apple2js/js/cards/videoterm.ts

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import { allocMemPages, debug } from '../util';
import { Card, Restorable, byte, Color, memory, word } from '../types';
import { ROM, VIDEO_ROM } from '../roms/cards/videoterm';
interface VideotermState {
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curReg: byte;
startPos: word;
cursorPos: word;
bank: byte;
buffer: memory;
regs: byte[];
}
const LOC = {
IOREG: 0x80,
IOVAL: 0x81
} as const;
const REGS = {
CURSOR_UPPER: 0x0A,
CURSOR_LOWER: 0x0B,
STARTPOS_HI: 0x0C,
STARTPOS_LO: 0x0D,
CURSOR_HI: 0x0E,
CURSOR_LO: 0x0F,
LIGHTPEN_HI: 0x10,
LIGHTPEN_LO: 0x11
} as const;
const CURSOR_MODES = {
SOLID: 0x00,
HIDDEN: 0x01,
BLINK: 0x10,
FAST_BLINK: 0x11
} as const;
const BLACK: Color = [0x00, 0x00, 0x00];
const WHITE: Color = [0xff, 0xff, 0xff];
export default class Videoterm implements Card, Restorable<VideotermState> {
private regs = [
0x7b, // 00 - Horiz. total
0x50, // 01 - Horiz. displayed
0x62, // 02 - Horiz. sync pos
0x29, // 03 - Horiz. sync width
0x1b, // 04 - Vert. total
0x08, // 05 - Vert. adjust
0x18, // 06 - Vert. displayed
0x19, // 07 - Vert. sync pos
0x00, // 08 - Interlaced
0x08, // 09 - Max. scan line
0xc0, // 0A - Cursor upper
0x08, // 0B - Cursor lower
0x00, // 0C - Startpos Hi
0x00, // 0D - Startpos Lo
0x00, // 0E - Cursor Hi
0x00, // 0F - Cursor Lo
0x00, // 10 - Lightpen Hi
0x00 // 11 - Lightpen Lo
];
private blink = false;
private curReg = 0;
private startPos: word;
private cursorPos: word;
private shouldRefresh: boolean;
// private cursor = 0;
private bank = 0;
private buffer = allocMemPages(8);
private imageData;
private dirty = false;
constructor() {
debug('Videx Videoterm');
this.imageData = new ImageData(560, 192);
for (let idx = 0; idx < 560 * 192 * 4; idx++) {
this.imageData.data[idx] = 0xff;
}
for (let idx = 0; idx < 0x800; idx++) {
this.buffer[idx] = idx & 0xff;
}
this.refresh();
setInterval(() => {
this.blink = !this.blink;
this.refreshCursor(false);
}, 300);
}
private updateBuffer(addr: word, val: byte) {
this.buffer[addr] = val;
val &= 0x7f; // XXX temp
const saddr = (0x800 + addr - this.startPos) & 0x7ff;
const data = this.imageData.data;
const row = (saddr / 80) & 0xff;
const col = saddr % 80;
const x = col * 7;
const y = row << 3;
const c = val << 4;
let color;
if (row < 25) {
this.dirty = true;
for (let idx = 0; idx < 8; idx++) {
let cdata = VIDEO_ROM[c + idx];
for (let jdx = 0; jdx < 7; jdx++) {
if (cdata & 0x80) {
color = WHITE;
} else {
color = BLACK;
}
data[(y + idx) * 560 * 4 + (x + jdx) * 4] = color[0];
data[(y + idx) * 560 * 4 + (x + jdx) * 4 + 1] = color[1];
data[(y + idx) * 560 * 4 + (x + jdx) * 4 + 2] = color[2];
cdata <<= 1;
}
}
}
}
private refreshCursor(fromRegs: boolean) {
const addr = this.regs[REGS.CURSOR_HI] << 8 | this.regs[REGS.CURSOR_LO];
const saddr = (0x800 + addr - this.startPos) & 0x7ff;
const data = this.imageData.data;
