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295 lines
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HTML
295 lines
19 KiB
HTML
4 years ago
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<html lang="en">
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<head>
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<title>Nios II Options - Using the GNU Compiler Collection (GCC)</title>
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<meta http-equiv="Content-Type" content="text/html">
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<meta name="description" content="Using the GNU Compiler Collection (GCC)">
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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="up" href="Submodel-Options.html#Submodel-Options" title="Submodel Options">
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<link rel="prev" href="NDS32-Options.html#NDS32-Options" title="NDS32 Options">
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<link rel="next" href="Nvidia-PTX-Options.html#Nvidia-PTX-Options" title="Nvidia PTX Options">
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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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funds for GNU development.-->
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<style type="text/css"><!--
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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="Nios-II-Options"></a>
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<p>
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Next: <a rel="next" accesskey="n" href="Nvidia-PTX-Options.html#Nvidia-PTX-Options">Nvidia PTX Options</a>,
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Previous: <a rel="previous" accesskey="p" href="NDS32-Options.html#NDS32-Options">NDS32 Options</a>,
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Up: <a rel="up" accesskey="u" href="Submodel-Options.html#Submodel-Options">Submodel Options</a>
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<hr>
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</div>
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<h4 class="subsection">3.17.31 Nios II Options</h4>
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<p><a name="index-Nios-II-options-2135"></a><a name="index-Altera-Nios-II-options-2136"></a>
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These are the options defined for the Altera Nios II processor.
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<dl>
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<dt><code>-G </code><var>num</var><dd><a name="index-G-2137"></a><a name="index-smaller-data-references-2138"></a>Put global and static objects less than or equal to <var>num</var> bytes
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into the small data or BSS sections instead of the normal data or BSS
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sections. The default value of <var>num</var> is 8.
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<br><dt><code>-mgpopt=</code><var>option</var><br><dt><code>-mgpopt</code><dt><code>-mno-gpopt</code><dd><a name="index-mgpopt-2139"></a><a name="index-mno_002dgpopt-2140"></a>Generate (do not generate) GP-relative accesses. The following
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<var>option</var> names are recognized:
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<dl>
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<dt>‘<samp><span class="samp">none</span></samp>’<dd>Do not generate GP-relative accesses.
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<br><dt>‘<samp><span class="samp">local</span></samp>’<dd>Generate GP-relative accesses for small data objects that are not
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external or weak. Also use GP-relative addressing for objects that
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have been explicitly placed in a small data section via a <code>section</code>
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attribute.
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<br><dt>‘<samp><span class="samp">global</span></samp>’<dd>As for ‘<samp><span class="samp">local</span></samp>’, but also generate GP-relative accesses for
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small data objects that are external or weak. If you use this option,
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you must ensure that all parts of your program (including libraries) are
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compiled with the same <samp><span class="option">-G</span></samp> setting.
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<br><dt>‘<samp><span class="samp">data</span></samp>’<dd>Generate GP-relative accesses for all data objects in the program. If you
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use this option, the entire data and BSS segments
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of your program must fit in 64K of memory and you must use an appropriate
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linker script to allocate them within the addressible range of the
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global pointer.
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<br><dt>‘<samp><span class="samp">all</span></samp>’<dd>Generate GP-relative addresses for function pointers as well as data
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pointers. If you use this option, the entire text, data, and BSS segments
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of your program must fit in 64K of memory and you must use an appropriate
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linker script to allocate them within the addressible range of the
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global pointer.
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</dl>
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<p><samp><span class="option">-mgpopt</span></samp> is equivalent to <samp><span class="option">-mgpopt=local</span></samp>, and
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<samp><span class="option">-mno-gpopt</span></samp> is equivalent to <samp><span class="option">-mgpopt=none</span></samp>.
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<p>The default is <samp><span class="option">-mgpopt</span></samp> except when <samp><span class="option">-fpic</span></samp> or
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<samp><span class="option">-fPIC</span></samp> is specified to generate position-independent code.
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Note that the Nios II ABI does not permit GP-relative accesses from
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shared libraries.
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<p>You may need to specify <samp><span class="option">-mno-gpopt</span></samp> explicitly when building
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programs that include large amounts of small data, including large
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GOT data sections. In this case, the 16-bit offset for GP-relative
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addressing may not be large enough to allow access to the entire
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small data section.
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<br><dt><code>-mel</code><dt><code>-meb</code><dd><a name="index-mel-2141"></a><a name="index-meb-2142"></a>Generate little-endian (default) or big-endian (experimental) code,
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respectively.
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<br><dt><code>-mbypass-cache</code><dt><code>-mno-bypass-cache</code><dd><a name="index-mno_002dbypass_002dcache-2143"></a><a name="index-mbypass_002dcache-2144"></a>Force all load and store instructions to always bypass cache by
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using I/O variants of the instructions. The default is not to
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bypass the cache.
