Add support for EIP-1087: Net storage gas metering for the EVM about evmc

[chfast]

cc @Arachnid

[gumb0]

The EIP suggests different costs when the slot is modified for the first time in transaction vs subsequent modification in the same transaction, so I think this proposal doesn't cover this difference.

[chfast]

The EIP suggessts different costs when the slot is modified for the first time in transaction vs subsequent modification in the same transaction, so I think this proposal doesn't cover this difference.

You are right. I didn't wanted to make it so much detailed. I meant "include any distinctive storage status need to implement Constantinople".

I added modified_dirty status which means "a dirty storage slot was modified".

[gumb0]

Sufficient statuses I think would be

• unmodified
• added_clear // modified for the first time the slot that was zero
• modified_clear // modified for the first time the slot that was non-zero
• modified_dirty

(Refunds for deleting are handled outside of VM in transaction finalization)

[chfast]

I will work on this.

[chfast]

I'm closing it as partly done in #52. The list would have to extended for EIP-1087, but nothing complicated is expected.