var DDRAM = new Array(104);
var CGRAM = new Array(64);

var lastAdrsSet='DDRAM';
var AC = 0;
var AC = 0;
var range = 16; // 16 chars only

//function set
var DL = 1;  //  8-bit interface data
var N = 0;   //  1-line display
var F = 0;   //  5 * 8 dot character font
//Display on/off control:
var D = 0;   //  Display off
var C = 0;   //  Cursor off
var B = 0;   //  Blinking off
//Entry mode set:
var ID = 1;  //  Increment by 1
var S = 0;   //  No shift
// Cursor or display shift command:
var RL = 1;
var SC = 0;

function reset() {
    DDRAM = new Array(104);
    CGRAM = new Array(64);

    lastAdrsSet='DDRAM';
    AC = 0;
    AC = 0;
    range = 16; // 16 chars only
    
    //function set
    DL = 1;  //  8-bit interface data
    N = 0;   //  1-line display
    F = 0;   //  5 * 8 dot character font
    //Display on/off control:
    D = 0;   //  Display off
    C = 0;   //  Cursor off
    B = 0;   //  Blinking off
    //Entry mode set:
    ID = 1;  //  Increment by 1
    S = 0;   //  No shift
    range = 16; // 16 chars only
    document.ctrl.lcdpinsHex.value = 0;
    document.ctrl.lcdpinsDec.value = 0;
    document.ctrl.ctrlpins.value = 'Etkisiz, komut yaz';

    for(var q=0;q<DDRAM.length;q++) {
        DDRAM[q]=20;
    }

    for(var q=0;q<CGRAM.length;q++) {
        CGRAM[q]=0;
    }
    
    for(var i=0; i < 8; i++) {
        for(var j=0; j < 8; j++) {
            chrtbl[i][j]=0;
            
        }
    }
    
    shiftChars = 0;
    
    initCurrDispChrs();
    
    updateDisp();
    
    ln2Off();
    
    blinkCur();
    updateStats();
    
    
    
    
    
    // alert('reset done !')
}


var upNib = 0;
var lowNib = 0;
var gotUpNib = 0;
function lcd(data,eGoLow,rwState,rsState) {
    //window.status=('data: '+data+'\n'+'eGoLow: '+eGoLow+'\n'+'rwState: '+rwState+'\n'+'rsState: '+rsState)
    
    if(eGoLow == 1) { // E goes LOW, this is when instructions are evaluated, chars written 
        if(rsState == 0 & rwState == 0) {
            //alert('write to IR, \n evaluate instruction')
            if(DL == 1) {
                evalInstr(data);
            } else {
                if(gotUpNib == 0) {
                    upNib = data;
                    gotUpNib = 1;
                    instrpeek(instr);
                } else {
                    lowNib = data;
                    gotUpNib = 0;
                    evalInstr((upNib << 4) | lowNib);
                }
                
            }
        }
        if(rsState == 1 & rwState == 0) {
            //alert('write to DR, \n print character')
            if(DL == 1) {
                writeData(data);
            } else {
                if(gotUpNib == 0) {
                    upNib = data;
                    gotUpNib = 1;
                    instrpeek(instr)
                } else {
                    lowNib = data;
                    gotUpNib = 0;
                    writeData((upNib << 4) | lowNib);
                }
                
            }
            
            instrpeek(baseConv(document.ctrl.lcdpinsHex.value,16));
        }
        updateStats();
        return;
    }

    if(eGoLow != 1 & rwState == 1) { // E is 1. Data or address reads are done 
        if(rsState == 0 & rwState == 1) {
            alert('Meşgul bayrağı ve adres okuma \n Bu simulatorde okuma işlemleri yapılamıyor ! \n         Şimdilik !');
        }
        if(rsState == 1 & rwState == 1) {
            alert('DATA kaydedicsinden okuma  \n  Bu simulatorde okuma işlemleri yapılamıyor ! \n         Şimdilik !');
        }
        return;
    }
}

