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64 lines
1.3 KiB
C
64 lines
1.3 KiB
C
#include "fe.h"
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/*
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Replace (f,g) with (g,g) if b == 1;
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replace (f,g) with (f,g) if b == 0.
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Preconditions: b in {0,1}.
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*/
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void fe_cmov(fe f,const fe g,unsigned int b)
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{
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crypto_int32 f0 = f[0];
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crypto_int32 f1 = f[1];
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crypto_int32 f2 = f[2];
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crypto_int32 f3 = f[3];
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crypto_int32 f4 = f[4];
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crypto_int32 f5 = f[5];
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crypto_int32 f6 = f[6];
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crypto_int32 f7 = f[7];
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crypto_int32 f8 = f[8];
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crypto_int32 f9 = f[9];
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crypto_int32 g0 = g[0];
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crypto_int32 g1 = g[1];
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crypto_int32 g2 = g[2];
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crypto_int32 g3 = g[3];
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crypto_int32 g4 = g[4];
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crypto_int32 g5 = g[5];
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crypto_int32 g6 = g[6];
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crypto_int32 g7 = g[7];
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crypto_int32 g8 = g[8];
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crypto_int32 g9 = g[9];
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crypto_int32 x0 = f0 ^ g0;
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crypto_int32 x1 = f1 ^ g1;
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crypto_int32 x2 = f2 ^ g2;
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crypto_int32 x3 = f3 ^ g3;
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crypto_int32 x4 = f4 ^ g4;
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crypto_int32 x5 = f5 ^ g5;
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crypto_int32 x6 = f6 ^ g6;
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crypto_int32 x7 = f7 ^ g7;
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crypto_int32 x8 = f8 ^ g8;
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crypto_int32 x9 = f9 ^ g9;
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b = -b;
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x0 &= b;
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x1 &= b;
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x2 &= b;
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x3 &= b;
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x4 &= b;
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x5 &= b;
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x6 &= b;
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x7 &= b;
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x8 &= b;
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x9 &= b;
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f[0] = f0 ^ x0;
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f[1] = f1 ^ x1;
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f[2] = f2 ^ x2;
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f[3] = f3 ^ x3;
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f[4] = f4 ^ x4;
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f[5] = f5 ^ x5;
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f[6] = f6 ^ x6;
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f[7] = f7 ^ x7;
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f[8] = f8 ^ x8;
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f[9] = f9 ^ x9;
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}
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