curve25519.c: reformat code to follow coding guidelines

Fixes #7698

Reviewed-by: Matt Caswell <matt@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/7750)

(cherry picked from commit 3a17b9a46ecf54a30073534dff04e3223ff98813)

1 files changed, 2344 insertions, 2228 deletions

diff --git a/crypto/ec/curve25519.c b/crypto/ec/curve25519.c
index d6a2bb6cd8..d331784685 100644
--- a/crypto/ec/curve25519.c
+++ b/crypto/ec/curve25519.c
@@ -744,18 +744,19 @@ static void x25519_scalar_mult(uint8_t out[32], const uint8_t scalar[32],
 
 /*
  * Reference base 2^25.5 implementation.
- */
-/*
+ *
  * This code is mostly taken from the ref10 version of Ed25519 in SUPERCOP
  * 20141124 (http://bench.cr.yp.to/supercop.html).
  *
  * The field functions are shared by Ed25519 and X25519 where possible.
  */
 
-/* fe means field element. Here the field is \Z/(2^255-19). An element t,
+/*
+ * fe means field element. Here the field is \Z/(2^255-19). An element t,
  * entries t[0]...t[9], represents the integer t[0]+2^26 t[1]+2^51 t[2]+2^77
  * t[3]+2^102 t[4]+...+2^230 t[9]. Bounds on each t[i] vary depending on
- * context.  */
+ * context.
+ */
 typedef int32_t fe[10];
 
 static const int64_t kBottom25Bits = 0x1ffffffLL;
@@ -763,72 +764,78 @@ static const int64_t kBottom26Bits = 0x3ffffffLL;
 static const int64_t kTop39Bits = 0xfffffffffe000000LL;
 static const int64_t kTop38Bits = 0xfffffffffc000000LL;
 
-static uint64_t load_3(const uint8_t *in) {
-  uint64_t result;
-  result = (uint64_t)in[0];
-  result |= ((uint64_t)in[1]) << 8;
-  result |= ((uint64_t)in[2]) << 16;
-  return result;
+static uint64_t load_3(const uint8_t *in)
+{
+    uint64_t result;
+
+    result = (uint64_t)in[0];
+    result |= ((uint64_t)in[1]) << 8;
+    result |= ((uint64_t)in[2]) << 16;
+    return result;
 }
 
-static uint64_t load_4(const uint8_t *in) {
-  uint64_t result;
-  result = (uint64_t)in[0];
-  result |= ((uint64_t)in[1]) << 8;
-  result |= ((uint64_t)in[2]) << 16;
-  result |= ((uint64_t)in[3]) << 24;
-  return result;
+static uint64_t load_4(const uint8_t *in)
+{
+    uint64_t result;
+
+    result = (uint64_t)in[0];
+    result |= ((uint64_t)in[1]) << 8;
+    result |= ((uint64_t)in[2]) << 16;
+    result |= ((uint64_t)in[3]) << 24;
+    return result;
 }
 
-static void fe_frombytes(fe h, const uint8_t *s) {
-  /* Ignores top bit of h. */
-  int64_t h0 = load_4(s);
-  int64_t h1 = load_3(s + 4) << 6;
-  int64_t h2 = load_3(s + 7) << 5;
-  int64_t h3 = load_3(s + 10) << 3;
-  int64_t h4 = load_3(s + 13) << 2;
-  int64_t h5 = load_4(s + 16);
-  int64_t h6 = load_3(s + 20) << 7;
-  int64_t h7 = load_3(s + 23) << 5;
-  int64_t h8 = load_3(s + 26) << 4;
-  int64_t h9 = (load_3(s + 29) & 8388607) << 2;
-  int64_t carry0;
-  int64_t carry1;
-  int64_t carry2;
-  int64_t carry3;
-  int64_t carry4;
-  int64_t carry5;
-  int64_t carry6;
-  int64_t carry7;
-  int64_t carry8;
-  int64_t carry9;
-
-  carry9 = h9 + (1 << 24); h0 += (carry9 >> 25) * 19; h9 -= carry9 & kTop39Bits;
-  carry1 = h1 + (1 << 24); h2 += carry1 >> 25; h1 -= carry1 & kTop39Bits;
-  carry3 = h3 + (1 << 24); h4 += carry3 >> 25; h3 -= carry3 & kTop39Bits;
-  carry5 = h5 + (1 << 24); h6 += carry5 >> 25; h5 -= carry5 & kTop39Bits;
-  carry7 = h7 + (1 << 24); h8 += carry7 >> 25; h7 -= carry7 & kTop39Bits;
-
-  carry0 = h0 + (1 << 25); h1 += carry0 >> 26; h0 -= carry0 & kTop38Bits;
-  carry2 = h2 + (1 << 25); h3 += carry2 >> 26; h2 -= carry2 & kTop38Bits;
-  carry4 = h4 + (1 << 25); h5 += carry4 >> 26; h4 -= carry4 & kTop38Bits;
-  carry6 = h6 + (1 << 25); h7 += carry6 >> 26; h6 -= carry6 & kTop38Bits;
-  carry8 = h8 + (1 << 25); h9 += carry8 >> 26; h8 -= carry8 & kTop38Bits;
-
-  h[0] = (int32_t)h0;
-  h[1] = (int32_t)h1;
-  h[2] = (int32_t)h2;
-  h[3] = (int32_t)h3;
-  h[4] = (int32_t)h4;
-  h[5] = (int32_t)h5;
-  h[6] = (int32_t)h6;
-  h[7] = (int32_t)h7;
-  h[8] = (int32_t)h8;
-  h[9] = (int32_t)h9;
+static void fe_frombytes(fe h, const uint8_t *s)
+{
+    /* Ignores top bit of h. */
+    int64_t h0 = load_4(s);
+    int64_t h1 = load_3(s + 4) << 6;
+    int64_t h2 = load_3(s + 7) << 5;
+    int64_t h3 = load_3(s + 10) << 3;
+    int64_t h4 = load_3(s + 13) << 2;
+    int64_t h5 = load_4(s + 16);
+    int64_t h6 = load_3(s + 20) << 7;
+    int64_t h7 = load_3(s + 23) << 5;
+    int64_t h8 = load_3(s + 26) << 4;
+    int64_t h9 = (load_3(s + 29) & 8388607) << 2;
+    int64_t carry0;
+    int64_t carry1;
+    int64_t carry2;
+    int64_t carry3;
+    int64_t carry4;
+    int64_t carry5;
+    int64_t carry6;
+    int64_t carry7;
+    int64_t carry8;
+    int64_t carry9;
+
+    carry9 = h9 + (1 << 24); h0 += (carry9 >> 25) * 19; h9 -= carry9 & kTop39Bits;
+    carry1 = h1 + (1 << 24); h2 += carry1 >> 25; h1 -= carry1 & kTop39Bits;
+    carry3 = h3 + (1 << 24); h4 += carry3 >> 25; h3 -= carry3 & kTop39Bits;
+    carry5 = h5 + (1 << 24); h6 += carry5 >> 25; h5 -= carry5 & kTop39Bits;
+    carry7 = h7 + (1 << 24); h8 += carry7 >> 25; h7 -= carry7 & kTop39Bits;
+
+    carry0 = h0 + (1 << 25); h1 += carry0 >> 26; h0 -= carry0 & kTop38Bits;
+    carry2 = h2 + (1 << 25); h3 += carry2 >> 26; h2 -= carry2 & kTop38Bits;
+    carry4 = h4 + (1 << 25); h5 += carry4 >> 26; h4 -= carry4 & kTop38Bits;
+    carry6 = h6 + (1 << 25); h7 += carry6 >> 26; h6 -= carry6 & kTop38Bits;
+    carry8 = h8 + (1 << 25); h9 += carry8 >> 26; h8 -= carry8 & kTop38Bits;
+
+    h[0] = (int32_t)h0;
+    h[1] = (int32_t)h1;
+    h[2] = (int32_t)h2;
+    h[3] = (int32_t)h3;
+    h[4] = (int32_t)h4;
+    h[5] = (int32_t)h5;
+    h[6] = (int32_t)h6;
+    h[7] = (int32_t)h7;
+    h[8] = (int32_t)h8;
+    h[9] = (int32_t)h9;
 }
 