function evalInstr(instr) {
    clearMsgs();
    addMsg('E\'nin düşen kenarında işletilen komut:');
    
    if((instr & maskSetDDRAMadrs) == instrSetDDRAMadrs) {
        setDDRadrs(instr & 0x7f);
        lastAdrsSet = 'DDRAM';
        addMsg('\n DDRAM adresini ' + AC + ' yap. ');
        return;
    }

    if((instr & maskSetCGRAMadrs) == instrSetCGRAMadrs) {
        AC = (instr & 0x3f)+64;
        updateUndCurs()
        lastAdrsSet = 'CGRAM';
        addMsg('\n CGRAM adresini ' + (AC - 64) + ' yap. ');
        return;
    }

    if((instr & maskFuncSet) == instrFuncSet) {
        addMsg('\n Fonksiyon belirleme: ');
        if(instr & eithtBitMode) {
            addMsg('8 bit arabirim, ');
            if(DL == 0) {
                DL = 1;
                for(var i=0; i<4; i++) {
                    togImage('d'+i);
                }
            }
            DL = 1;
        } else {
            addMsg('4 bit arabirim, ');
            //fix... 15 August 2004 14:09
            //if((gotUpNib == 0) && (DL==1)) {
            //    upNib = instr >> 4;
            //    gotUpNib = 1;
            //    instr = instr >> 4
            // }
            // end of fix ...15 August 2004 14:09
            DL = 0;
            for(var i=0; i<4; i++) {
                document['d'+i].src = 'b1t.gif';
            }
            var newVal = document.ctrl.lcdpinsDec.value >> 4;
            document.ctrl.lcdpinsHex.value = baseDisp(newVal,16);
            document.ctrl.lcdpinsDec.value = baseDisp(newVal,10);
        }
        
        if(instr & twoLines) {
            addMsg('2 satır, ');
            N = 1;
            range = 32;
            ln2On();
            updateDisp();
        } else {
            addMsg('1 satır, ');
            N = 0;
            range = 16;
            updateDisp();
            ln2Off();
            
        }
        
        if(instr & largeFont) {
            addMsg('5*10 font, ');
            F = 1;
            alert('\n Bu LCD sadece 5*7 fontunu destekler !!!');
        } else {
            addMsg('5*8 font, ');
            F = 0;
        }
        
        return;
    }

    if((instr & maskCursorDisplay) == instrCursorDisplay) {
        addMsg('\n İmleç ya da displayi kaydır:'); 
        var yon = '';

        if(instr & rightLeft) {
            yon = 'sağa kaydır.';
            RL = 1;
        } else {
            yon = 'sola kaydır.';
            RL = -1;
        }

        if(instr & shiftOrCursorMove) {
            addMsg(' displayi ' + yon);
            SC = 1;
            shiftChars -=RL;
            lastAdrsSet = 'DDRAM';
            updateDisp();
        } else {
            addMsg(' imleci ' + yon);
            SC = 0;
            lastAdrsSet = 'DDRAM';
            incdcrDDRadrs(RL);
            updateDisp();
        }       

        return;
    }

    if((instr & maskEntryMode) == instrEntryMode) {
        addMsg('\n Giriş modu seçimi: ');
        if(instr & incCursorPos) {
            addMsg('imleci ilerlet, ');
            ID = 1;
        } else {
            addMsg('imleci geri al, ');
            ID = -1; 
        }
        
        if(instr & scrollDisp) {
            addMsg('kayan display, ');
            S = 1;
        } else {
            addMsg('sabit display, ');
            S = 0;
        }
        
        return;
    }

    if((instr & maskDisplayCtrl) == instrDisplayCtrl) {
        addMsg('\n Display aç/kapa: ');
        if(instr & displayOn) {
            addMsg('\n  display AÇIK, ');
            D = 1;
            dispBlanked = 0;
            updateDisp();
        } else {
            addMsg('\n  display KAPALI, ');
            D  = 0;
            updateDisp();
        }
        
