1 /*
2    This file is basically ref10/fe_frombytes.h.
3 */
4 
5 #include "fe.h"
6 
7 #ifdef HAVE_AVX_ASM
8 
9 static uint64_t
10 load_3(const unsigned char *in)
11 {
12   uint64_t result;
13   result = (uint64_t) in[0];
14   result |= ((uint64_t) in[1]) << 8;
15   result |= ((uint64_t) in[2]) << 16;
16   return result;
17 }
18 
19 static uint64_t
20 load_4(const unsigned char *in)
21 {
22   uint64_t result;
23   result = (uint64_t) in[0];
24   result |= ((uint64_t) in[1]) << 8;
25   result |= ((uint64_t) in[2]) << 16;
26   result |= ((uint64_t) in[3]) << 24;
27   return result;
28 }
29 
30 void
31 fe_frombytes(fe h, const unsigned char *s)
32 {
33   uint64_t h0 = load_4(s);
34   uint64_t h1 = load_3(s + 4) << 6;
35   uint64_t h2 = load_3(s + 7) << 5;
36   uint64_t h3 = load_3(s + 10) << 3;
37   uint64_t h4 = load_3(s + 13) << 2;
38   uint64_t h5 = load_4(s + 16);
39   uint64_t h6 = load_3(s + 20) << 7;
40   uint64_t h7 = load_3(s + 23) << 5;
41   uint64_t h8 = load_3(s + 26) << 4;
42   uint64_t h9 = (load_3(s + 29) & 8388607) << 2;
43   uint64_t carry0;
44   uint64_t carry1;
45   uint64_t carry2;
46   uint64_t carry3;
47   uint64_t carry4;
48   uint64_t carry5;
49   uint64_t carry6;
50   uint64_t carry7;
51   uint64_t carry8;
52   uint64_t carry9;
53 
54   carry9 = h9 >> 25; h0 += carry9 * 19; h9 &= 0x1FFFFFF;
55   carry1 = h1 >> 25; h2 += carry1; h1 &= 0x1FFFFFF;
56   carry3 = h3 >> 25; h4 += carry3; h3 &= 0x1FFFFFF;
57   carry5 = h5 >> 25; h6 += carry5; h5 &= 0x1FFFFFF;
58   carry7 = h7 >> 25; h8 += carry7; h7 &= 0x1FFFFFF;
59 
60   carry0 = h0 >> 26; h1 += carry0; h0 &= 0x3FFFFFF;
61   carry2 = h2 >> 26; h3 += carry2; h2 &= 0x3FFFFFF;
62   carry4 = h4 >> 26; h5 += carry4; h4 &= 0x3FFFFFF;
63   carry6 = h6 >> 26; h7 += carry6; h6 &= 0x3FFFFFF;
64   carry8 = h8 >> 26; h9 += carry8; h8 &= 0x3FFFFFF;
65 
66   h[0] = h0;
67   h[1] = h1;
68   h[2] = h2;
69   h[3] = h3;
70   h[4] = h4;
71   h[5] = h5;
72   h[6] = h6;
73   h[7] = h7;
74   h[8] = h8;
75   h[9] = h9;
76 }
77 
78 #endif
79