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8.4 KiB
HTML
127 lines
8.4 KiB
HTML
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<html lang="en">
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<head>
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<title>CRIS-Opts - Using as</title>
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<meta name="description" content="Using as">
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<link title="Top" rel="start" href="index.html#Top">
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<link rel="up" href="CRIS_002dDependent.html#CRIS_002dDependent" title="CRIS-Dependent">
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<link rel="next" href="CRIS_002dExpand.html#CRIS_002dExpand" title="CRIS-Expand">
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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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This file documents the GNU Assembler "as".
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Copyright (C) 1991-2019 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
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or any later version published by the Free Software Foundation;
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with no Invariant Sections, with no Front-Cover Texts, and with no
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Back-Cover Texts. A copy of the license is included in the
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section entitled ``GNU Free Documentation License''.
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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="CRIS-Opts"></a>
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<a name="CRIS_002dOpts"></a>
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<p>
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Next: <a rel="next" accesskey="n" href="CRIS_002dExpand.html#CRIS_002dExpand">CRIS-Expand</a>,
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Up: <a rel="up" accesskey="u" href="CRIS_002dDependent.html#CRIS_002dDependent">CRIS-Dependent</a>
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<hr>
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</div>
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<h4 class="subsection">9.9.1 Command-line Options</h4>
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<p><a name="index-options_002c-CRIS-879"></a><a name="index-CRIS-options-880"></a>The CRIS version of <code>as</code> has these
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machine-dependent command-line options.
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<p><a name="index-g_t_0040option_007b_002d_002demulation_003dcriself_007d-command_002dline-option_002c-CRIS-881"></a><a name="index-g_t_0040option_007b_002d_002demulation_003dcrisaout_007d-command_002dline-option_002c-CRIS-882"></a><a name="index-CRIS-_0040option_007b_002d_002demulation_003dcriself_007d-command_002dline-option-883"></a><a name="index-CRIS-_0040option_007b_002d_002demulation_003dcrisaout_007d-command_002dline-option-884"></a>
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The format of the generated object files can be either ELF or
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a.out, specified by the command-line options
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<samp><span class="option">--emulation=crisaout</span></samp> and <samp><span class="option">--emulation=criself</span></samp>.
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The default is ELF (criself), unless <code>as</code> has been
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configured specifically for a.out by using the configuration
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name <code>cris-axis-aout</code>.
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<p><a name="index-g_t_0040option_007b_002d_002dunderscore_007d-command_002dline-option_002c-CRIS-885"></a><a name="index-g_t_0040option_007b_002d_002dno_002dunderscore_007d-command_002dline-option_002c-CRIS-886"></a><a name="index-CRIS-_0040option_007b_002d_002dunderscore_007d-command_002dline-option-887"></a><a name="index-CRIS-_0040option_007b_002d_002dno_002dunderscore_007d-command_002dline-option-888"></a>There are two different link-incompatible ELF object file
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variants for CRIS, for use in environments where symbols are
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expected to be prefixed by a leading ‘<samp><span class="samp">_</span></samp>’ character and for
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environments without such a symbol prefix. The variant used for
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GNU/Linux port has no symbol prefix. Which variant to produce
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is specified by either of the options <samp><span class="option">--underscore</span></samp> and
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<samp><span class="option">--no-underscore</span></samp>. The default is <samp><span class="option">--underscore</span></samp>.
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Since symbols in CRIS a.out objects are expected to have a
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‘<samp><span class="samp">_</span></samp>’ prefix, specifying <samp><span class="option">--no-underscore</span></samp> when
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generating a.out objects is an error. Besides the object format
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difference, the effect of this option is to parse register names
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differently (see <a href="crisnous.html#crisnous">crisnous</a>). The <samp><span class="option">--no-underscore</span></samp>
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option makes a ‘<samp><span class="samp">$</span></samp>’ register prefix mandatory.