        if(instr & cursorOn) {
            addMsg('imleç AÇIK, ');
            C = 1;
            updateUndCurs();
        } else {
            addMsg('imleç KAPALI, ');
            C  = 0;
            updateUndCurs();
        }
        
        if(instr & blinkOn) {
            addMsg('yanıp-sönme AÇIK, ');
            B = 1;
        } else {
            addMsg('yanıp-sönme KAPALI, ');
            B  = 0;
        }   
        
        return;
    }


    if((instr & maskClearDisplay) == instrClearDisplay) {
        addMsg('\n Displayi silme komutu.');
        for(var i=0; i<104;i++) {
            DDRAM[i]=0x20;
        }
        ID = 1;
        setDDRadrs(0);
        lastAdrsSet = 'DDRAM';
        updateDisp();
        
        return;
    }

    if((instr & maskCursorHome) == instrCursorHome) {
        addMsg('\n İmleci başlangıç konumuna getir. ');
        shiftChars = 0;
        setDDRadrs(0);
        lastAdrsSet = 'DDRAM';
        updateDisp();
        
        return;
    }

    addMsg('\nGeçersiz komut !');
    return;
}

function writeData(data) {
    if(lastAdrsSet == 'DDRAM') {
        DDRAM[AC] = data;
        if(S) {
            shiftChars += ID;
        }
        incdcrDDRadrs(ID);
        updateDisp();
    } else {
        //alert('writing to cgram viewer')
        CGRAM[AC%64] = data;
        var ACmn64 = AC % 64;
        chrtbl[Math.floor(ACmn64/8)][ACmn64 % 8] = data & 31; //this goes to CGRAM viewer
        document['cgp'+ ACmn64].src = (data & 31) +'.gif';
        incdcrCGRadrs(ID); 
        cgramChanged();
    }

}

function readBfAndAdr() {

}

function readDataReg() {


}

var adrs = 1; 
var chr = 0;
currDispChrs = new Array(32);
var shiftChars = 0;
//var offset = 0
function updateDisp() {

    setCurrDispChrs();
    if(D==0) {
        if(dispBlanked != 1) {
            blankDisp();
        }
        return 
    }

    if(N == 0) {
        if(shiftChars > 79 || shiftChars < -79) {
            shiftChars=0
        }
    } else {
        if(shiftChars > 39 || shiftChars < -39) {
            shiftChars=0
        }
    }
    
    
    if(N == 0) {
        for(var ln=0; ln<16; ln++) {
            if(currDispChrs[ln][chr] != DDRAM[currDispChrs[ln][adrs]]) {
                pchr(DDRAM[currDispChrs[ln][adrs]],ln)
                currDispChrs[ln][chr] = DDRAM[currDispChrs[ln][adrs]]
                //cursPos = DDRAM[currDispChrs[ln][adrs]]
                //blinkChar = DDRAM[currDispChrs[ln][adrs] + 1]
            }
        }   
    } else {
        for(var ln=0; ln<32; ln++) {
            if(currDispChrs[ln][chr] != DDRAM[currDispChrs[ln][adrs]]) {
                pchr(DDRAM[currDispChrs[ln][adrs]],ln)
                currDispChrs[ln][chr] = DDRAM[currDispChrs[ln][adrs]]
                //cursPos = DDRAM[currDispChrs[ln][adrs]]
                //blinkChar = DDRAM[currDispChrs[ln][adrs] + 1]
            }
        }   
    }
    /* thhese are to clear the cursor trace in case of LCD scroll*/
    pchr(currDispChrs[0][chr],0)
    pchr(currDispChrs[15][chr],15)
    if(range == 32) {
        pchr(currDispChrs[16][chr],16)
        pchr(currDispChrs[31][chr],31)
    }

    updateUndCurs()
}

function cgramChanged() {
    if(D == 1) {
        for(var i=0; i<range; i++) {
            if(currDispChrs[i][chr] < 8) {
                pchr(currDispChrs[i][chr],i)
            }
        }
        
