Line data    Source code

       1             : #include "tommath_private.h"
       2             : #ifdef BN_MP_SET_DOUBLE_C
       3             : /* LibTomMath, multiple-precision integer library -- Tom St Denis */
       4             : /* SPDX-License-Identifier: Unlicense */
       5             : 
       6             : #if defined(__STDC_IEC_559__) || defined(__GCC_IEC_559) || defined(__x86_64__) || defined(_M_X64) || defined(_M_AMD64) || defined(__i386__) || defined(_M_X86) || defined(__aarch64__) || defined(__arm__)
       7           0 : mp_err mp_set_double(mp_int *a, double b)
       8             : {
       9           0 :    uint64_t frac;
      10           0 :    int exp;
      11           0 :    mp_err err;
      12           0 :    union {
      13             :       double   dbl;
      14             :       uint64_t bits;
      15             :    } cast;
      16           0 :    cast.dbl = b;
      17             : 
      18           0 :    exp = (int)((unsigned)(cast.bits >> 52) & 0x7FFu);
      19           0 :    frac = (cast.bits & ((1uLL << 52) - 1uLL)) | (1uLL << 52);
      20             : 
      21           0 :    if (exp == 0x7FF) { /* +-inf, NaN */
      22           0 :       return MP_VAL;
      23             :    }
      24           0 :    exp -= 1023 + 52;
      25             : 
      26           0 :    mp_set_u64(a, frac);
      27             : 
      28           0 :    err = (exp < 0) ? mp_div_2d(a, -exp, a, NULL) : mp_mul_2d(a, exp, a);
      29           0 :    if (err != MP_OKAY) {
      30           0 :       return err;
      31             :    }
      32             : 
      33           0 :    if (((cast.bits >> 63) != 0uLL) && !MP_IS_ZERO(a)) {
      34           0 :       a->sign = MP_NEG;
      35             :    }
      36             : 
      37           0 :    return MP_OKAY;
      38             : }
      39             : #else
      40             : /* pragma message() not supported by several compilers (in mostly older but still used versions) */
      41             : #  ifdef _MSC_VER
      42             : #    pragma message("mp_set_double implementation is only available on platforms with IEEE754 floating point format")
      43             : #  else
      44             : #    warning "mp_set_double implementation is only available on platforms with IEEE754 floating point format"
      45             : #  endif
      46             : #endif
      47             : #endif