From 93b7b350fe9f9c8423435f54d6ec2e4ba4ac354a Mon Sep 17 00:00:00 2001
From: Morty <yiweichi1@gmail.com>
Date: Thu, 31 Jul 2025 18:37:27 +0800
Subject: [PATCH 1/3] feat: override difficulty opcode to always return zero

---
 src/instructions.rs | 16 +++++++++++++++-
 1 file changed, 15 insertions(+), 1 deletion(-)

diff --git a/src/instructions.rs b/src/instructions.rs
index 59f2b8a..d887824 100644
--- a/src/instructions.rs
+++ b/src/instructions.rs
@@ -16,6 +16,8 @@ use std::rc::Rc;
 
 const HISTORY_STORAGE_ADDRESS: Address = address!("0x0000F90827F1C53a10cb7A02335B175320002935");
 const HISTORY_SERVE_WINDOW: u64 = 8191;
+// const DIFFICULTY: U256 = U256::ZERO;
+const DIFFICULTY: U256 = U256::from_limbs([1233, 0, 0, 0]);
 
 /// Holds the EVM instruction table for Scroll.
 pub struct ScrollInstructions<WIRE: InterpreterTypes, HOST> {
@@ -67,9 +69,10 @@ where
 /// - `TLOAD`
 /// - `SELFDESTRUCT`
 /// - `MCOPY`
+/// - `DIFFICULTY`
 pub fn make_scroll_instruction_table<WIRE: InterpreterTypes, HOST: ScrollContextTr>(
 ) -> InstructionTable<WIRE, HOST> {
-    let mut table = instruction_table::<WIRE, HOST>();
+    let mut table: [fn(InstructionContext<'_, HOST, WIRE>); 256] = instruction_table::<WIRE, HOST>();
 
     // override the instructions
     table[opcode::BLOCKHASH as usize] = blockhash::<WIRE, HOST>;
@@ -78,6 +81,7 @@ pub fn make_scroll_instruction_table<WIRE: InterpreterTypes, HOST: ScrollContext
     table[opcode::TLOAD as usize] = tload::<WIRE, HOST>;
     table[opcode::SELFDESTRUCT as usize] = selfdestruct::<WIRE, HOST>;
     table[opcode::MCOPY as usize] = mcopy::<WIRE, HOST>;
+    table[opcode::DIFFICULTY as usize] = difficulty::<WIRE, HOST>;
 
     table
 }
@@ -216,6 +220,16 @@ fn mcopy<WIRE: InterpreterTypes, H: ScrollContextTr>(context: InstructionContext
     interpreter.memory.copy(dst, src, len);
 }
 
+/// Implements the DIFFICULTY instruction.
+///
+/// Pushes the block difficulty(default to 0) onto the stack.
+pub fn difficulty<WIRE: InterpreterTypes, H: Host + ?Sized>(
+    context: InstructionContext<'_, H, WIRE>,
+) {
+    gas!(context.interpreter, gas::BASE);
+    push!(context.interpreter, DIFFICULTY);
+}
+
 // HELPER FUNCTIONS
 // ================================================================================================
 

From c67a26eb613d4e0b3d1e7c5c8be0705dfeff7980 Mon Sep 17 00:00:00 2001
From: Morty <yiweichi1@gmail.com>
Date: Thu, 31 Jul 2025 18:39:28 +0800
Subject: [PATCH 2/3] fix typo

---
 src/instructions.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/instructions.rs b/src/instructions.rs
index d887824..9524ca8 100644
--- a/src/instructions.rs
+++ b/src/instructions.rs
@@ -72,7 +72,7 @@ where
 /// - `DIFFICULTY`
 pub fn make_scroll_instruction_table<WIRE: InterpreterTypes, HOST: ScrollContextTr>(
 ) -> InstructionTable<WIRE, HOST> {
-    let mut table: [fn(InstructionContext<'_, HOST, WIRE>); 256] = instruction_table::<WIRE, HOST>();
+    let mut table = instruction_table::<WIRE, HOST>();
 
     // override the instructions
     table[opcode::BLOCKHASH as usize] = blockhash::<WIRE, HOST>;

From 01030c48e50c55a9a2cf271478753c3f4aa84f9d Mon Sep 17 00:00:00 2001
From: Morty <yiweichi1@gmail.com>
Date: Thu, 31 Jul 2025 19:27:28 +0800
Subject: [PATCH 3/3] update DIFFICULTY

---
 src/instructions.rs | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/instructions.rs b/src/instructions.rs
index 9524ca8..c9a79ff 100644
--- a/src/instructions.rs
+++ b/src/instructions.rs
@@ -16,8 +16,7 @@ use std::rc::Rc;
 
 const HISTORY_STORAGE_ADDRESS: Address = address!("0x0000F90827F1C53a10cb7A02335B175320002935");
 const HISTORY_SERVE_WINDOW: u64 = 8191;
-// const DIFFICULTY: U256 = U256::ZERO;
-const DIFFICULTY: U256 = U256::from_limbs([1233, 0, 0, 0]);
+const DIFFICULTY: U256 = U256::ZERO;
 
 /// Holds the EVM instruction table for Scroll.
 pub struct ScrollInstructions<WIRE: InterpreterTypes, HOST> {