        updateUndCurs()
    }
}


var prevDDRAMadrCursAt = 0;
var cursPos = 0;
var cursOutOfDisp = 0
var undCursClrd = 0
function updateUndCurs() {
    cursOutOfDisp = 1
    if(D == 1) {
        for(var i=0; i<range; i++) {
            if(currDispChrs[i][adrs] == prevDDRAMadrCursAt) {
                pchr(DDRAM[currDispChrs[cursPos][adrs]],cursPos)
            }
        }
    } else if(D == 0 || ( C == 0 && B == 0)) {
        document['p'+ parseInt(cursPos * 8 + 7)].src = '0.gif';
        //currDispChrs[cursPos][chr] = 333;	// this is a fake value... so that the characer gets refreshed when cursor goes somewhere else
        //alert('remove und curs at ln 426')
        return;
    }

    for(var i=0; i<range; i++) {
        if(currDispChrs[i][adrs] == AC) {
            prevDDRAMadrCursAt = AC;
            cursPos = i;
            blinkChar = currDispChrs[i][chr];
            cursOutOfDisp = 0;
        }
    }
    
    if(C == 1 && cursOutOfDisp == 0) {
        document['p'+ parseInt(cursPos * 8 + 7)].src = '31.gif';
        //currDispChrs[cursPos][chr] = 333;	// this is a fake value... so that the characer gets refreshed when cursor goes somewhere else

        undCursClrd = 0
        //alert('put und curs')
    }

    /*if(C == 1 && cursOutOfDisp == 1 && undCursClrd == 0){
            pchr(blinkChar,cursPos)
            undCursClrd = 1
            //alert(' cleared und curs at >>>>' + cursPos)
    }*/

}



var blinked = 0;
var blinkChar = 0x20;
var undCntr = 0;
function blinkCur() {
    
    if(B == 0 || D == 0 || cursOutOfDisp == 1) {
        if(blinked == 1 && cursPos < range && cursOutOfDisp == 0) {
            pchr(blinkChar,cursPos)
            //currDispChrs[cursPos][chr] = 333;
            blinked = 0
            if(C == 1 && cursOutOfDisp == 0) {
                document['p'+ parseInt(cursPos * 8 + 7)].src = '31.gif'
                //alert('put und curs at ln 464')
                //undCntr++
                //window.status = undCntr;
            }
        }
        setTimeout("blinkCur()",379);
        return;
    }
    if(blinked == 1) {
        pchr(blinkChar,cursPos)
        //currDispChrs[cursPos][chr] = 333;
        blinked = 0
        setTimeout("blinkCur()",379)
        if(C == 1 && cursOutOfDisp == 0) {
            document['p'+ parseInt(cursPos * 8 + 7)].src = '31.gif'
            //currDispChrs[cursPos][chr] = 333;
            //alert('put und curs at ln 478')
        }
    } else {
        pchr(255,cursPos)
        document['p'+ parseInt(cursPos * 8 + 7)].src = '31.gif'
        //currDispChrs[cursPos][chr] = 333;
        blinked = 1
        setTimeout("blinkCur()",379)
        /*if(C == 1 && cursOutOfDisp == 0){
                document['p'+ parseInt(cursPos * 8 + 7)].src = '31.gif'
        }*/
    }
}

var dispBlanked = 0;
function blankDisp() {
    for(var i=0;i< range * 8;i++) {
        document['p'+i].src='0.gif';
    }
    for(var ln=0; ln<32; ln++) {
        currDispChrs[ln][chr] = 0x20
    }
    
    dispBlanked = 1
}

function setDDRadrs(address) {
    AC = address
    if(N==0) {
        if(AC > 79) {
            AC = 0
        }
    } else {
        if(AC > 64) {
        }
        if(AC > 39 && AC < 64) {
            AC = 64
        }
        if(AC > 103) {
            AC = 0
        }
    }
    updateUndCurs()
}

