[cctalk] Re: Delay slots, was: Re: Re: early microprocessor limited pipelining [was: Intel 8086 - 46 yrs. ago]

[Brian L. Stuart via cctalk]

> But the required are often dependent on variables that are not> known at 
> compile time, for example load/store delays, or branches> taken/not taken.  
> Run time interlocks deal with the actual conflicts> as they occur, while 
> compiler or programmer conflict avoidance> has to use the worst case 
> scenarios.
The observation that interlocks are not needed when the delay isknown and 
predictable, but are needed when the delay is varialbehas been around since the 
beginning.  The ENIAC didn't haveinterlocks for the multiplier or function 
tables, but did for the divider/square rooter and the card reader.  (The card 
punch had whatamounted to a completion signal that enforced the timing.)
BLS