diff --git a/src/libsodium/crypto_scalarmult/curve25519/donna_c64/curve25519_donna_c64.c b/src/libsodium/crypto_scalarmult/curve25519/donna_c64/curve25519_donna_c64.c
index c4763508..43e0a532 100644
--- a/src/libsodium/crypto_scalarmult/curve25519/donna_c64/curve25519_donna_c64.c
+++ b/src/libsodium/crypto_scalarmult/curve25519/donna_c64/curve25519_donna_c64.c
@@ -29,16 +29,13 @@
 
 #include "../scalarmult_curve25519.h"
 #include "curve25519_donna_c64.h"
+#include "private/curve25519_ref10.h"
 #include "private/common.h"
 #include "utils.h"
 
-typedef uint8_t u8;
-typedef uint64_t limb;
-typedef limb felem[5];
-
 /* Sum two numbers: output += in */
 static inline void
-fsum(limb *output, const limb *in)
+fe_add_self(fe output, const fe in)
 {
     output[0] += in[0];
     output[1] += in[1];
@@ -54,41 +51,38 @@ fsum(limb *output, const limb *in)
  * On return, out[i] < 2**55
  */
 static inline void
-fdifference_backwards(felem out, const felem in)
+fe_sub_backwards(fe out, const fe in)
 {
     /* 152 is 19 << 3 */
-    static const limb two54m152 = (((limb)1) << 54) - 152;
-    static const limb two54m8 = (((limb)1) << 54) - 8;
+    static const uint64_t two54m152 = (((uint64_t) 1) << 54) - 152;
+    static const uint64_t two54m8 = (((uint64_t) 1) << 54) - 8;
 
     out[0] = in[0] + two54m152 - out[0];
-    out[1] = in[1] + two54m8 - out[1];
-    out[2] = in[2] + two54m8 - out[2];
-    out[3] = in[3] + two54m8 - out[3];
-    out[4] = in[4] + two54m8 - out[4];
+    out[1] = in[1] + two54m8   - out[1];
+    out[2] = in[2] + two54m8   - out[2];
+    out[3] = in[3] + two54m8   - out[3];
+    out[4] = in[4] + two54m8   - out[4];
 }
 
 /* Multiply a number by a scalar: output = in * scalar */
 static inline void
-fscalar_product(felem output, const felem in, const limb scalar)
+fe_scalar_product(fe output, const fe in, const uint64_t scalar)
 {
+    const uint64_t mask = 0x7ffffffffffffULL;
     uint128_t a;
 
-    a = in[0] * (uint128_t)scalar;
-    output[0] = ((limb)a) & 0x7ffffffffffff;
+    a = in[0] * (uint128_t) scalar;
+    output[0] = ((uint64_t) a) & mask;
+    a = in[1] * (uint128_t) scalar + ((uint64_t) (a >> 51));
+    output[1] = ((uint64_t) a) & mask;
+    a = in[2] * (uint128_t) scalar + ((uint64_t) (a >> 51));
+    output[2] = ((uint64_t) a) & mask;
+    a = in[3] * (uint128_t) scalar + ((uint64_t) (a >> 51));
+    output[3] = ((uint64_t) a) & mask;
+    a = in[4] * (uint128_t) scalar + ((uint64_t) (a >> 51));
+    output[4] = ((uint64_t) a) & mask;
 
-    a = in[1] * (uint128_t)scalar + ((limb)(a >> 51));
-    output[1] = ((limb)a) & 0x7ffffffffffff;
-
-    a = in[2] * (uint128_t)scalar + ((limb)(a >> 51));
-    output[2] = ((limb)a) & 0x7ffffffffffff;
-
-    a = in[3] * (uint128_t)scalar + ((limb)(a >> 51));
-    output[3] = ((limb)a) & 0x7ffffffffffff;
-
-    a = in[4] * (uint128_t)scalar + ((limb)(a >> 51));
-    output[4] = ((limb)a) & 0x7ffffffffffff;
-
-    output[0] += (a >> 51) * 19;
+    output[0] += (a >> 51) * 19ULL;
 }
 
