128 bit signed and unsigned integer types

[Moritz Warning]

On Sun, 28 Dec 2008 17:17:03 -0200, Miles wrote:

> Walter Bright wrote:
>> You know, the unimplemented 128 bit integer types. Does anyone have a
>> use for these?
> 
> In distributed systems, *a lot*.
> 
> 1. In network programming, IPv6 addresses are becoming very common
> (nobody should ever think about writing a network-enabled application
> without native IPv6 support nowadays). IPv6 addresses are 128-bit. No
> arithmetic is needed, just copy, comparison and bitwise, masking and
> bitshift operations.
> 
> 2. Also, UUIDs[1] and other similar universal identification schemes are
> very common, we use them all the time in distributed systems. They are
> 128-bit numbers, only copy, comparison and bitwise operations are
> needed.
> 
> 3. In cryptography, also very common in distributed systems, it is
> common to have symmetric ciphers with key sizes of 128 and 256-bits. We
> currently have to break the cypher blocks in peaces and move a lot of
> the complexity up to the algorithm level in order to process such data
> in 32 or 64-bit registers and variables. It would be great if
> cryptographers could trust compilers to do this in the lower level
> (properly using SSE registers and so).
> 
> In all these cases, bigints are completely inadequate. I currently have
> to use (for the first two cases) a struct with operators implemented in
> asm (with different versions for x86 and x64) for efficient manipulation
> of these numbers. All this in C and C++.
> 
> 
> [1] http://en.wikipedia.org/wiki/Universally_Unique_Identifier

Good point.