GuardState Class Reference

#include <GuardState.hh>

Inheritance diagram for GuardState:

Collaboration diagram for GuardState:

Public Member Functions
	GuardState (const ReadableState &targetRegister, int latency)
virtual	~GuardState ()
virtual const SimValue &	value () const
virtual void	endClock ()
virtual void	advanceClock ()
Public Member Functions inherited from ClockedState
	ClockedState ()
virtual	~ClockedState ()
virtual void	reset ()
	this is called at (re)initialization of the simulation More...
Public Member Functions inherited from ReadableState
	ReadableState ()
virtual	~ReadableState ()

Protected Member Functions
	GuardState ()
	Only subclasses allowed to create empty GuardStates. More...

Private Member Functions
	GuardState (const GuardState &)
	Copying not allowed. More...
GuardState &	operator= (const GuardState &)
	Assignment not allowed. More...

Private Attributes
const ReadableState *	target_
	The target register watched by this guard. More...
std::vector< SimValue >	history_
	Value history ring buffer. More...
int	position_
	History ring buffer position. Point to the index of the current value of the guard. More...

Detailed Description

Models the programmer visible delay of guards with latency more than 1.

GuardState with latency of 1 is the default latency which can be modeled with a direct reference to the guarded register, thus this class should not be used to model such cases. Guard latency of 1 means that the guard value can be used in the same instruction in which the value itself can be used. Thus, in case of a register guard, the instruction following the write to the register. For example, guard with latency of 2 means that there is one instruction cycle after updating the value of the guard in which the new value is not yet visible, and so on. This latency is modeled with a ring buffer which represents the history of guard's target values.

Definition at line 60 of file GuardState.hh.

Constructor & Destructor Documentation

GuardState() [1/3]

GuardState::GuardState	(	const ReadableState &	targetRegister,
		int	latency
	)

Constructor.

Parameters

targetRegister	The target register this guard watches.
latency	The total guard latency modeled.

Definition at line 50 of file GuardState.cc.

                 :
    target_(&targetRegister) {
    assert(latency && "Use DirectGuardState for 0-cycle latency");
    for (int i = 0; i < latency; ++i) {
        history_.push_back(targetRegister.value());
    }
    position_ = 0;
}

References assert, history_, position_, and ReadableState::value().

Here is the call graph for this function:

~GuardState()

GuardState::~GuardState ( )

virtual

Destructor.

Definition at line 73 of file GuardState.cc.

                        {
}

GuardState() [2/3]

GuardState::GuardState ( )

protected

Only subclasses allowed to create empty GuardStates.

Constructor.

Creates an empty GuardState, only to be used by subclasses, i.e., NullGuardState.

Definition at line 67 of file GuardState.cc.

                       : target_(NULL), position_(-1) {
}

GuardState() [3/3]

GuardState::GuardState ( const GuardState &  )

private

Copying not allowed.

Member Function Documentation

advanceClock()

void GuardState::advanceClock ( )

virtual

Updates the guard value history.

Implements ClockedState.

Reimplemented in DirectGuardState.

Definition at line 89 of file GuardState.cc.

                         {
    history_[position_] = target_->value();
    position_ = (position_ + 1);
    if ((size_t)position_ >= history_.size())
      position_ = 0;
}

References history_, position_, target_, and ReadableState::value().

Here is the call graph for this function:

endClock()

void GuardState::endClock ( )

virtual

Does nothing.

The guard history is updated in advanceClock().

Implements ClockedState.

Reimplemented in DirectGuardState.

Definition at line 82 of file GuardState.cc.

                     {
}

operator=()

GuardState& GuardState::operator= ( const GuardState &  )

private

Assignment not allowed.

value()

const SimValue & GuardState::value ( ) const

virtual

Returns the current value of the guard, taking the latency in account.

Returns

The current value of the guard.

Implements ReadableState.

Reimplemented in DirectGuardState.

Definition at line 102 of file GuardState.cc.

                        {
    return history_[position_];
}

References history_, and position_.

Member Data Documentation

history_

std::vector<SimValue> GuardState::history_

private

Value history ring buffer.

Definition at line 86 of file GuardState.hh.

Referenced by advanceClock(), GuardState(), and value().

position_

int GuardState::position_

private

History ring buffer position. Point to the index of the current value of the guard.

Definition at line 89 of file GuardState.hh.

Referenced by advanceClock(), GuardState(), and value().

target_

const ReadableState* GuardState::target_

private

The target register watched by this guard.

Definition at line 84 of file GuardState.hh.

Referenced by advanceClock().

---

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

• GuardState.hh
• GuardState.cc