🚀 go-pugleaf

In article <9776793f-9ef9-4448...@googlegroups.com>,
fishtoprecords  <pat2...@gmail.com> wrote:
>The mapping of C from PDP-11 machine instructions is pretty obvious if you look at the early PDP-11
>hardware documentation and your basic K&R
>
>I am pretty sure that one of the early papers also mentions it.

Indeed it does.  From Dennis Ritchie's paper "The Development of the C Language"

 Thompson went a step further by inventing the ++ and -- operators,
 which increment or decrement; their prefix or postfix position
 determines whether the alteration occurs before or after noting the
 value of the operand. They were not in the earliest versions of B, but
 appeared along the way. People often guess that they were created to
 use the auto-increment and auto-decrement address modes provided by
 the DEC PDP-11 on which C and Unix first became popular. This is
 historically impossible, since there was no PDP-11 when B was
 developed. The PDP-7, however, did have a few "auto-increment" memory
 cells, with the property that an indirect memory reference through
 them incremented the cell. This feature probably suggested such
 operators to Thompson; the generalization to make them both prefix and
 postfix was his own. Indeed, the auto-increment cells were not used
 directly in implementation of the operators, and a stronger motivation
 for the innovation was probably his observation that the translation
 of ++x was smaller than that of x=x+1.

https://www.bell-labs.com/usr/dmr/www/chist.pdf

The myth that the PDP-11 inspired the C ++ and -- operators is
completely false.  Can we put it to bed now, please?  

-- 
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John Levine, jo...@iecc.com, Primary Perpetrator of "The Internet for Dummies",
Please consider the environment before reading this e-mail. https://jl.ly