function incdcrDDRadrs(incordcr) {
    //alert('ddradrs decreasing !' + AC)
    if(N == 0) {
        AC += incordcr
        if(AC < 0) {
            AC = 79
        }
        AC %= 80
    } else {
        AC += incordcr
        if(AC < 0) {
            AC = 103
        }
        if(AC > 39 && AC < 64) {
            AC = 64
        }
        if(AC > 103) {
            AC = 0
        }
    }
    //if(AC < 0 || (AC > 39 && AC < 64) || AC >= 104){alert('AC invalid !!!! >>>>'+ AC)}
}

function incdcrCGRadrs(incordcr) {
    AC += incordcr
    if(AC-64 < 0) {
        AC = 63
    }
    if(AC-64 > 63) {
        AC = 0
    }
}

function initCurrDispChrs() {
    //if(N == 0){
    for(var i=0;i<16;i++) {
        currDispChrs[i]= new Array(2)
        currDispChrs[i][chr]= 0x20;
        currDispChrs[i][adrs]= i;
    }
    //}
    //else{
    for(var i=16;i<32;i++) {
        currDispChrs[i]= new Array(2)
        currDispChrs[i][chr]= 0x20;
        currDispChrs[i][adrs]= 48 + i;
    }
    //}

}

function setCurrDispChrs() {
    if(N == 0) {
        for(var i=0; i<16; i++) {
            //if(shiftChars < 0){
            currDispChrs[i][adrs]= (i + 80 + shiftChars) % 80   //adrs
            //}
        }
    } else {
        for(var i=0; i<16; i++) {
            //if(shiftChars < 0){
            currDispChrs[i][adrs]= (i + 40 + shiftChars) % 40   //adrs
            //}
        }
        for(var i=16; i<32; i++) {
            if(shiftChars < 0) {
                currDispChrs[i][adrs]= (i + 40 + shiftChars + 48) //adrs
                if(currDispChrs[i][adrs] > 103)
                    currDispChrs[i][adrs] = (currDispChrs[i][adrs] % 104) + 64
            } else {
                currDispChrs[i][adrs]= i  + shiftChars + 48 //adrs
                if(currDispChrs[i][adrs] > 103)
                    currDispChrs[i][adrs] = (currDispChrs[i][adrs] % 104) + 64
            }
        }
    }
}

function updateStats() {
    cursOutOfDisp = 1;
    for(var i=0; i<range; i++) {
        if(currDispChrs[i][adrs] == AC) {
            cursOutOfDisp = 0;
        }
    }

    document.ctrl.lastAdrsSet.value = lastAdrsSet + '\'e.';
    if(D == 1)
        document.ctrl.D.value = 'AÇIK.';
    else
        document.ctrl.D.value = 'KAPALI.';  
    
    if(cursOutOfDisp == 1)
        document.ctrl.cursOutOfDisp.value = 'görünmez.';
    else
        document.ctrl.cursOutOfDisp.value = 'görünür.';  

    if(ID == 1)
        document.ctrl.ID.value = 'atrıyor.';
    else
        document.ctrl.ID.value = 'azalıyor.';
    
    if(S == 1)
        document.ctrl.S.value = 'kayıyor.';
    else
        document.ctrl.S.value = 'kaymıyor.';
    if(lastAdrsSet == 'CGRAM')
        document.ctrl.AC.value = (AC-64);
    else
        document.ctrl.AC.value = AC;

    if(C == 0 && B == 0) {
        document.ctrl.C.value = 'KAPALI.';
    } else {
        if(C == 1 && B == 1) {
            document.ctrl.C.value = 'AÇIK, kırpışıyor.';
        }
        if(C == 0 && B == 1) {
            document.ctrl.C.value = 'kırpışıyor.';
        }
        if(C == 1 && B == 0) {
            document.ctrl.C.value = 'AÇIK.';
        }
    }
    
    
    if(N == 1) {
        document.ctrl.ln2adr.value = currDispChrs[16][adrs] + '..' + currDispChrs[31][adrs];
    } else {
        document.ctrl.ln2adr.value =  '- -' ;
    }
    document.ctrl.ln1adr.value = currDispChrs[0][adrs] + '..' + currDispChrs[15][adrs];
}