Copper.cpp

//
//  Copper.cpp
//  SDL3Test
//
//  Created by Matt Parsons on 16/02/2026.
//

#include "Copper.hpp"
//#include "Bus.hpp"
#include "Gayle.hpp"

// Register handler
uint16_t Copper::COPCON(bool isWrite, uint16_t value){
    if(isWrite){
        cdang = value & 0x2;
        return 0;
    }
    return cdang ? 0x2 : 0x0;
}

uint16_t Copper::COP1LCH(bool isWrite, uint16_t value){
    if(isWrite){
        cop1lc = (cop1lc & 0x0000FFFF) | (value << 16);
        return 0;
    }
    return cop1lc >> 16;
}
uint16_t Copper::COP1LCL(bool isWrite, uint16_t value){
    if(isWrite){
        cop1lc = (cop1lc & 0xFFFF0000) | value;
        return 0;
    }
    return cop1lc & 0xFFFF;
}
uint16_t Copper::COP2LCH(bool isWrite, uint16_t value){
    if(isWrite){ cop2lc = (cop2lc & 0x0000FFFF) | (value << 16); return 0; }
    return cop2lc >> 16;
}
uint16_t Copper::COP2LCL(bool isWrite, uint16_t value){
    if(isWrite){ cop2lc = (cop2lc & 0xFFFF0000) | value; return 0; }
    return cop2lc & 0xFFFF;
}
uint16_t Copper::COPJMP1(bool isWrite, uint16_t value){
    Reset(1);
    return 0;
}
uint16_t Copper::COPJMP2(bool isWrite, uint16_t value){
    Reset(2);
    return 0;
}




void Copper::Init(void* bus){
    this->bus = bus;
    cop1lc  = 0;
    cop2lc  = 0;
    pc      = 0;
    state   = 0;
    halted  = true;
    
}

void Copper::Reset(int list){
    pc    = (list == 1) ? cop1lc : cop2lc;
    halted = false;
    state = 0;
}

bool Copper::isMove(){ return !(ir1 & 0x0001); }
bool Copper::isWait(){ return  (ir1 & 0x0001) && !(ir2 & 0x0001); }
bool Copper::isSkip(){ return  (ir1 & 0x0001) &&  (ir2 & 0x0001); }

bool Copper::waitMet(){

    /*
    uint8_t vp = (ir1 >> 8) & 0xFF;
    uint8_t hp = (ir1 & 0xFE);
    uint8_t ve = (ir2 >> 8) | 0x80;  // vertical enable, bit 7 always set
    uint8_t he = (ir2 & 0xFE);
    
    uint16_t vhpos = ((Gayle*)bus)->chipset->denise.VHPOSR(false, 0);
    
    uint8_t vb = vhpos >> 8;
    uint8_t hb = vhpos & 0xFE;
     
    return ((vb & ve) > (vp & ve)) || ((vb & ve) == (vp & ve) && (hb & he) >= (hp & he));    // ((vb & ve) > (vp & ve)) || ((vb & ve) == (vp & ve) && (hb & he) >= (hp & he));
     */
    
    
    
    
    /*
    int vp = (ir1 >> 8) & 0xFF;
    int hp = (ir1 & 0xFF);
    int ve = (ir2 >> 8);// | 0x80;  // vertical enable, bit 7 always set
    int he = (ir2 & 0xFF);
    
    int vb = ((Gayle*)bus)->chipset->denise.Hline & 0xFF;
    int hb = ((Gayle*)bus)->chipset->denise.ColorClock;
    
    return ((vb & ve) > (vp & ve)) || ((vb & ve) == (vp & ve) && (hb & he) > (hp & he));// ((vb & ve) > (vp & ve)) || ((vb & ve) == (vp & ve) && (hb & he) >= (hp & he));
     */
    
    vhpos &= ir2;
    
    uint16_t v = (ir1 & ir2);

    if(vhpos >= v){
        return true;
    }
    return false;
}


bool Copper::Execute(){
    
    if( !(((Gayle*)bus)->chipset->dmacon & 0x280) ){
        return false;
    }
    
    // Don't do anything if halted - wait for COPJMP to reset us
    if(halted){
        return false;
    }
    
    vhpos = ((Gayle*)bus)->chipset->denise.VHPOSR(false, 0);
    
    
    switch(state){
        
        case 0:
            ir1   = ((Gayle*)bus)->chipram->Read16(pc);
            pc   += 2;
            state = 1;
            return true;
            
        case 1:
            ir2   = ((Gayle*)bus)->chipram->Read16(pc);
            pc   += 2;

            // On real hardware, MOVE executes during the IR2 fetch cycle
            if(isMove()){
                int reg = (ir1 & 0x1FE);

                // Copper cannot write to registers below 0x40
                // unless the danger bit (CDANG) in COPCON is set
                if(reg < 0x80 && !cdang){
                    halted = true;
                    return true;
                }

                ((Gayle*)bus)->chipset->Registers[reg >> 1](true,ir2);
                state = 0;  // No idle cycle after MOVE
                return true;
            }

            state = 2;  // WAIT/SKIP needs decode
            return true;

        case 2:
            if(isWait()){

                // WAIT for $FFFF,$FFFE is the standard end-of-list marker
                // and will never be satisfied - halt the copper
                if(ir1 == 0xFFFF && ir2 == 0xFFFE){
                    halted = true;
                    return false;
                }

            state = 3;  //always one extra cycle

            }else if(isSkip()){
                if(waitMet()){
                    pc += 4;
                }
                state = 4;
            }

            return false;
            
            
            
            
        case 3:
            
            if(vhpos > ir1){
                state = 4;
              //  printf("Wait Met sinple\n");
                return false;
            }
            
            //printf("Line %d, Clock %d: Request Wait for: %d, %d\n", vhpos >> 8, ((Gayle*)bus)->chipset->denise.ColorClock,ir1 >> 8, ir1 & 0xFF);
            if(waitMet()){
              //  printf("Wait MEt old\n");
                state = 4;
                return false;
            }
           // printf("Line %d, Clock %d: Waiting for: %d, %d\n", vhpos >> 8, ((Gayle*)bus)->chipset->denise.ColorClock,ir1 >> 8, ir1 & 0xFF);
            return false;
            
        case 4:
            //Copper needs an idle cycle after the Wait completes
            state = 0;
            return false;
    }
    return false;
}