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/*
* Lowest Level MPI Algorithms
* (C) 1999-2008,2013 Jack Lloyd
* 2006 Luca Piccarreta
*
* Distributed under the terms of the Botan license
*/
#ifndef BOTAN_MP_WORD_MULADD_H__
#define BOTAN_MP_WORD_MULADD_H__
#include <botan/mp_types.h>
namespace Botan {
extern "C" {
/*
* Word Multiply/Add
*/
inline word word_madd2(word a, word b, word* c)
{
#if defined(BOTAN_HAS_MP_DWORD)
const dword s = static_cast<dword>(a) * b + *c;
*c = static_cast<word>(s >> BOTAN_MP_WORD_BITS);
return static_cast<word>(s);
#else
static_assert(BOTAN_MP_WORD_BITS == 64, "Unexpected word size");
word hi = 0, lo = 0;
mul64x64_128(a, b, &lo, &hi);
lo += *c;
hi += (lo < *c); // carry?
*c = hi;
return lo;
#endif
}
/*
* Word Multiply/Add
*/
inline word word_madd3(word a, word b, word c, word* d)
{
#if defined(BOTAN_HAS_MP_DWORD)
const dword s = static_cast<dword>(a) * b + c + *d;
*d = static_cast<word>(s >> BOTAN_MP_WORD_BITS);
return static_cast<word>(s);
#else
static_assert(BOTAN_MP_WORD_BITS == 64, "Unexpected word size");
word hi = 0, lo = 0;
mul64x64_128(a, b, &lo, &hi);
lo += c;
hi += (lo < c); // carry?
lo += *d;
hi += (lo < *d); // carry?
*d = hi;
return lo;
#endif
}
}
}
#endif
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