blob: 27e5514b4d90ecf7cae439b893c531543856e53e (
plain) (
tree)
|
|
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">
<html>
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<title>Mu - 101screen.subx</title>
<meta name="Generator" content="Vim/8.1">
<meta name="plugin-version" content="vim8.1_v1">
<meta name="syntax" content="none">
<meta name="settings" content="number_lines,use_css,pre_wrap,no_foldcolumn,expand_tabs,line_ids,prevent_copy=">
<meta name="colorscheme" content="minimal-dark">
<style type="text/css">
<!--
pre { white-space: pre-wrap; font-family: monospace; color: #000000; background-color: #a8a8a8; }
body { font-size:12pt; font-family: monospace; color: #000000; background-color: #a8a8a8; }
a { color:inherit; }
* { font-size:12pt; font-size: 1em; }
.SpecialChar { color: #d70000; }
.subxComment { color: #005faf; }
.subxS1Comment { color: #0000af; }
.LineNr { }
.subxFunction { color: #af5f00; text-decoration: underline; }
.Constant { color: #008787; }
-->
</style>
<script type='text/javascript'>
<!--
/* function to open any folds containing a jumped-to line before jumping to it */
function JumpToLine()
{
var lineNum;
lineNum = window.location.hash;
lineNum = lineNum.substr(1); /* strip off '#' */
if (lineNum.indexOf('L') == -1) {
lineNum = 'L'+lineNum;
}
var lineElem = document.getElementById(lineNum);
/* Always jump to new location even if the line was hidden inside a fold, or
* we corrected the raw number to a line ID.
*/
if (lineElem) {
lineElem.scrollIntoView(true);
}
return true;
}
if ('onhashchange' in window) {
window.onhashchange = JumpToLine;
}
-->
</script>
</head>
<body onload='JumpToLine();'>
<a href='https://github.com/akkartik/mu/blob/main/101screen.subx'>https://github.com/akkartik/mu/blob/main/101screen.subx</a>
<pre id='vimCodeElement'>
<span id="L1" class="LineNr"> 1 </span><span class="subxComment"># Primitives for screen control.</span>
<span id="L2" class="LineNr"> 2 </span><span class="subxComment">#</span>
<span id="L3" class="LineNr"> 3 </span><span class="subxComment"># We need to do this in machine code because Mu doesn't have global variables</span>
<span id="L4" class="LineNr"> 4 </span><span class="subxComment"># yet (for the start of video memory).</span>
<span id="L5" class="LineNr"> 5 </span>
<span id="L6" class="LineNr"> 6 </span>== code
<span id="L7" class="LineNr"> 7 </span>
<span id="L8" class="LineNr"> 8 </span><span class="subxFunction">pixel-on-real-screen</span>: <span class="subxComment"># x: int, y: int, color: int</span>
<span id="L9" class="LineNr"> 9 </span> <span class="subxS1Comment"># . prologue</span>
<span id="L10" class="LineNr">10 </span> 55/push-ebp
<span id="L11" class="LineNr">11 </span> 89/<- %ebp 4/r32/esp
<span id="L12" class="LineNr">12 </span> <span class="subxS1Comment"># . save registers</span>
<span id="L13" class="LineNr">13 </span> 50/push-eax
<span id="L14" class="LineNr">14 </span> 51/push-ecx
<span id="L15" class="LineNr">15 </span> <span class="subxComment"># bounds checks</span>
<span id="L16" class="LineNr">16 </span> 8b/-> *(ebp+8) 0/r32/eax
<span id="L17" class="LineNr">17 </span> 3d/compare-eax-and 0/imm32
<span id="L18" class="LineNr">18 </span> 7c/jump-if-< $pixel-on-real-screen:end/disp8
<span id="L19" class="LineNr">19 </span> 3d/compare-eax-and 0x400/imm32/screen-width=1024
<span id="L20" class="LineNr">20 </span> 7d/jump-if->= $pixel-on-real-screen:end/disp8
<span id="L21" class="LineNr">21 </span> 8b/-> *(ebp+0xc) 0/r32/eax
<span id="L22" class="LineNr">22 </span> 3d/compare-eax-and 0/imm32
<span id="L23" class="LineNr">23 </span> 7c/jump-if-< $pixel-on-real-screen:end/disp8
<span id="L24" class="LineNr">24 </span> 3d/compare-eax-and 0x300/imm32/screen-height=768
<span id="L25" class="LineNr">25 </span> 7d/jump-if->= $pixel-on-real-screen:end/disp8
<span id="L26" class="LineNr">26 </span> <span class="subxComment"># eax = y*1024 + x</span>
<span id="L27" class="LineNr">27 </span> 8b/-> *(ebp+0xc) 0/r32/eax
<span id="L28" class="LineNr">28 </span> c1/shift 4/subop/left %eax 0xa/imm8
<span id="L29" class="LineNr">29 </span> 03/add-> *(ebp+8) 0/r32/eax
<span id="L30" class="LineNr">30 </span> <span class="subxComment"># eax += location of frame buffer</span>
<span id="L31" class="LineNr">31 </span> 03/add-> *<span class="SpecialChar"><a href='boot.subx.html#L636'>Video-memory-addr</a></span> 0/r32/eax
<span id="L32" class="LineNr">32 </span> <span class="subxComment"># *eax = color</span>
<span id="L33" class="LineNr">33 </span> 8b/-> *(ebp+0x10) 1/r32/ecx
<span id="L34" class="LineNr">34 </span> 88/byte<- *eax 1/r32/CL
<span id="L35" class="LineNr">35 </span><span class="Constant">$pixel-on-real-screen:end</span>:
<span id="L36" class="LineNr">36 </span> <span class="subxS1Comment"># . restore registers</span>
<span id="L37" class="LineNr">37 </span> 59/pop-to-ecx
<span id="L38" class="LineNr">38 </span> 58/pop-to-eax
<span id="L39" class="LineNr">39 </span> <span class="subxS1Comment"># . epilogue</span>
<span id="L40" class="LineNr">40 </span> 89/<- %esp 5/r32/ebp
<span id="L41" class="LineNr">41 </span> 5d/pop-to-ebp
<span id="L42" class="LineNr">42 </span> c3/return
</pre>
</body>
</html>
<!-- vim: set foldmethod=manual : -->
|