/*
* Ed25519
* (C) 2017 Ribose Inc
*
* Based on the public domain code from SUPERCOP ref10 by
* Peter Schwabe, Daniel J. Bernstein, Niels Duif, Tanja Lange, Bo-Yin Yang
*
* Botan is released under the Simplified BSD License (see license.txt)
*/

#include <botan/internal/ed25519_internal.h>

namespace Botan {

/*
Input:
  a[0]+256*a[1]+...+256^31*a[31] = a
  b[0]+256*b[1]+...+256^31*b[31] = b
  c[0]+256*c[1]+...+256^31*c[31] = c

Output:
  s[0]+256*s[1]+...+256^31*s[31] = (ab+c) mod l
  where l = 2^252 + 27742317777372353535851937790883648493.
*/

void sc_muladd(uint8_t* s, const uint8_t* a, const uint8_t* b, const uint8_t* c)
   {
   const int64_t X20 = (1 << 20);
   const int64_t X21 = (1 << 21);

   int64_t a0 = 2097151 & load_3(a);
   int64_t a1 = 2097151 & (load_4(a + 2) >> 5);
   int64_t a2 = 2097151 & (load_3(a + 5) >> 2);
   int64_t a3 = 2097151 & (load_4(a + 7) >> 7);
   int64_t a4 = 2097151 & (load_4(a + 10) >> 4);
   int64_t a5 = 2097151 & (load_3(a + 13) >> 1);
   int64_t a6 = 2097151 & (load_4(a + 15) >> 6);
   int64_t a7 = 2097151 & (load_3(a + 18) >> 3);
   int64_t a8 = 2097151 & load_3(a + 21);
   int64_t a9 = 2097151 & (load_4(a + 23) >> 5);
   int64_t a10 = 2097151 & (load_3(a + 26) >> 2);
   int64_t a11 = (load_4(a + 28) >> 7);
   int64_t b0 = 2097151 & load_3(b);
   int64_t b1 = 2097151 & (load_4(b + 2) >> 5);
   int64_t b2 = 2097151 & (load_3(b + 5) >> 2);
   int64_t b3 = 2097151 & (load_4(b + 7) >> 7);
   int64_t b4 = 2097151 & (load_4(b + 10) >> 4);
   int64_t b5 = 2097151 & (load_3(b + 13) >> 1);
   int64_t b6 = 2097151 & (load_4(b + 15) >> 6);
   int64_t b7 = 2097151 & (load_3(b + 18) >> 3);
   int64_t b8 = 2097151 & load_3(b + 21);
   int64_t b9 = 2097151 & (load_4(b + 23) >> 5);
   int64_t b10 = 2097151 & (load_3(b + 26) >> 2);
   int64_t b11 = (load_4(b + 28) >> 7);
   int64_t c0 = 2097151 & load_3(c);
   int64_t c1 = 2097151 & (load_4(c + 2) >> 5);
   int64_t c2 = 2097151 & (load_3(c + 5) >> 2);
   int64_t c3 = 2097151 & (load_4(c + 7) >> 7);
   int64_t c4 = 2097151 & (load_4(c + 10) >> 4);
   int64_t c5 = 2097151 & (load_3(c + 13) >> 1);
   int64_t c6 = 2097151 & (load_4(c + 15) >> 6);
   int64_t c7 = 2097151 & (load_3(c + 18) >> 3);
   int64_t c8 = 2097151 & load_3(c + 21);
   int64_t c9 = 2097151 & (load_4(c + 23) >> 5);
   int64_t c10 = 2097151 & (load_3(c + 26) >> 2);
   int64_t c11 = (load_4(c + 28) >> 7);
   int64_t s0;
   int64_t s1;
   int64_t s2;
   int64_t s3;
   int64_t s4;
   int64_t s5;
   int64_t s6;
   int64_t s7;
   int64_t s8;
   int64_t s9;
   int64_t s10;
   int64_t s11;
   int64_t s12;
   int64_t s13;
   int64_t s14;
   int64_t s15;
   int64_t s16;
   int64_t s17;
   int64_t s18;
   int64_t s19;
   int64_t s20;
   int64_t s21;
   int64_t s22;
   int64_t s23;
   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;
   int64_t carry10;
   int64_t carry11;
   int64_t carry12;
   int64_t carry13;
   int64_t carry14;
   int64_t carry15;
   int64_t carry16;
   int64_t carry17;
   int64_t carry18;
   int64_t carry19;
   int64_t carry20;
   int64_t carry21;
   int64_t carry22;