-/* Preconditions:
- *  |h| bounded by 1.1*2^26,1.1*2^25,1.1*2^26,1.1*2^25,etc.
+/*
+ * Preconditions:
+ *   |h| bounded by 1.1*2^26,1.1*2^25,1.1*2^26,1.1*2^25,etc.
  *
  * Write p=2^255-19; q=floor(h/p).
  * Basic claim: q = floor(2^(-255)(h + 19 2^(-25)h9 + 2^(-1))).
@@ -848,102 +855,112 @@ static void fe_frombytes(fe h, const uint8_t *s) {
  *   Then 0<x<2^255 so floor(2^(-255)x) = 0 so floor(q+2^(-255)x) = q.
  *
  *   Have q+2^(-255)x = 2^(-255)(h + 19 2^(-25) h9 + 2^(-1))
- *   so floor(2^(-255)(h + 19 2^(-25) h9 + 2^(-1))) = q. */
-static void fe_tobytes(uint8_t *s, const fe h) {
-  int32_t h0 = h[0];
-  int32_t h1 = h[1];
-  int32_t h2 = h[2];
-  int32_t h3 = h[3];
-  int32_t h4 = h[4];
-  int32_t h5 = h[5];
-  int32_t h6 = h[6];
-  int32_t h7 = h[7];
-  int32_t h8 = h[8];
-  int32_t h9 = h[9];
-  int32_t q;
-
-  q = (19 * h9 + (((int32_t) 1) << 24)) >> 25;
-  q = (h0 + q) >> 26;
-  q = (h1 + q) >> 25;
-  q = (h2 + q) >> 26;
-  q = (h3 + q) >> 25;
-  q = (h4 + q) >> 26;
-  q = (h5 + q) >> 25;
-  q = (h6 + q) >> 26;
-  q = (h7 + q) >> 25;
-  q = (h8 + q) >> 26;
-  q = (h9 + q) >> 25;
-
-  /* Goal: Output h-(2^255-19)q, which is between 0 and 2^255-20. */
-  h0 += 19 * q;
-  /* Goal: Output h-2^255 q, which is between 0 and 2^255-20. */
-
-  h1 += h0 >> 26; h0 &= kBottom26Bits;
-  h2 += h1 >> 25; h1 &= kBottom25Bits;
-  h3 += h2 >> 26; h2 &= kBottom26Bits;
-  h4 += h3 >> 25; h3 &= kBottom25Bits;
-  h5 += h4 >> 26; h4 &= kBottom26Bits;
-  h6 += h5 >> 25; h5 &= kBottom25Bits;
-  h7 += h6 >> 26; h6 &= kBottom26Bits;
-  h8 += h7 >> 25; h7 &= kBottom25Bits;
-  h9 += h8 >> 26; h8 &= kBottom26Bits;
-                  h9 &= kBottom25Bits;
-                  /* h10 = carry9 */
-
-  /* Goal: Output h0+...+2^255 h10-2^255 q, which is between 0 and 2^255-20.
-   * Have h0+...+2^230 h9 between 0 and 2^255-1;
-   * evidently 2^255 h10-2^255 q = 0.
-   * Goal: Output h0+...+2^230 h9.  */
-
-  s[0] = (uint8_t)(h0 >> 0);
-  s[1] = (uint8_t)(h0 >> 8);
-  s[2] = (uint8_t)(h0 >> 16);
-  s[3] = (uint8_t)((h0 >> 24) | ((uint32_t)(h1) << 2));
-  s[4] = (uint8_t)(h1 >> 6);
-  s[5] = (uint8_t)(h1 >> 14);
-  s[6] = (uint8_t)((h1 >> 22) | ((uint32_t)(h2) << 3));
-  s[7] = (uint8_t)(h2 >> 5);
-  s[8] = (uint8_t)(h2 >> 13);
-  s[9] = (uint8_t)((h2 >> 21) | ((uint32_t)(h3) << 5));
-  s[10] = (uint8_t)(h3 >> 3);
-  s[11] = (uint8_t)(h3 >> 11);
-  s[12] = (uint8_t)((h3 >> 19) | ((uint32_t)(h4) << 6));
-  s[13] = (uint8_t)(h4 >> 2);
-  s[14] = (uint8_t)(h4 >> 10);
-  s[15] = (uint8_t)(h4 >> 18);
-  s[16] = (uint8_t)(h5 >> 0);
-  s[17] = (uint8_t)(h5 >> 8);
-  s[18] = (uint8_t)(h5 >> 16);
-  s[19] = (uint8_t)((h5 >> 24) | ((uint32_t)(h6) << 1));
-  s[20] = (uint8_t)(h6 >> 7);
-  s[21] = (uint8_t)(h6 >> 15);
-  s[22] = (uint8_t)((h6 >> 23) | ((uint32_t)(h7) << 3));
-  s[23] = (uint8_t)(h7 >> 5);
-  s[24] = (uint8_t)(h7 >> 13);
-  s[25] = (uint8_t)((h7 >> 21) | ((uint32_t)(h8) << 4));
-  s[26] = (uint8_t)(h8 >> 4);
-  s[27] = (uint8_t)(h8 >> 12);
-  s[28] = (uint8_t)((h8 >> 20) | ((uint32_t)(h9) << 6));
-  s[29] = (uint8_t)(h9 >> 2);
-  s[30] = (uint8_t)(h9 >> 10);
-  s[31] = (uint8_t)(h9 >> 18);
+ *   so floor(2^(-255)(h + 19 2^(-25) h9 + 2^(-1))) = q.
+ */
+static void fe_tobytes(uint8_t *s, const fe h)
+{
+    int32_t h0 = h[0];
+    int32_t h1 = h[1];
+    int32_t h2 = h[2];
+    int32_t h3 = h[3];
+    int32_t h4 = h[4];
+    int32_t h5 = h[5];
+    int32_t h6 = h[6];
+    int32_t h7 = h[7];
+    int32_t h8 = h[8];
+    int32_t h9 = h[9];
+    int32_t q;
+
+    q = (19 * h9 + (((int32_t) 1) << 24)) >> 25;
+    q = (h0 + q) >> 26;
+    q = (h1 + q) >> 25;
+    q = (h2 + q) >> 26;
+    q = (h3 + q) >> 25;
+    q = (h4 + q) >> 26;
+    q = (h5 + q) >> 25;
+    q = (h6 + q) >> 26;
+    q = (h7 + q) >> 25;
+    q = (h8 + q) >> 26;
+    q = (h9 + q) >> 25;
+
+    /* Goal: Output h-(2^255-19)q, which is between 0 and 2^255-20. */
+    h0 += 19 * q;
+    /* Goal: Output h-2^255 q, which is between 0 and 2^255-20. */
+
+    h1 += h0 >> 26; h0 &= kBottom26Bits;
+    h2 += h1 >> 25; h1 &= kBottom25Bits;
+    h3 += h2 >> 26; h2 &= kBottom26Bits;
+    h4 += h3 >> 25; h3 &= kBottom25Bits;
+    h5 += h4 >> 26; h4 &= kBottom26Bits;
+    h6 += h5 >> 25; h5 &= kBottom25Bits;
+    h7 += h6 >> 26; h6 &= kBottom26Bits;
+    h8 += h7 >> 25; h7 &= kBottom25Bits;
+    h9 += h8 >> 26; h8 &= kBottom26Bits;
+                    h9 &= kBottom25Bits;
+    /* h10 = carry9 */
+
+    /*
+     * Goal: Output h0+...+2^255 h10-2^255 q, which is between 0 and 2^255-20.
+     * Have h0+...+2^230 h9 between 0 and 2^255-1;
+     * evidently 2^255 h10-2^255 q = 0.
+     * Goal: Output h0+...+2^230 h9.
+     */
+    s[0] = (uint8_t)(h0 >> 0);
+    s[1] = (uint8_t)(h0 >> 8);
+    s[2] = (uint8_t)(h0 >> 16);
+    s[3] = (uint8_t)((h0 >> 24) | ((uint32_t)(h1) << 2));
+    s[4] = (uint8_t)(h1 >> 6);
+    s[5] = (uint8_t)(h1 >> 14);
+    s[6] = (uint8_t)((h1 >> 22) | ((uint32_t)(h2) << 3));
+    s[7] = (uint8_t)(h2 >> 5);
+    s[8] = (uint8_t)(h2 >> 13);
+    s[9] = (uint8_t)((h2 >> 21) | ((uint32_t)(h3) << 5));
+    s[10] = (uint8_t)(h3 >> 3);
+    s[11] = (uint8_t)(h3 >> 11);
+    s[12] = (uint8_t)((h3 >> 19) | ((uint32_t)(h4) << 6));
+    s[13] = (uint8_t)(h4 >> 2);
+    s[14] = (uint8_t)(h4 >> 10);
+    s[15] = (uint8_t)(h4 >> 18);
+    s[16] = (uint8_t)(h5 >> 0);
+    s[17] = (uint8_t)(h5 >> 8);
+    s[18] = (uint8_t)(h5 >> 16);
+    s[19] = (uint8_t)((h5 >> 24) | ((uint32_t)(h6) << 1));
+    s[20] = (uint8_t)(h6 >> 7);
+    s[21] = (uint8_t)(h6 >> 15);
+    s[22] = (uint8_t)((h6 >> 23) | ((uint32_t)(h7) << 3));
+    s[23] = (uint8_t)(h7 >> 5);
+    s[24] = (uint8_t)(h7 >> 13);
+    s[25] = (uint8_t)((h7 >> 21) | ((uint32_t)(h8) << 4));
+    s[26] = (uint8_t)(h8 >> 4);
+    s[27] = (uint8_t)(h8 >> 12);
+    s[28] = (uint8_t)((h8 >> 20) | ((uint32_t)(h9) << 6));
+    s[29] = (uint8_t)(h9 >> 2);
+    s[30] = (uint8_t)(h9 >> 10);
+    s[31] = (uint8_t)(h9 >> 18);
 }
 
