blob: ecb4cfea5df4803c45d6351ec752a475b4f8ab79 [file] [log] [blame]
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/*
// Intel(R) Integrated Performance Primitives. Cryptography Primitives.
// Internal operations over GF(p) extension.
//
// Context:
// cpGFpGetOptimalWinSize()
//
*/
#include "owncp.h"
#include "pcpbnumisc.h"
#include "pcpgfpxstuff.h"
#include "gsscramble.h"
static int div_upper(int a, int d)
{ return (a+d-1)/d; }
static int getNumOperations(int bitsize, int w)
{
int n_overhead = (1<<w) -1;
int n_ops = div_upper(bitsize, w) + n_overhead;
return n_ops;
}
int cpGFpGetOptimalWinSize(int bitsize)
{
int w_opt = 1;
int n_opt = getNumOperations(bitsize, w_opt);
int w_trial;
for(w_trial=w_opt+1; w_trial<=IPP_MAX_EXPONENT_NUM; w_trial++) {
int n_trial = getNumOperations(bitsize, w_trial);
if(n_trial>=n_opt) break;
w_opt = w_trial;
n_opt = n_trial;
}
return w_opt;
}