 /* Multiply two numbers: output = in2 * in
@@ -100,10 +94,11 @@ fscalar_product(felem output, const felem in, const limb scalar)
  * On return, output[i] < 2**52
  */
 static inline void
-fmul(felem output, const felem in2, const felem in)
+fe_mul_restrict(fe output, const fe in2, const fe in)
 {
+    const uint64_t mask = 0x7ffffffffffffULL;
     uint128_t t[5];
-    limb      r0, r1, r2, r3, r4, s0, s1, s2, s3, s4, c;
+    uint64_t  r0, r1, r2, r3, r4, s0, s1, s2, s3, s4, c;
 
     r0 = in[0];
     r1 = in[1];
@@ -117,45 +112,45 @@ fmul(felem output, const felem in2, const felem in)
     s3 = in2[3];
     s4 = in2[4];
 
-    t[0] = ((uint128_t)r0) * s0;
-    t[1] = ((uint128_t)r0) * s1 + ((uint128_t)r1) * s0;
-    t[2] = ((uint128_t)r0) * s2 + ((uint128_t)r2) * s0 + ((uint128_t)r1) * s1;
-    t[3] = ((uint128_t)r0) * s3 + ((uint128_t)r3) * s0 + ((uint128_t)r1) * s2
-           + ((uint128_t)r2) * s1;
-    t[4] = ((uint128_t)r0) * s4 + ((uint128_t)r4) * s0 + ((uint128_t)r3) * s1
-           + ((uint128_t)r1) * s3 + ((uint128_t)r2) * s2;
+    t[0] = ((uint128_t) r0) * s0;
+    t[1] = ((uint128_t) r0) * s1 + ((uint128_t) r1) * s0;
+    t[2] = ((uint128_t) r0) * s2 + ((uint128_t) r2) * s0 + ((uint128_t) r1) * s1;
+    t[3] = ((uint128_t) r0) * s3 + ((uint128_t) r3) * s0 + ((uint128_t) r1) * s2
+           + ((uint128_t) r2) * s1;
+    t[4] = ((uint128_t) r0) * s4 + ((uint128_t) r4) * s0 + ((uint128_t) r3) * s1
+           + ((uint128_t) r1) * s3 + ((uint128_t) r2) * s2;
 
-    r4 *= 19;
-    r1 *= 19;
-    r2 *= 19;
-    r3 *= 19;
+    r4 *= 19ULL;
+    r1 *= 19ULL;
+    r2 *= 19ULL;
+    r3 *= 19ULL;
 
-    t[0] += ((uint128_t)r4) * s1 + ((uint128_t)r1) * s4 + ((uint128_t)r2) * s3
-            + ((uint128_t)r3) * s2;
-    t[1] += ((uint128_t)r4) * s2 + ((uint128_t)r2) * s4 + ((uint128_t)r3) * s3;
-    t[2] += ((uint128_t)r4) * s3 + ((uint128_t)r3) * s4;
-    t[3] += ((uint128_t)r4) * s4;
+    t[0] += ((uint128_t) r4) * s1 + ((uint128_t) r1) * s4 + ((uint128_t) r2) * s3
+            + ((uint128_t) r3) * s2;
+    t[1] += ((uint128_t) r4) * s2 + ((uint128_t) r2) * s4 + ((uint128_t) r3) * s3;
+    t[2] += ((uint128_t) r4) * s3 + ((uint128_t) r3) * s4;
+    t[3] += ((uint128_t) r4) * s4;
 
-    r0 = (limb)t[0] & 0x7ffffffffffff;
-    c = (limb)(t[0] >> 51);
+    r0 = (uint64_t) t[0] & mask;
+    c = (uint64_t) (t[0] >> 51);
     t[1] += c;
-    r1 = (limb)t[1] & 0x7ffffffffffff;
-    c = (limb)(t[1] >> 51);
+    r1 = (uint64_t) t[1] & mask;
+    c = (uint64_t) (t[1] >> 51);
     t[2] += c;
-    r2 = (limb)t[2] & 0x7ffffffffffff;
-    c = (limb)(t[2] >> 51);
+    r2 = (uint64_t) t[2] & mask;
+    c = (uint64_t) (t[2] >> 51);
     t[3] += c;
-    r3 = (limb)t[3] & 0x7ffffffffffff;
-    c = (limb)(t[3] >> 51);
+    r3 = (uint64_t) t[3] & mask;
+    c = (uint64_t) (t[3] >> 51);
     t[4] += c;
-    r4 = (limb)t[4] & 0x7ffffffffffff;
-    c = (limb)(t[4] >> 51);
-    r0 += c * 19;
+    r4 = (uint64_t) t[4] & mask;
+    c = (uint64_t) (t[4] >> 51);
+    r0 += c * 19ULL;
     c = r0 >> 51;
-    r0 = r0 & 0x7ffffffffffff;
+    r0 = r0 & mask;
     r1 += c;
     c = r1 >> 51;
-    r1 = r1 & 0x7ffffffffffff;
+    r1 = r1 & mask;
     r2 += c;
 
