float to fixed point 16:16

fixed.cpp

#include <cstdint>
#include <cstring>

// float to int
int32_t float_to_int(float myfloat) {
    uint32_t fint = 0;
    memcpy(&fint, (void*)&myfloat, 4);
    constexpr uint32_t mask_fract = (1u << 23) - 1;
    const uint32_t fract = (fint & mask_fract) | (1u << 23);
    const uint32_t fexpn = (fint >> 23) & 0xff;
    const uint32_t fsign = (fint >> 31) & 1u;
    const int32_t t = fract << ((fexpn - 127) - 23);
    return fsign ? ~t + 1 : t;
}

// float to 16:16 fixed point
int32_t float_to_fixed(float myfloat) {
    uint32_t fint = 0;
    memcpy(&fint, (void*)&myfloat, 4);
    constexpr uint32_t mask_fract = (1u << 23) - 1;
    const uint32_t fract = (fint & mask_fract) | (1u << 23);
    const uint32_t fexpn = (fint >> 23) & 0xff;
    const uint32_t fsign = (fint >> 31) & 1u;
    const int32_t t = fract << ((fexpn - 127) - 7);
    return fsign ? ~t + (1 << 16) : t;
}

int main() {
    return float_to_fixed(-124.0f) >> 16;
}