ext/ipp/sources/ippcp/pcpbnu_msbit.c

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/* 
//  Purpose:
//     Intel(R) Integrated Performance Primitives. Cryptography Primitives.
//     Internal Unsigned BNU misc functionality
// 
//  Contents:
//     cpMSBit_BNU()
// 
*/

#include "owncp.h"
#include "pcpbnumisc.h"

/*F*
//    Name: cpMSBit_BNU
//
// Purpose: Returns Most Significant Bit of the BNU.
//
// Returns:
//       Most Significant Bit of the BNU
//
// Parameters:
//    pA          BigNum A
//    nsA         size of A
//
// Note:
//    if BNU==0, -1 will return
*F*/

int cpMSBit_BNU(const BNU_CHUNK_T* pA, cpSize nsA)
{
   int msb;
   FIX_BNU(pA, nsA);
   msb  = nsA*BNU_CHUNK_BITS - cpNLZ_BNU(pA[nsA-1]) -1;
   return msb;
}