third draft: add bitfields to D

[claptrap]

On Sunday, 21 July 2024 at 20:56:00 UTC, Dom DiSc wrote:

> Vice Versa. The address space of 64bit is so huge, having extra 
> lines for all the unused high bits is a waste of electricity. 
> Using them to address individual bits enables us to write 
> consistent, less complex code, e.g. no invalid patterns for 
> basic types with gaps (e.g. boolean). And this code need not be 
> slower - alignment and shifting can be optimized away in the 
> background / hardware, the compiler can arrange variables to 
> minimize gaps and speed up access by aligning.

Neither x64 or Arm use all 64 bits, AFAIK they only use the 
bottom 48 bits, the upper 16 should be zeroed.