Simplify secp256k1_fe_{impl_,}verify

bitcoin-core · May 11, 2023 · 50d9163 · 50d9163
1 parent 44eb1d8
commit 50d9163
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Showing 3 changed files with 24 additions and 27 deletions.
diff --git a/src/field_10x26_impl.h b/src/field_10x26_impl.h
@@ -15,26 +15,25 @@
 #ifdef VERIFY
 static void secp256k1_fe_impl_verify(const secp256k1_fe *a) {
     const uint32_t *d = a->n;
-    int m = a->normalized ? 1 : 2 * a->magnitude, r = 1;
-    r &= (d[0] <= 0x3FFFFFFUL * m);
-    r &= (d[1] <= 0x3FFFFFFUL * m);
-    r &= (d[2] <= 0x3FFFFFFUL * m);
-    r &= (d[3] <= 0x3FFFFFFUL * m);
-    r &= (d[4] <= 0x3FFFFFFUL * m);
-    r &= (d[5] <= 0x3FFFFFFUL * m);
-    r &= (d[6] <= 0x3FFFFFFUL * m);
-    r &= (d[7] <= 0x3FFFFFFUL * m);
-    r &= (d[8] <= 0x3FFFFFFUL * m);
-    r &= (d[9] <= 0x03FFFFFUL * m);
+    int m = a->normalized ? 1 : 2 * a->magnitude;
+    VERIFY_CHECK(d[0] <= 0x3FFFFFFUL * m);
+    VERIFY_CHECK(d[1] <= 0x3FFFFFFUL * m);
+    VERIFY_CHECK(d[2] <= 0x3FFFFFFUL * m);
+    VERIFY_CHECK(d[3] <= 0x3FFFFFFUL * m);
+    VERIFY_CHECK(d[4] <= 0x3FFFFFFUL * m);
+    VERIFY_CHECK(d[5] <= 0x3FFFFFFUL * m);
+    VERIFY_CHECK(d[6] <= 0x3FFFFFFUL * m);
+    VERIFY_CHECK(d[7] <= 0x3FFFFFFUL * m);
+    VERIFY_CHECK(d[8] <= 0x3FFFFFFUL * m);
+    VERIFY_CHECK(d[9] <= 0x03FFFFFUL * m);
     if (a->normalized) {
-        if (r && (d[9] == 0x03FFFFFUL)) {
+        if (d[9] == 0x03FFFFFUL) {
             uint32_t mid = d[8] & d[7] & d[6] & d[5] & d[4] & d[3] & d[2];
             if (mid == 0x3FFFFFFUL) {
-                r &= ((d[1] + 0x40UL + ((d[0] + 0x3D1UL) >> 26)) <= 0x3FFFFFFUL);
+                VERIFY_CHECK((d[1] + 0x40UL + ((d[0] + 0x3D1UL) >> 26)) <= 0x3FFFFFFUL);
             }
         }
     }
-    VERIFY_CHECK(r == 1);
 }
 #endif
 

diff --git a/src/field_5x52_impl.h b/src/field_5x52_impl.h
@@ -21,19 +21,18 @@
 #ifdef VERIFY
 static void secp256k1_fe_impl_verify(const secp256k1_fe *a) {
     const uint64_t *d = a->n;
-    int m = a->normalized ? 1 : 2 * a->magnitude, r = 1;
+    int m = a->normalized ? 1 : 2 * a->magnitude;
    /* secp256k1 'p' value defined in "Standards for Efficient Cryptography" (SEC2) 2.7.1. */
-    r &= (d[0] <= 0xFFFFFFFFFFFFFULL * m);
-    r &= (d[1] <= 0xFFFFFFFFFFFFFULL * m);
-    r &= (d[2] <= 0xFFFFFFFFFFFFFULL * m);
-    r &= (d[3] <= 0xFFFFFFFFFFFFFULL * m);
-    r &= (d[4] <= 0x0FFFFFFFFFFFFULL * m);
+    VERIFY_CHECK(d[0] <= 0xFFFFFFFFFFFFFULL * m);
+    VERIFY_CHECK(d[1] <= 0xFFFFFFFFFFFFFULL * m);
+    VERIFY_CHECK(d[2] <= 0xFFFFFFFFFFFFFULL * m);
+    VERIFY_CHECK(d[3] <= 0xFFFFFFFFFFFFFULL * m);
+    VERIFY_CHECK(d[4] <= 0x0FFFFFFFFFFFFULL * m);
     if (a->normalized) {
-        if (r && (d[4] == 0x0FFFFFFFFFFFFULL) && ((d[3] & d[2] & d[1]) == 0xFFFFFFFFFFFFFULL)) {
-            r &= (d[0] < 0xFFFFEFFFFFC2FULL);
+        if ((d[4] == 0x0FFFFFFFFFFFFULL) && ((d[3] & d[2] & d[1]) == 0xFFFFFFFFFFFFFULL)) {
+            VERIFY_CHECK(d[0] < 0xFFFFEFFFFFC2FULL);
         }
     }
-    VERIFY_CHECK(r == 1);
 }
 #endif
 

diff --git a/src/field_impl.h b/src/field_impl.h
@@ -154,12 +154,11 @@ static void secp256k1_fe_verify(const secp256k1_fe *a) { (void)a; }
 static void secp256k1_fe_impl_verify(const secp256k1_fe *a);
 static void secp256k1_fe_verify(const secp256k1_fe *a) {
     /* Magnitude between 0 and 32. */
-    int r = (a->magnitude >= 0) & (a->magnitude <= 32);
+    VERIFY_CHECK((a->magnitude >= 0) && (a->magnitude <= 32));
     /* Normalized is 0 or 1. */
-    r &= (a->normalized == 0) | (a->normalized == 1);
+    VERIFY_CHECK((a->normalized == 0) || (a->normalized == 1));
     /* If normalized, magnitude must be 0 or 1. */
-    if (a->normalized) r &= (a->magnitude <= 1);
-    VERIFY_CHECK(r == 1);
+    if (a->normalized) VERIFY_CHECK(a->magnitude <= 1);
     /* Invoke implementation-specific checks. */
     secp256k1_fe_impl_verify(a);
 }