Extracting an exponent without knowing the size of the mantissa & exponent

I've come up with this:

Code:

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typedef union _pawkfdunion
{
        pawkfd num;
        pawku  val;
        pawcu  raw[sizeof(pawkfd)];
} pawkfdunion;

static pawvu pawkfd_man_len = 0;

PAWSTR_API pawvu    pawkfdexp( pawkfd src )
{
        pawvu i = pawkfd_man_len;
        pawkfdunion kfd = {0};
        if ( !i )
        {
#        ifdef PAWKFD_INF
                kfd.num = PAWKFD_INF;
                kfd.num--;
#        else
                kfd.num = PAWKFD_MAX;
#        endif
                kfd.raw[sizeof(pawkfd)-1] &= PAWCD_MAX;
                for ( ; kfd.val & 1u; ++i, kfd.val >>= 1 );
                pawkfd_man_len = i;
        }
        kfd.num = src;
        kfd.raw[sizeof(pawkfd)-1] &= PAWCD_MAX;
        return (kfd.val >> i);
}

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Assume pawku means __uint128, pawkfd means _Float128x & pawcu always means unsigned char, does anyone see any potential issues with this?

Quote:

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Originally Posted by awsdert

]
Assume pawku means __uint128, pawkfd means _Float128x & pawcu always means unsigned char, does anyone see any potential issues with this?

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What does it do with denormalized numbers? Does it handles non-numbers like infinity?

Quote:

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Originally Posted by hamster_nz

What does it do with denormalized numbers? Does it handles non-numbers like infinity?

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This function is just to extract the exponent so that I can construct a string from the float, because I'm doing this for a custom library that is to work with or without libc I have to avoid relying on external libraries which in all likelihood rely on libc anyways, in other words I have to rely ONLY on what the system and the compiler provide me with, unfortunately I can't find any predefines or builtins or otherwise that would provide me the exponent & mantissa width directly so calculating it with the assumption that the exponent is one lower than it's max value is the only way I can think of to obtain the mantissa length and in turn the exponent width which in turn allows me to get the exponent itself