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| 2 | +<html> |
| 3 | +<head> |
| 4 | +<title>API Extensions</title> |
| 5 | +<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1"> |
| 6 | +<meta name="Author" content="Mike Pall"> |
| 7 | +<meta name="Copyright" content="Copyright (C) 2005-2009, Mike Pall"> |
| 8 | +<meta name="Language" content="en"> |
| 9 | +<link rel="stylesheet" type="text/css" href="bluequad.css" media="screen"> |
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| 11 | +</head> |
| 12 | +<body> |
| 13 | +<div id="site"> |
| 14 | +<a href="http://luajit.org"><span>Lua<span id="logo">JIT</span></span></a> |
| 15 | +</div> |
| 16 | +<div id="head"> |
| 17 | +<h1>API Extensions</h1> |
| 18 | +</div> |
| 19 | +<div id="nav"> |
| 20 | +<ul><li> |
| 21 | +<a href="luajit.html">LuaJIT</a> |
| 22 | +<ul><li> |
| 23 | +<a href="install.html">Installation</a> |
| 24 | +</li><li> |
| 25 | +<a href="running.html">Running</a> |
| 26 | +</li><li> |
| 27 | +<a class="current" href="api.html">API Extensions</a> |
| 28 | +</li></ul> |
| 29 | +</li><li> |
| 30 | +<a href="status.html">Status</a> |
| 31 | +<ul><li> |
| 32 | +<a href="changes.html">Changes</a> |
| 33 | +</li></ul> |
| 34 | +</li><li> |
| 35 | +<a href="faq.html">FAQ</a> |
| 36 | +</li><li> |
| 37 | +<a href="http://luajit.org/download.html">Download <span class="ext">»</span></a> |
| 38 | +</li></ul> |
| 39 | +</div> |
| 40 | +<div id="main"> |
| 41 | +<p> |
| 42 | +LuaJIT is fully upwards-compatible with Lua 5.1. It supports all |
| 43 | +<a href="http://www.lua.org/manual/5.1/manual.html#5"><span class="ext">»</span> standard Lua |
| 44 | +library functions</a> and the full set of |
| 45 | +<a href="http://www.lua.org/manual/5.1/manual.html#3"><span class="ext">»</span> Lua/C API |
| 46 | +functions</a>. |
| 47 | +</p> |
| 48 | +<p> |
| 49 | +LuaJIT is also fully ABI-compatible to Lua 5.1 at the linker/dynamic |
| 50 | +loader level. This means you can compile a C module against the |
| 51 | +standard Lua headers and load the same shared library from either Lua |
| 52 | +or LuaJIT. |
| 53 | +</p> |
| 54 | + |
| 55 | +<h2 id="bit"><tt>bit.*</tt> — Bitwise Operations</h2> |
| 56 | +<p> |
| 57 | +LuaJIT supports all bitwise operations as defined by |
| 58 | +<a href="http://bitop.luajit.org"><span class="ext">»</span> Lua BitOp</a>: |
| 59 | +</p> |
| 60 | +<pre class="code"> |
| 61 | +bit.tobit bit.tohex bit.bnot bit.band bit.bor bit.bxor |
| 62 | +bit.lshift bit.rshift bit.arshift bit.rol bit.ror bit.bswap |
| 63 | +</pre> |
| 64 | +<p> |
| 65 | +This module is a LuaJIT built-in — you don't need to download or |
| 66 | +install Lua BitOp. The Lua BitOp site has full documentation for all |
| 67 | +<a href="http://bitop.luajit.org/api.html"><span class="ext">»</span> Lua BitOp API functions</a>. |
| 68 | +</p> |
| 69 | +<p> |
| 70 | +Please make sure to <tt>require</tt> the module before using any of |
| 71 | +its functions: |
| 72 | +</p> |
| 73 | +<pre class="code"> |
| 74 | +local bit = require("bit") |
| 75 | +</pre> |
| 76 | +<p> |
| 77 | +An already installed Lua BitOp module is ignored by LuaJIT. |
| 78 | +This way you can use bit operations from both Lua and LuaJIT on a |
| 79 | +shared installation. |
| 80 | +</p> |
| 81 | + |
| 82 | +<h2 id="jit"><tt>jit.*</tt> — JIT compiler control</h2> |
| 83 | +<p> |
| 84 | +The functions in this built-in module control the behavior |
| 85 | +of the JIT compiler engine. |
| 86 | +</p> |
| 87 | + |
| 88 | +<h3 id="jit_onoff"><tt>jit.on()<br> |
| 89 | +jit.off()</tt></h3> |
| 90 | +<p> |
| 91 | +Turns the whole JIT compiler on (default) or off. |
| 92 | +</p> |
| 93 | +<p> |
| 94 | +These functions are typically used with the command line options |
| 95 | +<tt>-j on</tt> or <tt>-j off</tt>. |
| 96 | +</p> |
| 97 | + |
| 98 | +<h3 id="jit_flush"><tt>jit.flush()</tt></h3> |
| 99 | +<p> |
| 100 | +Flushes the whole cache of compiled code. |
| 101 | +</p> |
| 102 | + |
| 103 | +<h3 id="jit_flush_tr"><tt>jit.flush(tr)</tt></h3> |
