What happens with named primitives in CM ?

Hi folks. I was inspecting for example the CM of  Integer >> #bitAnd:   and the first literal is an array like this: #(#LargeIntegers #primDigitBitAnd 0 17)

I understand the first and the second elements, but I don't the third and the fourth. What are they? (0 and 17) because then even seem to change their value.

I am asking because I am serializing CompiledMethod and then at materialization time I am putting just two zeros for the moment. But I am not sure what they mean.

Thanks in advance,

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Mariano
http://marianopeck.wordpress.com