8bitworkshop/src/machine/sms.ts

import { Z80, Z80State } from "../common/cpu/ZilogZ80";
import { BasicScanlineMachine } from "../common/devices";
import { BaseZ80VDPBasedMachine } from "./vdp_z80";
import { KeyFlags, newAddressDecoder, padBytes, Keys, makeKeycodeMap, newKeyboardHandler } from "../common/emu";
import { hex, lzgmini, stringToByteArray } from "../common/util";
import { TssChannelAdapter, MasterAudio, SN76489_Audio } from "../common/audio";
import { TMS9918A, SMSVDP } from "../common/video/tms9918a";

// http://www.smspower.org/Development/Index
// http://www.smspower.org/uploads/Development/sg1000.txt
// http://www.smspower.org/uploads/Development/richard.txt
// http://www.smspower.org/uploads/Development/msvdp-20021112.txt
// http://www.smspower.org/uploads/Development/SN76489-20030421.txt

var SG1000_KEYCODE_MAP = makeKeycodeMap([
  [Keys.UP,    0, 0x1],
  [Keys.DOWN,  0, 0x2],
  [Keys.LEFT,  0, 0x4],
  [Keys.RIGHT, 0, 0x8],
  [Keys.A,     0, 0x10],
  [Keys.B,     0, 0x20],

  [Keys.P2_UP,    0, 0x40],
  [Keys.P2_DOWN,  0, 0x80],
  [Keys.P2_LEFT,  1, 0x1],
  [Keys.P2_RIGHT, 1, 0x2],
  [Keys.P2_A,     1, 0x4],
  [Keys.P2_B,     1, 0x8],
  [Keys.VK_BACK_SLASH,    1, 0x10], // reset
]);

export class SG1000 extends BaseZ80VDPBasedMachine {

  numVisibleScanlines = 240;
  defaultROMSize = 0xc000;
  ram = new Uint8Array(0x400);
  
  constructor() {
    super();
    this.init(this, this.newIOBus(), new SN76489_Audio(new MasterAudio()));
  }
  
  getKeyboardMap() { return SG1000_KEYCODE_MAP; }

  vdpInterrupt() {
    this.probe.logInterrupt(0xff);
    return this.cpu.interrupt(0xff); // RST 0x38
  }
  
   read = newAddressDecoder([
     [0xc000, 0xffff,  0x3ff, (a) => { return this.ram[a]; }],
     [0x0000, 0xbfff, 0xffff, (a) => { return this.rom[a]; }],
   ]);
   write = newAddressDecoder([
     [0xc000, 0xffff,  0x3ff, (a,v) => { this.ram[a] = v; }],
   ]);
  
  getVCounter() : number { return 0; }
  getHCounter() : number { return 0; }
  setMemoryControl(v:number) { }
  setIOPortControl(v:number) { }

  newIOBus() {
    return {
      read: (addr:number) => {
        addr &= 0xff;
        //console.log('IO read', hex(addr,4));
        switch (addr & 0xc1) {
          case 0x40: return this.getVCounter();
          case 0x41: return this.getHCounter();
          case 0x80: return this.vdp.readData();
          case 0x81: return this.vdp.readStatus();
          case 0xc0: return this.inputs[0] ^ 0xff;
          case 0xc1: return this.inputs[1] ^ 0xff;
        }
        return 0;
      },
      write: (addr:number, val:number) => {
        addr &= 0xff;
        val &= 0xff;
        //console.log('IO write', hex(addr,4), hex(val,2));
        switch (addr & 0xc1) {
          case 0x00: return this.setMemoryControl(val);
          case 0x01: return this.setIOPortControl(val);
          case 0x40:
          case 0x41: return this.psg.setData(val);
          case 0x80: return this.vdp.writeData(val);
          case 0x81: return this.vdp.writeAddress(val);
        }
      }
    };
  }
  
