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/* TomsFastMath, a fast ISO C bignum library.
*
* This project is meant to fill in where LibTomMath
* falls short. That is speed ;-)
*
* This project is public domain and free for all purposes.
*
* Tom St Denis, tomstdenis@gmail.com
*/
#include <tfm_private.h>
void fp_to_unsigned_bin(fp_int *a, unsigned char *b)
{
/* If we know the endianness of this architecture, and we're using
32-bit fp_digits, we can optimize this */
#if (defined(ENDIAN_LITTLE) || defined(ENDIAN_BIG)) && !defined(FP_64BIT)
/* But not for both simultaneously */
#if defined(ENDIAN_LITTLE) && defined(ENDIAN_BIG)
#error Both ENDIAN_LITTLE and ENDIAN_BIG defined.
#endif
{
int c = fp_unsigned_bin_size(a);
unsigned char *pd = (unsigned char *)a->dp;
/* read the bytes out */
#ifdef ENDIAN_BIG
{
/* Use Duff's device to unroll the loop. */
int idx = (c - 1) & ~3;
switch (c % 4) {
case 0: do { b[idx+0] = *pd++;
case 3: b[idx+1] = *pd++;
case 2: b[idx+2] = *pd++;
case 1: b[idx+3] = *pd++;
idx -= 4;
} while ((c -= 4) > 0);
}
}
#else
for (c -= 1; c >= 0; c -= 1) {
b[c] = *pd++;
}
#endif
}
#else
int x;
fp_int t;
fp_init_copy(&t, a);
x = 0;
while (fp_iszero (&t) == FP_NO) {
b[x++] = (unsigned char) (t.dp[0] & 255);
fp_div_2d (&t, 8, &t, NULL);
}
fp_reverse (b, x);
#endif
}
/* $Source$ */
/* $Revision$ */
/* $Date$ */
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