EVM: From Solidity to byte code, memory and storage

[@guru2491987]

This is such an amazing talk. Very much appreciate the amount of work that has gone into the slides and the content. I have a much deeper understanding of the EVM thanks to these 1.5 hours. Thank you Peter, David and team.

[@leeren_]

Been trying to dig KZbin for ages for a more in-depth talk on the mechanics of the EVM. Just wow - this is incredible. Thank you so much. Hope to help on the education side soon :)

[@fode-diop]

This presentation is straight 🔥 Good stuff!

[@ludwigthouvenin2012]

This is a goldmine, thank you for this amazing presentation.

[@frankzheng7925]

An amazing talk about EVM!

[@TheDFIPodcast]

So much win! This is demystifying the deep CS underbelly of Ethereum. Thank you for creating this content!

[@gaofan2856]

this channel is a hidden gem

[@MartinMarchev]

Amazing talk! Congrats and the great content and its delivery. Thanks for sharing it with us. 🙏🏻

[@0xRoman-c2r]

Awesome video! Thanks for the lecture, very interesting to learn about it

[@humzakhan288]

This is an amazing presentation. The level of detail is top notch. Keep up the good work!

[@xmlyyuan]

Very detailed videdo. Also good for knowing how VM works inside in general.

[@zes7215]

no such thing as interestx or etc or not

[@AnonymousSkimaHarvey]

This is pure gold. Thank you so much ! (all i need to move on level 18 on Ethernaut)

[@0xTyfn]

Huge thanks for your hard work sir. I really appreciate it 🎉

[@EngenhariadeSoftwareLuciana]

Impressive talk!!! Thank you for sharing.

[@wpmeng2859]

Really solidity deep study. Thanks.

[@ashh3051]

Really solid deep dive. Thanks.

[@nickeast4853]

thanks for the detailed explanation !! =] really want to learn more from you ! may I ask a question ? @42:48, why does it have to revert if "CALLDATASIZE - 4" is less than 32 bytes ?

[@estela3185]

Amazing video, thank you. Cordiale.

[@crypto_peng]

Definetely would like to have the new version but more visualized explanation for OP_Code again!! Still can't understand very well. Thank you sir!

[@qazawatzirak2596]

Nice explanation. At 20:10 we have the byteCode of runtime. The deploy transaction stores only Init Code fragment (i.e. Contructor). At 27:53 we are doing a code copy (from where it is). My question is, where is the Code ? From where the code is fed to EVM since the transaction does not include the byteCode of runtime ? Meaning, do we send the actual byteCode separately alongside the deploy transaction to a Node ? Also at 30:49, the code (runtime) is copied into the blockchain. Is it copied into the Merkle Praticia tree storage of that deploying account address ? Increasing the deployers nonce

[@EthereumEngineeringGroup]

The deployment transaction's data includes the byte code of the init code and the run time Solidity code. That is, have a look at the output of solc --bin SomeContract.sol . Those bytes of data for a deploy transaction are treated as code. The codecopy copies the code that is after the init code from where code is executing to memory. A reference to that location in memory is then returned, indicating the code that should be deployed.

[@lorenzocanocesconetto2577]

Great talk! Let me point out a small correction though, at 30:53 the second argument of return, i.e., stack[1], is the length of the data and not the ending address

[@EthereumEngineeringGroup]

Correct. At some point, I should re-do the talk with many small / minor corrections.

[@abstractumx]

thanks for sharing!

[@0xatharva952]

I am 2 years late.. yet learning soo much!

[@0xcoder542]

Hi Peter, Thank you for contributing such a valuable video about the Ethereum EVM. I'm interested in the State and the Patricia Trie I would appreciate it if you could share with me the video that you mentioned in this video. Many thanks

[@EthereumEngineeringGroup]

I think that is going to be one of the videos on Stateless. Have a look at the channel, look at the Videos tab, and then go to the video that was just before this one.

[@MrCoreyTexas]

The slide at 57:27 was confusing to me, because I was looking for 0x14, which is what gets assigned to valAddress in the code. Then I realized that 0x05 is 0x14 shifted right 2 bits. So the solidity compiler internally shifts 0x14 right 2 bits, putting 0x05 in the code, then outputs a shift left by 98 bits. Why does it do this? Well, I guess if it had to store 0x100, it could shift that to the right 8 bits, and put 0x01 in the code. So its output would be 1 byte less. Talk about microoptimization! So it doesn't really need to do it for 0x14 but it does anyways to simplify the code of the compiler.

