# Difference between revisions of "Talk:Ieee arithmetic"

--Alexander Kogtenkov 3 February 2010 (UTC) Most probably C compilers inline functions, but just to be sure, I'd convert them into the macros:

```#define to_raw_bits(d) *((EIF_NATURAL_64*)&(d))

#define eif_is_nan_bits(value) ((value & ~RTU64C(0x8000000000000000)) > RTU64C(0x7ff0000000000000))

#define eif_is_nan(v) ((*((EIF_NATURAL_64 *)&(v)) & ~RTU64C(0x8000000000000000)) > RTU64C(0x7ff0000000000000))```

Does it affect the benchmarks?

--manus 17:59, 3 February 2010 (UTC) Actually it does not on Windows for sure, I've verified that it was inlined. But you are right that those could be simply defined as macros.
--manus 20:25, 3 February 2010 (UTC) I've done again some of the benchmarks and on windows at least, some of them are slower when I use a macro. I'm no sure why as I haven't looked at the generated assembly code.

--Colin-adams 14:48, 3 February 2010 (UTC) Not IEEE arithmetic, nor maths, NaN = NaN is never true. And placing NaNs in a sort order isn't write either - REAL_32/64 are not totally ordered types.

--manus 17:57, 3 February 2010 (UTC) How do you solve the problem of assertions then in ARRAY.put for example?

--Alexander Kogtenkov 20:01, 3 February 2010 (UTC)

• Does it mean that `REAL_GENERAL` should inherit `PART_COMPARABLE` rather than `COMPARABLE`?
• Do we need 2 equality queries: one that tells two objects represent the same value (it is used to ensure `copy` does what is expected, and it is used to implement `~`) and the other one that tells that the numbers are equal in terms of ordering relation of `(PART_)COMPARABLE`?

```inserted: v = v  implies (item (i) = v)