 /* h = f */
-static void fe_copy(fe h, const fe f) {
-  memmove(h, f, sizeof(int32_t) * 10);
+static void fe_copy(fe h, const fe f)
+{
+    memmove(h, f, sizeof(int32_t) * 10);
 }
 
 /* h = 0 */
-static void fe_0(fe h) { memset(h, 0, sizeof(int32_t) * 10); }
+static void fe_0(fe h)
+{
+    memset(h, 0, sizeof(int32_t) * 10);
+}
 
 /* h = 1 */
-static void fe_1(fe h) {
-  memset(h, 0, sizeof(int32_t) * 10);
-  h[0] = 1;
+static void fe_1(fe h)
+{
+    memset(h, 0, sizeof(int32_t) * 10);
+    h[0] = 1;
 }
 
-/* h = f + g
+/*
+ * h = f + g
+ *
  * Can overlap h with f or g.
  *
  * Preconditions:
@@ -951,15 +968,20 @@ static void fe_1(fe h) {
  *    |g| bounded by 1.1*2^25,1.1*2^24,1.1*2^25,1.1*2^24,etc.
  *
  * Postconditions:
- *    |h| bounded by 1.1*2^26,1.1*2^25,1.1*2^26,1.1*2^25,etc. */
-static void fe_add(fe h, const fe f, const fe g) {
-  unsigned i;
-  for (i = 0; i < 10; i++) {
-    h[i] = f[i] + g[i];
-  }
+ *    |h| bounded by 1.1*2^26,1.1*2^25,1.1*2^26,1.1*2^25,etc.
+ */
+static void fe_add(fe h, const fe f, const fe g)
+{
+    unsigned i;
+
+    for (i = 0; i < 10; i++) {
+        h[i] = f[i] + g[i];
+    }
 }
 
-/* h = f - g
+/*
+ * h = f - g
+ *
  * Can overlap h with f or g.
  *
  * Preconditions:
@@ -967,15 +989,20 @@ static void fe_add(fe h, const fe f, const fe g) {
  *    |g| bounded by 1.1*2^25,1.1*2^24,1.1*2^25,1.1*2^24,etc.
  *
  * Postconditions:
- *    |h| bounded by 1.1*2^26,1.1*2^25,1.1*2^26,1.1*2^25,etc. */
-static void fe_sub(fe h, const fe f, const fe g) {
-  unsigned i;
-  for (i = 0; i < 10; i++) {
-    h[i] = f[i] - g[i];
-  }
+ *    |h| bounded by 1.1*2^26,1.1*2^25,1.1*2^26,1.1*2^25,etc.
+ */
+static void fe_sub(fe h, const fe f, const fe g)
+{
+    unsigned i;
+
+    for (i = 0; i < 10; i++) {
+        h[i] = f[i] - g[i];
+    }
 }
 