     output[0] = r0;
@@ -166,11 +161,12 @@ fmul(felem output, const felem in2, const felem in)
 }
 
 static inline void
-fsquare_times(felem output, const felem in, limb count)
+fe_square_times(fe output, const fe in, uint64_t count)
 {
+    const uint64_t mask = 0x7ffffffffffffULL;
     uint128_t t[5];
-    limb      r0, r1, r2, r3, r4, c;
-    limb      d0, d1, d2, d4, d419;
+    uint64_t  r0, r1, r2, r3, r4, c;
+    uint64_t  d0, d1, d2, d4, d419;
 
     r0 = in[0];
     r1 = in[1];
@@ -181,41 +177,41 @@ fsquare_times(felem output, const felem in, limb count)
     do {
         d0 = r0 * 2;
         d1 = r1 * 2;
-        d2 = r2 * 2 * 19;
-        d419 = r4 * 19;
+        d2 = r2 * 2 * 19ULL;
+        d419 = r4 * 19ULL;
         d4 = d419 * 2;
 
-        t[0] = ((uint128_t)r0) * r0 + ((uint128_t)d4) * r1
-               + (((uint128_t)d2) * (r3));
-        t[1] = ((uint128_t)d0) * r1 + ((uint128_t)d4) * r2
-               + (((uint128_t)r3) * (r3 * 19));
-        t[2] = ((uint128_t)d0) * r2 + ((uint128_t)r1) * r1
-               + (((uint128_t)d4) * (r3));
-        t[3] = ((uint128_t)d0) * r3 + ((uint128_t)d1) * r2
-               + (((uint128_t)r4) * (d419));
-        t[4] = ((uint128_t)d0) * r4 + ((uint128_t)d1) * r3
-               + (((uint128_t)r2) * (r2));
+        t[0] = ((uint128_t) r0) * r0 + ((uint128_t) d4) * r1
+               + (((uint128_t) d2) * (r3));
+        t[1] = ((uint128_t) d0) * r1 + ((uint128_t) d4) * r2
+               + (((uint128_t) r3) * (r3 * 19ULL));
+        t[2] = ((uint128_t) d0) * r2 + ((uint128_t) r1) * r1
+               + (((uint128_t) d4) * (r3));
+        t[3] = ((uint128_t) d0) * r3 + ((uint128_t) d1) * r2
+               + (((uint128_t) r4) * (d419));
+        t[4] = ((uint128_t) d0) * r4 + ((uint128_t) d1) * r3
+               + (((uint128_t) r2) * (r2));
 
-        r0 = (limb)t[0] & 0x7ffffffffffff;
-        c = (limb)(t[0] >> 51);
+        r0 = (uint64_t) t[0] & mask;
+        c = (uint64_t) (t[0] >> 51);
         t[1] += c;
-        r1 = (limb)t[1] & 0x7ffffffffffff;
-        c = (limb)(t[1] >> 51);
+        r1 = (uint64_t) t[1] & mask;
+        c = (uint64_t) (t[1] >> 51);
         t[2] += c;
-        r2 = (limb)t[2] & 0x7ffffffffffff;
-        c = (limb)(t[2] >> 51);
+        r2 = (uint64_t) t[2] & mask;
+        c = (uint64_t) (t[2] >> 51);
         t[3] += c;
-        r3 = (limb)t[3] & 0x7ffffffffffff;
-        c = (limb)(t[3] >> 51);
+        r3 = (uint64_t) t[3] & mask;
+        c = (uint64_t) (t[3] >> 51);
         t[4] += c;
-        r4 = (limb)t[4] & 0x7ffffffffffff;
-        c = (limb)(t[4] >> 51);
-        r0 += c * 19;
+        r4 = (uint64_t) t[4] & mask;
+        c = (uint64_t) (t[4] >> 51);
+        r0 += c * 19ULL;
         c = r0 >> 51;
-        r0 = r0 & 0x7ffffffffffff;
+        r0 = r0 & mask;
         r1 += c;
         c = r1 >> 51;
-        r1 = r1 & 0x7ffffffffffff;
+        r1 = r1 & mask;
         r2 += c;
     } while (--count);
 
