mirror of
https://github.com/mist64/perfect6502.git
synced 2024-12-28 11:31:50 +00:00
296 lines
8.1 KiB
JavaScript
296 lines
8.1 KiB
JavaScript
/*
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Copyright (c) 2010 Brian Silverman, Barry Silverman
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Permission is hereby granted, free of charge, to any person obtaining a copy
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of this software and associated documentation files (the "Software"), to deal
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in the Software without restriction, including without limitation the rights
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to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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copies of the Software, and to permit persons to whom the Software is
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furnished to do so, subject to the following conditions:
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The above copyright notice and this permission notice shall be included in
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all copies or substantial portions of the Software.
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THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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THE SOFTWARE.
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*/
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var memory = Array();
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var code = [0xa9, 0x00, 0x20, 0x10, 0x00, 0x4c, 0x02, 0x00,
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0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
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0xe8, 0x88, 0xe6, 0x40, 0x38, 0x69, 0x02, 0x60];
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var cycle = 0;
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var trace = Array();
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var running = false;
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function go(n){
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for(var i=0;i<code.length;i++){
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mWrite(i, code[i]);
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setCellValue(i, code[i]);
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}
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mWrite(0xfffc, 0x00);
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mWrite(0xfffd, 0x00);
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steps();
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}
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function steps(){
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if(running) {
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step();
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setTimeout(steps, 0); // schedule the next poll
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}
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}
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function testNMI(n){
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initChip();
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mWrite(0x0000, 0x38); // set carry
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mWrite(0x0001, 0x4c); // jump to test code
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mWrite(0x0002, 0x06);
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mWrite(0x0003, 0x23);
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mWrite(0x22ff, 0x38); // set carry
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mWrite(0x2300, 0xea);
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mWrite(0x2301, 0xea);
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mWrite(0x2302, 0xea);
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mWrite(0x2303, 0xea);
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mWrite(0x2304, 0xb0); // branch carry set to self
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mWrite(0x2305, 0xfe);
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mWrite(0x2306, 0xb0); // branch carry set to self
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mWrite(0x2307, 0x01);
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mWrite(0x2308, 0x00); // brk should be skipped
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mWrite(0x2309, 0xa9); // anything
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mWrite(0x230a, 0xde); // anything
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mWrite(0x230b, 0xb0); // branch back with page crossing
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mWrite(0x230c, 0xf2);
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mWrite(0xc018, 0x40); // nmi handler
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mWrite(0xfffa, 0x18); // nmi vector
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mWrite(0xfffb, 0xc0);
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mWrite(0xfffc, 0x00); // reset vector
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mWrite(0xfffd, 0x00);
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for(var i=0;i<n;i++){step();}
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setLow('nmi');
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chipStatus();
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for(var i=0;i<8;i++){step();}
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setHigh('nmi');
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chipStatus();
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for(var i=0;i<16;i++){step();}
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}
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function initChip(){
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var start = now();
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for(var nn in nodes) nodes[nn].state = 'fl';
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nodes[ngnd].state = 'gnd';
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nodes[npwr].state = 'vcc';
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for(var tn in transistors) transistors[tn].on = false;
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setLow('res');
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setLow('clk0');
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setHigh('rdy'); setLow('so');
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setHigh('irq'); setHigh('nmi');
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recalcNodeList(allNodes());
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for(var i=0;i<8;i++){setHigh('clk0'), setLow('clk0');}
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setHigh('res');
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for(var i=0;i<18;i++){resetStep();}
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refresh();
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cycle = 0;
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trace = Array();
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chipStatus();
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console.log('initChip done after', now()-start);
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}
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function step(){
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trace[cycle]= {chip: stateString(), mem: getMem()};
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halfStep();
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cycle++;
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chipStatus();
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}
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function halfStep(){
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var clk = isNodeHigh(nodenames['clk0']);
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if (clk) {setLow('clk0'); handleBusRead(); }
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else {setHigh('clk0'); handleBusWrite();}
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refresh();
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}
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function resetStep(){
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var clk = isNodeHigh(nodenames['clk0']);
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if (clk) {setLow('clk0'); handleBusRead(); }
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else {setHigh('clk0'); handleBusWrite();}
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}
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function handleBusRead(){
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if(isNodeHigh(nodenames['rw'])) writeDataBus(mRead(readAddressBus()));
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}
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function handleBusWrite(){
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if(!isNodeHigh(nodenames['rw'])){
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var a = readAddressBus();
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var d = readDataBus();
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mWrite(a,d);
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if(a<0x200) setCellValue(a,d);
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}
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}
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function readAddressBus(){return readBits('ab', 16);}
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function readDataBus(){return readBits('db', 8);}
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function readA(){return readBits('a', 8);}
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function readY(){return readBits('y', 8);}
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function readX(){return readBits('x', 8);}
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function readP(){return readBits('p', 8);}
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function readPstring(){
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var result;
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result = (isNodeHigh(nodenames['p7'])?'N':'n') +
