From ad0eb3ccd1c011c0506ced8377f002b2842fd84a Mon Sep 17 00:00:00 2001
From: enitrat <msaug@protonmail.com>
Date: Fri, 22 Nov 2024 00:26:32 +0800
Subject: [PATCH] add debug prints to locate long operations

---
 crates/evm/src/precompiles/modexp.cairo    |  2 ++
 crates/utils/src/crypto/modexp/lib.cairo   |  4 ++++
 crates/utils/src/crypto/modexp/mpnat.cairo | 11 ++++++++++-
 3 files changed, 16 insertions(+), 1 deletion(-)

diff --git a/crates/evm/src/precompiles/modexp.cairo b/crates/evm/src/precompiles/modexp.cairo
index d2b35b73e..4bf993da8 100644
--- a/crates/evm/src/precompiles/modexp.cairo
+++ b/crates/evm/src/precompiles/modexp.cairo
@@ -26,6 +26,7 @@ pub impl ModExp of Precompile {
     }
 
     fn exec(input: Span<u8>) -> Result<(u64, Span<u8>), EVMError> {
+        println!("Start: Executing Modexp Precompile");
         // The format of input is:
         // <length_of_BASE> <length_of_EXPONENT> <length_of_MODULUS> <BASE> <EXPONENT> <MODULUS>
         // Where every length is a 32-byte left-padded integer representing the number of bytes
@@ -98,6 +99,7 @@ pub impl ModExp of Precompile {
         let output = modexp(base, exponent, modulus);
 
         let return_data = output.pad_left_with_zeroes(mod_len);
+        println!("End: Executing Modexp Precompile");
         Result::Ok((gas.into(), return_data))
     }
 }
diff --git a/crates/utils/src/crypto/modexp/lib.cairo b/crates/utils/src/crypto/modexp/lib.cairo
index a904bf8af..0d0f707ec 100644
--- a/crates/utils/src/crypto/modexp/lib.cairo
+++ b/crates/utils/src/crypto/modexp/lib.cairo
@@ -7,13 +7,17 @@ use crate::felt_vec::{Felt252VecTrait};
 /// Computes `(base ^ exp) % modulus`, where all values are given as big-endian
 /// encoded bytes.
 pub fn modexp(base: Span<u8>, exp: Span<u8>, modulus: Span<u8>) -> Span<u8> {
+    println!("Start: MPNAT::from_big_endian operation");
     let mut x = MPNatTrait::from_big_endian(base);
     let mut m = MPNatTrait::from_big_endian(modulus);
+    println!("End: MPNAT::from_big_endian operation");
 
     if m.digits.len == 1 && m.digits[0] == 0 {
         return [].span();
     }
 
+    println!("Start: modpow operation");
     let mut result = x.modpow(exp, ref m);
+    println!("End: modpow operation");
     result.digits.to_be_bytes()
 }
diff --git a/crates/utils/src/crypto/modexp/mpnat.cairo b/crates/utils/src/crypto/modexp/mpnat.cairo
index 5f461837f..f04238306 100644
--- a/crates/utils/src/crypto/modexp/mpnat.cairo
+++ b/crates/utils/src/crypto/modexp/mpnat.cairo
@@ -384,9 +384,13 @@ pub impl MPNatTraitImpl of MPNatTrait {
         }
 
         if modulus.is_power_of_two() { // return
+            println!("Start: modpow_with_power_of_two operation");
             return self.modpow_with_power_of_two(exp, ref modulus);
+            println!("End: modpow_with_power_of_two operation");
         } else if modulus.is_odd() {
+            println!("Start: modpow_montgomery operation");
             return self.modpow_montgomery(exp, ref modulus);
+            println!("End: modpow_montgomery operation");
         }
 
         // If the modulus is not a power of two and not an odd number then
@@ -457,13 +461,18 @@ pub impl MPNatTraitImpl of MPNatTrait {
         };
 
         let mut base_copy = MPNat { digits: self.digits.duplicate(), };
+        println!("Start: modpow_montgomery operation");
         let mut x1 = base_copy.modpow_montgomery(exp, ref odd);
+        println!("End: modpow_montgomery operation");
+        println!("Start: modpow_with_power_of_two operation");
         let mut x2 = self.modpow_with_power_of_two(exp, ref power_of_two);
+        println!("End: modpow_with_power_of_two operation");
 
+        println!("Start: koc_2017_inverse operation");
         let mut odd_inv = Self::koc_2017_inverse(
             ref odd, trailing_zeros * WORD_BITS + additional_zero_bits
         );
-
+        println!("End: koc_2017_inverse operation");
         let s = power_of_two.digits.len();
         let mut scratch: Felt252Vec<Word> = Felt252VecImpl::new();
         scratch.expand(s).unwrap();