@@ -226,133 +222,6 @@ fsquare_times(felem output, const felem in, limb count)
     output[4] = r4;
 }
 
-#ifdef NATIVE_LITTLE_ENDIAN
-static inline limb
-load_limb(const u8 *in)
-{
-    limb out;
-
-    memcpy(&out, in, sizeof(limb));
-    return out;
-}
-static inline void
-store_limb(u8 *out, limb in)
-{
-    memcpy(out, &in, sizeof(limb));
-}
-#else
-static inline limb
-load_limb(const u8 *in)
-{
-    return ((limb)in[0]) | (((limb)in[1]) << 8) | (((limb)in[2]) << 16)
-           | (((limb)in[3]) << 24) | (((limb)in[4]) << 32)
-           | (((limb)in[5]) << 40) | (((limb)in[6]) << 48)
-           | (((limb)in[7]) << 56);
-}
-
-static inline void
-store_limb(u8 *out, limb in)
-{
-    out[0] = in & 0xff;
-    out[1] = (in >> 8) & 0xff;
-    out[2] = (in >> 16) & 0xff;
-    out[3] = (in >> 24) & 0xff;
-    out[4] = (in >> 32) & 0xff;
-    out[5] = (in >> 40) & 0xff;
-    out[6] = (in >> 48) & 0xff;
-    out[7] = (in >> 56) & 0xff;
-}
-#endif
-
-/* Take a little-endian, 32-byte number and expand it into polynomial form */
-static void
-fexpand(limb *output, const u8 *in)
-{
-    output[0] = load_limb(in) & 0x7ffffffffffff;
-    output[1] = (load_limb(in + 6) >> 3) & 0x7ffffffffffff;
-    output[2] = (load_limb(in + 12) >> 6) & 0x7ffffffffffff;
-    output[3] = (load_limb(in + 19) >> 1) & 0x7ffffffffffff;
-    output[4] = (load_limb(in + 24) >> 12) & 0x7ffffffffffff;
-}
-
-/* Take a fully reduced polynomial form number and contract it into a
- * little-endian, 32-byte array
- */
-static void
-fcontract(u8 *output, const felem input)
-{
-    uint128_t t[5];
-
-    t[0] = input[0];
-    t[1] = input[1];
-    t[2] = input[2];
-    t[3] = input[3];
-    t[4] = input[4];
-
-    t[1] += t[0] >> 51;
-    t[0] &= 0x7ffffffffffff;
-    t[2] += t[1] >> 51;
-    t[1] &= 0x7ffffffffffff;
-    t[3] += t[2] >> 51;
-    t[2] &= 0x7ffffffffffff;
-    t[4] += t[3] >> 51;
-    t[3] &= 0x7ffffffffffff;
-    t[0] += 19 * (t[4] >> 51);
-    t[4] &= 0x7ffffffffffff;
-
-    t[1] += t[0] >> 51;
-    t[0] &= 0x7ffffffffffff;
-    t[2] += t[1] >> 51;
-    t[1] &= 0x7ffffffffffff;
-    t[3] += t[2] >> 51;
-    t[2] &= 0x7ffffffffffff;
-    t[4] += t[3] >> 51;
-    t[3] &= 0x7ffffffffffff;
-    t[0] += 19 * (t[4] >> 51);
-    t[4] &= 0x7ffffffffffff;
-
-    /* now t is between 0 and 2^255-1, properly carried. */
-    /* case 1: between 0 and 2^255-20. case 2: between 2^255-19 and 2^255-1. */
-
-    t[0] += 19;
-
-    t[1] += t[0] >> 51;
-    t[0] &= 0x7ffffffffffff;
-    t[2] += t[1] >> 51;
-    t[1] &= 0x7ffffffffffff;
-    t[3] += t[2] >> 51;
-    t[2] &= 0x7ffffffffffff;
-    t[4] += t[3] >> 51;
-    t[3] &= 0x7ffffffffffff;
-    t[0] += 19 * (t[4] >> 51);
-    t[4] &= 0x7ffffffffffff;
-
-    /* now between 19 and 2^255-1 in both cases, and offset by 19. */
-
-    t[0] += 0x8000000000000 - 19;
-    t[1] += 0x8000000000000 - 1;
-    t[2] += 0x8000000000000 - 1;
-    t[3] += 0x8000000000000 - 1;
-    t[4] += 0x8000000000000 - 1;
-
-    /* now between 2^255 and 2^256-20, and offset by 2^255. */
-
-    t[1] += t[0] >> 51;
-    t[0] &= 0x7ffffffffffff;
-    t[2] += t[1] >> 51;
-    t[1] &= 0x7ffffffffffff;
-    t[3] += t[2] >> 51;
-    t[2] &= 0x7ffffffffffff;
-    t[4] += t[3] >> 51;
-    t[3] &= 0x7ffffffffffff;
-    t[4] &= 0x7ffffffffffff;
-
-    store_limb(output, t[0] | (t[1] << 51));
-    store_limb(output + 8, (t[1] >> 13) | (t[2] << 38));
-    store_limb(output + 16, (t[2] >> 26) | (t[3] << 25));
-    store_limb(output + 24, (t[3] >> 39) | (t[4] << 12));
-}
-
 /* Input: Q, Q', Q-Q'
  * Output: 2Q, Q+Q'
  *
@@ -363,42 +232,41 @@ fcontract(u8 *output, const felem input)
  *   qmqp: short form, preserved
  */
 static void
-fmonty(limb *x2, limb *z2,         /* output 2Q */
-       limb *x3, limb *z3,         /* output Q + Q' */
-       limb *x, limb *z,           /* input Q */
-       limb *xprime, limb *zprime, /* input Q' */
-       const limb *qmqp /* input Q - Q' */)
+fe_mont_y(fe x2,     fe z2,     /* output 2Q */
+          fe x3,     fe z3,     /* output Q + Q' */
+          fe x,      fe z,      /* input Q */
+          fe xprime, fe zprime, /* input Q' */
+          const fe qmqp         /* input Q - Q' */)
 {
-    limb origx[5], origxprime[5], zzz[5], xx[5], zz[5], xxprime[5], zzprime[5],
-        zzzprime[5];
+    fe origx, origxprime, zzz, xx, zz, xxprime, zzprime, zzzprime;
 