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(isNodeHigh(nodenames['p6'])?'V':'v') +
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'-' +
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(isNodeHigh(nodenames['p3'])?'B':'b') +
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(isNodeHigh(nodenames['p3'])?'D':'d') +
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(isNodeHigh(nodenames['p2'])?'I':'i') +
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(isNodeHigh(nodenames['p1'])?'Z':'z') +
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(isNodeHigh(nodenames['p0'])?'C':'c');
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return result;
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}
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function readSP(){return readBits('s', 8);}
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function readPC(){return (readBits('pch', 8)<<8) + readBits('pcl', 8);}
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function readPCL(){return readBits('pcl', 8);}
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function readPCH(){return readBits('pch', 8);}
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function readBit(name){
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return isNodeHigh(nodenames[name])?1:0;
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}
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function readBits(name, n){
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var res = 0;
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for(var i=0;i<n;i++){
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var nn = nodenames[name+i];
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res+=((isNodeHigh(nn))?1:0)<<i;
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}
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return res;
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}
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function writeDataBus(x){
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var recalcs = Array();
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for(var i=0;i<8;i++){
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var nn = nodenames['db'+i];
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var n = nodes[nn];
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if((x%2)==0) {n.pulldown=true; n.pullup=false;}
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else {n.pulldown=false; n.pullup=true;}
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recalcs.push(nn);
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x>>=1;
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}
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recalcNodeList(recalcs);
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}
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function mRead(a){
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if(memory[a]==undefined) return 0;
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else return memory[a];
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}
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function mWrite(a, d){memory[a]=d;}
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function clkNodes(){
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var res = Array();
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res.push(943);
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for(var i in nodes[943].gates){
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var t = transistors[nodes[943].gates[i]];
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if(t.c1==npwr) res.push(t.c2);
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if(t.c2==npwr) res.push(t.c1);
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}
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hiliteNode(res);
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}
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function runChip(){
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var start = document.getElementById('start');
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var stop = document.getElementById('stop');
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start.style.visibility = 'hidden';
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stop.style.visibility = 'visible';
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running = true;
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steps();
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}
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function stopChip(){
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var start = document.getElementById('start');
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var stop = document.getElementById('stop');
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start.style.visibility = 'visible';
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stop.style.visibility = 'hidden';
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running = false;
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}
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function resetChip(){
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stopChip();
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setStatus('resetting 6502...');
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setTimeout(initChip,0);
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}
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function stepForward(){
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stopChip();
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step();
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}
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function stepBack(){
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if(cycle==0) return;
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showState(trace[--cycle].chip);
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setMem(trace[cycle].mem);
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var clk = isNodeHigh(nodenames['clk0']);
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if(!clk) writeDataBus(mRead(readAddressBus()));
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chipStatus();
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}
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function chipStatus(){
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var ab = readAddressBus();
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var machine1 =
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' halfcyc:' + cycle +
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' phi0:' + readBit('clk0') +
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' AB:' + hexWord(ab) +
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' D:' + hexByte(readDataBus()) +
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' RnW:' + readBit('rw');
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var machine2 =
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' PC:' + hexWord(readPC()) +
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' A:' + hexByte(readA()) +
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' X:' + hexByte(readX()) +
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' Y:' + hexByte(readY()) +
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' SP:' + hexByte(readSP()) +
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' ' + readPstring();
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var machine3 =
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' Sync:' + readBit('sync')
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' IRQ:' + readBit('irq') +
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' NMI:' + readBit('nmi');
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var machine4 =
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' IR:' + hexByte(255 - readBits('notir', 8)) +
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' idl:' + hexByte(255 - readBits('idl', 8)) +
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' alu:' + hexByte(255 - readBits('alu', 8)) +
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' TCstate:' + readBit('clock1') + readBit('clock2') +
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readBit('t2') + readBit('t3') + readBit('t4') + readBit('t5');
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var machine5 =
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' notRdy0:' + readBit('notRdy0') +
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' fetch:' + readBit('fetch') +
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' clearIR:' + readBit('clearIR') +
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' D1x1:' + readBit('D1x1');
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setStatus(machine1 + "<br>" + machine2);
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if (loglevel>2) {
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console.log(machine1 + " " + machine2 + " " + machine3 + " " + machine4 + " " + machine5);
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}
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selectCell(ab);
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}
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function getMem(){
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var res = Array();
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for(var i=0;i<0x200;i++) res.push(mRead(i));
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return res;
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}
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function setMem(arr){
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for(var i=0;i<0x200;i++){mWrite(i, arr[i]); setCellValue(i, arr[i]);}
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}
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function hexWord(n){return (0x10000+n).toString(16).substring(1)}
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function hexByte(n){return (0x100+n).toString(16).substring(1)}
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