EIP-150: Add information about previous gas costs

[chfast]

Because Yellow Paper only describes the latest mainnet hard fork, there is not official source of information were the gas costs before the changes of EIP-150 are provided.

[chfast]

CC @pirapira

[chfast]

CC @vbuterin

[fulldecent]

@chfast Please see https://github.com/ethereum/yellowpaper#versions this includes prior versions of the Yellow Paper as affected by each hard fork.

Please less mentions here and more asking questions like this on Stack Overflow.

[MicahZoltu]

I think having the previous values in the EIP is useful. The yellowpaper is generally known to be incredibly hard to read, and often times internet searches turn up EIPs rather than SO or yellowpaper. I personally don't see a problem with including this, especially since someone else did all of the work to research it and submit the PR.

[fulldecent]

Aah. I see see we are updating the EIP here, not the yellow paper. Yes, I totally agree, this is helpful.

[ali8889]

???

[axic]

I vote for merging this.

@Arachnid what is process of merging such a change?

[axic]

@vbuterin can you approve this?

[nicksavers]

Why is it necessary to know what they were previously?
Leaving them out would make the EIP more general and could be applied whatever they were.

[fulldecent]

If previous gas costs are not relevant, then the words "increase gas cost to" can be changed to "set gas cost to".

[axic]

I think EIP certainly is locked into being applied to a certain state. Look at the other wording, "replace this calculation with X". I think it is relevant to apply the previous cost there.