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<br><dt><code>-mno-cache-volatile</code><dt><code>-mcache-volatile</code><dd><a name="index-mcache_002dvolatile-2145"></a><a name="index-mno_002dcache_002dvolatile-2146"></a>Volatile memory access bypass the cache using the I/O variants of
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the load and store instructions. The default is not to bypass the cache.
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<br><dt><code>-mno-fast-sw-div</code><dt><code>-mfast-sw-div</code><dd><a name="index-mno_002dfast_002dsw_002ddiv-2147"></a><a name="index-mfast_002dsw_002ddiv-2148"></a>Do not use table-based fast divide for small numbers. The default
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is to use the fast divide at <samp><span class="option">-O3</span></samp> and above.
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<br><dt><code>-mno-hw-mul</code><dt><code>-mhw-mul</code><dt><code>-mno-hw-mulx</code><dt><code>-mhw-mulx</code><dt><code>-mno-hw-div</code><dt><code>-mhw-div</code><dd><a name="index-mno_002dhw_002dmul-2149"></a><a name="index-mhw_002dmul-2150"></a><a name="index-mno_002dhw_002dmulx-2151"></a><a name="index-mhw_002dmulx-2152"></a><a name="index-mno_002dhw_002ddiv-2153"></a><a name="index-mhw_002ddiv-2154"></a>Enable or disable emitting <code>mul</code>, <code>mulx</code> and <code>div</code> family of
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instructions by the compiler. The default is to emit <code>mul</code>
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and not emit <code>div</code> and <code>mulx</code>.
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<br><dt><code>-mcustom-</code><var>insn</var><code>=</code><var>N</var><dt><code>-mno-custom-</code><var>insn</var><dd><a name="index-mcustom_002d_0040var_007binsn_007d-2155"></a><a name="index-mno_002dcustom_002d_0040var_007binsn_007d-2156"></a>Each <samp><span class="option">-mcustom-</span><var>insn</var><span class="option">=</span><var>N</var></samp> option enables use of a
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custom instruction with encoding <var>N</var> when generating code that uses
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<var>insn</var>. For example, <samp><span class="option">-mcustom-fadds=253</span></samp> generates custom
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instruction 253 for single-precision floating-point add operations instead
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of the default behavior of using a library call.
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<p>The following values of <var>insn</var> are supported. Except as otherwise
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noted, floating-point operations are expected to be implemented with
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normal IEEE 754 semantics and correspond directly to the C operators or the
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equivalent GCC built-in functions (see <a href="Other-Builtins.html#Other-Builtins">Other Builtins</a>).
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<p>Single-precision floating point:
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<dl>
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<dt>‘<samp><span class="samp">fadds</span></samp>’, ‘<samp><span class="samp">fsubs</span></samp>’, ‘<samp><span class="samp">fdivs</span></samp>’, ‘<samp><span class="samp">fmuls</span></samp>’<dd>Binary arithmetic operations.
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<br><dt>‘<samp><span class="samp">fnegs</span></samp>’<dd>Unary negation.
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<br><dt>‘<samp><span class="samp">fabss</span></samp>’<dd>Unary absolute value.
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<br><dt>‘<samp><span class="samp">fcmpeqs</span></samp>’, ‘<samp><span class="samp">fcmpges</span></samp>’, ‘<samp><span class="samp">fcmpgts</span></samp>’, ‘<samp><span class="samp">fcmples</span></samp>’, ‘<samp><span class="samp">fcmplts</span></samp>’, ‘<samp><span class="samp">fcmpnes</span></samp>’<dd>Comparison operations.
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<br><dt>‘<samp><span class="samp">fmins</span></samp>’, ‘<samp><span class="samp">fmaxs</span></samp>’<dd>Floating-point minimum and maximum. These instructions are only
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generated if <samp><span class="option">-ffinite-math-only</span></samp> is specified.
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<br><dt>‘<samp><span class="samp">fsqrts</span></samp>’<dd>Unary square root operation.
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<br><dt>‘<samp><span class="samp">fcoss</span></samp>’, ‘<samp><span class="samp">fsins</span></samp>’, ‘<samp><span class="samp">ftans</span></samp>’, ‘<samp><span class="samp">fatans</span></samp>’, ‘<samp><span class="samp">fexps</span></samp>’, ‘<samp><span class="samp">flogs</span></samp>’<dd>Floating-point trigonometric and exponential functions. These instructions
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are only generated if <samp><span class="option">-funsafe-math-optimizations</span></samp> is also specified.
