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/*******************************************************************************
* Copyright 2017-2018 Intel Corporation
* All Rights Reserved.
*
* If this software was obtained under the Intel Simplified Software License,
* the following terms apply:
*
* The source code, information and material ("Material") contained herein is
* owned by Intel Corporation or its suppliers or licensors, and title to such
* Material remains with Intel Corporation or its suppliers or licensors. The
* Material contains proprietary information of Intel or its suppliers and
* licensors. The Material is protected by worldwide copyright laws and treaty
* provisions. No part of the Material may be used, copied, reproduced,
* modified, published, uploaded, posted, transmitted, distributed or disclosed
* in any way without Intel's prior express written permission. No license under
* any patent, copyright or other intellectual property rights in the Material
* is granted to or conferred upon you, either expressly, by implication,
* inducement, estoppel or otherwise. Any license under such intellectual
* property rights must be express and approved by Intel in writing.
*
* Unless otherwise agreed by Intel in writing, you may not remove or alter this
* notice or any other notice embedded in Materials by Intel or Intel's
* suppliers or licensors in any way.
*
*
* If this software was obtained under the Apache License, Version 2.0 (the
* "License"), the following terms apply:
*
* You may not use this file except in compliance with the License. You may
* obtain a copy of the License at http://www.apache.org/licenses/LICENSE-2.0
*
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
*
* See the License for the specific language governing permissions and
* limitations under the License.
*******************************************************************************/
/******* FILE MODIFIED FROM ORIGINAL 2019u1 RELEASE TO AVOID WARNINGS *********/
/*
//
// Purpose:
// Cryptography Primitive. Modular Arithmetic Engine. General Functionality
//
// Contents:
// gs_mont_inv()
//
*/
#include "owndefs.h"
#include "owncp.h"
#include "pcpbnumisc.h"
#include "pcpbnuarith.h"
#include "gsmodstuff.h"
#include "pcpmask_ct.h"
__INLINE BNU_CHUNK_T* cpPow2_ct(int bit, BNU_CHUNK_T* dst, int len)
{
int slot = bit/BNU_CHUNK_BITS;
BNU_CHUNK_T value = (BNU_CHUNK_T)1 << (bit%BNU_CHUNK_BITS);
int i;
len -= (int)cpIsEqu_ct(slot, len);
for(i=0; i<len; i++) {
BNU_CHUNK_T mask = cpIsEqu_ct(slot, i);
dst[i] = value & mask;
}
return dst;
}
/*
// returns r = mont(a^-1)
// a in desidue domain
// r in Montgomery domain
*/
BNU_CHUNK_T* gs_mont_inv(BNU_CHUNK_T* pr, const BNU_CHUNK_T* pa, gsModEngine* pME, alm_inv alm_inversion)
{
int k = alm_inversion(pr, pa, pME);
if(0==k)
return NULL;
{
int mLen = MOD_LEN(pME);
int m = mLen*BNU_CHUNK_BITS;
mod_mul mon_mul = MOD_METHOD(pME)->mul;
BNU_CHUNK_T* t = gsModPoolAlloc(pME, 1);
//tbcd: temporary excluded: assert(NULL!=t);
if(k<=m) {
mon_mul(pr, pr, MOD_MNT_R2(pME), pME);
k += m;
}
//ZEXPAND_BNU(t, 0, mLen);
//SET_BIT(t, 2*m-k); /* t = 2^(2*m-k) */
cpPow2_ct(2*m-k, t, mLen);
mon_mul(pr, pr, t, pME);
gsModPoolFree(pME, 1);
return pr;
}
}
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