fixed_raw_from_ieee754_bits()

bool fl::detail::fixed_raw_from_ieee754_bits ( u32 bits, int frac_bits, i64 * out )

inline

Definition at line 216 of file json.h.

                                                                                        {
    const bool negative = (bits & 0x80000000u) != 0;
    const u32 exp_bits = (bits >> 23) & 0xFFu;
    const u32 mantissa_bits = bits & 0x007FFFFFu;
    if (exp_bits == 0xFFu) {
        return false;
    }
 
    u64 significand = mantissa_bits;
    int exponent = -126;
    if (exp_bits != 0) {
        significand |= 0x00800000u;
        exponent = static_cast<int>(exp_bits) - 127;
    }
 
    const int shift = exponent + frac_bits - 23;
    u64 magnitude = 0;
    if (shift >= 0) {
        if (shift >= 63 || significand > (u64(0x7FFFFFFFFFFFFFFF) >> shift)) {
            return false;
        }
        magnitude = significand << shift;
    } else {
        magnitude = round_shift_right_u64(significand, -shift);
    }
    if ((!negative && magnitude > u64(0x7FFFFFFFFFFFFFFF)) ||
        (negative && magnitude > (u64(0x7FFFFFFFFFFFFFFF) + 1u))) {
        return false;
    }
    *out = negative
        ? (magnitude == (u64(0x7FFFFFFFFFFFFFFF) + 1u)
            ? static_cast<i64>(0x8000000000000000ull)
            : -static_cast<i64>(magnitude))
        : static_cast<i64>(magnitude);

Referenced by fl::json::as_fixed_point().

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