From 04c2ab89e5a62d511717610324e4fd7099d2c57e Mon Sep 17 00:00:00 2001
From: Gali Michlevich <gali@starkware.co>
Date: Sun, 9 Feb 2025 15:39:03 +0200
Subject: [PATCH] PackedFelt252Packed27

---
 .../crates/prover_types/src/simd.rs           | 26 ++++++++++++++++++-
 1 file changed, 25 insertions(+), 1 deletion(-)

diff --git a/stwo_cairo_prover/crates/prover_types/src/simd.rs b/stwo_cairo_prover/crates/prover_types/src/simd.rs
index cf90a2611..514670914 100644
--- a/stwo_cairo_prover/crates/prover_types/src/simd.rs
+++ b/stwo_cairo_prover/crates/prover_types/src/simd.rs
@@ -11,7 +11,7 @@ use stwo_prover::core::backend::simd::m31::PackedM31;
 use stwo_prover::core::fields::FieldExpOps;
 
 use super::cpu::{UInt16, UInt32, UInt64, PRIME};
-use crate::cpu::{BigUInt, CasmState, Felt252};
+use crate::cpu::{BigUInt, CasmState, Felt252, Felt252Packed27};
 
 pub const LOG_N_LANES: u32 = 4;
 
@@ -373,6 +373,10 @@ impl PackedFelt252 {
         let limbs = arr.map(|felt| std::array::from_fn(|i| felt.get_m31(i)));
         Self::from_limbs(<_ as Pack>::pack(limbs))
     }
+
+    pub fn from_packed_felt252_packed27(packed27: PackedFelt252Packed27) -> Self {
+        Self::from_array(&std::array::from_fn(|i| Felt252::from(packed27.value[i])))
+    }
 }
 
 // TODO(Ohad): These are very slow, optimize.
@@ -447,6 +451,26 @@ impl DivExtend for PackedM31 {
     }
 }
 
+#[derive(Clone, Copy)]
+pub struct PackedFelt252Packed27 {
+    value: [Felt252Packed27; N_LANES],
+}
+impl PackedFelt252Packed27 {
+    pub fn from_packed_felt252packed27(other: PackedFelt252Packed27) -> Self {
+        Self { value: other.value }
+    }
+    pub fn get_m31(&self, index: usize) -> PackedM31 {
+        PackedM31::from_array(std::array::from_fn(|i| self.value[i].get_m31(index)))
+    }
+}
+impl Pack for Felt252Packed27 {
+    type SimdType = PackedFelt252Packed27;
+
+    fn pack(inputs: [Self; N_LANES]) -> Self::SimdType {
+        PackedFelt252Packed27 { value: inputs }
+    }
+}
+
 // TODO(Gali): Change to an efficient implementation.
 #[derive(Copy, Clone, Debug)]
 pub struct PackedBigUInt<const B: usize, const L: usize, const F: usize> {