Struct BitSel 

pub struct BitSel<R = usize>
where
    R: BitRegister,
{ /* private fields */ }

Available on crate feature evm only.

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.

Implementations

impl<R> BitSel<R>

where R: BitRegister,

pub fn new(sel: R) -> Option<BitSel<R>>

Wraps a selector value as a known-good selection in an R register.

Parameters

• sel: A one-hot selection mask of a bit in an R register.

Returns

This returns Some(sel) when it is a power of two (exactly one bit set and all others cleared), and None when it is not.

pub unsafe fn new_unchecked(sel: R) -> BitSel<R>

Wraps a selector value as an assumed-good selection in an R register.

Parameters

• sel: A one-hot selection mask of a bit in an R register.

Returns

This unconditionally marks sel as a one-hot bit selector.

Safety

If the sel value has zero or multiple bits set, then it is invalid to be used as a BitSel and the program is incorrect. Debug builds will panic; release builds do not inspect the value or specify a behavior.

pub fn into_inner(self) -> R

Removes the one-hot selection wrapper, leaving the internal mask.

pub fn mask(self) -> BitMask<R>

Computes a bit-mask for self. This is a type-cast.

pub fn range_all() -> impl Iterator<Item = BitSel<R>> + DoubleEndedIterator + ExactSizeIterator + FusedIterator

Iterates over all possible selector values.

Trait Implementations

impl<R> Binary for BitSel<R>

where R: BitRegister,

fn fmt(&self, fmt: &mut Formatter<'_>) -> Result<(), Error>

Formats the value using the given formatter.

impl<R> Clone for BitSel<R>

where R: Clone + BitRegister,

fn clone(&self) -> BitSel<R>

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl<R> Debug for BitSel<R>

where R: BitRegister,

fn fmt(&self, fmt: &mut Formatter<'_>) -> Result<(), Error>

Formats the value using the given formatter.

impl<R> Default for BitSel<R>

where R: Default + BitRegister,

fn default() -> BitSel<R>

Returns the “default value” for a type.

impl<R> Display for BitSel<R>

where R: BitRegister,

fn fmt(&self, fmt: &mut Formatter<'_>) -> Result<(), Error>

Formats the value using the given formatter.

impl<R> Hash for BitSel<R>

where R: Hash + BitRegister,

fn hash<__H>(&self, state: &mut __H)

where __H: Hasher,

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl<R> Ord for BitSel<R>

where R: Ord + BitRegister,

fn cmp(&self, other: &BitSel<R>) -> Ordering

This method returns an Ordering between self and other.

fn max(self, other: Self) -> Self

where Self: Sized,

Compares and returns the maximum of two values.

fn min(self, other: Self) -> Self

where Self: Sized,

Compares and returns the minimum of two values.

fn clamp(self, min: Self, max: Self) -> Self

where Self: Sized,

Restrict a value to a certain interval.

impl<R> PartialEq for BitSel<R>

where R: PartialEq + BitRegister,

fn eq(&self, other: &BitSel<R>) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl<R> PartialOrd for BitSel<R>

where R: PartialOrd + BitRegister,

fn partial_cmp(&self, other: &BitSel<R>) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

fn lt(&self, other: &Rhs) -> bool

Tests less than (for self and other) and is used by the < operator.

fn le(&self, other: &Rhs) -> bool

Tests less than or equal to (for self and other) and is used by the <= operator.

fn gt(&self, other: &Rhs) -> bool

Tests greater than (for self and other) and is used by the > operator.

fn ge(&self, other: &Rhs) -> bool

Tests greater than or equal to (for self and other) and is used by the >= operator.

impl<R> Sum<BitSel<R>> for BitMask<R>

where R: BitRegister,

fn sum<I>(iter: I) -> BitMask<R>

where I: Iterator<Item = BitSel<R>>,

Takes an iterator and generates Self from the elements by “summing up” the items.

impl<R> Copy for BitSel<R>

where R: Copy + BitRegister,

impl<R> Eq for BitSel<R>

where R: Eq + BitRegister,

impl<R> StructuralPartialEq for BitSel<R>

where R: BitRegister,

Layout

Note: Unable to compute type layout, possibly due to this type having generic parameters. Layout can only be computed for concrete, fully-instantiated types.