From d505a2c236728ad31586de92e80c0962829bafc1 Mon Sep 17 00:00:00 2001
From: malatrax <simon.malatrait@grenoble-inp.org>
Date: Thu, 12 Dec 2024 14:16:08 +0100
Subject: [PATCH] feat: scaffold Processor component

---
 .../src/components/processor/component.rs     | 96 +++++++++++++++++++
 .../src/components/processor/mod.rs           |  1 +
 2 files changed, 97 insertions(+)
 create mode 100644 crates/brainfuck_prover/src/components/processor/component.rs

diff --git a/crates/brainfuck_prover/src/components/processor/component.rs b/crates/brainfuck_prover/src/components/processor/component.rs
new file mode 100644
index 0000000..66f04e3
--- /dev/null
+++ b/crates/brainfuck_prover/src/components/processor/component.rs
@@ -0,0 +1,96 @@
+use crate::components::{
+    instruction::table::InstructionElements, io::table::IoElements, memory::table::MemoryElements,
+    ProcessorClaim,
+};
+use stwo_prover::{
+    constraint_framework::{EvalAtRow, FrameworkComponent, FrameworkEval},
+    core::{channel::Channel, fields::qm31::SecureField},
+};
+
+/// Implementation of `Component` and `ComponentProver`
+/// for the `SimdBackend` from the constraint framework provided by Stwo
+pub type ProcessorComponent = FrameworkComponent<ProcessorEval>;
+
+/// The AIR for the Processor component.
+///
+/// Constraints are defined through the `FrameworkEval`
+/// provided by the constraint framework of Stwo.
+pub struct ProcessorEval {
+    log_size: u32,
+    _input_lookup_elements: IoElements,
+    _output_lookup_elements: IoElements,
+    _memory_lookup_elements: MemoryElements,
+    _instruction_lookup_elements: InstructionElements,
+}
+
+impl ProcessorEval {
+    pub const fn new(
+        claim: &ProcessorClaim,
+        input_lookup_elements: IoElements,
+        output_lookup_elements: IoElements,
+        memory_lookup_elements: MemoryElements,
+        instruction_lookup_elements: InstructionElements,
+    ) -> Self {
+        Self {
+            log_size: claim.log_size,
+            _input_lookup_elements: input_lookup_elements,
+            _output_lookup_elements: output_lookup_elements,
+            _memory_lookup_elements: memory_lookup_elements,
+            _instruction_lookup_elements: instruction_lookup_elements,
+        }
+    }
+}
+
+impl FrameworkEval for ProcessorEval {
+    /// Returns the log size from the main claim.
+    fn log_size(&self) -> u32 {
+        self.log_size
+    }
+
+    /// The degree of the constraints is bounded by the size of the trace.
+    ///
+    /// Returns the ilog2 (upper) bound of the constraint degree for the component.
+    fn max_constraint_log_degree_bound(&self) -> u32 {
+        self.log_size + 1
+    }
+
+    /// Defines the AIR for the Processor component
+    ///
+    /// Registers values from the current row are obtained through masks.
+    /// When you apply a mask, you target the current column and then pass to the next
+    /// one: the register order matters to correctly fetch them.
+    ///
+    /// - Use `eval.next_trace_mask()` to get the current register from the main trace
+    ///   (`ORIGINAL_TRACE_IDX`)
+    ///
+    /// Use `eval.add_constraint` to define a local constraint (boundary, transition).
+    /// Use `eval.add_to_relation` to define a global constraint for the logUp protocol.
+    ///
+    /// The logUp must be finalized with `eval.finalize_logup()`.
+    #[allow(clippy::similar_names)]
+    fn evaluate<E: EvalAtRow>(&self, _eval: E) -> E {
+        todo!()
+    }
+}
+
+/// The claim of the interaction phase 2 (with the logUp protocol).
+///
+/// The total sum is the computed sum of the logUp extension column,
+/// including the padded rows.
+/// It allows proving that the Processor main trace is:
+/// - A permutation of the Memory trace.
+/// - A permutation of a subset of the Instruction trace.
+/// - That the I/O values are the ones in the I/O components, in the same order.
+#[derive(Debug, Eq, PartialEq)]
+pub struct InteractionClaim {
+    /// The computed sum of the logUp extension column, including padded rows.
+    pub claimed_sum: SecureField,
+}
+
+impl InteractionClaim {
+    /// Mix the sums from the logUp protocol into the Fiat-Shamir [`Channel`],
+    /// to bound the proof to the trace.
+    pub fn mix_into(&self, channel: &mut impl Channel) {
+        channel.mix_felts(&[self.claimed_sum]);
+    }
+}
diff --git a/crates/brainfuck_prover/src/components/processor/mod.rs b/crates/brainfuck_prover/src/components/processor/mod.rs
index 13971b0..570dae2 100644
--- a/crates/brainfuck_prover/src/components/processor/mod.rs
+++ b/crates/brainfuck_prover/src/components/processor/mod.rs
@@ -1 +1,2 @@
+pub mod component;
 pub mod table;