Remove blobbasefee from block header

evm_arithmetization/src/cpu/kernel/asm/memory/metadata.asm

@@ -268,10 +268,6 @@ global sys_chainid:
     %mload_global_metadata(@GLOBAL_METADATA_BLOCK_BASE_FEE)
 %endmacro
 
-%macro blobbasefee
-    %mload_global_metadata(@GLOBAL_METADATA_BLOCK_BLOB_BASE_FEE)
-%endmacro
-
 global sys_basefee:
     // stack: kexit_info
     %charge_gas_const(@GAS_BASE)
@@ -318,7 +314,7 @@ global sys_blobbasefee:
     // stack: kexit_info
     %charge_gas_const(@GAS_BASE)
     // stack: kexit_info
-    %blobbasefee
+    PROVER_INPUT(blobbasefee)
     // stack: blobbasefee, kexit_info
     SWAP1
     EXIT_KERNEL

evm_arithmetization/src/cpu/kernel/constants/global_metadata.rs

@@ -49,7 +49,6 @@ pub(crate) enum GlobalMetadata {
     BlockGasLimit,
     BlockChainId,
     BlockBaseFee,
-    BlockBlobBaseFee,
     BlockBlobGasUsed,
     BlockExcessBlobGas,
     BlockGasUsed,
@@ -115,7 +114,7 @@ pub(crate) enum GlobalMetadata {
 }
 
 impl GlobalMetadata {
-    pub(crate) const COUNT: usize = 56;
+    pub(crate) const COUNT: usize = 55;
 
     /// Unscales this virtual offset by their respective `Segment` value.
     pub(crate) const fn unscale(&self) -> usize {
@@ -146,7 +145,6 @@ impl GlobalMetadata {
             Self::BlockChainId,
             Self::BlockBaseFee,
             Self::BlockGasUsed,
-            Self::BlockBlobBaseFee,
             Self::BlockBlobGasUsed,
             Self::BlockExcessBlobGas,
             Self::BlockGasUsedBefore,
@@ -207,7 +205,6 @@ impl GlobalMetadata {
             Self::BlockGasLimit => "GLOBAL_METADATA_BLOCK_GAS_LIMIT",
             Self::BlockChainId => "GLOBAL_METADATA_BLOCK_CHAIN_ID",
             Self::BlockBaseFee => "GLOBAL_METADATA_BLOCK_BASE_FEE",
-            Self::BlockBlobBaseFee => "GLOBAL_METADATA_BLOCK_BLOB_BASE_FEE",
             Self::BlockBlobGasUsed => "GLOBAL_METADATA_BLOCK_BLOB_GAS_USED",
             Self::BlockExcessBlobGas => "GLOBAL_METADATA_BLOCK_EXCESS_BLOB_GAS",
             Self::BlockGasUsed => "GLOBAL_METADATA_BLOCK_GAS_USED",

evm_arithmetization/src/cpu/kernel/constants/mod.rs

@@ -316,10 +316,15 @@ const MAX_NONCE: (&str, u64) = ("MAX_NONCE", 0xffffffffffffffff);
 const CALL_STACK_LIMIT: (&str, u64) = ("CALL_STACK_LIMIT", 1024);
 
 /// Cancun-related constants
-/// See <https://eips.ethereum.org/EIPS/eip-4788#deployment>.
+/// See <https://eips.ethereum.org/EIPS/eip-4788> and
+/// <https://eips.ethereum.org/EIPS/eip-4844>.
 pub mod cancun_constants {
     use super::*;
 
+    pub const BLOB_BASE_FEE_UPDATE_FRACTION: U256 = U256([0x32f0ed, 0, 0, 0]);
+
+    pub const MIN_BLOB_BASE_FEE: U256 = U256::one();
+
     pub const BEACON_ROOTS_ADDRESS: (&str, [u8; 20]) = (
         "BEACON_ROOTS_ADDRESS",
         hex!("000F3df6D732807Ef1319fB7B8bB8522d0Beac02"),

evm_arithmetization/src/cpu/kernel/interpreter.rs

@@ -243,10 +243,6 @@ impl<F: Field> Interpreter<F> {
             (GlobalMetadata::BlockGasLimit, metadata.block_gaslimit),
             (GlobalMetadata::BlockChainId, metadata.block_chain_id),
             (GlobalMetadata::BlockBaseFee, metadata.block_base_fee),
-            (
-                GlobalMetadata::BlockBlobBaseFee,
-                metadata.block_blob_base_fee,
-            ),
             (
                 GlobalMetadata::BlockCurrentHash,
                 h2u(inputs.block_hashes.cur_hash),

evm_arithmetization/src/generation/mod.rs

@@ -130,10 +130,6 @@ fn apply_metadata_and_tries_memops<F: RichField + Extendable<D>, const D: usize>
             h2u(inputs.block_hashes.cur_hash),
         ),
         (GlobalMetadata::BlockGasUsed, metadata.block_gas_used),
-        (
-            GlobalMetadata::BlockBlobBaseFee,
-            metadata.block_blob_base_fee,
-        ),
         (
             GlobalMetadata::BlockBlobGasUsed,
             metadata.block_blob_gas_used,

evm_arithmetization/src/generation/prover_input.rs

@@ -1,4 +1,5 @@
 use core::mem::transmute;
+use std::cmp::min;
 use std::collections::{BTreeSet, HashMap};
 use std::str::FromStr;
 
