feat: RISC-V 256-bit Integer Chip Implementations (#716)

* feat: RISC-V base ALU int256 chip
* feat: remove eDSL support for U256 arithmetic, ECC, and modular arithmetic

.github/workflows/benchmark-call.yml

@@ -10,7 +10,6 @@ on:
         options:
           - verify_fibair
           - fibonacci
-          - alu256_e2e
           - small_e2e
       instance_type:
         type: string
@@ -93,12 +92,6 @@ jobs:
         run: |
           python3 ../ci/scripts/bench.py $BIN_NAME $CMD_ARGS
 
-      - name: Run benchmark
-        if: inputs.benchmark_name == 'alu256_e2e'
-        working-directory: lib/recursion
-        run: |
-          python3 ../../ci/scripts/bench.py $BIN_NAME $CMD_ARGS
-
       - name: Run benchmark
         if: inputs.benchmark_name == 'small_e2e'
         working-directory: lib/recursion

.github/workflows/recursion-bench.yml

@@ -24,20 +24,6 @@ env:
   AXIOM_FAST_TEST: "1"
 
 jobs:
-  benchmark_alu256_e2e:
-    uses: ./.github/workflows/benchmark-call.yml
-    # run on pull request with label 'run-benchmark' or 'run-benchmark-e2e'
-    # and always run on push to main
-    if: |
-      (github.event_name == 'pull_request' &&
-      (contains(github.event.pull_request.labels.*.name, 'run-benchmark') ||
-      contains(github.event.pull_request.labels.*.name, 'run-benchmark-e2e'))) ||
-      (github.event_name == 'push' && github.ref == 'refs/heads/main')
-    with:
-      instance_type: 64cpu-linux-arm64
-      benchmark_name: alu256_e2e
-    secrets: inherit
-
   benchmark_small_e2e:
     uses: ./.github/workflows/benchmark-call.yml
     # run on non-draft pull request with label 'run-benchmark'

lib/recursion/Cargo.toml

@@ -49,9 +49,6 @@ cfg-if = { workspace = true }
 [dev-dependencies]
 ax-circuit-primitives.workspace = true
 
-[[bin]]
-name = "alu256_e2e"
-
 [[bin]]
 name = "small_e2e"
 

lib/recursion/src/hints.rs

@@ -1,6 +1,5 @@
 use std::cmp::Reverse;
 
-use ax_circuit_primitives::bigint::utils::big_uint_to_num_limbs;
 use ax_stark_backend::{
     keygen::types::TraceWidth,
     prover::{
@@ -10,11 +9,9 @@ use ax_stark_backend::{
 };
 use ax_stark_sdk::config::baby_bear_poseidon2::BabyBearPoseidon2Config;
 use axvm_native_compiler::ir::{
-    unsafe_array_transmute, Array, BigUintVar, Builder, Config, Ext, Felt, MemVariable, Usize, Var,
-    DIGEST_SIZE, LIMB_BITS, NUM_LIMBS,
+    unsafe_array_transmute, Array, Builder, Config, Ext, Felt, MemVariable, Usize, Var, DIGEST_SIZE,
 };
 use itertools::Itertools;
-use num_bigint_dig::BigUint;
 use p3_baby_bear::{BabyBear, DiffusionMatrixBabyBear};
 use p3_commit::ExtensionMmcs;
 use p3_field::{extension::BinomialExtensionField, AbstractExtensionField, AbstractField, Field};
@@ -472,27 +469,6 @@ impl Hintable<InnerConfig> for Commitments<BabyBearPoseidon2Config> {
     }
 }
 
-impl Hintable<InnerConfig> for BigUint {
-    type HintVariable = BigUintVar<InnerConfig>;
-
-    fn read(builder: &mut Builder<InnerConfig>) -> Self::HintVariable {
-        let ret = builder.uninit_biguint();
-        for i in 0..NUM_LIMBS {
-            // FIXME: range check for each element.
-            let v = builder.hint_var();
-            builder.set_value(&ret, i, v);
-        }
-        ret
-    }
-
-    fn write(&self) -> Vec<Vec<<InnerConfig as Config>::N>> {
-        vec![big_uint_to_num_limbs(self, LIMB_BITS, NUM_LIMBS)
-            .iter()
-            .map(|x| <InnerConfig as Config>::N::from_canonical_usize(*x))
-            .collect()]
-    }
-}
-
 #[cfg(test)]
 mod test {
     use axvm_circuit::system::program::util::execute_program;

toolchain/instructions/src/lib.rs

@@ -150,40 +150,6 @@ pub enum ModularArithmeticOpcode {
     DIV,
 }
 
-// to be deleted and replaced by Rv32Alu256Opcodes below
-#[derive(
-    Copy, Clone, Debug, PartialEq, Eq, PartialOrd, Ord, EnumCount, EnumIter, FromRepr, UsizeOpcode,
-)]
-#[opcode_offset = 0x180]
-#[repr(usize)]
-pub enum U256Opcode {
-    // maybe later we will make it uint and specify the parameters in the config
-    ADD,
-    SUB,
-    LT,
-    EQ,
-    XOR,
-    AND,
-    OR,
-    SLT,
-
-    SLL,
-    SRL,
-    SRA,
-
-    MUL,
-}
-impl U256Opcode {
-    // Excludes multiplication
-    pub fn arithmetic_opcodes() -> impl Iterator<Item = U256Opcode> {
-        (U256Opcode::ADD as usize..=U256Opcode::SLT as usize).map(U256Opcode::from_usize)
-    }
-
-    pub fn shift_opcodes() -> impl Iterator<Item = U256Opcode> {
-        (U256Opcode::SLL as usize..=U256Opcode::SRA as usize).map(U256Opcode::from_usize)
-    }
-}
-
 // to be deleted and replaced by Rv32SwOpcode
 #[derive(
     Copy, Clone, Debug, PartialEq, Eq, PartialOrd, Ord, EnumCount, EnumIter, FromRepr, UsizeOpcode,