   s0 = c0 + a0*b0;
   s1 = c1 + a0*b1 + a1*b0;
   s2 = c2 + a0*b2 + a1*b1 + a2*b0;
   s3 = c3 + a0*b3 + a1*b2 + a2*b1 + a3*b0;
   s4 = c4 + a0*b4 + a1*b3 + a2*b2 + a3*b1 + a4*b0;
   s5 = c5 + a0*b5 + a1*b4 + a2*b3 + a3*b2 + a4*b1 + a5*b0;
   s6 = c6 + a0*b6 + a1*b5 + a2*b4 + a3*b3 + a4*b2 + a5*b1 + a6*b0;
   s7 = c7 + a0*b7 + a1*b6 + a2*b5 + a3*b4 + a4*b3 + a5*b2 + a6*b1 + a7*b0;
   s8 = c8 + a0*b8 + a1*b7 + a2*b6 + a3*b5 + a4*b4 + a5*b3 + a6*b2 + a7*b1 + a8*b0;
   s9 = c9 + a0*b9 + a1*b8 + a2*b7 + a3*b6 + a4*b5 + a5*b4 + a6*b3 + a7*b2 + a8*b1 + a9*b0;
   s10 = c10 + a0*b10 + a1*b9 + a2*b8 + a3*b7 + a4*b6 + a5*b5 + a6*b4 + a7*b3 + a8*b2 + a9*b1 + a10*b0;
   s11 = c11 + a0*b11 + a1*b10 + a2*b9 + a3*b8 + a4*b7 + a5*b6 + a6*b5 + a7*b4 + a8*b3 + a9*b2 + a10*b1 + a11*b0;
   s12 = a1*b11 + a2*b10 + a3*b9 + a4*b8 + a5*b7 + a6*b6 + a7*b5 + a8*b4 + a9*b3 + a10*b2 + a11*b1;
   s13 = a2*b11 + a3*b10 + a4*b9 + a5*b8 + a6*b7 + a7*b6 + a8*b5 + a9*b4 + a10*b3 + a11*b2;
   s14 = a3*b11 + a4*b10 + a5*b9 + a6*b8 + a7*b7 + a8*b6 + a9*b5 + a10*b4 + a11*b3;
   s15 = a4*b11 + a5*b10 + a6*b9 + a7*b8 + a8*b7 + a9*b6 + a10*b5 + a11*b4;
   s16 = a5*b11 + a6*b10 + a7*b9 + a8*b8 + a9*b7 + a10*b6 + a11*b5;
   s17 = a6*b11 + a7*b10 + a8*b9 + a9*b8 + a10*b7 + a11*b6;
   s18 = a7*b11 + a8*b10 + a9*b9 + a10*b8 + a11*b7;
   s19 = a8*b11 + a9*b10 + a10*b9 + a11*b8;
   s20 = a9*b11 + a10*b10 + a11*b9;
   s21 = a10*b11 + a11*b10;
   s22 = a11*b11;
   s23 = 0;

