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author | Kartik Agaram <vc@akkartik.com> | 2019-01-16 00:12:55 -0800 |
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committer | Kartik Agaram <vc@akkartik.com> | 2019-01-16 00:12:55 -0800 |
commit | 76733e1995222034c11c4af542c799c648b79678 (patch) | |
tree | 9a341b0984e782c7c6e536950d9ed23a34c4bf93 /html/subx/066allocate.subx.html | |
parent | 05cffaa69feed557cf09ba8d81f4959e1ff6610a (diff) | |
download | mu-76733e1995222034c11c4af542c799c648b79678.tar.gz |
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-rw-r--r-- | html/subx/066allocate.subx.html | 271 |
1 files changed, 0 insertions, 271 deletions
diff --git a/html/subx/066allocate.subx.html b/html/subx/066allocate.subx.html deleted file mode 100644 index 74be6f73..00000000 --- a/html/subx/066allocate.subx.html +++ /dev/null @@ -1,271 +0,0 @@ -<!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 - subx/066allocate.subx</title> -<meta name="Generator" content="Vim/8.0"> -<meta name="plugin-version" content="vim7.4_v2"> -<meta name="syntax" content="none"> -<meta name="settings" content="number_lines,use_css,no_foldcolumn,expand_tabs,line_ids,prevent_copy="> -<meta name="colorscheme" content="minimal-light"> -<style type="text/css"> -<!-- -pre { font-family: monospace; color: #000000; background-color: #c6c6c6; } -body { font-size:12pt; font-family: monospace; color: #000000; background-color: #c6c6c6; } -a { color:inherit; } -* { font-size:12pt; font-size: 1em; } -.subxComment { color: #005faf; } -.Constant { color: #008787; } -.LineNr { } -.subxS1Comment { color: #0000af; } -.SpecialChar { color: #d70000; } -.subxFunction { color: #af5f00; text-decoration: underline; } -.subxTest { color: #5f8700; } -.Normal { color: #000000; background-color: #c6c6c6; padding-bottom: 1px; } -.subxS2Comment { color: #8a8a8a; } ---> -</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; - } - 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/master/subx/066allocate.subx'>https://github.com/akkartik/mu/blob/master/subx/066allocate.subx</a> -<pre id='vimCodeElement'> -<span id="L1" class="LineNr"> 1 </span><span class="subxComment"># Helper to dynamically allocate memory on the heap.</span> -<span id="L2" class="LineNr"> 2 </span><span class="subxComment">#</span> -<span id="L3" class="LineNr"> 3 </span><span class="subxComment"># We'd like to be able to write tests for functions that allocate memory,</span> -<span id="L4" class="LineNr"> 4 </span><span class="subxComment"># making assertions on the precise addresses used. To achieve this we'll pass</span> -<span id="L5" class="LineNr"> 5 </span><span class="subxComment"># in an *allocation descriptor* to allocate from.</span> -<span id="L6" class="LineNr"> 6 </span><span class="subxComment">#</span> -<span id="L7" class="LineNr"> 7 </span><span class="subxComment"># Allocation descriptors are also useful outside of tests. Assembly and machine</span> -<span id="L8" class="LineNr"> 8 </span><span class="subxComment"># code are of necessity unsafe languages, and one of the most insidious kinds</span> -<span id="L9" class="LineNr"> 9 </span><span class="subxComment"># of bugs unsafe languages expose us to are dangling pointers to memory that</span> -<span id="L10" class="LineNr"> 10 </span><span class="subxComment"># has been freed and potentially even reused for something totally different.</span> -<span id="L11" class="LineNr"> 11 </span><span class="subxComment"># To reduce the odds of such "use after free" errors, SubX programs tend to not</span> -<span id="L12" class="LineNr"> 12 </span><span class="subxComment"># reclaim and reuse dynamically allocated memory. (Running out of memory is far</span> -<span id="L13" class="LineNr"> 13 </span><span class="subxComment"># easier to debug.) Long-running programs that want to reuse memory are mostly</span> -<span id="L14" class="LineNr"> 14 </span><span class="subxComment"># on their own to be careful. However, they do get one bit of help: they can</span> -<span id="L15" class="LineNr"> 15 </span><span class="subxComment"># carve out chunks of memory and then allocate from them manually using this</span> -<span id="L16" class="LineNr"> 16 </span><span class="subxComment"># very same 'allocate' helper. They just need a new allocation descriptor for</span> -<span id="L17" class="LineNr"> 17 </span><span class="subxComment"># their book-keeping.</span> -<span id="L18" class="LineNr"> 18 </span> -<span id="L19" class="LineNr"> 19 </span>== data -<span id="L20" class="LineNr"> 20 </span> -<span id="L21" class="LineNr"> 21 </span><span class="subxComment"># The 'global' allocation descriptor. Pass this into 'allocate' to claim a</span> -<span id="L22" class="LineNr"> 22 </span><span class="subxComment"># hitherto unused bit of memory.</span> -<span id="L23" class="LineNr"> 23 </span><span class="SpecialChar">Heap</span>: -<span id="L24" class="LineNr"> 24 </span> <span class="Special |