Struct Transaction 

pub struct Transaction {
    pub addr: u32,
    pub width: Width,
    pub write: bool,
    pub phase: Phase,
    pub remaining: u32,
}

A bus transaction in progress.

Modeled as a small state machine rather than an atomic operation, so the scheduler can advance the RCP between the address and data phases — the property that makes a device able to observe the bus mid-transaction.

Fields

addr: u32

Physical address.

width: Width

Transfer size.

write: bool

Is this a write? Writes are throttled by EOK rather than waiting for Evalid.

phase: Phase

Which phase is on the wire.

remaining: u32

SClock cycles remaining in the current phase.

Implementations

impl Transaction

pub const fn begin(addr: u32, width: Width, write: bool) -> Self

Begin a transaction. It starts in the address phase, which occupies one SClock cycle.

pub const fn step(&mut self, service_cycles: u32) -> bool

Advance one SClock cycle. Returns true once the transaction completes.

service_cycles is the target’s latency — the unbounded wait between the phases, and where M lives (docs/accuracy-ledger.md C-1). It is a parameter rather than a constant precisely so it cannot be quietly tuned: the caller must supply a value it can justify.

pub const fn total_cycles(width: Width, service_cycles: u32) -> u32

Total SClock cycles this transaction occupies, given a target latency.

One address cycle, the target’s service time, then one cycle per beat.

Trait Implementations

impl Clone for Transaction

fn clone(&self) -> Transaction

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for Transaction

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

Formats the value using the given formatter.

impl<'de> Deserialize<'de> for Transaction

fn deserialize<__D>(__deserializer: __D) -> Result<Self, __D::Error>

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl PartialEq for Transaction

fn eq(&self, other: &Transaction) -> 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 Serialize for Transaction

fn serialize<__S>(&self, __serializer: __S) -> Result<__S::Ok, __S::Error>

where __S: Serializer,

Serialize this value into the given Serde serializer.

impl Copy for Transaction

impl Eq for Transaction

impl StructuralPartialEq for Transaction