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94 lines
5.5 KiB
HTML
94 lines
5.5 KiB
HTML
4 years ago
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<html lang="en">
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<head>
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<title>RTL - GNU Compiler Collection (GCC) Internals</title>
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<meta http-equiv="Content-Type" content="text/html">
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<meta name="description" content="GNU Compiler Collection (GCC) Internals">
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<meta name="generator" content="makeinfo 4.13">
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<link title="Top" rel="start" href="index.html#Top">
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<link rel="prev" href="Tree-SSA.html#Tree-SSA" title="Tree SSA">
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<link rel="next" href="Control-Flow.html#Control-Flow" title="Control Flow">
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<link href="http://www.gnu.org/software/texinfo/" rel="generator-home" title="Texinfo Homepage">
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<!--
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Copyright (C) 1988-2015 Free Software Foundation, Inc.
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Permission is granted to copy, distribute and/or modify this document
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under the terms of the GNU Free Documentation License, Version 1.3 or
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any later version published by the Free Software Foundation; with the
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Invariant Sections being ``Funding Free Software'', the Front-Cover
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Texts being (a) (see below), and with the Back-Cover Texts being (b)
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(see below). A copy of the license is included in the section entitled
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``GNU Free Documentation License''.
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(a) The FSF's Front-Cover Text is:
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A GNU Manual
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(b) The FSF's Back-Cover Text is:
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You have freedom to copy and modify this GNU Manual, like GNU
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software. Copies published by the Free Software Foundation raise
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funds for GNU development.-->
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--></style>
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</head>
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<body>
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<div class="node">
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<a name="RTL"></a>
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<p>
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Next: <a rel="next" accesskey="n" href="Control-Flow.html#Control-Flow">Control Flow</a>,
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Previous: <a rel="previous" accesskey="p" href="Tree-SSA.html#Tree-SSA">Tree SSA</a>,
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Up: <a rel="up" accesskey="u" href="index.html#Top">Top</a>
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<hr>
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</div>
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<h2 class="chapter">13 RTL Representation</h2>
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<p><a name="index-RTL-representation-2534"></a><a name="index-representation-of-RTL-2535"></a><a name="index-Register-Transfer-Language-_0028RTL_0029-2536"></a>
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The last part of the compiler work is done on a low-level intermediate
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representation called Register Transfer Language. In this language, the
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instructions to be output are described, pretty much one by one, in an
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algebraic form that describes what the instruction does.
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<p>RTL is inspired by Lisp lists. It has both an internal form, made up of
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structures that point at other structures, and a textual form that is used
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in the machine description and in printed debugging dumps. The textual
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form uses nested parentheses to indicate the pointers in the internal form.
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<ul class="menu">
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<li><a accesskey="1" href="RTL-Objects.html#RTL-Objects">RTL Objects</a>: Expressions vs vectors vs strings vs integers.
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<li><a accesskey="2" href="RTL-Classes.html#RTL-Classes">RTL Classes</a>: Categories of RTL expression objects, and their structure.
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<li><a accesskey="3" href="Accessors.html#Accessors">Accessors</a>: Macros to access expression operands or vector elts.
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<li><a accesskey="4" href="Special-Accessors.html#Special-Accessors">Special Accessors</a>: Macros to access specific annotations on RTL.
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<li><a accesskey="5" href="Flags.html#Flags">Flags</a>: Other flags in an RTL expression.
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<li><a accesskey="6" href="Machine-Modes.html#Machine-Modes">Machine Modes</a>: Describing the size and format of a datum.
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<li><a accesskey="7" href="Constants.html#Constants">Constants</a>: Expressions with constant values.
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<li><a accesskey="8" href="Regs-and-Memory.html#Regs-and-Memory">Regs and Memory</a>: Expressions representing register contents or memory.
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<li><a accesskey="9" href="Arithmetic.html#Arithmetic">Arithmetic</a>: Expressions representing arithmetic on other expressions.
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<li><a href="Comparisons.html#Comparisons">Comparisons</a>: Expressions representing comparison of expressions.
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<li><a href="Bit_002dFields.html#Bit_002dFields">Bit-Fields</a>: Expressions representing bit-fields in memory or reg.
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<li><a href="Vector-Operations.html#Vector-Operations">Vector Operations</a>: Expressions involving vector datatypes.
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<li><a href="Conversions.html#Conversions">Conversions</a>: Extending, truncating, floating or fixing.
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<li><a href="RTL-Declarations.html#RTL-Declarations">RTL Declarations</a>: Declaring volatility, constancy, etc.
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<li><a href="Side-Effects.html#Side-Effects">Side Effects</a>: Expressions for storing in registers, etc.
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<li><a href="Incdec.html#Incdec">Incdec</a>: Embedded side-effects for autoincrement addressing.
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<li><a href="Assembler.html#Assembler">Assembler</a>: Representing <code>asm</code> with operands.
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<li><a href="Debug-Information.html#Debug-Information">Debug Information</a>: Expressions representing debugging information.
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<li><a href="Insns.html#Insns">Insns</a>: Expression types for entire insns.
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<li><a href="Calls.html#Calls">Calls</a>: RTL representation of function call insns.
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<li><a href="Sharing.html#Sharing">Sharing</a>: Some expressions are unique; others *must* be copied.
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<li><a href="Reading-RTL.html#Reading-RTL">Reading RTL</a>: Reading textual RTL from a file.
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</ul>
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</body></html>
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