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Merge pull request #157 from dmitrystu/optimized-loop
loop optimization
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commit
1933872bba
35
aes.c
35
aes.c
@ -412,23 +412,23 @@ static void Cipher(state_t* state, const uint8_t* RoundKey)
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uint8_t round = 0;
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// Add the First round key to the state before starting the rounds.
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AddRoundKey(0, state, RoundKey);
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AddRoundKey(0, state, RoundKey);
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// There will be Nr rounds.
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// The first Nr-1 rounds are identical.
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// These Nr-1 rounds are executed in the loop below.
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for (round = 1; round < Nr; ++round)
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// These Nr rounds are executed in the loop below.
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// Last one without MixColumns()
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for (round = 1; ; ++round)
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{
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SubBytes(state);
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ShiftRows(state);
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if (round == Nr) {
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break;
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}
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MixColumns(state);
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AddRoundKey(round, state, RoundKey);
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}
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// The last round is given below.
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// The MixColumns function is not here in the last round.
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SubBytes(state);
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ShiftRows(state);
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// Add round key to last round
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AddRoundKey(Nr, state, RoundKey);
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}
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@ -438,24 +438,23 @@ static void InvCipher(state_t* state, const uint8_t* RoundKey)
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uint8_t round = 0;
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// Add the First round key to the state before starting the rounds.
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AddRoundKey(Nr, state, RoundKey);
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AddRoundKey(Nr, state, RoundKey);
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// There will be Nr rounds.
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// The first Nr-1 rounds are identical.
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// These Nr-1 rounds are executed in the loop below.
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for (round = (Nr - 1); round > 0; --round)
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// These Nr rounds are executed in the loop below.
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// Last one without InvMixColumn()
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for (round = (Nr - 1); ; --round)
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{
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InvShiftRows(state);
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InvSubBytes(state);
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AddRoundKey(round, state, RoundKey);
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if (round == 0) {
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break;
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}
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InvMixColumns(state);
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}
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// The last round is given below.
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// The MixColumns function is not here in the last round.
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InvShiftRows(state);
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InvSubBytes(state);
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AddRoundKey(0, state, RoundKey);
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}
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#endif // #if (defined(CBC) && CBC == 1) || (defined(ECB) && ECB == 1)
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