moved u128+u128 to int128.h

Author: dderjoel

src/field_5x52_int128_impl.h

@@ -57,26 +57,9 @@ static FIAT_SECP256K1_DETTMAN_FIAT_INLINE uint64_t u64_and_u128_u64(secp256k1_ui
 }
 
 static FIAT_SECP256K1_DETTMAN_FIAT_INLINE secp256k1_uint128 u128_add_u128_u128(secp256k1_uint128 a, secp256k1_uint128 b) {
-  uint64_t bl; 
-  uint64_t bh; 
-  uint64_t rh;
-  uint64_t rl;
   secp256k1_uint128 r = a;
 
-  bl = secp256k1_u128_to_u64(&b);
-
-  /* adding low b to r*/
-  secp256k1_u128_accum_u64(&r, bl);
-
-  rl = secp256k1_u128_to_u64(&r);
-  rh = secp256k1_u128_hi_u64(&r);
-
-  /* adding high b*/
-  bh = secp256k1_u128_hi_u64(&b);
-  rh += bh;
-
-  /* saving all in r*/
-  secp256k1_u128_load(&r, rh, rl);
+  secp256k1_u128_accum(&r, &b);
 
   return r;
 }

src/int128.h

@@ -28,6 +28,11 @@ static SECP256K1_INLINE void secp256k1_u128_accum_mul(secp256k1_uint128 *r, uint
  */
 static SECP256K1_INLINE void secp256k1_u128_accum_u64(secp256k1_uint128 *r, uint64_t a);
 
+/* Add an unsigned 128-bit value a to r.
+ * The final result is taken modulo 2^128.
+ */
+static SECP256K1_INLINE void secp256k1_u128_accum(secp256k1_uint128 *r, secp256k1_uint128 *a);
+
 /* Unsigned (logical) right shift.
  * Non-constant time in n.
  */

src/int128_native_impl.h

@@ -20,6 +20,10 @@ static SECP256K1_INLINE void secp256k1_u128_accum_u64(secp256k1_uint128 *r, uint
    *r += a;
 }
 
+static SECP256K1_INLINE void secp256k1_u128_accum(secp256k1_uint128 *r, secp256k1_uint128 *a){
+   *r += *a;
+}
+
 static SECP256K1_INLINE void secp256k1_u128_rshift(secp256k1_uint128 *r, unsigned int n) {
    VERIFY_CHECK(n < 128);
    *r >>= n;

src/int128_struct_impl.h

@@ -71,6 +71,11 @@ static SECP256K1_INLINE void secp256k1_u128_accum_u64(secp256k1_uint128 *r, uint
    r->hi += r->lo < a;
 }
 
+static SECP256K1_INLINE void secp256k1_u128_accum(secp256k1_uint128 *r, secp256k1_uint128 *a){
+   r->lo += a->lo;
+   r->hi += r->lo < a->lo + a->hi;
+}
+
 /* Unsigned (logical) right shift.
  * Non-constant time in n.
  */