-/* h = f * g
+/*
+ * h = f * g
+ *
  * Can overlap h with f or g.
  *
  * Preconditions:
@@ -1001,224 +1028,228 @@ static void fe_sub(fe h, const fe f, const fe g) {
  * 10 of them are 2-way parallelizable and vectorizable.
  * Can get away with 11 carries, but then data flow is much deeper.
  *
- * With tighter constraints on inputs can squeeze carries into int32. */
-static void fe_mul(fe h, const fe f, const fe g) {
-  int32_t f0 = f[0];
-  int32_t f1 = f[1];
-  int32_t f2 = f[2];
-  int32_t f3 = f[3];
-  int32_t f4 = f[4];
-  int32_t f5 = f[5];
-  int32_t f6 = f[6];
-  int32_t f7 = f[7];
-  int32_t f8 = f[8];
-  int32_t f9 = f[9];
-  int32_t g0 = g[0];
-  int32_t g1 = g[1];
-  int32_t g2 = g[2];
-  int32_t g3 = g[3];
-  int32_t g4 = g[4];
-  int32_t g5 = g[5];
-  int32_t g6 = g[6];
-  int32_t g7 = g[7];
-  int32_t g8 = g[8];
-  int32_t g9 = g[9];
-  int32_t g1_19 = 19 * g1; /* 1.959375*2^29 */
-  int32_t g2_19 = 19 * g2; /* 1.959375*2^30; still ok */
-  int32_t g3_19 = 19 * g3;
-  int32_t g4_19 = 19 * g4;
-  int32_t g5_19 = 19 * g5;
-  int32_t g6_19 = 19 * g6;
-  int32_t g7_19 = 19 * g7;
-  int32_t g8_19 = 19 * g8;
-  int32_t g9_19 = 19 * g9;
-  int32_t f1_2 = 2 * f1;
-  int32_t f3_2 = 2 * f3;
-  int32_t f5_2 = 2 * f5;
-  int32_t f7_2 = 2 * f7;
-  int32_t f9_2 = 2 * f9;
-  int64_t f0g0    = f0   * (int64_t) g0;
-  int64_t f0g1    = f0   * (int64_t) g1;
-  int64_t f0g2    = f0   * (int64_t) g2;
-  int64_t f0g3    = f0   * (int64_t) g3;
-  int64_t f0g4    = f0   * (int64_t) g4;
-  int64_t f0g5    = f0   * (int64_t) g5;
-  int64_t f0g6    = f0   * (int64_t) g6;
-  int64_t f0g7    = f0   * (int64_t) g7;
-  int64_t f0g8    = f0   * (int64_t) g8;
-  int64_t f0g9    = f0   * (int64_t) g9;
-  int64_t f1g0    = f1   * (int64_t) g0;
-  int64_t f1g1_2  = f1_2 * (int64_t) g1;
-  int64_t f1g2    = f1   * (int64_t) g2;
-  int64_t f1g3_2  = f1_2 * (int64_t) g3;
-  int64_t f1g4    = f1   * (int64_t) g4;
-  int64_t f1g5_2  = f1_2 * (int64_t) g5;
-  int64_t f1g6    = f1   * (int64_t) g6;
-  int64_t f1g7_2  = f1_2 * (int64_t) g7;
-  int64_t f1g8    = f1   * (int64_t) g8;
-  int64_t f1g9_38 = f1_2 * (int64_t) g9_19;
-  int64_t f2g0    = f2   * (int64_t) g0;
-  int64_t f2g1    = f2   * (int64_t) g1;
-  int64_t f2g2    = f2   * (int64_t) g2;
-  int64_t f2g3    = f2   * (int64_t) g3;
-  int64_t f2g4    = f2   * (int64_t) g4;
-  int64_t f2g5    = f2   * (int64_t) g5;
-  int64_t f2g6    = f2   * (int64_t) g6;
-  int64_t f2g7    = f2   * (int64_t) g7;
-  int64_t f2g8_19 = f2   * (int64_t) g8_19;
-  int64_t f2g9_19 = f2   * (int64_t) g9_19;
-  int64_t f3g0    = f3   * (int64_t) g0;
-  int64_t f3g1_2  = f3_2 * (int64_t) g1;
-  int64_t f3g2    = f3   * (int64_t) g2;
-  int64_t f3g3_2  = f3_2 * (int64_t) g3;
-  int64_t f3g4    = f3   * (int64_t) g4;
-  int64_t f3g5_2  = f3_2 * (int64_t) g5;
-  int64_t f3g6    = f3   * (int64_t) g6;
-  int64_t f3g7_38 = f3_2 * (int64_t) g7_19;
-  int64_t f3g8_19 = f3   * (int64_t) g8_19;
-  int64_t f3g9_38 = f3_2 * (int64_t) g9_19;
-  int64_t f4g0    = f4   * (int64_t) g0;
-  int64_t f4g1    = f4   * (int64_t) g1;
-  int64_t f4g2    = f4   * (int64_t) g2;
-  int64_t f4g3    = f4   * (int64_t) g3;
-  int64_t f4g4    = f4   * (int64_t) g4;
-  int64_t f4g5    = f4   * (int64_t) g5;
-  int64_t f4g6_19 = f4   * (int64_t) g6_19;
-  int64_t f4g7_19 = f4   * (int64_t) g7_19;
-  int64_t f4g8_19 = f4   * (int64_t) g8_19;
-  int64_t f4g9_19 = f4   * (int64_t) g9_19;
-  int64_t f5g0    = f5   * (int64_t) g0;
-  int64_t f5g1_2  = f5_2 * (int64_t) g1;
-  int64_t f5g2    = f5   * (int64_t) g2;
-  int64_t f5g3_2  = f5_2 * (int64_t) g3;
-  int64_t f5g4    = f5   * (int64_t) g4;
-  int64_t f5g5_38 = f5_2 * (int64_t) g5_19;
-  int64_t f5g6_19 = f5   * (int64_t) g6_19;
-  int64_t f5g7_38 = f5_2 * (int64_t) g7_19;
-  int64_t f5g8_19 = f5   * (int64_t) g8_19;
-  int64_t f5g9_38 = f5_2 * (int64_t) g9_19;
-  int64_t f6g0    = f6   * (int64_t) g0;
-  int64_t f6g1    = f6   * (int64_t) g1;
-  int64_t f6g2    = f6   * (int64_t) g2;
-  int64_t f6g3    = f6   * (int64_t) g3;
-  int64_t f6g4_19 = f6   * (int64_t) g4_19;
-  int64_t f6g5_19 = f6   * (int64_t) g5_19;
-  int64_t f6g6_19 = f6   * (int64_t) g6_19;
-  int64_t f6g7_19 = f6   * (int64_t) g7_19;
-  int64_t f6g8_19 = f6   * (int64_t) g8_19;
-  int64_t f6g9_19 = f6   * (int64_t) g9_19;
-  int64_t f7g0    = f7   * (int64_t) g0;
-  int64_t f7g1_2  = f7_2 * (int64_t) g1;
-  int64_t f7g2    = f7   * (int64_t) g2;
-  int64_t f7g3_38 = f7_2 * (int64_t) g3_19;
-  int64_t f7g4_19 = f7   * (int64_t) g4_19;
-  int64_t f7g5_38 = f7_2 * (int64_t) g5_19;
-  int64_t f7g6_19 = f7   * (int64_t) g6_19;
