From 37a01a32477f9e26933c4f8de475ae24fa3ee01c Mon Sep 17 00:00:00 2001
From: ChihChengLiang <chihchengliang@gmail.com>
Date: Thu, 22 Feb 2024 03:09:30 +0800
Subject: [PATCH] WIP

---
 .../src/evm_circuit/util/common_gadget.rs     | 27 +++++++++++++++----
 1 file changed, 22 insertions(+), 5 deletions(-)

diff --git a/zkevm-circuits/src/evm_circuit/util/common_gadget.rs b/zkevm-circuits/src/evm_circuit/util/common_gadget.rs
index f8e11ef9e86..2eb3a751dc3 100644
--- a/zkevm-circuits/src/evm_circuit/util/common_gadget.rs
+++ b/zkevm-circuits/src/evm_circuit/util/common_gadget.rs
@@ -452,14 +452,14 @@ impl<F: Field> TransferToGadget<F> {
 /// setting it's code_hash = EMPTY_HASH.   The receiver account is also created
 /// unconditionally if must_create is true.  This gadget is used in BeginTx.
 #[derive(Clone, Debug)]
-pub(crate) struct TransferWithGasFeeGadget<F> {
-    sender_sub_fee: UpdateBalanceGadget<F, 2, false>,
+pub(crate) struct TransferWithGasFeeGadget<F, const WITH_FEE: bool> {
+    sender_sub_fee: Option<UpdateBalanceGadget<F, 2, false>>,
     sender_sub_value: UpdateBalanceGadget<F, 2, false>,
     receiver: TransferToGadget<F>,
     value_is_zero: IsZeroWordGadget<F, Word32Cell<F>>,
 }
 
-impl<F: Field> TransferWithGasFeeGadget<F> {
+impl<F: Field, const WITH_FEE: bool> TransferWithGasFeeGadget<F, WITH_FEE> {
     #[allow(clippy::too_many_arguments)]
     pub(crate) fn construct(
         cb: &mut EVMConstraintBuilder<F>,
@@ -468,10 +468,14 @@ impl<F: Field> TransferWithGasFeeGadget<F> {
         receiver_exists: Expression<F>,
         must_create: Expression<F>,
         value: Word32Cell<F>,
-        gas_fee: Word32Cell<F>,
         reversion_info: &mut ReversionInfo<F>,
+        gas_fee: Option<Word32Cell<F>>,
     ) -> Self {
-        let sender_sub_fee = cb.decrease_balance(sender_address.to_word(), gas_fee, None);
+        let sender_sub_fee = if WITH_FEE {
+            Some(cb.decrease_balance(sender_address.to_word(), gas_fee.expect("fee exists"), None))
+        } else {
+            None
+        };
         let value_is_zero = cb.is_zero_word(&value);
         // Skip transfer if value == 0
         let sender_sub_value = cb.condition(not::expr(value_is_zero.expr()), |cb| {
@@ -517,6 +521,19 @@ impl<F: Field> TransferWithGasFeeGadget<F> {
         // +1 Write Account (sender) Balance
         // +1 Write Account (receiver) Balance
         not::expr(self.value_is_zero.expr()) * 2.expr()
+
+
+        /// without gas 
+
+         // +1 Write Account (receiver) CodeHash (account creation via code_hash update)
+         or::expr([
+            not::expr(self.value_is_zero.expr()) * not::expr(self.receiver.receiver_exists.clone()),
+            self.receiver.must_create.clone()]
+        ) * 1.expr() +
+// +1 Write Account (sender) Balance
+// +1 Write Account (receiver) Balance
+not::expr(self.value_is_zero.expr()) * 2.expr()
+
     }
 
     #[allow(clippy::too_many_arguments)]