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#include "tommath_private.h"
#ifdef BN_MP_SET_DOUBLE_C
/* LibTomMath, multiple-precision integer library -- Tom St Denis
*
* LibTomMath is a library that provides multiple-precision
* integer arithmetic as well as number theoretic functionality.
*
* The library was designed directly after the MPI library by
* Michael Fromberger but has been written from scratch with
* additional optimizations in place.
*
* SPDX-License-Identifier: Unlicense
*/
#if defined(__STDC_IEC_559__) || defined(__GCC_IEC_559)
int mp_set_double(mp_int *a, double b)
{
uint64_t frac;
int exp, res;
union {
double dbl;
uint64_t bits;
} cast;
cast.dbl = b;
exp = (int)((unsigned)(cast.bits >> 52) & 0x7FFU);
frac = (cast.bits & ((1ULL << 52) - 1ULL)) | (1ULL << 52);
if (exp == 0x7FF) { /* +-inf, NaN */
return MP_VAL;
}
exp -= 1023 + 52;
res = mp_set_long_long(a, frac);
if (res != MP_OKAY) {
return res;
}
res = (exp < 0) ? mp_div_2d(a, -exp, a, NULL) : mp_mul_2d(a, exp, a);
if (res != MP_OKAY) {
return res;
}
if (((cast.bits >> 63) != 0ULL) && !IS_ZERO(a)) {
a->sign = MP_NEG;
}
return MP_OKAY;
}
#else
/* pragma message() not supported by several compilers (in mostly older but still used versions) */
# ifdef _MSC_VER
# pragma message("mp_set_double implementation is only available on platforms with IEEE754 floating point format")
# else
# warning "mp_set_double implementation is only available on platforms with IEEE754 floating point format"
# endif
#endif
#endif
/* ref: $Format:%D$ */
/* git commit: $Format:%H$ */
/* commit time: $Format:%ai$ */
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