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Diffstat (limited to 'src/field_5x52_int128_impl.h')
-rw-r--r--src/field_5x52_int128_impl.h84
1 files changed, 41 insertions, 43 deletions
diff --git a/src/field_5x52_int128_impl.h b/src/field_5x52_int128_impl.h
index c476428672..e552fb4319 100644
--- a/src/field_5x52_int128_impl.h
+++ b/src/field_5x52_int128_impl.h
@@ -15,7 +15,7 @@
#define VERIFY_BITS(x, n) do { } while(0)
#endif
-SECP256K1_INLINE static void secp256k1_fe_mul_inner(const uint64_t *a, const uint64_t *b, uint64_t *r) {
+SECP256K1_INLINE static void secp256k1_fe_mul_inner(const uint64_t *a, const uint64_t * SECP256K1_RESTRICT b, uint64_t *r) {
VERIFY_BITS(a[0], 56);
VERIFY_BITS(a[1], 56);
VERIFY_BITS(a[2], 56);
@@ -26,6 +26,7 @@ SECP256K1_INLINE static void secp256k1_fe_mul_inner(const uint64_t *a, const uin
VERIFY_BITS(b[2], 56);
VERIFY_BITS(b[3], 56);
VERIFY_BITS(b[4], 52);
+ VERIFY_CHECK(r != b);
const uint64_t M = 0xFFFFFFFFFFFFFULL, R = 0x1000003D10ULL;
/* [... a b c] is a shorthand for ... + a<<104 + b<<52 + c<<0 mod n.
@@ -33,15 +34,17 @@ SECP256K1_INLINE static void secp256k1_fe_mul_inner(const uint64_t *a, const uin
* Note that [x 0 0 0 0 0] = [x*R].
*/
+ uint64_t a0 = a[0], a1 = a[1], a2 = a[2], a3 = a[3], a4 = a[4];
+
__int128 c, d;
- d = (__int128)a[0] * b[3]
- + (__int128)a[1] * b[2]
- + (__int128)a[2] * b[1]
- + (__int128)a[3] * b[0];
+ d = (__int128)a0 * b[3]
+ + (__int128)a1 * b[2]
+ + (__int128)a2 * b[1]
+ + (__int128)a3 * b[0];
VERIFY_BITS(d, 114);
/* [d 0 0 0] = [p3 0 0 0] */
- c = (__int128)a[4] * b[4];
+ c = (__int128)a4 * b[4];
VERIFY_BITS(c, 112);
/* [c 0 0 0 0 d 0 0 0] = [p8 0 0 0 0 p3 0 0 0] */
d += (c & M) * R; c >>= 52;
@@ -53,11 +56,11 @@ SECP256K1_INLINE static void secp256k1_fe_mul_inner(const uint64_t *a, const uin
VERIFY_BITS(d, 63);
/* [c 0 0 0 0 d t3 0 0 0] = [p8 0 0 0 0 p3 0 0 0] */
- d += (__int128)a[0] * b[4]
- + (__int128)a[1] * b[3]
- + (__int128)a[2] * b[2]
- + (__int128)a[3] * b[1]
- + (__int128)a[4] * b[0];
+ d += (__int128)a0 * b[4]
+ + (__int128)a1 * b[3]
+ + (__int128)a2 * b[2]
+ + (__int128)a3 * b[1]
+ + (__int128)a4 * b[0];
VERIFY_BITS(d, 115);
/* [c 0 0 0 0 d t3 0 0 0] = [p8 0 0 0 p4 p3 0 0 0] */
d += c * R;
@@ -72,13 +75,13 @@ SECP256K1_INLINE static void secp256k1_fe_mul_inner(const uint64_t *a, const uin
VERIFY_BITS(t4, 48);
/* [d t4+(tx<<48) t3 0 0 0] = [p8 0 0 0 p4 p3 0 0 0] */
- c = (__int128)a[0] * b[0];
+ c = (__int128)a0 * b[0];
VERIFY_BITS(c, 112);
/* [d t4+(tx<<48) t3 0 0 c] = [p8 0 0 0 p4 p3 0 0 p0] */
- d += (__int128)a[1] * b[4]
- + (__int128)a[2] * b[3]
- + (__int128)a[3] * b[2]
