DFlipFlop.cpp

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// Copyright 2015 - 2026, GIBIS-UNIFESP and the wiRedPanda contributors
// SPDX-License-Identifier: GPL-3.0-or-later
 
#include "App/Element/GraphicElements/DFlipFlop.h"
 
#include "App/Element/ElementFactory.h"
#include "App/Element/ElementInfo.h"
#include "App/Wiring/Port.h"
 
template<>
struct ElementInfo<DFlipFlop> {
    static constexpr ElementConstraints constraints{
        .type = ElementType::DFlipFlop,
        .group = ElementGroup::Memory,
        .minInputSize = 4,
        .maxInputSize = 4,
        .minOutputSize = 2,
        .maxOutputSize = 2,
        .canChangeAppearance = true,
    };
    static_assert(validate(constraints));
 
    static ElementMetadata metadata()
    {
        auto meta = metadataFromConstraints(constraints);
        meta.pixmapPath = []{ return DFlipFlop::pixmapPath(); };
        meta.titleText = QT_TRANSLATE_NOOP("DFlipFlop", "D-FLIP-FLOP");
        meta.translatedName = QT_TRANSLATE_NOOP("DFlipFlop", "D-Flip-Flop");
        meta.trContext = "DFlipFlop";
        return meta;
    }
 
    static inline const bool registered = []() {
        ElementMetadataRegistry::registerMetadata(metadata());
        ElementFactory::registerCreator(constraints.type, [] { return new DFlipFlop(); });
        return true;
    }();
};
 
DFlipFlop::DFlipFlop(QGraphicsItem *parent)
    : GraphicElement(ElementType::DFlipFlop, parent)
{
    // Call the most-derived override explicitly (see SRFlipFlop.cpp for rationale).
    DFlipFlop::updatePortsProperties();
}
 
void DFlipFlop::updatePortsProperties()
{
    // Standard D flip-flop pin layout: D and Clock on the left,
    // active-low ~Preset and ~Clear on top/bottom (asynchronous overrides),
    // Q and ~Q on the right.
    inputPort(0)->setPos( 0, 16);     inputPort(0)->setName("Data");
    inputPort(1)->setPos( 0, 48);     inputPort(1)->setName("Clock");
    inputPort(2)->setPos(32,  0);     inputPort(2)->setName("~Preset");
    inputPort(3)->setPos(32, 64);     inputPort(3)->setName("~Clear");
 
    outputPort(0)->setPos(64, 16);    outputPort(0)->setName("Q");
    outputPort(1)->setPos(64, 48);    outputPort(1)->setName("~Q");
 
    // ~Preset and ~Clear are optional; when unconnected they default to Active (HIGH = not asserted)
    // because these signals are active-low — leaving them floating means "no override"
    inputPort(2)->setRequired(false);
    inputPort(3)->setRequired(false);
 
    inputPort(2)->setDefaultStatus(Status::Active);
    inputPort(3)->setDefaultStatus(Status::Active);
 
    // Initial state: Q=0, ~Q=1 (reset/cleared state)
    outputPort(0)->setDefaultStatus(Status::Inactive);
    outputPort(1)->setDefaultStatus(Status::Active);
}
 
void DFlipFlop::updateTheme()
{
    // Reload the pixmap before delegating to the base class (see SRFlipFlop.cpp).
    setPixmap(pixmapPath());
    GraphicElement::updateTheme();
}
 
void DFlipFlop::updateLogic()
{
    if (!simUpdateInputs()) {
        // Forget the last clock level while inputs are invalid: edge
        // detection requires lastClk == Inactive, so recovery with the clock
        // already high cannot fabricate a rising edge from stale state.
        m_simLastClk = Status::Unknown;
        return;
    }
    Status q0 = simOutputs().at(0);
    Status q1 = simOutputs().at(1);
    const Status D = simInputs().at(0);
    const Status clk = simInputs().at(1);
    const Status prst = simInputs().at(2);
    const Status clr = simInputs().at(3);
 
    if (clk == Status::Active && m_simLastClk == Status::Inactive) {
        q0 = m_simLastValue;
        q1 = (m_simLastValue == Status::Active) ? Status::Inactive : Status::Active;
    }
 
    if (prst == Status::Inactive || clr == Status::Inactive) {
        q0 = (prst == Status::Inactive) ? Status::Active : Status::Inactive;
        q1 = (clr == Status::Inactive) ? Status::Active : Status::Inactive;
    }
    m_simLastClk = clk;
    m_simLastValue = D;
    setOutputValue(0, q0);
    setOutputValue(1, q1);
}
 
void DFlipFlop::resetSimState()
{
    // Reset Q/~Q to power-on defaults via the base class, then restore the
    // edge-detection variables so column 0 of the next sweep is treated as
    // a fresh start (no phantom rising edge from a prior run).
    GraphicElement::resetSimState();
    m_simLastClk   = Status::Inactive;
    m_simLastValue = Status::Active;
}