Result of ac_ieee_float32 addition has wrong sign if AC_RND_INF rounding mode is used

[xovano]

ac_ieee32_float32::add returns a result with wrong sign for some combinations of operand values if AC_RND_INF rounding mode is used. The following program

#include "ac_std_float.h"
#include <cstdint>
#include <cstring>
#include <iomanip>
#include <iostream>

int main() {
    std::uint32_t au = 0x380470edu;
    std::uint32_t bu = 0x447fffffu;

    float af, bf;
    std::memcpy(&af, &au, sizeof af);
    std::memcpy(&bf, &bu, sizeof bf);

    ac_ieee_float32 a = af;
    ac_ieee_float32 b = bf;
    ac_ieee_float32 c = a.add<AC_RND_INF, false>(b);

    std::cout << std::setprecision(9) << a << " + " << b << " = " << c << std::endl;
}

prints

3.15764228e-05 + 1023.99994 = -1024

which is obviously wrong. It seems that the code that determines sign of result has bug.

Compilers used: MinGW-w64 GCC 8.0.1 x86_64 and MSVC 2019 (v16.7.2).

[miklhh]

Has this been addressed yet?

[andres-takach]

Yes it was addressed in version v4.1.0. The mention of the fix was missed in the release notes.

[miklhh]

Yes it was addressed in version v4.1.0. The mention of the fix was missed in the release notes.

Thank you Andres.