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</dl>
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<p>Double-precision floating point:
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<dl>
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<dt>‘<samp><span class="samp">faddd</span></samp>’, ‘<samp><span class="samp">fsubd</span></samp>’, ‘<samp><span class="samp">fdivd</span></samp>’, ‘<samp><span class="samp">fmuld</span></samp>’<dd>Binary arithmetic operations.
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<br><dt>‘<samp><span class="samp">fnegd</span></samp>’<dd>Unary negation.
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<br><dt>‘<samp><span class="samp">fabsd</span></samp>’<dd>Unary absolute value.
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<br><dt>‘<samp><span class="samp">fcmpeqd</span></samp>’, ‘<samp><span class="samp">fcmpged</span></samp>’, ‘<samp><span class="samp">fcmpgtd</span></samp>’, ‘<samp><span class="samp">fcmpled</span></samp>’, ‘<samp><span class="samp">fcmpltd</span></samp>’, ‘<samp><span class="samp">fcmpned</span></samp>’<dd>Comparison operations.
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<br><dt>‘<samp><span class="samp">fmind</span></samp>’, ‘<samp><span class="samp">fmaxd</span></samp>’<dd>Double-precision minimum and maximum. These instructions are only
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generated if <samp><span class="option">-ffinite-math-only</span></samp> is specified.
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<br><dt>‘<samp><span class="samp">fsqrtd</span></samp>’<dd>Unary square root operation.
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<br><dt>‘<samp><span class="samp">fcosd</span></samp>’, ‘<samp><span class="samp">fsind</span></samp>’, ‘<samp><span class="samp">ftand</span></samp>’, ‘<samp><span class="samp">fatand</span></samp>’, ‘<samp><span class="samp">fexpd</span></samp>’, ‘<samp><span class="samp">flogd</span></samp>’<dd>Double-precision trigonometric and exponential functions. These instructions
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are only generated if <samp><span class="option">-funsafe-math-optimizations</span></samp> is also specified.
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</dl>
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<p>Conversions:
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<dl>
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<dt>‘<samp><span class="samp">fextsd</span></samp>’<dd>Conversion from single precision to double precision.
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<br><dt>‘<samp><span class="samp">ftruncds</span></samp>’<dd>Conversion from double precision to single precision.
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<br><dt>‘<samp><span class="samp">fixsi</span></samp>’, ‘<samp><span class="samp">fixsu</span></samp>’, ‘<samp><span class="samp">fixdi</span></samp>’, ‘<samp><span class="samp">fixdu</span></samp>’<dd>Conversion from floating point to signed or unsigned integer types, with
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truncation towards zero.
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<br><dt>‘<samp><span class="samp">round</span></samp>’<dd>Conversion from single-precision floating point to signed integer,
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rounding to the nearest integer and ties away from zero.
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This corresponds to the <code>__builtin_lroundf</code> function when
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<samp><span class="option">-fno-math-errno</span></samp> is used.
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<br><dt>‘<samp><span class="samp">floatis</span></samp>’, ‘<samp><span class="samp">floatus</span></samp>’, ‘<samp><span class="samp">floatid</span></samp>’, ‘<samp><span class="samp">floatud</span></samp>’<dd>Conversion from signed or unsigned integer types to floating-point types.
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</dl>
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<p>In addition, all of the following transfer instructions for internal
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registers X and Y must be provided to use any of the double-precision
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floating-point instructions. Custom instructions taking two
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double-precision source operands expect the first operand in the
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64-bit register X. The other operand (or only operand of a unary
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operation) is given to the custom arithmetic instruction with the
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least significant half in source register <var>src1</var> and the most
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significant half in <var>src2</var>. A custom instruction that returns a
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double-precision result returns the most significant 32 bits in the
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destination register and the other half in 32-bit register Y.
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GCC automatically generates the necessary code sequences to write
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register X and/or read register Y when double-precision floating-point
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instructions are used.
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<dl>
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<dt>‘<samp><span class="samp">fwrx</span></samp>’<dd>Write <var>src1</var> into the least significant half of X and <var>src2</var> into
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the most significant half of X.
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<br><dt>‘<samp><span class="samp">fwry</span></samp>’<dd>Write <var>src1</var> into Y.
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<br><dt>‘<samp><span class="samp">frdxhi</span></samp>’, ‘<samp><span class="samp">frdxlo</span></samp>’<dd>Read the most or least (respectively) significant half of X and store it in
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<var>dest</var>.
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<br><dt>‘<samp><span class="samp">frdy</span></samp>’<dd>Read the value of Y and store it into <var>dest</var>.
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</dl>
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<p>Note that you can gain more local control over generation of Nios II custom
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instructions by using the <code>target("custom-</code><var>insn</var><code>=</code><var>N</var><code>")</code>
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and <code>target("no-custom-</code><var>insn</var><code>")</code> function attributes
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(see <a href="Function-Attributes.html#Function-Attributes">Function Attributes</a>)
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or pragmas (see <a href="Function-Specific-Option-Pragmas.html#Function-Specific-Option-Pragmas">Function Specific Option Pragmas</a>).
