From 8d31dab5ce13bf8901d2e270f2f9d66bdfda1115 Mon Sep 17 00:00:00 2001
From: pdobacz <5735525+pdobacz@users.noreply.github.com>
Date: Thu, 1 Feb 2024 20:40:15 +0100
Subject: [PATCH] Spec out behavior of legacy CREATE/CREATE2 w/ eof initcode

---
 spec/eof.md | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/spec/eof.md b/spec/eof.md
index 70a833c..dc184a6 100644
--- a/spec/eof.md
+++ b/spec/eof.md
@@ -159,13 +159,17 @@ Code executing within an EOF environment will behave differently than legacy cod
 - If the target account of `EXTCODESIZE` is an EOF contract, then it will return 2.
 - The instruction `JUMPDEST` is renamed to `NOP` and remains charging 1 gas without any effect.
     - Note: jumpdest-analysis is not performed anymore.
-- EOF contract may not deploy legacy code
-- Legacy contract may not deploy EOF code
-- ~~If a `DELEGATECALL` crosses an EOF<>legacy boundary, then it returns 0 to signal failure (i.e. legacy->EOF and EOF->legacy `DELEGATECALL`s are disallowed).~~
+- EOF contract may not deploy legacy code (it is naturally rejected on the code validation stage)
+- Legacy contract or legacy creation tx may not deploy EOF code per [EIP-3541](https://eips.ethereum.org/EIPS/eip-3541):
+- If instructions `CREATE` and `CREATE2` have EOF code as initcode (starting with `EF00` magic)
+    - deployment fails (returns 0 on the stack)
+    - caller's nonce is not updated and gas for initcode execution is not consumed
 - `DELEGATECALL` from an EOF contract to a legacy contract is disallowed, and it returns 0 to signal failure. We allow legacy to EOF path for existing proxy contracts to be able to use EOF upgrades.
 
 ### New Behavior
 
+The following instructions are introduced in EOF code:
+
 - `RJUMP (0xe0)` instruction
     - deduct 2 gas
     - read int16 operand `offset`, set `pc = offset + pc + 3`