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7324473f MC |
1 | /* Copyright (c) 2014 Cryptography Research, Inc. |
2 | * Released under the MIT License. See LICENSE.txt for license information. | |
3 | */ | |
4 | ||
5 | #include "f_field.h" | |
6 | ||
7 | #if (defined(__OPTIMIZE__) && !defined(__OPTIMIZE_SIZE__) && !I_HATE_UNROLLED_LOOPS) \ | |
8 | || defined(DECAF_FORCE_UNROLL) | |
9 | #define REPEAT8(_x) _x _x _x _x _x _x _x _x | |
10 | #define FOR_LIMB(_i,_start,_end,_x) do { _i=_start; REPEAT8( if (_i<_end) { _x; } _i++;) } while (0) | |
11 | #else | |
12 | #define FOR_LIMB(_i,_start,_end,_x) do { for (_i=_start; _i<_end; _i++) _x; } while (0) | |
13 | #endif | |
14 | ||
15 | void gf_mul (gf_s *__restrict__ cs, const gf as, const gf bs) { | |
16 | const uint32_t *a = as->limb, *b = bs->limb; | |
17 | uint32_t *c = cs->limb; | |
18 | ||
19 | uint64_t accum0 = 0, accum1 = 0, accum2 = 0; | |
20 | uint32_t mask = (1<<28) - 1; | |
21 | ||
22 | uint32_t aa[8], bb[8]; | |
23 | ||
24 | int i,j; | |
25 | for (i=0; i<8; i++) { | |
26 | aa[i] = a[i] + a[i+8]; | |
27 | bb[i] = b[i] + b[i+8]; | |
28 | } | |
29 | ||
30 | FOR_LIMB(j,0,8,{ | |
31 | accum2 = 0; | |
32 | ||
33 | FOR_LIMB (i,0,j+1,{ | |
34 | accum2 += widemul(a[j-i],b[i]); | |
35 | accum1 += widemul(aa[j-i],bb[i]); | |
36 | accum0 += widemul(a[8+j-i], b[8+i]); | |
37 | }); | |
38 | ||
39 | accum1 -= accum2; | |
40 | accum0 += accum2; | |
41 | accum2 = 0; | |
42 | ||
43 | FOR_LIMB (i,j+1,8,{ | |
44 | accum0 -= widemul(a[8+j-i], b[i]); | |
45 | accum2 += widemul(aa[8+j-i], bb[i]); | |
46 | accum1 += widemul(a[16+j-i], b[8+i]); | |
47 | }); | |
48 | ||
49 | accum1 += accum2; | |
50 | accum0 += accum2; | |
51 | ||
52 | c[j] = ((uint32_t)(accum0)) & mask; | |
53 | c[j+8] = ((uint32_t)(accum1)) & mask; | |
54 | ||
55 | accum0 >>= 28; | |
56 | accum1 >>= 28; | |
57 | }); | |
58 | ||
59 | accum0 += accum1; | |
60 | accum0 += c[8]; | |
61 | accum1 += c[0]; | |
62 | c[8] = ((uint32_t)(accum0)) & mask; | |
63 | c[0] = ((uint32_t)(accum1)) & mask; | |
64 | ||
65 | accum0 >>= 28; | |
66 | accum1 >>= 28; | |
67 | c[9] += ((uint32_t)(accum0)); | |
68 | c[1] += ((uint32_t)(accum1)); | |
69 | } | |
70 | ||
71 | void gf_mulw_unsigned (gf_s *__restrict__ cs, const gf as, uint32_t b) { | |
72 | assert(b<1<<28); | |
73 | ||
74 | const uint32_t *a = as->limb; | |
75 | uint32_t *c = cs->limb; | |
76 | ||
77 | uint64_t accum0 = 0, accum8 = 0; | |
78 | uint32_t mask = (1ull<<28)-1; | |
79 | ||
80 | int i; | |
81 | FOR_LIMB(i,0,8,{ | |
82 | accum0 += widemul(b, a[i]); | |
83 | accum8 += widemul(b, a[i+8]); | |
84 | ||
85 | c[i] = accum0 & mask; accum0 >>= 28; | |
86 | c[i+8] = accum8 & mask; accum8 >>= 28; | |
87 | }); | |
88 | ||
89 | accum0 += accum8 + c[8]; | |
90 | c[8] = accum0 & mask; | |
91 | c[9] += accum0 >> 28; | |
92 | ||
93 | accum8 += c[0]; | |
94 | c[0] = accum8 & mask; | |
95 | c[1] += accum8 >> 28; | |
96 | } | |
97 | ||
98 | void gf_sqr (gf_s *__restrict__ cs, const gf as) { | |
99 | gf_mul(cs,as,as); /* Performs better with a dedicated square */ | |
100 | } | |
101 |