Well. Fast c doesn't look quite like regular C, but seeing C optimised for speed isn't rare.

Looking at older C code is still better than seeing the hoops people jump through to get [insert programming language] to run at regular C speeds.

Fast C usually doesn't include weird workarounds for things like Implementation-specific GC quirks or bending language semantcs to force it to do what you want.

No, fast C in the 80's and early 90's meant writing code that was actually like this:

    naked void my_C_func()
    {
      asm {
       ...
      }
    }

Which basically meant using C as a poor man's macro assembler and nothing to do with what ANSI C is.

There were also other tricks related to unions and bit fiddling.

In those days, on 8 and 16 bit home computers, C was seen like managed languages are nowadays.

I see what you mean. I never did those gigs, so I wouldn't know. In hindsight I don't regret it :)