}

///

export class SMS extends SG1000 {

  cartram = new Uint8Array(0);
  pagingRegisters = new Uint8Array(4);
  romPageMask : number;
  latchedHCounter = 0;
  ioControlFlags = 0;
  // TODO: hide bottom scanlines
  ram = new Uint8Array(0x2000);
  
  newVDP(frameData, cru, flicker) {
    return new SMSVDP(frameData, cru, flicker);
  }

  reset() {
    super.reset();
    this.pagingRegisters.set([0,0,1,2]);
  }

  getVCounter() {
    var y = this.scanline;
    return (y <= 0xda) ? (y) : (y - 6);
  }
  getHCounter() {
    return this.latchedHCounter;
  }
  computeHCounter() {
    return 0;
    /*
    var t0 = this.startLineTstates;
    var t1 = this.cpu.getTstates();
    return (t1-t0) & 0xff; // TODO
    */
  }
  setIOPortControl(v:number) {
    if ((v ^ this.ioControlFlags) & 0xa0) { // either joystick TH pin
      this.latchedHCounter = this.computeHCounter();
      //console.log("H:"+hex(this.latchedHCounter)+" V:"+hex(this.getVCounter()));
    }
    this.ioControlFlags = v;
  }
  
  
  getPagedROM(a:number, reg:number) {
    //if (!(a&0xff)) console.log(hex(a), reg, this.pagingRegisters[reg], this.romPageMask);
    return this.rom[a + ((this.pagingRegisters[reg] & this.romPageMask) << 14)]; // * $4000
  }

 read = newAddressDecoder([
   [0xc000, 0xffff, 0x1fff, (a) => { return this.ram[a]; }],
   [0x0000, 0x03ff,  0x3ff, (a) => { return this.rom[a]; }],
   [0x0400, 0x3fff, 0x3fff, (a) => { return this.getPagedROM(a,1); }],
   [0x4000, 0x7fff, 0x3fff, (a) => { return this.getPagedROM(a,2); }],
   [0x8000, 0xbfff, 0x3fff, (a) => {
     var reg0 = this.pagingRegisters[0]; // RAM select?
     if (reg0 & 0x8) {
       return this.cartram[(reg0 & 0x4) ? a+0x4000 : a];
     } else {
       return this.getPagedROM(a,3);
     }
   }],
 ]);
 
 write = newAddressDecoder([
   [0xc000, 0xfffb, 0x1fff, (a,v) => {
     this.ram[a] = v;
   }],
   [0xfffc, 0xffff,    0x3, (a,v) => {
     this.pagingRegisters[a] = v;
     this.ram[a+0x1ffc] = v;
   }],
   [0x8000, 0xbfff, 0x3fff, (a,v) => {
     var reg0 = this.pagingRegisters[0]; // RAM select?
     if (reg0 & 0x8) {
       if (this.cartram.length == 0)
         this.cartram = new Uint8Array(0x8000); // create cartridge RAM lazily
       this.cartram[(reg0 & 0x4) ? a+0x4000 : a] = v;
     }
   }],
 ]);

  loadROM(data:Uint8Array) {
    if (data.length <= 0xc000) {
      this.rom = padBytes(data, 0xc000);
      this.romPageMask = 3; // only pages 0, 1, 2
    } else {
      switch (data.length) {
        case 0x10000:
        case 0x20000:
        case 0x40000:
        case 0x80000:
          this.rom = data;
          this.romPageMask = (data.length >> 14) - 1; // div $4000
          break;
        default:
          throw Error("Unknown rom size: $" + hex(data.length));
      }
    }
    //console.log("romPageMask: " + hex(this.romPageMask));
    this.reset();
  }

  loadState(state) {
    super.loadState(state);
    this.pagingRegisters.set(state.pr);
    this.cartram.set(state.cr);
    this.latchedHCounter = state.lhc;
    this.ioControlFlags = state.iocf;
  }
  saveState() {
    var state = super.saveState();
    state['pr'] = this.pagingRegisters.slice(0);
    state['cr'] = this.cartram.slice(0);
    state['lhc'] = this.latchedHCounter;
    state['iocf'] = this.ioControlFlags;
    return state;
  }
  getDebugInfo(category, state) {
    switch (category) {
      case 'SMS': // TODO
        return super.getDebugInfo(category, state) +
          "\nBank Regs: " + this.pagingRegisters + "\n";
      default: return super.getDebugInfo(category, state);
    }
  }
}