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Added resolve passes
author lost@starbug
date Wed, 14 Apr 2010 20:49:04 -0600
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children 34dfc9747f23
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1 LWASM Internals
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2 ===============
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3
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4 LWASM is a table-driven assembler that notionally uses two passes. However,
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5 it implements its assembly in several passes as follows.
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7 Pass 1
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8 ------
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10 This pass reads the entire source code and parses each line into an internal
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11 representation. Macros, file inclusions, and conditional assembly
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12 instructions are resolved at this point as well. Instructions with known
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13 sizes will have their sizes resolved at this point.
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15 Pass 2
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16 ------
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18 Check all exported symbols for validity and set them as imports if the
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19 assembler state says so. Also resolve all symbol references in all
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20 expressions to be direct references either to the symbol table or
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21 to the import list.
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23 Pass 3
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24 ------
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26 This pass resolves all instruction sizes that can be resolved without
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27 forcing any instruction sizes. This pass will run repeatedly until no
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28 no new resolution occurs.
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30 Pass 4
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31 ------
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33 Work through all un-resolved instructions and force sizes. After each size
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34 is forced, try re-resolving all other instructions. This is done starting
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35 at the beginning of the source and working forward. If any instruction does
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36 not resolve when forced, an error will be thrown.