From 350b9029989a433480152efb00fa3300235fa578 Mon Sep 17 00:00:00 2001
From: Sladuca <sladuca777@gmail.com>
Date: Wed, 28 Dec 2022 11:30:24 -0500
Subject: [PATCH] add or gadget

---
 plonky2/src/gadgets/arithmetic.rs | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/plonky2/src/gadgets/arithmetic.rs b/plonky2/src/gadgets/arithmetic.rs
index 39755bd4..e7b124b9 100644
--- a/plonky2/src/gadgets/arithmetic.rs
+++ b/plonky2/src/gadgets/arithmetic.rs
@@ -337,6 +337,12 @@ impl<F: RichField + Extendable<D>, const D: usize> CircuitBuilder<F, D> {
         BoolTarget::new_unsafe(self.mul(b1.target, b2.target))
     }
 
+    // computes the arithmetic extension of logical "or": `b1 + b2 - b1 * b2`
+    pub fn or(&mut self, b1: BoolTarget, b2: BoolTarget) -> BoolTarget {
+        let res_minus_b2 = self.arithmetic(-F::ONE, F::ONE, b1.target, b2.target, b1.target);
+        BoolTarget::new_unsafe(self.add(res_minus_b2, b2.target))
+    }
+
     pub fn _if(&mut self, b: BoolTarget, x: Target, y: Target) -> Target {
         let not_b = self.not(b);
         let maybe_x = self.mul(b.target, x);