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Comment by mansr | Hacker News Reader

The Texas Instruments C55x DSP has 16-bit bytes. See the compiler documentation at http://www.ti.com/litv/pdf/spru281f section 5.3 if you do not believe me. This DSP has more unusual properties:

  type               size (bits)
  ------------------------------
  char               16
  short              16
  int                16
  long               32
  long long          40
  float              32
  double             32
  pointer (data)     16 or 23
  pointer (function) 24

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That's hilarious. I wonder why "long long" is 40 bits?

And... A non-function-pointer is "16 or 23" bits? Nice.

What's the proper scenario to use "long" instead of "int"? I've never bothered to use it.

>What's the proper scenario to use "long" instead of "int"? I've never bothered to use it.

It was necessary with 16-bit processors, because ints were 16-bit shorts, and longs were 32-bits.

With modern processors and OS', there isn't really a reason to use it. In fact, it's potentially dangerous if you're writing *nix code that's supposed to run on 64 or 32-bit systems. In that case, you don't want to use longs, because they're 32-bits on a 32-bit compile, but 64 on 64-bits on a 64-bit compiler. For Windows, int and long are interchangable 32-bit values, which is another reason to avoid using longs as much as possible when writing portable code.

I wonder why "long long" is 40 bits?

The immediate reason is that the ALU is 40 bits wide. The reason it has this particular size is probably a tradeoff between computational power vs silicon area and power consumption.

A non-function-pointer is "16 or 23" bits?

Near and far pointers, sort of.

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