fix the wrong index bit of permutation list generation in ntt.c

chipsalliance · Jan 14, 2025 · 536bcb5 · 536bcb5
1 parent 8f4f8e9
commit 536bcb5
Showing 1 changed file with 4 additions and 3 deletions.
diff --git a/tests/eval/_ntt/ntt.c b/tests/eval/_ntt/ntt.c
@@ -30,19 +30,20 @@ void ntt(const int *array, int l, const int *twindle, int p, int *dst) {
       : "r"(n));
 
   // prepare the permutation list
-  for (int k = 0; 2 * k <= l; k++) {
+  for (int k = 0; 2 * k < l; k++) {
     asm("vand.vx v8, v4, %0\n"
         "vsub.vv v4, v4, v8\n"
         "vsll.vx v8, v8, %1\n" // get the k-th digit and shift left
 
         "vand.vx v12, v4, %2\n"
         "vsub.vv v4, v4, v12\n"
-        "vsrl.vx v12, v12, %1\n" // get the (l-k)-th digit and shift right
+        "vsrl.vx v12, v12, %1\n" // get the (l-k-1)-th digit and shift right
 
         "vor.vv v4, v4, v8\n"
         "vor.vv v4, v4, v12\n"
+
         :
-        : "r"(1 << k), "r"(l - 1 - 2 * k), "r"(1 << (l - k)));
+        : "r"(1 << k), "r"(l - 1 - 2 * k), "r"(1 << (l - k - 1)));
   }
 
   asm("vsetvli zero, %0, e32, m8, tu, mu\n"