bb::stdlib::DataBusDepot< Builder > Class Template Reference

Class for managing propagation of databus return data commitments used in consistency checks. More...

#include <databus.hpp>

Public Types
using	Curve = stdlib::bn254< Builder >
using	Commitment = typename Curve::Group
using	CommitmentNative = typename Curve::AffineElementNative
using	FrNative = typename Curve::ScalarFieldNative

Public Member Functions
void	set_kernel_return_data_commitment (const Commitment &commitment)
bool	app_return_data_slots_are_empty () const
	Whether all app return-data slots are currently empty.
void	set_app_return_data_commitment (const Commitment &commitment)
	Record an app return-data commitment in the next available slot.
Commitment	get_kernel_return_data_commitment (Builder &builder)
	Get the previously set kernel return data commitment if it exists, else a default one.
Commitment	get_app_return_data_commitment (Builder &builder, const size_t idx)
	Get the previously set app return data commitment if it exists, else a default one.

Static Public Member Functions
static Commitment	construct_default_commitment (Builder &builder)
	Construct a default commitment for the databus return data.

Public Attributes
std::array< Commitment, MAX_APPS_PER_KERNEL >	app_return_data_commitments
Commitment	kernel_return_data_commitment
std::array< bool, MAX_APPS_PER_KERNEL >	app_return_data_commitment_exists
bool	kernel_return_data_commitment_exists = false

Detailed Description

template<class Builder>
class bb::stdlib::DataBusDepot< Builder >

Class for managing propagation of databus return data commitments used in consistency checks.

The databus consistency checks establish the transfer of data between two circuits (i-1 and i) in a third circuit (i+1) via commitment equality checks of the form [R_{i-1}] = [C_i], where R and C represent return data and calldata, respectively. In practice, circuit (i+1) is given access to [R_{i-1}] via the public inputs of \pi_i, and it has access to [C_i] directly from \pi_i. The consistency checks in circuit (i+1) are thus of the form \pi_i.public_inputs.[R_{i-1}] = \pi_i.[C_i].

For consistent behavior across kernels, every kernel propagates MAX_APPS_PER_KERNEL + 1 return-data commitments via its public inputs: one for the previous kernel and one per app slot. If any of these does not exist (e.g., the first kernel has no previous kernel; a kernel with fewer than MAX apps leaves the trailing app slots unset), it is populated with a default commitment value that will satisfy the consistency check on the next cycle. The "empty" calldata column on the next kernel side will commit to the same default value, so the commitments agree and the consistency check passes trivially.

Template Parameters

Builder

Definition at line 93 of file databus.hpp.

Member Typedef Documentation

Commitment

template<class Builder >

using bb::stdlib::DataBusDepot< Builder >::Commitment = typename Curve::Group

Definition at line 96 of file databus.hpp.

CommitmentNative

template<class Builder >

using bb::stdlib::DataBusDepot< Builder >::CommitmentNative = typename Curve::AffineElementNative

Definition at line 97 of file databus.hpp.

Curve

template<class Builder >

using bb::stdlib::DataBusDepot< Builder >::Curve = stdlib::bn254<Builder>

Definition at line 95 of file databus.hpp.

FrNative

template<class Builder >

using bb::stdlib::DataBusDepot< Builder >::FrNative = typename Curve::ScalarFieldNative

Definition at line 98 of file databus.hpp.

Member Function Documentation

app_return_data_slots_are_empty()

template<class Builder >

bool bb::stdlib::DataBusDepot< Builder >::app_return_data_slots_are_empty ( ) const

inline

Whether all app return-data slots are currently empty.

Used to assert the kernel-boundary invariant: at the start of each kernel completion, every slot must have been drained by the prior kernel's get-loop so that set_app_return_data_commitment begins filling from slot 0.

Definition at line 124 of file databus.hpp.

construct_default_commitment()

template<class Builder >

static Commitment bb::stdlib::DataBusDepot< Builder >::construct_default_commitment ( Builder &  builder )

inlinestatic

Construct a default commitment for the databus return data.

Returns the point at infinity. This matches the commitment to a databus column containing only zero-valued entries (DEFAULT_VALUE = 0), regardless of the polynomial offset used for disabled rows.

Definition at line 158 of file databus.hpp.

get_app_return_data_commitment()

template<class Builder >

Commitment bb::stdlib::DataBusDepot< Builder >::get_app_return_data_commitment ( Builder &  builder, const size_t  idx  )

inline

Get the previously set app return data commitment if it exists, else a default one.

Definition at line 182 of file databus.hpp.

get_kernel_return_data_commitment()

template<class Builder >

Commitment bb::stdlib::DataBusDepot< Builder >::get_kernel_return_data_commitment ( Builder &  builder )

inline

Get the previously set kernel return data commitment if it exists, else a default one.

Definition at line 169 of file databus.hpp.

set_app_return_data_commitment()

template<class Builder >

void bb::stdlib::DataBusDepot< Builder >::set_app_return_data_commitment ( const Commitment &  commitment )

inline

Record an app return-data commitment in the next available slot.

Slot assignment is implicit: the depot fills slot 0 first, then slot 1, etc., as apps are processed in the kernel's verification queue. Slots are released by get_app_return_data_commitment; each kernel-completion pass drains every slot via the get-loop in Chonk::complete_kernel_circuit_logic, so the next kernel begins filling from slot 0 again.

Definition at line 141 of file databus.hpp.

set_kernel_return_data_commitment()

template<class Builder >

void bb::stdlib::DataBusDepot< Builder >::set_kernel_return_data_commitment ( const Commitment &  commitment )

inline

Definition at line 112 of file databus.hpp.

Member Data Documentation

app_return_data_commitment_exists

template<class Builder >

std::array<bool, MAX_APPS_PER_KERNEL> bb::stdlib::DataBusDepot< Builder >::app_return_data_commitment_exists

Initial value:

= []() {
        std::array<bool, MAX_APPS_PER_KERNEL> result{};
        result.fill(false);
        return result;
    }()

Definition at line 105 of file databus.hpp.

app_return_data_commitments

template<class Builder >

std::array<Commitment, MAX_APPS_PER_KERNEL> bb::stdlib::DataBusDepot< Builder >::app_return_data_commitments

Definition at line 101 of file databus.hpp.

kernel_return_data_commitment

template<class Builder >

Commitment bb::stdlib::DataBusDepot< Builder >::kernel_return_data_commitment

Definition at line 102 of file databus.hpp.

kernel_return_data_commitment_exists

template<class Builder >

bool bb::stdlib::DataBusDepot< Builder >::kernel_return_data_commitment_exists = false

Definition at line 110 of file databus.hpp.

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The documentation for this class was generated from the following file:

• src/barretenberg/stdlib/primitives/databus/databus.hpp