-    memcpy(origx, x, 5 * sizeof(limb));
-    fsum(x, z);
-    fdifference_backwards(z, origx); /* does x - z */
+    memcpy(origx, x, 5 * sizeof(uint64_t));
+    fe_add_self(x, z);
+    fe_sub_backwards(z, origx); /* does x - z */
 
-    memcpy(origxprime, xprime, sizeof(limb) * 5);
-    fsum(xprime, zprime);
-    fdifference_backwards(zprime, origxprime);
-    fmul(xxprime, xprime, z);
-    fmul(zzprime, x, zprime);
-    memcpy(origxprime, xxprime, sizeof(limb) * 5);
-    fsum(xxprime, zzprime);
-    fdifference_backwards(zzprime, origxprime);
-    fsquare_times(x3, xxprime, 1);
-    fsquare_times(zzzprime, zzprime, 1);
-    fmul(z3, zzzprime, qmqp);
+    memcpy(origxprime, xprime, sizeof(uint64_t) * 5);
+    fe_add_self(xprime, zprime);
+    fe_sub_backwards(zprime, origxprime);
+    fe_mul_restrict(xxprime, xprime, z);
+    fe_mul_restrict(zzprime, x, zprime);
+    memcpy(origxprime, xxprime, sizeof(uint64_t) * 5);
+    fe_add_self(xxprime, zzprime);
+    fe_sub_backwards(zzprime, origxprime);
+    fe_square_times(x3, xxprime, 1);
+    fe_square_times(zzzprime, zzprime, 1);
+    fe_mul_restrict(z3, zzzprime, qmqp);
 
-    fsquare_times(xx, x, 1);
-    fsquare_times(zz, z, 1);
-    fmul(x2, xx, zz);
-    fdifference_backwards(zz, xx); /* does zz = xx - zz */
-    fscalar_product(zzz, zz, 121665);
-    fsum(zzz, xx);
-    fmul(z2, zz, zzz);
+    fe_square_times(xx, x, 1);
+    fe_square_times(zz, z, 1);
+    fe_mul_restrict(x2, xx, zz);
+    fe_sub_backwards(zz, xx); /* does zz = xx - zz */
+    fe_scalar_product(zzz, zz, 121665);
+    fe_add_self(zzz, xx);
+    fe_mul_restrict(z2, zz, zzz);
 }
 
 /* -----------------------------------------------------------------------------
-   Maybe swap the contents of two limb arrays (@a and @b), each @len elements
+   Maybe swap the contents of two uint64_t arrays (@a and @b), each @len elements
    long. Perform the swap iff @swap is non-zero.
 
