mirror of
https://github.com/fadden/6502bench.git
synced 2024-06-12 23:29:32 +00:00
184 lines
7.1 KiB
HTML
184 lines
7.1 KiB
HTML
<!DOCTYPE html>
|
|
<html lang="en">
|
|
<head>
|
|
<!-- START: /incl-head.html -->
|
|
<!-- common head elements -->
|
|
<meta charset="utf-8"/>
|
|
<meta name="viewport" content="width=device-width, initial-scale=1"/>
|
|
|
|
<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.6.0/jquery.min.js"
|
|
integrity="sha384-vtXRMe3mGCbOeY7l30aIg8H9p3GdeSe4IFlP6G8JMa7o7lXvnz3GFKzPxzJdPfGK" crossorigin="anonymous"></script>
|
|
<link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/font-awesome/4.7.0/css/font-awesome.min.css"/>
|
|
<link rel="stylesheet" href="../main.css"/>
|
|
<!-- END: /incl-head.html -->
|
|
|
|
<title>Inline Data - SourceGen Tutorial</title>
|
|
</head>
|
|
|
|
<body>
|
|
|
|
<!-- START: /incl-masthead.html -->
|
|
<div id="masthead">
|
|
<!--<div class="masthead-title" style="background-image: url('images/screenshot-mainwin.png');">-->
|
|
<div class="masthead-title">
|
|
6502bench
|
|
</div>
|
|
</div>
|
|
<!-- END: /incl-masthead.html -->
|
|
|
|
<!-- START: /incl-topnav.html active:#topnav-sgtutorial -->
|
|
<div id="topnav">
|
|
<!-- top navigation bar contents -->
|
|
<nav>
|
|
<a id="topnav-home" href=".././">HOME</a>
|
|
<a id="topnav-sgtutorial" class="active" href="../sgtutorial">SourceGen Tutorial</a>
|
|
<a id="topnav-menuicon" href="javascript:void(0);" class="icon" onclick="toggleSidenav()">
|
|
<i class="fa fa-bars"></i>
|
|
</a>
|
|
</nav>
|
|
<script>
|
|
// Sidenav toggle function.
|
|
//
|
|
// Use a jQuery function to toggle the sidenav bar. The initial state
|
|
// is undefined / inherited, so it will pop in and out as the screen
|
|
// resizes around the "large" breakpoint.
|
|
function toggleSidenav() {
|
|
$("#sidenav").toggle("fast");
|
|
}
|
|
</script>
|
|
</div>
|
|
<!-- END: /incl-topnav.html -->
|
|
|
|
<!-- START: incl-sidenav.html active:#sidenav-inline-data -->
|
|
<div id="sidenav">
|
|
<!-- side navigation bar contents -->
|
|
<ul>
|
|
<li id="sidenav-index"><a href="./">Introduction</a></li>
|
|
<li id="sidenav-about-disasm"><a href="about-disasm.html">About Disassembly</a></li>
|
|
<li id="sidenav-using-sourcegen"><a href="using-sourcegen.html">Using SourceGen</a>
|
|
<ul>
|
|
<li id="sidenav-moving-around"><a href="moving-around.html">Moving Around</a></li>
|
|
<li id="sidenav-simple-edits"><a href="simple-edits.html">Simple Edits</a></li>
|
|
<li id="sidenav-labels-symbols"><a href="labels-symbols.html">Labels & Symbols</a></li>
|
|
<li id="sidenav-editing-data"><a href="editing-data.html">Editing Data Operands</a></li>
|
|
<li id="sidenav-generating-code"><a href="generating-code.html">Generating Code</a></li>
|
|
</ul></li>
|
|
<li id="sidenav-digging-deeper"><a href="digging-deeper.html">Digging Deeper</a>
|
|
<ul>
|
|
<li id="sidenav-string-formatting"><a href="string-formatting.html">String Formatting</a></li>
|
|
<li id="sidenav-local-variables"><a href="local-variables.html">Local Variables</a></li>
|
|
<li id="sidenav-inline-data" class="active"><a href="inline-data.html">Inline Data</a></li>
|
|
<li id="sidenav-odds-ends"><a href="odds-ends.html">Odds & Ends</a></li>
|
|
</ul></li>
|
|
<li id="sidenav-advanced-topics"><a href="advanced-topics.html">Advanced Topics</a>
|
|
<ul>
|
|
<li id="sidenav-address-tables"><a href="address-tables.html">Address Tables</a></li>
|
|
<li id="sidenav-extension-scripts"><a href="extension-scripts.html">Extension Scripts</a></li>
|
|
<li id="sidenav-visualizations"><a href="visualizations.html">Visualizations</a></li>
|
|
</ul></li>
|
|
<li id="sidenav-suggestions"><a href="suggestions.html">Suggestions</a></li>
|
|
</ul>
|
|
</div>
|
|
<!-- END: incl-sidenav.html -->
|
|
|
|
<div id="main">
|
|
|
|
<h2>Inline Data</h2>
|
|
|
|
<div class="grid-container">
|
|
<div class="grid-item-image">
|
|
<img src="images/t2-206b.png" alt="t2-206b"/>
|
|
</div>
|
|
<div class="grid-item-text">
|
|
<p>Consider the code at address $206B. It's a <code>JSR</code> followed by some
|
|
ASCII text, then a $00 byte, and then what might be code.</p>
|
|
</div>
|
|
</div>
|
|
|
|
<div class="grid-container">
|
|
<div class="grid-item-image">
|
|
<img src="images/t2-20ab-1.png" alt="t2-20ab-1"/>
|
|
<br/>
|
|
...