-  int64_t f7g7_38 = f7_2 * (int64_t) g7_19;
-  int64_t f7g8_19 = f7   * (int64_t) g8_19;
-  int64_t f7g9_38 = f7_2 * (int64_t) g9_19;
-  int64_t f8g0    = f8   * (int64_t) g0;
-  int64_t f8g1    = f8   * (int64_t) g1;
-  int64_t f8g2_19 = f8   * (int64_t) g2_19;
-  int64_t f8g3_19 = f8   * (int64_t) g3_19;
-  int64_t f8g4_19 = f8   * (int64_t) g4_19;
-  int64_t f8g5_19 = f8   * (int64_t) g5_19;
-  int64_t f8g6_19 = f8   * (int64_t) g6_19;
-  int64_t f8g7_19 = f8   * (int64_t) g7_19;
-  int64_t f8g8_19 = f8   * (int64_t) g8_19;
-  int64_t f8g9_19 = f8   * (int64_t) g9_19;
-  int64_t f9g0    = f9   * (int64_t) g0;
-  int64_t f9g1_38 = f9_2 * (int64_t) g1_19;
-  int64_t f9g2_19 = f9   * (int64_t) g2_19;
-  int64_t f9g3_38 = f9_2 * (int64_t) g3_19;
-  int64_t f9g4_19 = f9   * (int64_t) g4_19;
-  int64_t f9g5_38 = f9_2 * (int64_t) g5_19;
-  int64_t f9g6_19 = f9   * (int64_t) g6_19;
-  int64_t f9g7_38 = f9_2 * (int64_t) g7_19;
-  int64_t f9g8_19 = f9   * (int64_t) g8_19;
-  int64_t f9g9_38 = f9_2 * (int64_t) g9_19;
-  int64_t h0 = f0g0+f1g9_38+f2g8_19+f3g7_38+f4g6_19+f5g5_38+f6g4_19+f7g3_38+f8g2_19+f9g1_38;
-  int64_t h1 = f0g1+f1g0   +f2g9_19+f3g8_19+f4g7_19+f5g6_19+f6g5_19+f7g4_19+f8g3_19+f9g2_19;
-  int64_t h2 = f0g2+f1g1_2 +f2g0   +f3g9_38+f4g8_19+f5g7_38+f6g6_19+f7g5_38+f8g4_19+f9g3_38;
-  int64_t h3 = f0g3+f1g2   +f2g1   +f3g0   +f4g9_19+f5g8_19+f6g7_19+f7g6_19+f8g5_19+f9g4_19;
-  int64_t h4 = f0g4+f1g3_2 +f2g2   +f3g1_2 +f4g0   +f5g9_38+f6g8_19+f7g7_38+f8g6_19+f9g5_38;
-  int64_t h5 = f0g5+f1g4   +f2g3   +f3g2   +f4g1   +f5g0   +f6g9_19+f7g8_19+f8g7_19+f9g6_19;
-  int64_t h6 = f0g6+f1g5_2 +f2g4   +f3g3_2 +f4g2   +f5g1_2 +f6g0   +f7g9_38+f8g8_19+f9g7_38;
-  int64_t h7 = f0g7+f1g6   +f2g5   +f3g4   +f4g3   +f5g2   +f6g1   +f7g0   +f8g9_19+f9g8_19;
-  int64_t h8 = f0g8+f1g7_2 +f2g6   +f3g5_2 +f4g4   +f5g3_2 +f6g2   +f7g1_2 +f8g0   +f9g9_38;
-  int64_t h9 = f0g9+f1g8   +f2g7   +f3g6   +f4g5   +f5g4   +f6g3   +f7g2   +f8g1   +f9g0   ;
-  int64_t carry0;
-  int64_t carry1;
-  int64_t carry2;
-  int64_t carry3;
-  int64_t carry4;
-  int64_t carry5;
-  int64_t carry6;
-  int64_t carry7;
-  int64_t carry8;
-  int64_t carry9;
-
-  /* |h0| <= (1.65*1.65*2^52*(1+19+19+19+19)+1.65*1.65*2^50*(38+38+38+38+38))
-   *   i.e. |h0| <= 1.4*2^60; narrower ranges for h2, h4, h6, h8
-   * |h1| <= (1.65*1.65*2^51*(1+1+19+19+19+19+19+19+19+19))
-   *   i.e. |h1| <= 1.7*2^59; narrower ranges for h3, h5, h7, h9 */
-
-  carry0 = h0 + (1 << 25); h1 += carry0 >> 26; h0 -= carry0 & kTop38Bits;
-  carry4 = h4 + (1 << 25); h5 += carry4 >> 26; h4 -= carry4 & kTop38Bits;
-  /* |h0| <= 2^25 */
-  /* |h4| <= 2^25 */
-  /* |h1| <= 1.71*2^59 */
-  /* |h5| <= 1.71*2^59 */
-
-  carry1 = h1 + (1 << 24); h2 += carry1 >> 25; h1 -= carry1 & kTop39Bits;
-  carry5 = h5 + (1 << 24); h6 += carry5 >> 25; h5 -= carry5 & kTop39Bits;
-  /* |h1| <= 2^24; from now on fits into int32 */
-  /* |h5| <= 2^24; from now on fits into int32 */
-  /* |h2| <= 1.41*2^60 */
-  /* |h6| <= 1.41*2^60 */
-
-  carry2 = h2 + (1 << 25); h3 += carry2 >> 26; h2 -= carry2 & kTop38Bits;
-  carry6 = h6 + (1 << 25); h7 += carry6 >> 26; h6 -= carry6 & kTop38Bits;
-  /* |h2| <= 2^25; from now on fits into int32 unchanged */
-  /* |h6| <= 2^25; from now on fits into int32 unchanged */
-  /* |h3| <= 1.71*2^59 */
-  /* |h7| <= 1.71*2^59 */
-
-  carry3 = h3 + (1 << 24); h4 += carry3 >> 25; h3 -= carry3 & kTop39Bits;
-  carry7 = h7 + (1 << 24); h8 += carry7 >> 25; h7 -= carry7 & kTop39Bits;
-  /* |h3| <= 2^24; from now on fits into int32 unchanged */
-  /* |h7| <= 2^24; from now on fits into int32 unchanged */
-  /* |h4| <= 1.72*2^34 */
-  /* |h8| <= 1.41*2^60 */
-
-  carry4 = h4 + (1 << 25); h5 += carry4 >> 26; h4 -= carry4 & kTop38Bits;
-  carry8 = h8 + (1 << 25); h9 += carry8 >> 26; h8 -= carry8 & kTop38Bits;
-  /* |h4| <= 2^25; from now on fits into int32 unchanged */
-  /* |h8| <= 2^25; from now on fits into int32 unchanged */
-  /* |h5| <= 1.01*2^24 */
-  /* |h9| <= 1.71*2^59 */
-
-  carry9 = h9 + (1 << 24); h0 += (carry9 >> 25) * 19; h9 -= carry9 & kTop39Bits;
-  /* |h9| <= 2^24; from now on fits into int32 unchanged */
-  /* |h0| <= 1.1*2^39 */
-
-  carry0 = h0 + (1 << 25); h1 += carry0 >> 26; h0 -= carry0 & kTop38Bits;
-  /* |h0| <= 2^25; from now on fits into int32 unchanged */
-  /* |h1| <= 1.01*2^24 */
-
-  h[0] = (int32_t)h0;
-  h[1] = (int32_t)h1;
-  h[2] = (int32_t)h2;
-  h[3] = (int32_t)h3;
-  h[4] = (int32_t)h4;
-  h[5] = (int32_t)h5;
-  h[6] = (int32_t)h6;
-  h[7] = (int32_t)h7;
-  h[8] = (int32_t)h8;
-  h[9] = (int32_t)h9;
+ * With tighter constraints on inputs can squeeze carries into int32.