   carry0 = (s0 + X20) >> 21;
   s1 += carry0;
   s0 -= carry0 * X21;
   carry2 = (s2 + X20) >> 21;
   s3 += carry2;
   s2 -= carry2 * X21;
   carry4 = (s4 + X20) >> 21;
   s5 += carry4;
   s4 -= carry4 * X21;
   carry6 = (s6 + X20) >> 21;
   s7 += carry6;
   s6 -= carry6 * X21;
   carry8 = (s8 + X20) >> 21;
   s9 += carry8;
   s8 -= carry8 * X21;
   carry10 = (s10 + X20) >> 21;
   s11 += carry10;
   s10 -= carry10 * X21;
   carry12 = (s12 + X20) >> 21;
   s13 += carry12;
   s12 -= carry12 * X21;
   carry14 = (s14 + X20) >> 21;
   s15 += carry14;
   s14 -= carry14 * X21;
   carry16 = (s16 + X20) >> 21;
   s17 += carry16;
   s16 -= carry16 * X21;
   carry18 = (s18 + X20) >> 21;
   s19 += carry18;
   s18 -= carry18 * X21;
   carry20 = (s20 + X20) >> 21;
   s21 += carry20;
   s20 -= carry20 * X21;
   carry22 = (s22 + X20) >> 21;
   s23 += carry22;
   s22 -= carry22 * X21;

   carry1 = (s1 + X20) >> 21;
   s2 += carry1;
   s1 -= carry1 * X21;
   carry3 = (s3 + X20) >> 21;
   s4 += carry3;
   s3 -= carry3 * X21;
   carry5 = (s5 + X20) >> 21;
   s6 += carry5;
   s5 -= carry5 * X21;
   carry7 = (s7 + X20) >> 21;
   s8 += carry7;
   s7 -= carry7 * X21;
   carry9 = (s9 + X20) >> 21;
   s10 += carry9;
   s9 -= carry9 * X21;
   carry11 = (s11 + X20) >> 21;
   s12 += carry11;
   s11 -= carry11 * X21;
   carry13 = (s13 + X20) >> 21;
   s14 += carry13;
   s13 -= carry13 * X21;
   carry15 = (s15 + X20) >> 21;
   s16 += carry15;
   s15 -= carry15 * X21;
   carry17 = (s17 + X20) >> 21;
   s18 += carry17;
   s17 -= carry17 * X21;
   carry19 = (s19 + X20) >> 21;
   s20 += carry19;
   s19 -= carry19 * X21;
   carry21 = (s21 + X20) >> 21;
   s22 += carry21;
   s21 -= carry21 * X21;

   s11 += s23 * 666643;
   s12 += s23 * 470296;
   s13 += s23 * 654183;
   s14 -= s23 * 997805;
   s15 += s23 * 136657;
   s16 -= s23 * 683901;
   s23 = 0;

   s10 += s22 * 666643;
   s11 += s22 * 470296;
   s12 += s22 * 654183;
   s13 -= s22 * 997805;
   s14 += s22 * 136657;
   s15 -= s22 * 683901;
   s22 = 0;

   s9 += s21 * 666643;
   s10 += s21 * 470296;
   s11 += s21 * 654183;
   s12 -= s21 * 997805;
   s13 += s21 * 136657;
   s14 -= s21 * 683901;
   s21 = 0;

   s8 += s20 * 666643;
   s9 += s20 * 470296;
   s10 += s20 * 654183;
   s11 -= s20 * 997805;
   s12 += s20 * 136657;
   s13 -= s20 * 683901;
   s20 = 0;

   s7 += s19 * 666643;
   s8 += s19 * 470296;
   s9 += s19 * 654183;
   s10 -= s19 * 997805;
   s11 += s19 * 136657;
   s12 -= s19 * 683901;
   s19 = 0;

   s6 += s18 * 666643;
   s7 += s18 * 470296;
   s8 += s18 * 654183;
   s9 -= s18 * 997805;
   s10 += s18 * 136657;
   s11 -= s18 * 683901;
   s18 = 0;

   carry6 = (s6 + X20) >> 21;
   s7 += carry6;
   s6 -= carry6 * X21;
   carry8 = (s8 + X20) >> 21;
   s9 += carry8;
   s8 -= carry8 * X21;
   carry10 = (s10 + X20) >> 21;
   s11 += carry10;
   s10 -= carry10 * X21;
   carry12 = (s12 + X20) >> 21;
   s13 += carry12;
   s12 -= carry12 * X21;
   carry14 = (s14 + X20) >> 21;
   s15 += carry14;
   s14 -= carry14 * X21;
   carry16 = (s16 + X20) >> 21;
   s17 += carry16;
   s16 -= carry16 * X21;

