EEI: Specify signness

[chfast]

Resolves #132.

[axic]

Can you split this into two PRs? One codifies what is happening in Hera right now, the other one changes to signed types.

[chfast]

Looks like a lot of unnecessary work.

[axic]

Looks like a lot of unnecessary work.

Yeah but it would be nice to merge what's going on right now, and then we can review the proposed changes and reason about them,

[axic]

Needs to be rebased.

We also need to make a decision about this and implement it in Hera.

@jakelang @poemm @gballet can you please review?

[poemm]

I looked through each edit. I see no reason for any of these arguments to be signed. It just adds complexity, adds checking overhead, and decreases possible address offsets, lengths, indices, and gas by a factor of approximately two.

I vote to interpret all of these arguments as unsigned integers. If a contract makes an error and uses a number which is negative in 2's complement, then they will probably quickly run out of gas.

[axic]

There seems to be strong opinions on this one. @chfast can you reflect on @poemm's points?

Do you think we can make a resolution in the next few days? If not, we have to move this off "Revision 4". Would like to close "Revision 4" before Monday.

[gballet]

Agreed with @poemm , already had to deal with nasty sign conversion bugs in the EEI and I don't want the extra complexity. Plus, modifying the i32ptr type is going to reduce the available memory from 4G down to 2G and I'm sure that's going to impact turbo-ewasm and wasmOS in the not too distant future.