+ */
+static void fe_mul(fe h, const fe f, const fe g)
+{
+    int32_t f0 = f[0];
+    int32_t f1 = f[1];
+    int32_t f2 = f[2];
+    int32_t f3 = f[3];
+    int32_t f4 = f[4];
+    int32_t f5 = f[5];
+    int32_t f6 = f[6];
+    int32_t f7 = f[7];
+    int32_t f8 = f[8];
+    int32_t f9 = f[9];
+    int32_t g0 = g[0];
+    int32_t g1 = g[1];
+    int32_t g2 = g[2];
+    int32_t g3 = g[3];
+    int32_t g4 = g[4];
+    int32_t g5 = g[5];
+    int32_t g6 = g[6];
+    int32_t g7 = g[7];
+    int32_t g8 = g[8];
+    int32_t g9 = g[9];
+    int32_t g1_19 = 19 * g1; /* 1.959375*2^29 */
+    int32_t g2_19 = 19 * g2; /* 1.959375*2^30; still ok */
+    int32_t g3_19 = 19 * g3;
+    int32_t g4_19 = 19 * g4;
+    int32_t g5_19 = 19 * g5;
+    int32_t g6_19 = 19 * g6;
+    int32_t g7_19 = 19 * g7;
+    int32_t g8_19 = 19 * g8;
+    int32_t g9_19 = 19 * g9;
+    int32_t f1_2 = 2 * f1;
+    int32_t f3_2 = 2 * f3;
+    int32_t f5_2 = 2 * f5;
+    int32_t f7_2 = 2 * f7;
+    int32_t f9_2 = 2 * f9;
+    int64_t f0g0    = f0   * (int64_t) g0;
+    int64_t f0g1    = f0   * (int64_t) g1;
+    int64_t f0g2    = f0   * (int64_t) g2;
+    int64_t f0g3    = f0   * (int64_t) g3;
+    int64_t f0g4    = f0   * (int64_t) g4;
+    int64_t f0g5    = f0   * (int64_t) g5;
+    int64_t f0g6    = f0   * (int64_t) g6;
+    int64_t f0g7    = f0   * (int64_t) g7;
+    int64_t f0g8    = f0   * (int64_t) g8;
+    int64_t f0g9    = f0   * (int64_t) g9;
+    int64_t f1g0    = f1   * (int64_t) g0;
+    int64_t f1g1_2  = f1_2 * (int64_t) g1;
+    int64_t f1g2    = f1   * (int64_t) g2;
+    int64_t f1g3_2  = f1_2 * (int64_t) g3;
+    int64_t f1g4    = f1   * (int64_t) g4;
+    int64_t f1g5_2  = f1_2 * (int64_t) g5;
+    int64_t f1g6    = f1   * (int64_t) g6;
+    int64_t f1g7_2  = f1_2 * (int64_t) g7;
+    int64_t f1g8    = f1   * (int64_t) g8;
+    int64_t f1g9_38 = f1_2 * (int64_t) g9_19;
+    int64_t f2g0    = f2   * (int64_t) g0;
+    int64_t f2g1    = f2   * (int64_t) g1;
+    int64_t f2g2    = f2   * (int64_t) g2;
+    int64_t f2g3    = f2   * (int64_t) g3;
+    int64_t f2g4    = f2   * (int64_t) g4;
+    int64_t f2g5    = f2   * (int64_t) g5;
+    int64_t f2g6    = f2   * (int64_t) g6;
+    int64_t f2g7    = f2   * (int64_t) g7;
+    int64_t f2g8_19 = f2   * (int64_t) g8_19;
+    int64_t f2g9_19 = f2   * (int64_t) g9_19;
+    int64_t f3g0    = f3   * (int64_t) g0;
+    int64_t f3g1_2  = f3_2 * (int64_t) g1;
+    int64_t f3g2    = f3   * (int64_t) g2;
+    int64_t f3g3_2  = f3_2 * (int64_t) g3;
+    int64_t f3g4    = f3   * (int64_t) g4;
+    int64_t f3g5_2  = f3_2 * (int64_t) g5;
+    int64_t f3g6    = f3   * (int64_t) g6;
+    int64_t f3g7_38 = f3_2 * (int64_t) g7_19;
+    int64_t f3g8_19 = f3   * (int64_t) g8_19;
+    int64_t f3g9_38 = f3_2 * (int64_t) g9_19;
+    int64_t f4g0    = f4   * (int64_t) g0;
+    int64_t f4g1    = f4   * (int64_t) g1;
+    int64_t f4g2    = f4   * (int64_t) g2;
+    int64_t f4g3    = f4   * (int64_t) g3;
+    int64_t f4g4    = f4   * (int64_t) g4;
+    int64_t f4g5    = f4   * (int64_t) g5;
+    int64_t f4g6_19 = f4   * (int64_t) g6_19;
+    int64_t f4g7_19 = f4   * (int64_t) g7_19;
+    int64_t f4g8_19 = f4   * (int64_t) g8_19;
+    int64_t f4g9_19 = f4   * (int64_t) g9_19;
+    int64_t f5g0    = f5   * (int64_t) g0;
+    int64_t f5g1_2  = f5_2 * (int64_t) g1;
+    int64_t f5g2    = f5   * (int64_t) g2;
+    int64_t f5g3_2  = f5_2 * (int64_t) g3;
+    int64_t f5g4    = f5   * (int64_t) g4;
+    int64_t f5g5_38 = f5_2 * (int64_t) g5_19;
+    int64_t f5g6_19 = f5   * (int64_t) g6_19;
+    int64_t f5g7_38 = f5_2 * (int64_t) g7_19;
+    int64_t f5g8_19 = f5   * (int64_t) g8_19;
+    int64_t f5g9_38 = f5_2 * (int64_t) g9_19;
+    int64_t f6g0    = f6   * (int64_t) g0;
+    int64_t f6g1    = f6   * (int64_t) g1;
+    int64_t f6g2    = f6   * (int64_t) g2;
+    int64_t f6g3    = f6   * (int64_t) g3;
+    int64_t f6g4_19 = f6   * (int64_t) g4_19;
+    int64_t f6g5_19 = f6   * (int64_t) g5_19;
+    int64_t f6g6_19 = f6   * (int64_t) g6_19;
+    int64_t f6g7_19 = f6   * (int64_t) g7_19;
+    int64_t f6g8_19 = f6   * (int64_t) g8_19;
+    int64_t f6g9_19 = f6   * (int64_t) g9_19;
+    int64_t f7g0    = f7   * (int64_t) g0;
+    int64_t f7g1_2  = f7_2 * (int64_t) g1;
+    int64_t f7g2    = f7   * (int64_t) g2;
+    int64_t f7g3_38 = f7_2 * (int64_t) g3_19;
+    int64_t f7g4_19 = f7   * (int64_t) g4_19;
+    int64_t f7g5_38 = f7_2 * (int64_t) g5_19;
+    int64_t f7g6_19 = f7   * (int64_t) g6_19;
+    int64_t f7g7_38 = f7_2 * (int64_t) g7_19;
+    int64_t f7g8_19 = f7   * (int64_t) g8_19;
+    int64_t f7g9_38 = f7_2 * (int64_t) g9_19;