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<p><a name="index-g_t_0040option_007b_002d_002dpic_007d-command_002dline-option_002c-CRIS-889"></a><a name="index-CRIS-_0040option_007b_002d_002dpic_007d-command_002dline-option-890"></a><a name="index-Position_002dindependent-code_002c-CRIS-891"></a><a name="index-CRIS-position_002dindependent-code-892"></a>The option <samp><span class="option">--pic</span></samp> must be passed to <code>as</code> in
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order to recognize the symbol syntax used for ELF (SVR4 PIC)
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position-independent-code (see <a href="crispic.html#crispic">crispic</a>). This will also
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affect expansion of instructions. The expansion with
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<samp><span class="option">--pic</span></samp> will use PC-relative rather than (slightly
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faster) absolute addresses in those expansions. This option is only
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valid when generating ELF format object files.
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<p><a name="index-g_t_0040option_007b_002d_002dmarch_003d_0040var_007barchitecture_007d_007d-command_002dline-option_002c-CRIS-893"></a><a name="index-CRIS-_0040option_007b_002d_002dmarch_003d_0040var_007barchitecture_007d_007d-command_002dline-option-894"></a><a name="index-Architecture-variant-option_002c-CRIS-895"></a><a name="index-CRIS-architecture-variant-option-896"></a>The option <samp><span class="option">--march=</span><var>architecture</var></samp>
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<a name="march_002doption"></a>specifies the recognized instruction set
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and recognized register names. It also controls the
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architecture type of the object file. Valid values for
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<var>architecture</var> are:
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<dl>
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<dt><code>v0_v10</code><dd>All instructions and register names for any architecture variant
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in the set v0<small class="dots">...</small>v10 are recognized. This is the
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default if the target is configured as cris-*.
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<br><dt><code>v10</code><dd>Only instructions and register names for CRIS v10 (as found in
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ETRAX 100 LX) are recognized. This is the default if the target
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is configured as crisv10-*.
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<br><dt><code>v32</code><dd>Only instructions and register names for CRIS v32 (code name
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Guinness) are recognized. This is the default if the target is
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configured as crisv32-*. This value implies
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<samp><span class="option">--no-mul-bug-abort</span></samp>. (A subsequent
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<samp><span class="option">--mul-bug-abort</span></samp> will turn it back on.)
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<br><dt><code>common_v10_v32</code><dd>Only instructions with register names and addressing modes with
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opcodes common to the v10 and v32 are recognized.
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</dl>
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<p><a name="index-g_t_0040option_007b_002dN_007d-command_002dline-option_002c-CRIS-897"></a><a name="index-CRIS-_0040option_007b_002dN_007d-command_002dline-option-898"></a>When <samp><span class="option">-N</span></samp> is specified, <code>as</code> will emit a
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warning when a 16-bit branch instruction is expanded into a
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32-bit multiple-instruction construct (see <a href="CRIS_002dExpand.html#CRIS_002dExpand">CRIS-Expand</a>).
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<p><a name="index-g_t_0040option_007b_002d_002dno_002dmul_002dbug_002dabort_007d-command_002dline-option_002c-CRIS-899"></a><a name="index-g_t_0040option_007b_002d_002dmul_002dbug_002dabort_007d-command_002dline-option_002c-CRIS-900"></a><a name="index-CRIS-_0040option_007b_002d_002dno_002dmul_002dbug_002dabort_007d-command_002dline-option-901"></a><a name="index-CRIS-_0040option_007b_002d_002dmul_002dbug_002dabort_007d-command_002dline-option-902"></a>
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Some versions of the CRIS v10, for example in the Etrax 100 LX,
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contain a bug that causes destabilizing memory accesses when a
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multiply instruction is executed with certain values in the
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first operand just before a cache-miss. When the
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<samp><span class="option">--mul-bug-abort</span></samp> command-line option is active (the
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default value), <code>as</code> will refuse to assemble a file
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containing a multiply instruction at a dangerous offset, one
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that could be the last on a cache-line, or is in a section with
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insufficient alignment. This placement checking does not catch
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any case where the multiply instruction is dangerously placed
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because it is located in a delay-slot. The
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<samp><span class="option">--mul-bug-abort</span></samp> command-line option turns off the
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checking.
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</body></html>
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