1Imager::Expr::Assem(3)User Contributed Perl DocumentationImager::Expr::Assem(3)
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NAME

6         Imager::Expr::Assem - an assembler for producing code for the Imager
7         register machine
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SYNOPSIS

10         use Imager::Expr::Assem;
11         my $expr = Imager::Expr->new(assem=>'...', ...)
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DESCRIPTION

14       This module is a simple Imager::Expr compiler that compiles a low-level
15       language that has a nearly 1-to-1 relationship to the internal
16       representation used for compiled register machine code.
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18   Syntax
19       Each line can contain multiple statements separated by semi-colons.
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21       Anything after '#' in a line is ignored.
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23       Types of statements:
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25       variable definition
26               "var" name:type
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28           defines variable name to have type, which can be any of "n" or
29           "num" for a numeric type or "pixel", "p" or "c" for a pixel or
30           color type.
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32           Variable names cannot include white-space.
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34       operators
35           Operators can be split into 3 basic types, those that have a result
36           value, those that don't and the null operator, eg. jump has no
37           value.
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39           The format for operators that return a value is typically:
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41               result = operator operand ...
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43           and for those that don't return a value:
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45               operator operand
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47           where operator is any valid register machine operator, result is
48           any variable defined with "var", and operands are variables,
49           constants or literals, or for jump operators, labels.
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51           The set operator can be simplified to:
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53               result = operator
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55           All operators maybe preceded by a label, which is any non-white-
56           space text immediately followed by a colon (':').
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BUGS

59       Note that the current optimizer may produce incorrect optimization for
60       your code, fortunately the optimizer will disable itself if you include
61       any jump operator in your code.  A single jump to anywhere after your
62       final "ret" operator can be used to disable the optimizer without
63       slowing down your code.
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65       There's currently no high-level code generation that can generate code
66       with loops or real conditions.
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SEE ALSO

69       Imager(3), transform.perl, regmach.c
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AUTHOR

72       Tony Cook <tony@develop-help.com>
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76perl v5.12.3                      2011-06-06            Imager::Expr::Assem(3)