+    int64_t f8g0    = f8   * (int64_t) g0;
+    int64_t f8g1    = f8   * (int64_t) g1;
+    int64_t f8g2_19 = f8   * (int64_t) g2_19;
+    int64_t f8g3_19 = f8   * (int64_t) g3_19;
+    int64_t f8g4_19 = f8   * (int64_t) g4_19;
+    int64_t f8g5_19 = f8   * (int64_t) g5_19;
+    int64_t f8g6_19 = f8   * (int64_t) g6_19;
+    int64_t f8g7_19 = f8   * (int64_t) g7_19;
+    int64_t f8g8_19 = f8   * (int64_t) g8_19;
+    int64_t f8g9_19 = f8   * (int64_t) g9_19;
+    int64_t f9g0    = f9   * (int64_t) g0;
+    int64_t f9g1_38 = f9_2 * (int64_t) g1_19;
+    int64_t f9g2_19 = f9   * (int64_t) g2_19;
+    int64_t f9g3_38 = f9_2 * (int64_t) g3_19;
+    int64_t f9g4_19 = f9   * (int64_t) g4_19;
+    int64_t f9g5_38 = f9_2 * (int64_t) g5_19;
+    int64_t f9g6_19 = f9   * (int64_t) g6_19;
+    int64_t f9g7_38 = f9_2 * (int64_t) g7_19;
+    int64_t f9g8_19 = f9   * (int64_t) g8_19;
+    int64_t f9g9_38 = f9_2 * (int64_t) g9_19;
+    int64_t h0 = f0g0+f1g9_38+f2g8_19+f3g7_38+f4g6_19+f5g5_38+f6g4_19+f7g3_38+f8g2_19+f9g1_38;
+    int64_t h1 = f0g1+f1g0   +f2g9_19+f3g8_19+f4g7_19+f5g6_19+f6g5_19+f7g4_19+f8g3_19+f9g2_19;
+    int64_t h2 = f0g2+f1g1_2 +f2g0   +f3g9_38+f4g8_19+f5g7_38+f6g6_19+f7g5_38+f8g4_19+f9g3_38;
+    int64_t h3 = f0g3+f1g2   +f2g1   +f3g0   +f4g9_19+f5g8_19+f6g7_19+f7g6_19+f8g5_19+f9g4_19;
+    int64_t h4 = f0g4+f1g3_2 +f2g2   +f3g1_2 +f4g0   +f5g9_38+f6g8_19+f7g7_38+f8g6_19+f9g5_38;
+    int64_t h5 = f0g5+f1g4   +f2g3   +f3g2   +f4g1   +f5g0   +f6g9_19+f7g8_19+f8g7_19+f9g6_19;
+    int64_t h6 = f0g6+f1g5_2 +f2g4   +f3g3_2 +f4g2   +f5g1_2 +f6g0   +f7g9_38+f8g8_19+f9g7_38;
+    int64_t h7 = f0g7+f1g6   +f2g5   +f3g4   +f4g3   +f5g2   +f6g1   +f7g0   +f8g9_19+f9g8_19;
+    int64_t h8 = f0g8+f1g7_2 +f2g6   +f3g5_2 +f4g4   +f5g3_2 +f6g2   +f7g1_2 +f8g0   +f9g9_38;
+    int64_t h9 = f0g9+f1g8   +f2g7   +f3g6   +f4g5   +f5g4   +f6g3   +f7g2   +f8g1   +f9g0   ;
+    int64_t carry0;
+    int64_t carry1;
+    int64_t carry2;
+    int64_t carry3;
+    int64_t carry4;
+    int64_t carry5;
+    int64_t carry6;
+    int64_t carry7;
+    int64_t carry8;
+    int64_t carry9;
+
+    /* |h0| <= (1.65*1.65*2^52*(1+19+19+19+19)+1.65*1.65*2^50*(38+38+38+38+38))
+     *   i.e. |h0| <= 1.4*2^60; narrower ranges for h2, h4, h6, h8
+     * |h1| <= (1.65*1.65*2^51*(1+1+19+19+19+19+19+19+19+19))
+     *   i.e. |h1| <= 1.7*2^59; narrower ranges for h3, h5, h7, h9 */
+
+    carry0 = h0 + (1 << 25); h1 += carry0 >> 26; h0 -= carry0 & kTop38Bits;
+    carry4 = h4 + (1 << 25); h5 += carry4 >> 26; h4 -= carry4 & kTop38Bits;
+    /* |h0| <= 2^25 */
+    /* |h4| <= 2^25 */
+    /* |h1| <= 1.71*2^59 */
+    /* |h5| <= 1.71*2^59 */
+
+    carry1 = h1 + (1 << 24); h2 += carry1 >> 25; h1 -= carry1 & kTop39Bits;
+    carry5 = h5 + (1 << 24); h6 += carry5 >> 25; h5 -= carry5 & kTop39Bits;
+    /* |h1| <= 2^24; from now on fits into int32 */
+    /* |h5| <= 2^24; from now on fits into int32 */
+    /* |h2| <= 1.41*2^60 */
+    /* |h6| <= 1.41*2^60 */
+
+    carry2 = h2 + (1 << 25); h3 += carry2 >> 26; h2 -= carry2 & kTop38Bits;
+    carry6 = h6 + (1 << 25); h7 += carry6 >> 26; h6 -= carry6 & kTop38Bits;
+    /* |h2| <= 2^25; from now on fits into int32 unchanged */
+    /* |h6| <= 2^25; from now on fits into int32 unchanged */
+    /* |h3| <= 1.71*2^59 */
+    /* |h7| <= 1.71*2^59 */
+
+    carry3 = h3 + (1 << 24); h4 += carry3 >> 25; h3 -= carry3 & kTop39Bits;
+    carry7 = h7 + (1 << 24); h8 += carry7 >> 25; h7 -= carry7 & kTop39Bits;
+    /* |h3| <= 2^24; from now on fits into int32 unchanged */
+    /* |h7| <= 2^24; from now on fits into int32 unchanged */
+    /* |h4| <= 1.72*2^34 */
+    /* |h8| <= 1.41*2^60 */
+
+    carry4 = h4 + (1 << 25); h5 += carry4 >> 26; h4 -= carry4 & kTop38Bits;
+    carry8 = h8 + (1 << 25); h9 += carry8 >> 26; h8 -= carry8 & kTop38Bits;
+    /* |h4| <= 2^25; from now on fits into int32 unchanged */
+    /* |h8| <= 2^25; from now on fits into int32 unchanged */
+    /* |h5| <= 1.01*2^24 */
+    /* |h9| <= 1.71*2^59 */
+
+    carry9 = h9 + (1 << 24); h0 += (carry9 >> 25) * 19; h9 -= carry9 & kTop39Bits;
+    /* |h9| <= 2^24; from now on fits into int32 unchanged */
+    /* |h0| <= 1.1*2^39 */
+
+    carry0 = h0 + (1 << 25); h1 += carry0 >> 26; h0 -= carry0 & kTop38Bits;
+    /* |h0| <= 2^25; from now on fits into int32 unchanged */
+    /* |h1| <= 1.01*2^24 */
+
+    h[0] = (int32_t)h0;
+    h[1] = (int32_t)h1;
+    h[2] = (int32_t)h2;
+    h[3] = (int32_t)h3;
+    h[4] = (int32_t)h4;
+    h[5] = (int32_t)h5;
+    h[6] = (int32_t)h6;
+    h[7] = (int32_t)h7;
+    h[8] = (int32_t)h8;
+    h[9] = (int32_t)h9;
 }
 
