> of the fourth digit.
>>>
>>> The word is (0105 << 8) + 0110 which 042510 as you showed,
>>> and similarly for the other words.
>>>
>>> paul
>>>
Received on Fri Jun 25 2004 - 18:47:40 BST