fix bn254_muladd test on rng

Author: dongliangCai

crates/test-artifacts/programs/elf/riscv32im-succinct-zkvm-elf

@@ -1,7 +1,7 @@
 #![no_main]
 sp1_zkvm::entrypoint!(main);
 
-use num::{BigUint, One};
+use num::{BigUint, Num, One};
 use rand::Rng;
 use sp1_zkvm::syscalls::sys_bn254_muladd;
 
@@ -28,33 +28,31 @@ fn biguint_to_bytes_le(x: BigUint) -> [u8; 32] {
 #[sp1_derive::cycle_tracker]
 pub fn main() {
     // Test with random numbers.
-    // let mut rng = rand::thread_rng();
-    // let mut x: [u8; 32] = rng.gen();
-    // let mut y: [u8; 32] = rng.gen();
-    // let z: [u8; 32] = rng.gen();
-
-    // // Convert byte arrays to BigUint
-    // let z_big = BigUint::from_bytes_le(&z);
-    // let x_big = BigUint::from_bytes_le(&x);
-    // // x = biguint_to_bytes_le(x_big.clone());
-    // let y_big = BigUint::from_bytes_le(&y);
-    // // y = biguint_to_bytes_le(y_big.clone());
-
-    let mut x: [u8; 32] = [0; 32];
-    x[0] = 2;
-    let mut y: [u8; 32] = [0; 32];
-    y[0] = 3;
-    let mut z: [u8; 32] = [0; 32];
-    z[0] = 4;
+    let mut rng = rand::thread_rng();
+    let mut x: [u8; 32] = rng.gen();
+    let mut y: [u8; 32] = rng.gen();
+    let mut z: [u8; 32] = rng.gen();
+
+    //bn254 scalar field modulus
+    let modulus = BigUint::from_str_radix(
+        "21888242871839275222246405745257275088548364400416034343698204186575808495617",
+        10,
+    )
+    .unwrap();
+
     // Convert byte arrays to BigUint
     let z_big = BigUint::from_bytes_le(&z);
     let x_big = BigUint::from_bytes_le(&x);
     let y_big = BigUint::from_bytes_le(&y);
 
+    x = biguint_to_bytes_le(&x_big % &modulus);
+    y = biguint_to_bytes_le(&y_big % &modulus);
+    z = biguint_to_bytes_le(&z_big % &modulus);
+
     let result_bytes = uint256_muladd(&x, &y, &z);
 
-    let result = (x_big * y_big) + z_big;
+    let result = ((x_big * y_big) + z_big) % modulus;
     let result_syscall = BigUint::from_bytes_le(&result_bytes);
 
-    assert_eq!(result, result_syscall); //10
+    assert_eq!(result, result_syscall);
 }