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<br><dt><code>-mcustom-fpu-cfg=</code><var>name</var><dd><a name="index-mcustom_002dfpu_002dcfg-2157"></a>
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This option enables a predefined, named set of custom instruction encodings
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(see <samp><span class="option">-mcustom-</span><var>insn</var></samp> above).
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Currently, the following sets are defined:
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<p><samp><span class="option">-mcustom-fpu-cfg=60-1</span></samp> is equivalent to:
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<pre class="smallexample"> -mcustom-fmuls=252
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-mcustom-fadds=253
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-mcustom-fsubs=254
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-fsingle-precision-constant
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</pre>
|
||
|
|
<p><samp><span class="option">-mcustom-fpu-cfg=60-2</span></samp> is equivalent to:
|
||
|
|
<pre class="smallexample"> -mcustom-fmuls=252
|
||
|
|
-mcustom-fadds=253
|
||
|
|
-mcustom-fsubs=254
|
||
|
|
-mcustom-fdivs=255
|
||
|
|
-fsingle-precision-constant
|
||
|
|
</pre>
|
||
|
|
<p><samp><span class="option">-mcustom-fpu-cfg=72-3</span></samp> is equivalent to:
|
||
|
|
<pre class="smallexample"> -mcustom-floatus=243
|
||
|
|
-mcustom-fixsi=244
|
||
|
|
-mcustom-floatis=245
|
||
|
|
-mcustom-fcmpgts=246
|
||
|
|
-mcustom-fcmples=249
|
||
|
|
-mcustom-fcmpeqs=250
|
||
|
|
-mcustom-fcmpnes=251
|
||
|
|
-mcustom-fmuls=252
|
||
|
|
-mcustom-fadds=253
|
||
|
|
-mcustom-fsubs=254
|
||
|
|
-mcustom-fdivs=255
|
||
|
|
-fsingle-precision-constant
|
||
|
|
</pre>
|
||
|
|
<p>Custom instruction assignments given by individual
|
||
|
|
<samp><span class="option">-mcustom-</span><var>insn</var><span class="option">=</span></samp> options override those given by
|
||
|
|
<samp><span class="option">-mcustom-fpu-cfg=</span></samp>, regardless of the
|
||
|
|
order of the options on the command line.
|
||
|
|
|
||
|
|
<p>Note that you can gain more local control over selection of a FPU
|
||
|
|
configuration by using the <code>target("custom-fpu-cfg=</code><var>name</var><code>")</code>
|
||
|
|
function attribute (see <a href="Function-Attributes.html#Function-Attributes">Function Attributes</a>)
|
||
|
|
or pragma (see <a href="Function-Specific-Option-Pragmas.html#Function-Specific-Option-Pragmas">Function Specific Option Pragmas</a>).
|
||
|
|
|
||
|
|
</dl>
|
||
|
|
|
||
|
|
<p>These additional ‘<samp><span class="samp">-m</span></samp>’ options are available for the Altera Nios II
|
||
|
|
ELF (bare-metal) target:
|
||
|
|
|
||
|
|
<dl>
|
||
|
|
<dt><code>-mhal</code><dd><a name="index-mhal-2158"></a>Link with HAL BSP. This suppresses linking with the GCC-provided C runtime
|
||
|
|
startup and termination code, and is typically used in conjunction with
|
||
|
|
<samp><span class="option">-msys-crt0=</span></samp> to specify the location of the alternate startup code
|
||
|
|
provided by the HAL BSP.
|
||
|
|
|
||
|
|
<br><dt><code>-msmallc</code><dd><a name="index-msmallc-2159"></a>Link with a limited version of the C library, <samp><span class="option">-lsmallc</span></samp>, rather than
|
||
|
|
Newlib.
|
||
|
|
|
||
|
|
<br><dt><code>-msys-crt0=</code><var>startfile</var><dd><a name="index-msys_002dcrt0-2160"></a><var>startfile</var> is the file name of the startfile (crt0) to use
|
||
|
|
when linking. This option is only useful in conjunction with <samp><span class="option">-mhal</span></samp>.
|
||
|
|
|
||
|
|
<br><dt><code>-msys-lib=</code><var>systemlib</var><dd><a name="index-msys_002dlib-2161"></a><var>systemlib</var> is the library name of the library that provides
|
||
|
|
low-level system calls required by the C library,
|
||
|
|
e.g. <code>read</code> and <code>write</code>.
|
||
|
|
This option is typically used to link with a library provided by a HAL BSP.
|
||
|
|
|
||
|
|
</dl>
|
||
|
|
|
||
|
|
</body></html>
|
||
|
|
|