apple2_hgr_font_tutorial/scroll_hgr_up_pixel.html
2016-01-09 19:30:14 -08:00

48 lines
1.7 KiB
HTML

<html>
<head>
</head>
<body>
<pre id="hexdump"></pre>
<script>
var hgr = [];
for( var y = 0; y < 193; ++y ) // Intentional 1 scanline too many!
hgr[ y ] = 0x2000 + ((y/64)|0)*0x28 + ((y%8)|0)*0x400 + ((y/8)&7)*0x80;
for( var y = 0; y < 192; ++y )
console.log( "[" + y + "]: " + hgr[y].toString(16).toUpperCase() );
function byte2hex$( byte )
{
return ("0" + byte.toString(16)).toUpperCase().substr(-2)
}
var address = 0x1402, out = "";
for( var y = 0; y < 192/8; ++y )
for( var x = 0; x < 8; ++x )
{
var row = y*8 + x; // Assumes hgr[] has a dummy 193rd scanline!
var src = hgr[ row + 1 ];
var dst = hgr[ row + 0 ];
var mem = "BD "
+ byte2hex$( (src >> 0) & 0xFF ) + " "
+ byte2hex$( (src >> 8) & 0xFF ) + " "
+ "9D "
+ byte2hex$( (dst >> 0) & 0xFF ) + " "
+ byte2hex$( (dst >> 8) & 0xFF ) + " ";
var txt = " "
+ " LDA $" + src.toString(16).toUpperCase() + ",Y "
+ ": STA $" + dst.toString(16).toUpperCase() + ",Y "
+ " ; [" + (" " + (row+1)).substr(-3)
+ "] -> [" + (" " + (row )).substr(-3) + "]" + "\n";
if (row != 191)
out += address.toString(16).toUpperCase() + ":" + mem + txt;
address += 6; // 6 bytes per line
}
console.log( out );
var pre = document.getElementById( "hexdump" );
pre.innerHTML = out;
</script>
</body>
</html>