    This function performs the swap without leaking any side-channel
@@ -406,15 +274,15 @@ fmonty(limb *x2, limb *z2,         /* output 2Q */
    -----------------------------------------------------------------------------
    */
 static void
-swap_conditional(limb a[5], limb b[5], limb iswap)
+swap_conditional(fe f, fe g, unsigned int b)
 {
-    const limb swap = -iswap;
-    unsigned   i;
+    const uint64_t mask = (uint64_t) (-(int64_t) b);
+    unsigned int   i;
 
-    for (i = 0; i < 5; ++i) {
-        const limb x = swap & (a[i] ^ b[i]);
-        a[i] ^= x;
-        b[i] ^= x;
+    for (i = 0; i < 5; i++) {
+        const uint64_t x = mask & (f[i] ^ g[i]);
+        f[i] ^= x;
+        g[i] ^= x;
     }
 }
 
@@ -425,25 +293,25 @@ swap_conditional(limb a[5], limb b[5], limb iswap)
  *   q: a point of the curve (short form)
  */
 static void
-cmult(limb *resultx, limb *resultz, const u8 *n, const limb *q)
+cmult(fe resultx, fe resultz, const uint8_t *n, const fe q)
 {
-    limb a[5] = { 0 }, b[5] = { 1 }, c[5] = { 1 }, d[5] = { 0 };
-    limb *nqpqx = a, *nqpqz = b, *nqx = c, *nqz = d, *t;
-    limb e[5] = { 0 }, f[5] = { 1 }, g[5] = { 0 }, h[5] = { 1 };
-    limb *nqpqx2 = e, *nqpqz2 = f, *nqx2 = g, *nqz2 = h;
+    fe a = { 0 }, b = { 1 }, c = { 1 }, d = { 0 };
+    uint64_t *nqpqx = a, *nqpqz = b, *nqx = c, *nqz = d, *t;
+    fe e = { 0 }, f = { 1 }, g = { 0 }, h = { 1 };
+    uint64_t *nqpqx2 = e, *nqpqz2 = f, *nqx2 = g, *nqz2 = h;
 
     unsigned i, j;
 
-    memcpy(nqpqx, q, sizeof(limb) * 5);
+    memcpy(nqpqx, q, sizeof(uint64_t) * 5);
 
     for (i = 0; i < 32; ++i) {
-        u8 byte = n[31 - i];
+        uint8_t byte = n[31 - i];
         for (j = 0; j < 8; ++j) {
-            const limb bit = byte >> 7;
+            const unsigned int bit = byte >> 7;
 
             swap_conditional(nqx, nqpqx, bit);
             swap_conditional(nqz, nqpqz, bit);
-            fmonty(nqx2, nqz2, nqpqx2, nqpqz2, nqx, nqz, nqpqx, nqpqz, q);
+            fe_mont_y(nqx2, nqz2, nqpqx2, nqpqz2, nqx, nqz, nqpqx, nqpqz, q);
             swap_conditional(nqx2, nqpqx2, bit);
             swap_conditional(nqz2, nqpqz2, bit);
 
@@ -464,8 +332,8 @@ cmult(limb *resultx, limb *resultz, const u8 *n, const limb *q)
         }
     }
 
-    memcpy(resultx, nqx, sizeof(limb) * 5);
-    memcpy(resultz, nqz, sizeof(limb) * 5);
+    memcpy(resultx, nqx, sizeof(uint64_t) * 5);
+    memcpy(resultz, nqz, sizeof(uint64_t) * 5);
 }
 
 /* -----------------------------------------------------------------------------
@@ -473,32 +341,32 @@ cmult(limb *resultx, limb *resultz, const u8 *n, const limb *q)
    -----------------------------------------------------------------------------
    */
 static void
-crecip(felem out, const felem z)
+crecip(fe out, const fe z)
 {
-    felem a, t0, b, c;
+    fe a, t0, b, c;
 