| 104 | +<p> |
| 105 | +Flushes the code for the specified root trace and all of its |
| 106 | +side traces from the cache. |
| 107 | +</p> |
| 108 | + |
| 109 | +<h3 id="jit_onoff_func"><tt>jit.on(func|true [,true|false])<br> |
| 110 | +jit.off(func|true [,true|false])<br> |
| 111 | +jit.flush(func|true [,true|false])</tt></h3> |
| 112 | +<p> |
| 113 | +<tt>jit.on</tt> enables JIT compilation for a Lua function (this is |
| 114 | +the default). |
| 115 | +</p> |
| 116 | +<p> |
| 117 | +<tt>jit.off</tt> disables JIT compilation for a Lua function and |
| 118 | +flushes any already compiled code from the code cache. |
| 119 | +</p> |
| 120 | +<p> |
| 121 | +<tt>jit.flush</tt> flushes the code, but doesn't affect the |
| 122 | +enable/disable status. |
| 123 | +</p> |
| 124 | +<p> |
| 125 | +The current function, i.e. the Lua function calling this library |
| 126 | +function, can also be specified by passing <tt>true</tt> as the first |
| 127 | +argument. |
| 128 | +</p> |
| 129 | +<p> |
| 130 | +If the second argument is <tt>true</tt>, JIT compilation is also |
| 131 | +enabled, disabled or flushed recursively for all subfunctions of a |
| 132 | +function. With <tt>false</tt> only the subfunctions are affected. |
| 133 | +</p> |
| 134 | +<p> |
| 135 | +The <tt>jit.on</tt> and <tt>jit.off</tt> functions only set a flag |
| 136 | +which is checked when the function is about to be compiled. They do |
| 137 | +not trigger immediate compilation. |
| 138 | +</p> |
| 139 | +<p> |
| 140 | +Typical usage is <tt>jit.off(true, true)</tt> in the main chunk |
| 141 | +of a module to turn off JIT compilation for the whole module for |
| 142 | +debugging purposes. |
| 143 | +</p> |
| 144 | + |
| 145 | +<h3 id="jit_version"><tt>jit.version</tt></h3> |
| 146 | +<p> |
| 147 | +Contains the LuaJIT version string. |
| 148 | +</p> |
| 149 | + |
| 150 | +<h3 id="jit_version_num"><tt>jit.version_num</tt></h3> |
| 151 | +<p> |
| 152 | +Contains the version number of the LuaJIT core. Version xx.yy.zz |
| 153 | +is represented by the decimal number xxyyzz. |
| 154 | +</p> |
| 155 | + |
| 156 | +<h3 id="jit_arch"><tt>jit.arch</tt></h3> |
| 157 | +<p> |
| 158 | +Contains the target architecture name (CPU and optional ABI). |
| 159 | +</p> |
| 160 | + |
| 161 | +<h2 id="jit_opt"><tt>jit.opt.*</tt> — JIT compiler optimization control</h2> |
| 162 | +<p> |
| 163 | +This module provides the backend for the <tt>-O</tt> command line |
| 164 | +option. |
| 165 | +</p> |
| 166 | +<p> |
| 167 | +You can also use it programmatically, e.g.: |
| 168 | +</p> |
| 169 | +<pre class="code"> |
| 170 | +jit.opt.start(2) -- same as -O2 |
| 171 | +jit.opt.start("-dce") |
| 172 | +jit.opt.start("hotloop=10", "hotexit=2") |
| 173 | +</pre> |
| 174 | +<p> |
| 175 | +Unlike in LuaJIT 1.x, the module is built-in and |
| 176 | +<b>optimization is turned on by default!</b> |
| 177 | +It's no longer necessary to run <tt>require("jit.opt").start()</tt>, |
| 178 | +which was one of the ways to enable optimization. |
| 179 | +</p> |
| 180 | + |
| 181 | +<h2 id="jit_util"><tt>jit.util.*</tt> — JIT compiler introspection</h2> |
| 182 | +<p> |
| 183 | +This module holds functions to introspect the bytecode, generated |
| 184 | +traces, the IR and the generated machine code. The functionality |
| 185 | +provided by this module is still in flux and therefore undocumented. |
| 186 | +</p> |
| 187 | +<p> |
| 188 | +The debug modules <tt>-jbc</tt>, <tt>-jv</tt> and <tt>-jdump</tt> make |
| 189 | +extensive use of these functions. Please check out their source code, |
| 190 | +if you want to know more. |
| 191 | +</p> |
| 192 | +<br class="flush"> |
| 193 | +</div> |
| 194 | +<div id="foot"> |
| 195 | +<hr class="hide"> |
| 196 | +Copyright © 2005-2009 Mike Pall |
| 197 | +<span class="noprint"> |
| 198 | +· |
| 199 | +<a href="contact.html">Contact</a> |
| 200 | +</span> |
| 201 | +</div> |
| 202 | +</body> |
| 203 | +</html> |
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