@@ -9,6 +10,9 @@ use num_bigint::BigUint;
 use plonky2::field::types::Field;
 use serde::{Deserialize, Serialize};
 
+use crate::cpu::kernel::constants::cancun_constants::{
+    BLOB_BASE_FEE_UPDATE_FRACTION, MIN_BLOB_BASE_FEE,
+};
 use crate::cpu::kernel::constants::context_metadata::ContextMetadata;
 use crate::cpu::kernel::constants::global_metadata::GlobalMetadata;
 use crate::cpu::kernel::interpreter::simulate_cpu_and_get_user_jumps;
@@ -48,6 +52,7 @@ impl<F: Field> GenerationState<F> {
             "sf" => self.run_sf(input_fn),
             "ffe" => self.run_ffe(input_fn),
             "rlp" => self.run_rlp(),
+            "blobbasefee" => self.run_blobbasefee(),
             "current_hash" => self.run_current_hash(),
             "account_code" => self.run_account_code(),
             "bignum_modmul" => self.run_bignum_modmul(),
@@ -136,6 +141,15 @@ impl<F: Field> GenerationState<F> {
             .ok_or(ProgramError::ProverInputError(OutOfRlpData))
     }
 
+    fn run_blobbasefee(&mut self) -> Result<U256, ProgramError> {
+        let excess_blob_gas = self.inputs.block_metadata.block_excess_blob_gas;
+        Ok(fake_exponential(
+            MIN_BLOB_BASE_FEE,
+            excess_blob_gas,
+            BLOB_BASE_FEE_UPDATE_FRACTION,
+        ))
+    }
+
     fn run_current_hash(&mut self) -> Result<U256, ProgramError> {
         Ok(U256::from_big_endian(&self.inputs.block_hashes.cur_hash.0))
     }
@@ -829,3 +843,17 @@ fn modexp(x: U256, e: U256, n: U256) -> Result<U256, ProgramError> {
 
     Ok(product)
 }
+
+/// See EIP-4844: <https://eips.ethereum.org/EIPS/eip-4844#helpers>.
+fn fake_exponential(factor: U256, numerator: U256, denominator: U256) -> U256 {
+    let mut i = 1;
+    let mut output = U256::zero();
+    let mut numerator_accum = factor * denominator;
+    while !numerator_accum.is_zero() {
+        output += numerator_accum;
+        numerator_accum *= numerator; // (denominator * i)
+        i += 1;
+    }
+
+    output // denominator
+}

evm_arithmetization/src/recursive_verifier.rs

@@ -379,7 +379,7 @@ pub(crate) fn get_memory_extra_looking_sum_circuit<F: RichField + Extendable<D>,
     // This contains the `block_beneficiary`, `block_random`, `block_base_fee`,
     // `block_blob_base_fee`, `block_blob_gas_used`, `block_excess_blob_gas`,
     // `parent_beacon_block_root` as well as `cur_hash`.
-    let block_fields_arrays: [(GlobalMetadata, &[Target]); 8] = [
+    let block_fields_arrays: [(GlobalMetadata, &[Target]); 7] = [
         (
             GlobalMetadata::BlockBeneficiary,
             &public_values.block_metadata.block_beneficiary,
@@ -392,10 +392,6 @@ pub(crate) fn get_memory_extra_looking_sum_circuit<F: RichField + Extendable<D>,
             GlobalMetadata::BlockBaseFee,
             &public_values.block_metadata.block_base_fee,
         ),
-        (
-            GlobalMetadata::BlockBlobBaseFee,
-            &public_values.block_metadata.block_blob_base_fee,
-        ),
         (
             GlobalMetadata::BlockBlobGasUsed,
             &public_values.block_metadata.block_blob_gas_used,
@@ -800,10 +796,6 @@ where
         block_metadata_target.block_gas_used,
         u256_to_u32(block_metadata.block_gas_used)?,
     );
-    // BlobBaseFee fits in 2 limbs
-    let blob_basefee = u256_to_u64(block_metadata.block_blob_base_fee)?;
-    witness.set_target(block_metadata_target.block_blob_base_fee[0], blob_basefee.0);
-    witness.set_target(block_metadata_target.block_blob_base_fee[1], blob_basefee.1);
     // BlobGasUsed fits in 2 limbs
     let blob_gas_used = u256_to_u64(block_metadata.block_blob_gas_used)?;
     witness.set_target(

evm_arithmetization/src/verifier.rs

@@ -194,10 +194,6 @@ where
             GlobalMetadata::BlockGasUsed,
             public_values.block_metadata.block_gas_used,
         ),
-        (
-            GlobalMetadata::BlockBlobBaseFee,
-            public_values.block_metadata.block_blob_base_fee,
-        ),
         (
             GlobalMetadata::BlockBlobGasUsed,
             public_values.block_metadata.block_blob_gas_used,
@@ -351,10 +347,6 @@ pub(crate) mod debug_utils {
                 GlobalMetadata::BlockGasUsed,
                 public_values.block_metadata.block_gas_used,
             ),
-            (
-                GlobalMetadata::BlockBlobBaseFee,
-                public_values.block_metadata.block_blob_base_fee,
-            ),
             (
                 GlobalMetadata::BlockBlobGasUsed,
                 public_values.block_metadata.block_blob_gas_used,