I was scribbling up a blather trying to create a definitive, clear explanation of pointers in C, wherein I was making a distinction between primitive and complex data types. The question that arose is what is the largest datum that is/has been treated as a primitive in C? I know of an extended FP type that the x87 unit used/uses that was ten bytes (the M68K FPU used an 80 bit type that embedded two extra bytes for padding), but AFAIK, these are not particularly common. I regard a "primitive" as something the CPU can handle atomically, but with the prevalence of built-in vector units, the distinction gets blurry. Does C ever treat these big data types as primitives, or is long long the largest primitive in common use today?