SuperMaxusa/demo.html Secret

## demo.html
<!doctype html>
<script src="libv86.js"></script>
<script>
"use strict";

var glyph_w = 8;  // px
var glyph_h = 16; // px

function dumpPlane() {
    const plane2 = new Blob([window.emulator.v86.cpu.devices.vga.plane2]);
    // from examples/arch.html
    var a = document.createElement("a");
    a.download = "dump.bin";
    a.href = window.URL.createObjectURL(plane2);
    a.dataset.downloadurl = "application/octet-stream:" + a.download + ":" + a.href;
    a.click();
}

function makeTile(bitmap) {
    const tile = new Uint8ClampedArray(glyph_w * glyph_h * 4);
    let row = 0, px = 0;

    while (px < tile.length) {
        for(let bit = 7; bit >= 0; bit--) {
            // if the current bit is not background
            if(((bitmap[row] >> bit) & 1) === 0) {
                tile[px] = 0;       // R
                tile[px + 1] = 0;   // G
                tile[px + 2] = 0;   // B
            // if the current bit is background
            } else {
                tile[px] = 255;     // R
                tile[px + 1] = 255; // G
                tile[px + 2] = 255; // B
            };

            tile[px + 3] = 255; // A
            px += 4;
        };
        row += 1;
    };

    return new ImageData(tile, glyph_w, glyph_h);
}

function displayFont() {
    const font = window.emulator.v86.cpu.devices.vga.plane2.subarray(0, 512 * 16);
    const canvas = document.getElementById("fontcanvas");
    const ctx = canvas.getContext("2d", { alpha: false });
    const tiles = [];

    // make tiles from VGA bitmaps
    for(let i = 0; i < font.length; i += glyph_h) {
        let offset = font.subarray(i, i + glyph_h);
        tiles.push(makeTile(offset));
    };

    let x = 0, y = 0;

    ctx.clearRect(0, 0, canvas.width, canvas.height);

    for(const tile of tiles) {
        if(x + glyph_w > canvas.width) {
            // go to next row
            x = 0;
            y += glyph_h;
        }

        // draw a char tile
        ctx.putImageData(tile, x, y);
        x += glyph_w;
    };
}

window.onload = function()
{
    var emulator = window.emulator = new V86({
        wasm_path: "v86.wasm",
        memory_size: 16 * 1024 * 1024,
        vga_memory_size: 2 * 1024 * 1024,
        screen_container: document.getElementById("screen_container"),
        bios: {
            url: "seabios.bin"
        },
        vga_bios: {
            url: "vgabios.bin"
        },
        fda: {
            url: "freedos13.img"
        },
        autostart: true,
    });

    emulator.add_listener("emulator-started", function() {
        setInterval(displayFont, 1000)
    });
}
</script>

<div id="screen_container">
    <div style="white-space: pre; font: 14px monospace; line-height: 14px"></div>
    <canvas style="display: none"></canvas>
</div>

<br />
<button onclick="dumpPlane()"> Dump plane 2 to .bin file</button>
<br />
<canvas id="fontcanvas" width="512" height="128"></canvas>

## floppy-sources.md

      
    Raw
  

              floppy-sources.md
            
          
FreeDOS: https://www.freedos.org/
MagiDuck: https://www.indiedb.com/games/magiduck
SCC (Small C Compiler for DOS): https://github.com/mras0/scc
GNU chcp: https://www.ibiblio.org/pub/micro/pc-stuff/freedos/files/repositories/1.3/pkg-html/gnuchcp.html
GNU chcp fonts: https://www.ibiblio.org/pub/micro/pc-stuff/freedos/files/repositories/1.3/pkg-html/gnufonts.html
Fontraption: https://github.com/viler-int10h/Fontraption
TinyASM: https://github.com/nanochess/tinyasm
CPI files: https://www.ibiblio.org/pub/micro/pc-stuff/freedos/files/repositories/1.3/pkg-html/cpidos.html


