Make DMD work with a struct as the main integral type

[yebblies]

@redstar

[ibuclaw]

Seems reasonable, though this is proof of concept by the looks.

[WalterBright]

What is the purpose of this?

[redstar]

It is the base of my cent/ucent implementation. As I can't use a cent/ucent I need to use a struct for emulation. This PR introduces the struct only.

[ibuclaw]

This is also the case for real_t too - all frontend code interacting with floating point already looks like this.

[ibuclaw]

Potentially casting between two software emulation types, yummy. 😋

[yebblies]

Yes, the intent is to find all uses of implicit construction and conversion where a struct implementing 128bit support can't be dropped in. If we are going to move forward with cent/ucent then this will need to be done, and it will be easier to debug and review without the actual 128bit changes.

[andralex]

I like this, it's akin to dogofooding. Less magic keeps us all more honest. Any chance this can be revived?

[AndrewEdwards]

@ibuclaw @yebblies

Besides being placed on the back-burner and completely forgotten, it is unclear why this PR is still open. @yebblies, please rebase. @ibuclaw, request finalization of review.

[ibuclaw]

The PR needs to be broken down into manageable pieces. As and if I get round to it. It's important for supporting cent types, and for using GCC types software integer types in GDC.

[ibuclaw]

Made some headway a number of years ago, rebased the branch on master now.

https://github.com/ibuclaw/dmd/tree/ctinteger

[dkorpel]

Closing this considering it is orphaned, and cent/ucent are deprecated now.

[deadalnix]

Reopening this.

Friend don't let friend make completely r*****ed decision such as deprecating cent/ucent. You might as well deprecate D with such a decision, unless you expect people to stop using 64bits CPU any time soon.

[dlang-bot]

Thanks for your pull request, @yebblies!

Bugzilla references

Your PR doesn't reference any Bugzilla issue.

If your PR contains non-trivial changes, please reference a Bugzilla issue or create a manual changelog.

Testing this PR locally

If you don't have a local development environment setup, you can use Digger to test this PR:

dub run digger -- build "master + dmd#6743"

[dkorpel]

I understand you're upset that there's no plan to implement cent and ucent, but I don't see how re-opening an abandoned PR accomplishes anything. Perhaps you can make a case for it in the news group, or e-mail Mike Parker and ask if you can discuss this in a monthly Foundation meeting.

[ibuclaw]

This is work that we're going to do at some point in the future anyway, irrespective of cent/ucent actually being in the language, having internal N-bit emulation of integers at compile-time would make a few things easier - just as we have N-bit emulation of floating point (well, gdc has, sorry to say ldc hasn't, neither dmd but meh)