   carry7 = (s7 + X20) >> 21;
   s8 += carry7;
   s7 -= carry7 * X21;
   carry9 = (s9 + X20) >> 21;
   s10 += carry9;
   s9 -= carry9 * X21;
   carry11 = (s11 + X20) >> 21;
   s12 += carry11;
   s11 -= carry11 * X21;
   carry13 = (s13 + X20) >> 21;
   s14 += carry13;
   s13 -= carry13 * X21;
   carry15 = (s15 + X20) >> 21;
   s16 += carry15;
   s15 -= carry15 * X21;

   s5 += s17 * 666643;
   s6 += s17 * 470296;
   s7 += s17 * 654183;
   s8 -= s17 * 997805;
   s9 += s17 * 136657;
   s10 -= s17 * 683901;
   s17 = 0;

   s4 += s16 * 666643;
   s5 += s16 * 470296;
   s6 += s16 * 654183;
   s7 -= s16 * 997805;
   s8 += s16 * 136657;
   s9 -= s16 * 683901;
   s16 = 0;

   s3 += s15 * 666643;
   s4 += s15 * 470296;
   s5 += s15 * 654183;
   s6 -= s15 * 997805;
   s7 += s15 * 136657;
   s8 -= s15 * 683901;
   s15 = 0;

   s2 += s14 * 666643;
   s3 += s14 * 470296;
   s4 += s14 * 654183;
   s5 -= s14 * 997805;
   s6 += s14 * 136657;
   s7 -= s14 * 683901;
   s14 = 0;

   s1 += s13 * 666643;
   s2 += s13 * 470296;
   s3 += s13 * 654183;
   s4 -= s13 * 997805;
   s5 += s13 * 136657;
   s6 -= s13 * 683901;
   s13 = 0;

   s0 += s12 * 666643;
   s1 += s12 * 470296;
   s2 += s12 * 654183;
   s3 -= s12 * 997805;
   s4 += s12 * 136657;
   s5 -= s12 * 683901;
   s12 = 0;

   carry0 = (s0 + X20) >> 21;
   s1 += carry0;
   s0 -= carry0 * X21;
   carry2 = (s2 + X20) >> 21;
   s3 += carry2;
   s2 -= carry2 * X21;
   carry4 = (s4 + X20) >> 21;
   s5 += carry4;
   s4 -= carry4 * X21;
   carry6 = (s6 + X20) >> 21;
   s7 += carry6;
   s6 -= carry6 * X21;
   carry8 = (s8 + X20) >> 21;
   s9 += carry8;
   s8 -= carry8 * X21;
   carry10 = (s10 + X20) >> 21;
   s11 += carry10;
   s10 -= carry10 * X21;

   carry1 = (s1 + X20) >> 21;
   s2 += carry1;
   s1 -= carry1 * X21;
   carry3 = (s3 + X20) >> 21;
   s4 += carry3;
   s3 -= carry3 * X21;
   carry5 = (s5 + X20) >> 21;
   s6 += carry5;
   s5 -= carry5 * X21;
   carry7 = (s7 + X20) >> 21;
   s8 += carry7;
   s7 -= carry7 * X21;
   carry9 = (s9 + X20) >> 21;
   s10 += carry9;
   s9 -= carry9 * X21;
   carry11 = (s11 + X20) >> 21;
   s12 += carry11;
   s11 -= carry11 * X21;

   s0 += s12 * 666643;
   s1 += s12 * 470296;
   s2 += s12 * 654183;
   s3 -= s12 * 997805;
   s4 += s12 * 136657;
   s5 -= s12 * 683901;
   s12 = 0;

