28 lines
532 B
C
28 lines
532 B
C
#include "sc25519.h"
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void sc25519_window4(signed char r[64], const sc25519 *s)
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{
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char carry;
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int i;
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for(i=0;i<16;i++)
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r[i] = (s->v[0] >> (4*i)) & 15;
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for(i=0;i<16;i++)
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r[i+16] = (s->v[1] >> (4*i)) & 15;
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for(i=0;i<16;i++)
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r[i+32] = (s->v[2] >> (4*i)) & 15;
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for(i=0;i<16;i++)
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r[i+48] = (s->v[3] >> (4*i)) & 15;
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/* Making it signed */
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carry = 0;
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for(i=0;i<63;i++)
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{
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r[i] += carry;
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r[i+1] += r[i] >> 4;
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r[i] &= 15;
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carry = r[i] >> 3;
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r[i] -= carry << 4;
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}
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r[63] += carry;
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}
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