zlacker

>>tromp+(OP)
IEEE754 64-bit representation already has infinity:

    uint64_t x = 0x7ff0000000000000ULL;
    printf("%f\n", *(double *)&x);

output:

    inf

But you could use a representation where 0 is 0, and 1 is infinity, saving 63 bits...

>>matja+5c6
That doesn't qualify the explicitly stated condition "a largest (finite) representable value".