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Long Division

A project log for Ferranti Pegasus Emulator

An emulator for a 1950's valve computer written in VB.NET

davedave 06/18/2016 at 23:093 Comments
This is giving me grief. The Pegasus Divide is a 77 bit number divided by a 38 bit number. When I first looked at the problem I wanted to do "proper" long division rather than repeated subtraction. However after reading the manuals I realized that that's actually what Pegasus does, so now I can start coding...

Discussions

dave wrote 07/26/2017 at 18:47 point

I think its restoring. The logic manual is here:-

https://1drv.ms/b/s!Ag4BJfE5B3onhNRPifkNMbxh0gFNCw

there is a detailed description in the first part of the manual, starting on physical page 16 on how it work.

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Ed S wrote 07/27/2017 at 18:14 point

Thanks! That looks like non-restoring to me, which is the better way to do it. I'd expect no less!

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Ed S wrote 07/26/2017 at 16:52 point

Do you know if Pegasus does a (pedestrian) restoring division, or a (speedy) non-restoring division? I'm wondering how early the joy of non-restoring division was used in practice.

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