-    /* 2 */ fsquare_times(a, z, 1); /* a = 2 */
-    /* 8 */ fsquare_times(t0, a, 2);
-    /* 9 */ fmul(b, t0, z); /* b = 9 */
-    /* 11 */ fmul(a, b, a); /* a = 11 */
-    /* 22 */ fsquare_times(t0, a, 1);
-    /* 2^5 - 2^0 = 31 */ fmul(b, t0, b);
-    /* 2^10 - 2^5 */ fsquare_times(t0, b, 5);
-    /* 2^10 - 2^0 */ fmul(b, t0, b);
-    /* 2^20 - 2^10 */ fsquare_times(t0, b, 10);
-    /* 2^20 - 2^0 */ fmul(c, t0, b);
-    /* 2^40 - 2^20 */ fsquare_times(t0, c, 20);
-    /* 2^40 - 2^0 */ fmul(t0, t0, c);
-    /* 2^50 - 2^10 */ fsquare_times(t0, t0, 10);
-    /* 2^50 - 2^0 */ fmul(b, t0, b);
-    /* 2^100 - 2^50 */ fsquare_times(t0, b, 50);
-    /* 2^100 - 2^0 */ fmul(c, t0, b);
-    /* 2^200 - 2^100 */ fsquare_times(t0, c, 100);
-    /* 2^200 - 2^0 */ fmul(t0, t0, c);
-    /* 2^250 - 2^50 */ fsquare_times(t0, t0, 50);
-    /* 2^250 - 2^0 */ fmul(t0, t0, b);
-    /* 2^255 - 2^5 */ fsquare_times(t0, t0, 5);
-    /* 2^255 - 21 */ fmul(out, t0, a);
+    /* 2 */              fe_square_times(a, z, 1); /* a = 2 */
+    /* 8 */              fe_square_times(t0, a, 2);
+    /* 9 */              fe_mul_restrict(b, t0, z); /* b = 9 */
+    /* 11 */             fe_mul_restrict(a, b, a); /* a = 11 */
+    /* 22 */             fe_square_times(t0, a, 1);
+    /* 2^5 - 2^0 = 31 */ fe_mul_restrict(b, t0, b);
+    /* 2^10 - 2^5 */     fe_square_times(t0, b, 5);
+    /* 2^10 - 2^0 */     fe_mul_restrict(b, t0, b);
+    /* 2^20 - 2^10 */    fe_square_times(t0, b, 10);
+    /* 2^20 - 2^0 */     fe_mul_restrict(c, t0, b);
+    /* 2^40 - 2^20 */    fe_square_times(t0, c, 20);
+    /* 2^40 - 2^0 */     fe_mul_restrict(t0, t0, c);
+    /* 2^50 - 2^10 */    fe_square_times(t0, t0, 10);
+    /* 2^50 - 2^0 */     fe_mul_restrict(b, t0, b);
+    /* 2^100 - 2^50 */   fe_square_times(t0, b, 50);
+    /* 2^100 - 2^0 */    fe_mul_restrict(c, t0, b);
+    /* 2^200 - 2^100 */  fe_square_times(t0, c, 100);
+    /* 2^200 - 2^0 */    fe_mul_restrict(t0, t0, c);
+    /* 2^250 - 2^50 */   fe_square_times(t0, t0, 50);
+    /* 2^250 - 2^0 */    fe_mul_restrict(t0, t0, b);
+    /* 2^255 - 2^5 */    fe_square_times(t0, t0, 5);
+    /* 2^255 - 21 */     fe_mul_restrict(out, t0, a);
 }
 
 static int
@@ -506,7 +374,7 @@ crypto_scalarmult_curve25519_donna_c64(unsigned char *q,
                                        const unsigned char *n,
                                        const unsigned char *p)
 {
-    limb           bp[5], x[5], z[5], zmone[5];
+    fe             bp, x, z, zmone;
     unsigned char *t = q;
     int            i;
 
@@ -517,11 +385,11 @@ crypto_scalarmult_curve25519_donna_c64(unsigned char *q,
     t[31] &= 127;
     t[31] |= 64;
 
-    fexpand(bp, p);
+    fe_frombytes(bp, p);
     cmult(x, z, t, bp);
     crecip(zmone, z);
-    fmul(z, x, zmone);
-    fcontract(q, z);
+    fe_mul_restrict(z, x, zmone);
+    fe_tobytes(q, z);
 
     return 0;
 }