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/*
* MPI Add, Subtract, Word Multiply
* (C) 1999-2010 Jack Lloyd
* 2006 Luca Piccarreta
*
* Botan is released under the Simplified BSD License (see license.txt)
*/
#include <botan/internal/mp_core.h>
#include <botan/internal/mp_asmi.h>
#include <botan/internal/mp_core.h>
#include <botan/exceptn.h>
#include <botan/mem_ops.h>
namespace Botan {
/*
* Two Operand Addition, No Carry
*/
word bigint_add2_nc(word x[], size_t x_size, const word y[], size_t y_size)
{
word carry = 0;
BOTAN_ASSERT(x_size >= y_size, "Expected sizes");
const size_t blocks = y_size - (y_size % 8);
for(size_t i = 0; i != blocks; i += 8)
carry = word8_add2(x + i, y + i, carry);
for(size_t i = blocks; i != y_size; ++i)
x[i] = word_add(x[i], y[i], &carry);
for(size_t i = y_size; i != x_size; ++i)
x[i] = word_add(x[i], 0, &carry);
return carry;
}
/*
* Three Operand Addition, No Carry
*/
word bigint_add3_nc(word z[], const word x[], size_t x_size,
const word y[], size_t y_size)
{
if(x_size < y_size)
{ return bigint_add3_nc(z, y, y_size, x, x_size); }
word carry = 0;
const size_t blocks = y_size - (y_size % 8);
for(size_t i = 0; i != blocks; i += 8)
carry = word8_add3(z + i, x + i, y + i, carry);
for(size_t i = blocks; i != y_size; ++i)
z[i] = word_add(x[i], y[i], &carry);
for(size_t i = y_size; i != x_size; ++i)
z[i] = word_add(x[i], 0, &carry);
return carry;
}
/*
* Two Operand Addition
*/
void bigint_add2(word x[], size_t x_size, const word y[], size_t y_size)
{
if(bigint_add2_nc(x, x_size, y, y_size))
x[x_size] += 1;
}
/*
* Three Operand Addition
*/
void bigint_add3(word z[], const word x[], size_t x_size,
const word y[], size_t y_size)
{
z[(x_size > y_size ? x_size : y_size)] +=
bigint_add3_nc(z, x, x_size, y, y_size);
}
/*
* Two Operand Subtraction
*/
word bigint_sub2(word x[], size_t x_size, const word y[], size_t y_size)
{
word borrow = 0;
BOTAN_ASSERT(x_size >= y_size, "Expected sizes");
const size_t blocks = y_size - (y_size % 8);
for(size_t i = 0; i != blocks; i += 8)
borrow = word8_sub2(x + i, y + i, borrow);
for(size_t i = blocks; i != y_size; ++i)
x[i] = word_sub(x[i], y[i], &borrow);
for(size_t i = y_size; i != x_size; ++i)
x[i] = word_sub(x[i], 0, &borrow);
return borrow;
}
/*
* Two Operand Subtraction x = y - x
*/
void bigint_sub2_rev(word x[], const word y[], size_t y_size)
{
word borrow = 0;
const size_t blocks = y_size - (y_size % 8);
for(size_t i = 0; i != blocks; i += 8)
borrow = word8_sub2_rev(x + i, y + i, borrow);
for(size_t i = blocks; i != y_size; ++i)
x[i] = word_sub(y[i], x[i], &borrow);
BOTAN_ASSERT(!borrow, "y must be greater than x");
}
/*
* Three Operand Subtraction
*/
word bigint_sub3(word z[], const word x[], size_t x_size,
const word y[], size_t y_size)
{
word borrow = 0;
BOTAN_ASSERT(x_size >= y_size, "Expected sizes");
const size_t blocks = y_size - (y_size % 8);
for(size_t i = 0; i != blocks; i += 8)
borrow = word8_sub3(z + i, x + i, y + i, borrow);
for(size_t i = blocks; i != y_size; ++i)
z[i] = word_sub(x[i], y[i], &borrow);
for(size_t i = y_size; i != x_size; ++i)
z[i] = word_sub(x[i], 0, &borrow);
return borrow;
}
/*
* Two Operand Linear Multiply
*/
void bigint_linmul2(word x[], size_t x_size, word y)
{
const size_t blocks = x_size - (x_size % 8);
word carry = 0;
for(size_t i = 0; i != blocks; i += 8)
carry = word8_linmul2(x + i, y, carry);
for(size_t i = blocks; i != x_size; ++i)
x[i] = word_madd2(x[i], y, &carry);
x[x_size] = carry;
}
/*
* Three Operand Linear Multiply
*/
void bigint_linmul3(word z[], const word x[], size_t x_size, word y)
{
const size_t blocks = x_size - (x_size % 8);
word carry = 0;
for(size_t i = 0; i != blocks; i += 8)
carry = word8_linmul3(z + i, x + i, y, carry);
for(size_t i = blocks; i != x_size; ++i)
z[i] = word_madd2(x[i], y, &carry);
z[x_size] = carry;
}
}
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