- + (__int128)a[4] * b[1];
+ d += (__int128)a1 * b[4]
+ + (__int128)a2 * b[3]
+ + (__int128)a3 * b[2]
+ + (__int128)a4 * b[1];
VERIFY_BITS(d, 115);
/* [d t4+(tx<<48) t3 0 0 c] = [p8 0 0 p5 p4 p3 0 0 p0] */
uint64_t u0 = d & M; d >>= 52;
@@ -92,48 +95,43 @@ SECP256K1_INLINE static void secp256k1_fe_mul_inner(const uint64_t *a, const uin
c += (__int128)u0 * (R >> 4);
VERIFY_BITS(c, 115);
/* [d 0 t4 t3 0 0 c] = [p8 0 0 p5 p4 p3 0 0 p0] */
- uint64_t t0 = c & M; c >>= 52;
- VERIFY_BITS(t0, 52);
+ r[0] = c & M; c >>= 52;
+ VERIFY_BITS(r[0], 52);
VERIFY_BITS(c, 61);
- /* [d 0 t4 t3 0 c t0] = [p8 0 0 p5 p4 p3 0 0 p0] */
+ /* [d 0 t4 t3 0 c r0] = [p8 0 0 p5 p4 p3 0 0 p0] */
- c += (__int128)a[0] * b[1]
- + (__int128)a[1] * b[0];
+ c += (__int128)a0 * b[1]
+ + (__int128)a1 * b[0];
VERIFY_BITS(c, 114);
- /* [d 0 t4 t3 0 c t0] = [p8 0 0 p5 p4 p3 0 p1 p0] */
- d += (__int128)a[2] * b[4]
- + (__int128)a[3] * b[3]
- + (__int128)a[4] * b[2];
+ /* [d 0 t4 t3 0 c r0] = [p8 0 0 p5 p4 p3 0 p1 p0] */
+ d += (__int128)a2 * b[4]
+ + (__int128)a3 * b[3]
+ + (__int128)a4 * b[2];
VERIFY_BITS(d, 114);
- /* [d 0 t4 t3 0 c t0] = [p8 0 p6 p5 p4 p3 0 p1 p0] */
+ /* [d 0 t4 t3 0 c r0] = [p8 0 p6 p5 p4 p3 0 p1 p0] */
c += (d & M) * R; d >>= 52;
VERIFY_BITS(c, 115);
VERIFY_BITS(d, 62);
- /* [d 0 0 t4 t3 0 c t0] = [p8 0 p6 p5 p4 p3 0 p1 p0] */
- uint64_t t1 = c & M; c >>= 52;
- VERIFY_BITS(t1, 52);
+ /* [d 0 0 t4 t3 0 c r0] = [p8 0 p6 p5 p4 p3 0 p1 p0] */
+ r[1] = c & M; c >>= 52;
+ VERIFY_BITS(r[1], 52);
VERIFY_BITS(c, 63);
- /* [d 0 0 t4 t3 c t1 t0] = [p8 0 p6 p5 p4 p3 0 p1 p0] */
+ /* [d 0 0 t4 t3 c r1 r0] = [p8 0 p6 p5 p4 p3 0 p1 p0] */
- c += (__int128)a[0] * b[2]
- + (__int128)a[1] * b[1]
- + (__int128)a[2] * b[0];
+ c += (__int128)a0 * b[2]
+ + (__int128)a1 * b[1]
+ + (__int128)a2 * b[0];
VERIFY_BITS(c, 114);
- /* [d 0 0 t4 t3 c t1 t0] = [p8 0 p6 p5 p4 p3 p2 p1 p0] */
- d += (__int128)a[3] * b[4]
- + (__int128)a[4] * b[3];
+ /* [d 0 0 t4 t3 c r1 r0] = [p8 0 p6 p5 p4 p3 p2 p1 p0] */
+ d += (__int128)a3 * b[4]
+ + (__int128)a4 * b[3];
VERIFY_BITS(d, 114);
- /* [d 0 0 t4 t3 c t1 t0] = [p8 p7 p6 p5 p4 p3 p2 p1 p0] */
+ /* [d 0 0 t4 t3 c t1 r0] = [p8 p7 p6 p5 p4 p3 p2 p1 p0] */
c += (d & M) * R; d >>= 52;
VERIFY_BITS(c, 115);
VERIFY_BITS(d, 62);
- /* [d 0 0 0 t4 t3 c t1 t0] = [p8 p7 p6 p5 p4 p3 p2 p1 p0] */
+ /* [d 0 0 0 t4 t3 c r1 r0] = [p8 p7 p6 p5 p4 p3 p2 p1 p0] */
- r[0] = t0;
- VERIFY_BITS(r[0], 52);
- /* [d 0 0 0 t4 t3 c t1 r0] = [p8 p7 p6 p5 p4 p3 p2 p1 p0] */
- r[1] = t1;
- VERIFY_BITS(r[1], 52);
/* [d 0 0 0 t4 t3 c r1 r0] = [p8 p7 p6 p5 p4 p3 p2 p1 p0] */
r[2] = c & M; c >>= 52;
VERIFY_BITS(r[2], 52);