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/* 
//  Purpose:
//     Intel(R) Integrated Performance Primitives. Cryptography Primitives.
//     Internal BNU32 arithmetic.
// 
//  Contents:
//     cpSub_BNU32()
// 
*/

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


/*F*
//    Name: cpSub_BNU32
//
// Purpose: substract BNU32.
//
// Returns:
//    borrow
//
// Parameters:
//    pA    source
//    pB    source
//    ns    size
//    pR    result
//
*F*/
Ipp32u cpSub_BNU32(Ipp32u* pR, const Ipp32u* pA, const Ipp32u* pB, cpSize ns)
{
   Ipp32u borrow = 0;
   cpSize i;
   for(i=0; i<ns; i++) {
      Ipp64u t = (Ipp64u)(pA[i]) - pB[i] - borrow;
      pR[i] = LODWORD(t);
      borrow = 0-HIDWORD(t);
   }
   return borrow;
}