|
|
<br/>
|
|
<img src="images/t2-20ab-2.png" alt="t2-20ab-2"/>
|
|
</div>
|
|
<div class="grid-item-text">
|
|
<p>Double-click on the <code>JSR</code> opcode
|
|
to jump to $20AB to see the function. It pulls the
|
|
call address off the stack, and uses it as a pointer. When it encounters
|
|
a zero byte, it breaks out of the loop, pushes the adjusted pointer
|
|
value back onto the stack, and returns.</p>
|
|
</div>
|
|
</div>
|
|
|
|
<div class="grid-container">
|
|
<div class="grid-item-text">
|
|
<p>This is an example of "inline data", where a function uses the return
|
|
address to get a pointer to data. The return address is adjusted to
|
|
point past the inline data before returning (technically, it points at
|
|
the very last byte of the inline data, because
|
|
<code>RTS</code> jumps to address + 1).</p>
|
|
</div>
|
|
</div>
|
|
|
|
<div class="grid-container">
|
|
<div class="grid-item-image">
|
|
<img src="images/t2-inline-tag.png" alt="t2-inline-tag"/>
|
|
</div>
|
|
<div class="grid-item-text">
|
|
<p>To format the data, we first need to tell SourceGen that there's data
|
|
in line with the code. Select the line at address $206E, then
|
|
shift-click the line at address $2077. Use
|
|
<samp>Actions > Tag Bytes As Inline Data</samp>
|
|
(<kbd class="key">Ctrl+H</kbd><kbd class="key">Ctrl+I</kbd>).</p>
|
|
</div>
|
|
</div>
|
|
|
|
<div class="grid-container">
|
|
<div class="grid-item-image">
|
|
<img src="images/t2-inline-after.png" alt="t2-inline-after"/>
|
|
</div>
|
|
<div class="grid-item-text">
|
|
<p>The data turns to single-byte values, and we now see the code
|
|
continuing at address $2078. We can format the data as a string by
|
|
using <samp>Actions > Edit Operand</samp>,
|
|
setting the Character Encoding to <samp>Low or High ASCII</samp>,
|
|
and selecting <samp>null-terminated strings</samp>.</p>
|
|
</div>
|
|
</div>
|
|
|
|
<div class="grid-container">
|
|
<div class="grid-item-text">
|
|
<p>That's pretty straightforward, but this could quickly become tedious if
|
|
there were a lot of these. SourceGen allows you to define scripts to
|
|
automate common formatting tasks. This is covered in the "Extension
|
|
Scripts" tutorial.</p>
|
|
</div>
|
|
</div>
|
|
|
|
|
|
</div> <!-- #main -->
|
|
|
|
<div id="prevnext">
|
|
<a href="local-variables.html" class="btn-previous">« Previous</a>
|
|
<a href="odds-ends.html" class="btn-next">Next »</a>
|
|
</div>
|
|
|
|
<!-- START: /incl-footer.html -->
|
|
<div id="footer">
|
|
<hr/>
|
|
<p>Copyright 2021 faddenSoft</p>
|
|
<!-- <p id="screen-size"></p>
|
|
<script>
|
|
var w = window.innerWidth;
|
|
var h = window.innerHeight;
|
|
var x = document.getElementById("screen-size");
|
|
x.innerHTML = "DEBUG: initial window size " + w + "x" + h;
|
|
</script> -->
|
|
</div>
|
|
<!-- END: /incl-footer.html -->
|
|
|
|
</body>
|
|
</html>
|