[@MrCoreyTexas]

Which brings to mind the next question, why does it PUSH5 0x13000000000? Why doesn't it PUSH1 0x13 and SHL by 32 bits? The mind boggles.

[@leeren_]

42:36 Isn't the revert condition specified by assembly revert if (CALLDATASIZE - 4) = CALLDATASIZE - 4 The ISZERO returns 1 if 0x20 >= CALLDATASIZE - 4, 1 if 0x20 < CALLDATASIZE - 4 So it reverts if CALLDATASIZE - 4

[@crypto_peng]

Where can I find the community? Nice sharing thanks.

[@EthereumEngineeringGroup]

Join the meet-up group: www.meetup.com/ethereum-engineering/

[@miketruk7639]

@27:09 Storage[1] = 3 Stack[0] is location to write to stack[1] is the value to write but in my mind its like PUSH1 0x03 -> stack[0] = 03 PUSH1 0x01 -> stack[0] = 03, stack[1] = 01 SSTORE -> stack[0] is location (3) and stack[1] is value (1) what am i missing?

[@EthereumEngineeringGroup]

stack[0] is the top of the stack. Hence, PUSH1 3: stack[0] = 3, PUSH1 5: stack[0] = 5, stack[1] = 3, and then PUSH1 7: stack[0] = 7, stack[1] = 5, and stack[2] = 3

[@Elyx0]

Wonder if they ever got to coding the array index underflow

[@SaurabhBhai-t8k]

At 1:04 my dog also bark who is there in laptop Screen 😄

[@Naz-yi9bs]

@18:11 it's mentioned that, val2 = 3; will set "val2" as a state variable. Is that also not the case with val1, it's declared but assigned, however, doesn't that still make it a state variable? Thank you for this amazing video.

[@EthereumEngineeringGroup]

@naz val1 is also a state variable. It will have its default value, which for uint256 is 0. However, what I was meaning was that in the constructor, all initial values of state variables are set-up.

[@carsonhalter3134]

@ 13:00 does anyone have the link to the video on Merkle Patricia Trie's?

[@EthereumEngineeringGroup]

kzbin.info/www/bejne/o3LTnXeDo7qWqpo

[@davidz8110]

This is really great talk! it helps me to get clear of the evm. BTW. could you help update the slide link, it is unavailable now. Thanks!

[@EthereumEngineeringGroup]

Link updated.

[@jayjelaso5354]

what happens to storage data that is persistent and then a revert happens, does it stay there? what about subsequent runs of the contract, does storage stay there for every run of the contract and does it use up the storage.

[@jayjelaso5354]

I have a million questions that are simple questions but are not addressed in the documentation and I am trying to piece together the functionality of progrmming in solidity. Sorry to be a downer thanks for all you help and comprising this too low drill down about stack storage and memory and call data

[@EthereumEngineeringGroup]

If there is a revert, storage is reverted to. It is as if the transaction didn't happen (except for the gas charges)

[@EthereumEngineeringGroup]

Storage is persistent across transaction executions

[@jayjelaso5354]

@@EthereumEngineeringGroup So previous slots used up are going to stay there and new transactions require new slot storage? thank you for your replies

[@crypto_peng]

13:50 - Why State Root is 160 bits, and Account Storage Root is 256 bits numbers?

[@EthereumEngineeringGroup]

Storage slots are in a 256 bit range. Account addresses are 160 bits.

[@crypto_peng]

@@EthereumEngineeringGroup got it!

[@0xsabir]

what's the init code fragment ? 18:45

[@EthereumEngineeringGroup]

Constructor, initialisation, plus copy the runtime code to the a return address position so it can be installed.

[@lzy-v5136]

53:57 - where is 0x37?

[@EthereumEngineeringGroup]

0x36 is a PUSH1 instruction. It pushes the next byte from code onto the stack. As such, the 0x3d value is what is as location 0x37.

[@grigrob9]

18:19 solc compile command

[@ViceCoin]

Any tools for AndroidOS?

[@EthereumEngineeringGroup]

Web3J is a Java library for interacting with Ethereum nodes.

[@ViceCoin]

@@EthereumEngineeringGroup All the insalls are CLI prompts (Windows). Any solidity editors for Android? I have a wireless keyboard.

[@vinuvinu5884]

Kannada

[@goodboy9758]

chi chi ikkada kuda entra