[Simh] pdp11 and unix

[Bill Cunningham]

  ----- Original Message ----- 
  From: Johnny Billquist 
  To: simh at trailing-edge.com 
  Sent: Friday, February 26, 2016 8:48 AM
  Subject: Re: [Simh] pdp11 and unix


  On 2016-02-26 01:50, Bill Cunningham wrote:
  >      When Ken Thompson coded UNIX it was in assembly. The first versions
  > anyway before B/NB/C. Is there in existance pdp11 (45 or 70 ?) intterupt
  > (vector) lists or IRQs and so, registers that shows how to code in
  > assembly on a pdp11? I am sure simh does it. Isn't what the "dep"
  > command is for?

  I'm not sure what you ask for. The first version of Unix was for a 
  PDP-7, so any PDP-11 information is irrelevant.
  UNix was then ported to the PDP-11, and was still written in assembler. 
  It was then rewritten in C, however, there are still parts that are 
  written in assembler. Not everything can be done in C...

  I was not aware they started on a PDP7. What about inline assembly. That's kinda C, isn't it?

  Bill
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