const row = (saddr / 80) & 0xff;
const col = saddr % 80;
const x = col * 7;
const y = row << 3;
const blinkmode = (this.regs[REGS.CURSOR_UPPER] & 0x60) >> 5;
if (fromRegs) {
if (addr !== this.cursorPos) {
const caddr = (0x800 + this.cursorPos - this.startPos) & 0x7ff;
this.updateBuffer(caddr, this.buffer[caddr]);
this.cursorPos = addr;
}
}
this.updateBuffer(addr, this.buffer[addr]);
if (blinkmode === CURSOR_MODES.HIDDEN) {
return;
}
if (this.blink || (blinkmode === CURSOR_MODES.SOLID)) {
this.dirty = true;
for (let idx = 0; idx < 8; idx++) {
const color = WHITE;
if (idx >= (this.regs[REGS.CURSOR_UPPER] & 0x1f) &&
idx <= (this.regs[REGS.CURSOR_LOWER] & 0x1f)) {
for (let jdx = 0; jdx < 7; jdx++) {
data[(y + idx) * 560 * 4 + (x + jdx) * 4] = color[0];
data[(y + idx) * 560 * 4 + (x + jdx) * 4 + 1] = color[1];
data[(y + idx) * 560 * 4 + (x + jdx) * 4 + 2] = color[2];
}
}
}
}
}
private updateStartPos() {
const startPos =
this.regs[REGS.STARTPOS_HI] << 8 |
this.regs[REGS.STARTPOS_LO];
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if (this.startPos !== startPos) {
this.startPos = startPos;
this.shouldRefresh = true;
}
}
private refresh() {
for (let idx = 0; idx < 0x800; idx++) {
this.updateBuffer(idx, this.buffer[idx]);
}
}
private access(off: byte, val?: byte) {
let result = undefined;
switch (off & 0x81) {
case LOC.IOREG:
if (val !== undefined) {
this.curReg = val;
} else {
result = this.curReg;
}
break;
case LOC.IOVAL:
if (val !== undefined) {
this.regs[this.curReg] = val;
switch (this.curReg) {
case REGS.CURSOR_UPPER:
case REGS.CURSOR_LOWER:
this.refreshCursor(true);
break;
case REGS.CURSOR_HI:
case REGS.CURSOR_LO:
this.refreshCursor(true);
break;
case REGS.STARTPOS_HI:
case REGS.STARTPOS_LO:
this.updateStartPos();
break;
}
} else {
result = this.regs[this.curReg];
}
break;
}
this.bank = (off & 0x0C) >> 2;
return result;
}
ioSwitch(off: byte, val?: byte) {
return this.access(off, val);
}
read(page: byte, off: byte) {
if (page < 0xcc) {
return ROM[(page & 0x03) << 8 | off];
} else if (page < 0xce){
const addr = ((page & 0x01) + (this.bank << 1)) << 8 | off;
return this.buffer[addr];
}
return 0;
}
write(page: byte, off: byte, val: byte) {
if (page > 0xcb && page < 0xce) {
const addr = ((page & 0x01) + (this.bank << 1)) << 8 | off;
this.updateBuffer(addr, val);
}
}
blit() {
if (this.shouldRefresh) {
this.refresh();
this.shouldRefresh = false;
}
if (this.dirty) {
this.dirty = false;
return this.imageData;
}
return;
}
getState() {
return {
curReg: this.curReg,
startPos: this.startPos,
cursorPos: this.cursorPos,
bank: this.bank,
buffer: new Uint8Array(this.buffer),
regs: [...this.regs],
};
}
setState(state: VideotermState) {
this.curReg = state.curReg;
this.startPos = state.startPos;
this.cursorPos = state.cursorPos;
this.bank = state.bank;
this.buffer = new Uint8Array(this.buffer);
this.regs = [...state.regs];
this.shouldRefresh = true;
this.dirty = true;
}
}