/*************************************************************************
* Copyright (C) 2002 Intel Corporation
*
* Licensed under the Apache License,  Version 2.0 (the "License");
* 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.
*************************************************************************/

/* 
//  Purpose:
//     Intel(R) Integrated Performance Primitives. Cryptography Primitives.
//     Internal BNU32 arithmetic.
// 
//  Contents:
//     cpDec_BNU32()
// 
*/

#include "owncp.h"
#include "pcpbnumisc.h"
#include "pcpbnu32misc.h"
#include "pcpbnu32arith.h"

/*F*
//    Name: cpDec_BNU32
//
// Purpose: BNU32 decrement.
//
// Returns:
//    borrow
//
// Parameters:
//    pA    source
//    pR    result
//    ns    size
//    v     borrow
//
*F*/

IPP_OWN_DEFN (Ipp32u, cpDec_BNU32, (Ipp32u* pR, const Ipp32u* pA, cpSize ns, Ipp32u v))
{
   Ipp32u borrow = v;
   int n;
   for(n=0; n<ns; n++) {
      Ipp64u t = (Ipp64u)(pA[n]) - (Ipp64u)borrow;
      pR[n] = IPP_LODWORD(t);
      borrow = IPP_HIDWORD(t)>>(32-1);
   }
   return borrow;
}
