From 650647337bb0344ca171d4d70fe878ae1a06ab9d Mon Sep 17 00:00:00 2001
From: Hadrien Croubois <hadrien.croubois@gmail.com>
Date: Fri, 26 Sep 2025 14:25:29 +0200
Subject: [PATCH] Rebase of top of forks/amsterdam

---
 src/ethereum/forks/amsterdam/utils/address.py | 27 ++++++++++
 .../amsterdam/vm/instructions/__init__.py     |  2 +
 .../forks/amsterdam/vm/instructions/system.py | 51 +++++++++++++++++--
 3 files changed, 76 insertions(+), 4 deletions(-)

diff --git a/src/ethereum/forks/amsterdam/utils/address.py b/src/ethereum/forks/amsterdam/utils/address.py
index 69f91d0a03..44954a006c 100644
--- a/src/ethereum/forks/amsterdam/utils/address.py
+++ b/src/ethereum/forks/amsterdam/utils/address.py
@@ -89,3 +89,30 @@ def compute_create2_contract_address(
     padded_address = left_pad_zero_bytes(canonical_address, 20)
 
     return Address(padded_address)
+
+
+def compute_setdelegate_contract_address(
+    address: Address, salt: Bytes32
+) -> Address:
+    """
+    Computes address of the delegation objects account that needs to be
+    created or updated, which is based on the sender address and salt.
+
+    Parameters
+    ----------
+    address :
+        The address of the account that wants to create the new account.
+    salt :
+        Address generation salt.
+
+    Returns
+    -------
+    address: `ethereum.osaka.fork_types.Address`
+        The computed address of the delegation object.
+    """
+    preimage = b"\xef\x01\x00" + address + salt
+    computed_address = keccak256(preimage)
+    canonical_address = computed_address[-20:]
+    padded_address = left_pad_zero_bytes(canonical_address, 20)
+
+    return Address(padded_address)
diff --git a/src/ethereum/forks/amsterdam/vm/instructions/__init__.py b/src/ethereum/forks/amsterdam/vm/instructions/__init__.py
index 9cc30668e7..6fcfef5c5d 100644
--- a/src/ethereum/forks/amsterdam/vm/instructions/__init__.py
+++ b/src/ethereum/forks/amsterdam/vm/instructions/__init__.py
@@ -210,6 +210,7 @@ class Ops(enum.Enum):
     RETURN = 0xF3
     DELEGATECALL = 0xF4
     CREATE2 = 0xF5
+    SETDELEGATE = 0xF6
     STATICCALL = 0xFA
     REVERT = 0xFD
     SELFDESTRUCT = 0xFF
@@ -365,4 +366,5 @@ class Ops(enum.Enum):
     Ops.STATICCALL: system_instructions.staticcall,
     Ops.REVERT: system_instructions.revert,
     Ops.CREATE2: system_instructions.create2,
+    Ops.SETDELEGATE: system_instructions.setdelegate,
 }
diff --git a/src/ethereum/forks/amsterdam/vm/instructions/system.py b/src/ethereum/forks/amsterdam/vm/instructions/system.py
index d7308821bd..05173c8246 100644
--- a/src/ethereum/forks/amsterdam/vm/instructions/system.py
+++ b/src/ethereum/forks/amsterdam/vm/instructions/system.py
@@ -19,6 +19,7 @@
 
 from ...fork_types import Address
 from ...state import (
+    account_exists,
     account_has_code_or_nonce,
     account_has_storage,
     get_account,
@@ -28,9 +29,12 @@
     set_account_balance,
 )
 from ...utils.address import (
-    compute_contract_address,
-    compute_create2_contract_address,
-    to_address_masked,
+    EOA_DELEGATION_MARKER,
+    PER_EMPTY_ACCOUNT_COST,
+    PER_AUTH_BASE_COST,
+    NULL_ADDRESS,
+    access_delegation,
+    is_valid_delegation,
 )
 from ...vm.eoa_delegation import access_delegation
 from .. import (
@@ -39,7 +43,7 @@
     incorporate_child_on_error,
     incorporate_child_on_success,
 )
-from ..exceptions import OutOfGasError, Revert, WriteInStaticContext
+from ..exceptions import AddressCollision, OutOfGasError, Revert, WriteInStaticContext
 from ..gas import (
     GAS_CALL_VALUE,
     GAS_COLD_ACCOUNT_ACCESS,
@@ -241,6 +245,45 @@ def create2(evm: Evm) -> None:
     evm.pc += Uint(1)
 
 
+def setdelegate(evm: EVM) -> None:
+    # GAS
+    charge_gas(evm, PER_EMPTY_ACCOUNT_COST)
+
+    # STATIC CHECK
+    if evm.message.is_static:
+        raise WriteInStaticContext
+
+    # STACK
+    target = to_address_masked(pop(evm.stack))
+    salt = pop(evm.stack).to_be_bytes32()
+
+    # OPERATION
+    location = compute_setdelegate_contract_address(
+        evm.message.current_target,
+        salt,
+    )
+
+    evm.accessed_addresses.add(location)
+
+    current_code = get_account(state, location).code
+    if current_code != b"" and not is_valid_delegation(current_code):
+        raise AddressCollision
+
+    if account_exists(state, location):
+        evm.refund_counter += U256(PER_EMPTY_ACCOUNT_COST - PER_AUTH_BASE_COST)
+
+    if target == NULL_ADDRESS:
+        code_to_set = b""
+    else:
+        code_to_set = EOA_DELEGATION_MARKER + target
+    set_code(state, location, code_to_set)
+
+    push(evm.stack, location)
+
+    # PROGRAM COUNTER
+    evm.pc += Uint(1)
+
+
 def return_(evm: Evm) -> None:
     """
     Halts execution returning output data.