41 lines
1.0 KiB
C
41 lines
1.0 KiB
C
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#include <tommath.h>
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#ifdef BN_MP_REDUCE_IS_2K_L_C
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/* LibTomMath, multiple-precision integer library -- Tom St Denis
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*
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* LibTomMath is a library that provides multiple-precision
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* integer arithmetic as well as number theoretic functionality.
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*
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* The library was designed directly after the MPI library by
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* Michael Fromberger but has been written from scratch with
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* additional optimizations in place.
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*
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* The library is free for all purposes without any express
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* guarantee it works.
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*
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* Tom St Denis, tomstdenis@iahu.ca, http://math.libtomcrypt.org
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*/
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/* determines if reduce_2k_l can be used */
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int mp_reduce_is_2k_l(mp_int *a)
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{
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int ix, iy;
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if (a->used == 0) {
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return MP_NO;
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} else if (a->used == 1) {
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return MP_YES;
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} else if (a->used > 1) {
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/* if more than half of the digits are -1 we're sold */
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for (iy = ix = 0; ix < a->used; ix++) {
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if (a->dp[ix] == MP_MASK) {
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++iy;
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}
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}
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return (iy >= (a->used/2)) ? MP_YES : MP_NO;
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}
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return MP_NO;
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}
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#endif
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