| # One-Hot Bit Selection Mask |
| |
| This type selects exactly one bit in a register. It is a [`BitPos`] shifted from |
| a counter to a selector, and is used to apply test and write operations to real |
| memory. |
| |
| ## Type Parameters |
| |
| - `R`: The register element this selector governs. |
| |
| ## Validity |
| |
| Values of this type are **required** to have exactly one bit set and all others |
| cleared. Any other value makes the program incorrect, and will cause memory |
| corruption. |
| |
| ## Construction |
| |
| This type is only constructed from `BitPos`, and is always equivalent to |
| `1 << BitPos`. |
| |
| The chain of custody from known-good [`BitIdx`] values, through proven-good |
| [`BitOrder`] implementations, into `BitPos` and then `BitSel` proves that values |
| of this type are always correct to apply to real memory. |
| |
| [`BitIdx`]: crate::index::BitIdx |
| [`BitOrder`]: crate::order::BitOrder |
| [`BitPos`]: crate::index::BitPos |