-/* h = f * f
+/*
+ * h = f * f
+ *
  * Can overlap h with f.
  *
  * Preconditions:
@@ -1227,286 +1258,307 @@ static void fe_mul(fe h, const fe f, const fe g) {
  * Postconditions:
  *    |h| bounded by 1.01*2^25,1.01*2^24,1.01*2^25,1.01*2^24,etc.
  *
- * See fe_mul.c for discussion of implementation strategy. */
-static void fe_sq(fe h, const fe f) {
-  int32_t f0 = f[0];
-  int32_t f1 = f[1];
-  int32_t f2 = f[2];
-  int32_t f3 = f[3];
-  int32_t f4 = f[4];
-  int32_t f5 = f[5];
-  int32_t f6 = f[6];
-  int32_t f7 = f[7];
-  int32_t f8 = f[8];
-  int32_t f9 = f[9];
-  int32_t f0_2 = 2 * f0;
-  int32_t f1_2 = 2 * f1;
-  int32_t f2_2 = 2 * f2;
-  int32_t f3_2 = 2 * f3;
-  int32_t f4_2 = 2 * f4;
-  int32_t f5_2 = 2 * f5;
-  int32_t f6_2 = 2 * f6;
-  int32_t f7_2 = 2 * f7;
-  int32_t f5_38 = 38 * f5; /* 1.959375*2^30 */
-  int32_t f6_19 = 19 * f6; /* 1.959375*2^30 */
-  int32_t f7_38 = 38 * f7; /* 1.959375*2^30 */
-  int32_t f8_19 = 19 * f8; /* 1.959375*2^30 */
-  int32_t f9_38 = 38 * f9; /* 1.959375*2^30 */
-  int64_t f0f0    = f0   * (int64_t) f0;
-  int64_t f0f1_2  = f0_2 * (int64_t) f1;
-  int64_t f0f2_2  = f0_2 * (int64_t) f2;
-  int64_t f0f3_2  = f0_2 * (int64_t) f3;
-  int64_t f0f4_2  = f0_2 * (int64_t) f4;
-  int64_t f0f5_2  = f0_2 * (int64_t) f5;
-  int64_t f0f6_2  = f0_2 * (int64_t) f6;
-  int64_t f0f7_2  = f0_2 * (int64_t) f7;
-  int64_t f0f8_2  = f0_2 * (int64_t) f8;
-  int64_t f0f9_2  = f0_2 * (int64_t) f9;
-  int64_t f1f1_2  = f1_2 * (int64_t) f1;
-  int64_t f1f2_2  = f1_2 * (int64_t) f2;
-  int64_t f1f3_4  = f1_2 * (int64_t) f3_2;
-  int64_t f1f4_2  = f1_2 * (int64_t) f4;
-  int64_t f1f5_4  = f1_2 * (int64_t) f5_2;
-  int64_t f1f6_2  = f1_2 * (int64_t) f6;
-  int64_t f1f7_4  = f1_2 * (int64_t) f7_2;
-  int64_t f1f8_2  = f1_2 * (int64_t) f8;
-  int64_t f1f9_76 = f1_2 * (int64_t) f9_38;
-  int64_t f2f2    = f2   * (int64_t) f2;
-  int64_t f2f3_2  = f2_2 * (int64_t) f3;
-  int64_t f2f4_2  = f2_2 * (int64_t) f4;
-  int64_t f2f5_2  = f2_2 * (int64_t) f5;
-  int64_t f2f6_2  = f2_2 * (int64_t) f6;
-  int64_t f2f7_2  = f2_2 * (int64_t) f7;
-  int64_t f2f8_38 = f2_2 * (int64_t) f8_19;
-  int64_t f2f9_38 = f2   * (int64_t) f9_38;
-  int64_t f3f3_2  = f3_2 * (int64_t) f3;
-  int64_t f3f4_2  = f3_2 * (int64_t) f4;
-  int64_t f3f5_4  = f3_2 * (int64_t) f5_2;
-  int64_t f3f6_2  = f3_2 * (int64_t) f6;
-  int64_t f3f7_76 = f3_2 * (int64_t) f7_38;
-  int64_t f3f8_38 = f3_2 * (int64_t) f8_19;
-  int64_t f3f9_76 = f3_2 * (int64_t) f9_38;
-  int64_t f4f4    = f4   * (int64_t) f4;
-  int64_t f4f5_2  = f4_2 * (int64_t) f5;
-  int64_t f4f6_38 = f4_2 * (int64_t) f6_19;
-  int64_t f4f7_38 = f4   * (int64_t) f7_38;
-  int64_t f4f8_38 = f4_2 * (int64_t) f8_19;
-  int64_t f4f9_38 = f4   * (int64_t) f9_38;
-  int64_t f5f5_38 = f5   * (int64_t) f5_38;
-  int64_t f5f6_38 = f5_2 * (int64_t) f6_