   carry0 = s0 >> 21;
   s1 += carry0;
   s0 -= carry0 * X21;
   carry1 = s1 >> 21;
   s2 += carry1;
   s1 -= carry1 * X21;
   carry2 = s2 >> 21;
   s3 += carry2;
   s2 -= carry2 * X21;
   carry3 = s3 >> 21;
   s4 += carry3;
   s3 -= carry3 * X21;
   carry4 = s4 >> 21;
   s5 += carry4;
   s4 -= carry4 * X21;
   carry5 = s5 >> 21;
   s6 += carry5;
   s5 -= carry5 * X21;
   carry6 = s6 >> 21;
   s7 += carry6;
   s6 -= carry6 * X21;
   carry7 = s7 >> 21;
   s8 += carry7;
   s7 -= carry7 * X21;
   carry8 = s8 >> 21;
   s9 += carry8;
   s8 -= carry8 * X21;
   carry9 = s9 >> 21;
   s10 += carry9;
   s9 -= carry9 * X21;
   carry10 = s10 >> 21;
   s11 += carry10;
   s10 -= carry10 * X21;
   carry11 = s11 >> 21;
   s12 += carry11;
   s11 -= carry11 * X21;

   s0 += s12 * 666643;
   s1 += s12 * 470296;
   s2 += s12 * 654183;
   s3 -= s12 * 997805;
   s4 += s12 * 136657;
   s5 -= s12 * 683901;
   s12 = 0;

   carry0 = s0 >> 21;
   s1 += carry0;
   s0 -= carry0 * X21;
   carry1 = s1 >> 21;
   s2 += carry1;
   s1 -= carry1 * X21;
   carry2 = s2 >> 21;
   s3 += carry2;
   s2 -= carry2 * X21;
   carry3 = s3 >> 21;
   s4 += carry3;
   s3 -= carry3 * X21;
   carry4 = s4 >> 21;
   s5 += carry4;
   s4 -= carry4 * X21;
   carry5 = s5 >> 21;
   s6 += carry5;
   s5 -= carry5 * X21;
   carry6 = s6 >> 21;
   s7 += carry6;
   s6 -= carry6 * X21;
   carry7 = s7 >> 21;
   s8 += carry7;
   s7 -= carry7 * X21;
   carry8 = s8 >> 21;
   s9 += carry8;
   s8 -= carry8 * X21;
   carry9 = s9 >> 21;
   s10 += carry9;
   s9 -= carry9 * X21;
   carry10 = s10 >> 21;
   s11 += carry10;
   s10 -= carry10 * X21;

   s[0] = s0 >> 0;
   s[1] = s0 >> 8;
   s[2] = (s0 >> 16) | (s1 << 5);
   s[3] = s1 >> 3;
   s[4] = s1 >> 11;
   s[5] = (s1 >> 19) | (s2 << 2);
   s[6] = s2 >> 6;
   s[7] = (s2 >> 14) | (s3 << 7);
   s[8] = s3 >> 1;
   s[9] = s3 >> 9;
   s[10] = (s3 >> 17) | (s4 << 4);
   s[11] = s4 >> 4;
   s[12] = s4 >> 12;
   s[13] = (s4 >> 20) | (s5 << 1);
   s[14] = s5 >> 7;
   s[15] = (s5 >> 15) | (s6 << 6);
   s[16] = s6 >> 2;
   s[17] = s6 >> 10;
   s[18] = (s6 >> 18) | (s7 << 3);
   s[19] = s7 >> 5;
   s[20] = s7 >> 13;
   s[21] = s8 >> 0;
   s[22] = s8 >> 8;
   s[23] = (s8 >> 16) | (s9 << 5);
   s[24] = s9 >> 3;
   s[25] = s9 >> 11;
   s[26] = (s9 >> 19) | (s10 << 2);
   s[27] = s10 >> 6;
   s[28] = (s10 >> 14) | (s11 << 7);
   s[29] = s11 >> 1;
   s[30] = s11 >> 9;
   s[31] = s11 >> 17;
   }

}