[Simh] Ferranti Pegasus Simulator

[Richard Cornwell]

Hi,

  You can always do the divide and conquer method. Or do it the old
  fashioned way 1 bit at a time :-). Check out My I7000 sim for
  examples of how to do this. Or my B5500 sim where I do basically DP
  divide, with 3 divides. I am going to have a similar problem when I
  redo my KA10 sim since it does a 71 bit by 36 bit divide. 

  Generally the divide loop does not slow the sim down noticeably, since
  the sim will already be 100 times faster then the original. 

Rich

> Whilst its not a SIMH simulator, I hope you can help. I want to write
> an emulator for the Pegasus. The Ferranti Pegasus was (there are none
> operating at present) a strange beast with two 18-bit instructions
> per 39-bit word. Generally, it does 39-bit twos complement
> arithmetic. The multiply results in a 77-bit result which I have no
> problems implementing. 
> Where I am struggling is with the divide. I need to be able to divide
> a 77-bit number by a 39-bit number and get a 39 bit quotient and a 39
> bit remainder. As the compiler I am using only does 64-bit numbers
> this is proving challenging. Any one got a good article on how to do
> this? 
> Dave Wade
> G4UGM



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Richard Cornwell
skyvis at sky-visions.com
http://sky-visions.com
LinkedIn:   https://www.linkedin.com/in/richard-cornwell-991076107
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