## vga.patch
diff --git a/src/vga.js b/src/vga.js
index 8e746f9..28d1122 100644
--- a/src/vga.js
+++ b/src/vga.js
@@ -677,7 +677,7 @@ VGAScreen.prototype.vga_memory_write = function(addr, value)
     {
         if(!(this.plane_write_bm & 0x3))
         {
-            // Ignore writes to font planes.
+            this.plane2[addr] = value;
             return;
         }
         this.vga_memory_write_text_mode(addr, value);
	<!doctype html>
	<script src="libv86.js"></script>
	<script>
	"use strict";

	var glyph_w = 8; // px
	var glyph_h = 16; // px

	function dumpPlane() {
	const plane2 = new Blob([window.emulator.v86.cpu.devices.vga.plane2]);
	// from examples/arch.html
	var a = document.createElement("a");
	a.download = "dump.bin";
	a.href = window.URL.createObjectURL(plane2);
	a.dataset.downloadurl = "application/octet-stream:" + a.download + ":" + a.href;
	a.click();
	}

	function makeTile(bitmap) {
	const tile = new Uint8ClampedArray(glyph_w * glyph_h * 4);
	let row = 0, px = 0;

	while (px < tile.length) {
	for(let bit = 7; bit >= 0; bit--) {
	// if the current bit is not background
	if(((bitmap[row] >> bit) & 1) === 0) {
	tile[px] = 0; // R
	tile[px + 1] = 0; // G
	tile[px + 2] = 0; // B
	// if the current bit is background
	} else {
	tile[px] = 255; // R
	tile[px + 1] = 255; // G
	tile[px + 2] = 255; // B
	};

	tile[px + 3] = 255; // A
	px += 4;
	};
	row += 1;
	};

	return new ImageData(tile, glyph_w, glyph_h);
	}

	function displayFont() {
	const font = window.emulator.v86.cpu.devices.vga.plane2.subarray(0, 512 * 16);
	const canvas = document.getElementById("fontcanvas");
	const ctx = canvas.getContext("2d", { alpha: false });
	const tiles = [];

	// make tiles from VGA bitmaps
	for(let i = 0; i < font.length; i += glyph_h) {
	let offset = font.subarray(i, i + glyph_h);
	tiles.push(makeTile(offset));
	};

	let x = 0, y = 0;

	ctx.clearRect(0, 0, canvas.width, canvas.height);

	for(const tile of tiles) {
	if(x + glyph_w > canvas.width) {
	// go to next row
	x = 0;
	y += glyph_h;
	}

	// draw a char tile
	ctx.putImageData(tile, x, y);
	x += glyph_w;
	};
	}

	window.onload = function()
	{
	var emulator = window.emulator = new V86({
	wasm_path: "v86.wasm",
	memory_size: 16 * 1024 * 1024,
	vga_memory_size: 2 * 1024 * 1024,
	screen_container: document.getElementById("screen_container"),
	bios: {
	url: "seabios.bin"
	},
	vga_bios: {
	url: "vgabios.bin"
	},
	fda: {
	url: "freedos13.img"
	},
	autostart: true,
	});

	emulator.add_listener("emulator-started", function() {
	setInterval(displayFont, 1000)
	});
	}
	</script>

	<div id="screen_container">
	<div style="white-space: pre; font: 14px monospace; line-height: 14px"></div>
	<canvas style="display: none"></canvas>
	</div>

	<br />
	<button onclick="dumpPlane()"> Dump plane 2 to .bin file</button>
	<br />
	<canvas id="fontcanvas" width="512" height="128"></canvas>
	diff --git a/src/vga.js b/src/vga.js
	index 8e746f9..28d1122 100644
	--- a/src/vga.js
	+++ b/src/vga.js
	@@ -677,7 +677,7 @@ VGAScreen.prototype.vga_memory_write = function(addr, value)
	{
	if(!(this.plane_write_bm & 0x3))
	{
	- // Ignore writes to font planes.
	+ this.plane2[addr] = value;
	return;
	}
	this.vga_memory_write_text_mode(addr, value);