#include "tommath_private.h"
#ifdef MP_SET_DOUBLE_C
/* LibTomMath, multiple-precision integer library -- Tom St Denis */
/* SPDX-License-Identifier: Unlicense */
#if defined(MP_HAS_SET_DOUBLE)
mp_err mp_set_double(mp_int *a, double b)
{
uint64_t frac;
int exp;
mp_err err;
union {
double dbl;
uint64_t bits;
} cast;
cast.dbl = b;
exp = (int)((unsigned)(cast.bits >> 52) & 0x7FFu);
frac = (cast.bits & (((uint64_t)1 << 52) - (uint64_t)1)) | ((uint64_t)1 << 52);
if (exp == 0x7FF) { /* +-inf, NaN */
return MP_VAL;
}
exp -= 1023 + 52;
mp_set_u64(a, frac);
err = (exp < 0) ? mp_div_2d(a, -exp, a, NULL) : mp_mul_2d(a, exp, a);
if (err != MP_OKAY) {
return err;
}
if (((cast.bits >> 63) != 0u) && !mp_iszero(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
