You cannot select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
150 lines
8.9 KiB
HTML
150 lines
8.9 KiB
HTML
<html lang="en">
|
|
<head>
|
|
<title>SPU Options - Using the GNU Compiler Collection (GCC)</title>
|
|
<meta http-equiv="Content-Type" content="text/html">
|
|
<meta name="description" content="Using the GNU Compiler Collection (GCC)">
|
|
<meta name="generator" content="makeinfo 4.13">
|
|
<link title="Top" rel="start" href="index.html#Top">
|
|
<link rel="up" href="Submodel-Options.html#Submodel-Options" title="Submodel Options">
|
|
<link rel="prev" href="SPARC-Options.html#SPARC-Options" title="SPARC Options">
|
|
<link rel="next" href="System-V-Options.html#System-V-Options" title="System V Options">
|
|
<link href="http://www.gnu.org/software/texinfo/" rel="generator-home" title="Texinfo Homepage">
|
|
<!--
|
|
Copyright (C) 1988-2015 Free Software Foundation, Inc.
|
|
|
|
Permission is granted to copy, distribute and/or modify this document
|
|
under the terms of the GNU Free Documentation License, Version 1.3 or
|
|
any later version published by the Free Software Foundation; with the
|
|
Invariant Sections being ``Funding Free Software'', the Front-Cover
|
|
Texts being (a) (see below), and with the Back-Cover Texts being (b)
|
|
(see below). A copy of the license is included in the section entitled
|
|
``GNU Free Documentation License''.
|
|
|
|
(a) The FSF's Front-Cover Text is:
|
|
|
|
A GNU Manual
|
|
|
|
(b) The FSF's Back-Cover Text is:
|
|
|
|
You have freedom to copy and modify this GNU Manual, like GNU
|
|
software. Copies published by the Free Software Foundation raise
|
|
funds for GNU development.-->
|
|
<meta http-equiv="Content-Style-Type" content="text/css">
|
|
<style type="text/css"><!--
|
|
pre.display { font-family:inherit }
|
|
pre.format { font-family:inherit }
|
|
pre.smalldisplay { font-family:inherit; font-size:smaller }
|
|
pre.smallformat { font-family:inherit; font-size:smaller }
|
|
pre.smallexample { font-size:smaller }
|
|
pre.smalllisp { font-size:smaller }
|
|
span.sc { font-variant:small-caps }
|
|
span.roman { font-family:serif; font-weight:normal; }
|
|
span.sansserif { font-family:sans-serif; font-weight:normal; }
|
|
--></style>
|
|
</head>
|
|
<body>
|
|
<div class="node">
|
|
<a name="SPU-Options"></a>
|
|
<p>
|
|
Next: <a rel="next" accesskey="n" href="System-V-Options.html#System-V-Options">System V Options</a>,
|
|
Previous: <a rel="previous" accesskey="p" href="SPARC-Options.html#SPARC-Options">SPARC Options</a>,
|
|
Up: <a rel="up" accesskey="u" href="Submodel-Options.html#Submodel-Options">Submodel Options</a>
|
|
<hr>
|
|
</div>
|
|
|
|
<h4 class="subsection">3.17.44 SPU Options</h4>
|
|
|
|
<p><a name="index-SPU-options-2556"></a>
|
|
These ‘<samp><span class="samp">-m</span></samp>’ options are supported on the SPU:
|
|
|
|
<dl>
|
|
<dt><code>-mwarn-reloc</code><dt><code>-merror-reloc</code><dd><a name="index-mwarn_002dreloc-2557"></a><a name="index-merror_002dreloc-2558"></a>
|
|
The loader for SPU does not handle dynamic relocations. By default, GCC
|
|
gives an error when it generates code that requires a dynamic
|
|
relocation. <samp><span class="option">-mno-error-reloc</span></samp> disables the error,
|
|
<samp><span class="option">-mwarn-reloc</span></samp> generates a warning instead.
|
|
|
|
<br><dt><code>-msafe-dma</code><dt><code>-munsafe-dma</code><dd><a name="index-msafe_002ddma-2559"></a><a name="index-munsafe_002ddma-2560"></a>
|
|
Instructions that initiate or test completion of DMA must not be
|
|
reordered with respect to loads and stores of the memory that is being
|
|
accessed.
|
|
With <samp><span class="option">-munsafe-dma</span></samp> you must use the <code>volatile</code> keyword to protect
|
|
memory accesses, but that can lead to inefficient code in places where the
|
|
memory is known to not change. Rather than mark the memory as volatile,
|
|
you can use <samp><span class="option">-msafe-dma</span></samp> to tell the compiler to treat
|
|
the DMA instructions as potentially affecting all memory.
|
|
|
|
<br><dt><code>-mbranch-hints</code><dd><a name="index-mbranch_002dhints-2561"></a>
|
|
By default, GCC generates a branch hint instruction to avoid
|
|
pipeline stalls for always-taken or probably-taken branches. A hint
|
|
is not generated closer than 8 instructions away from its branch.
|
|
There is little reason to disable them, except for debugging purposes,
|
|
or to make an object a little bit smaller.
|
|
|
|
<br><dt><code>-msmall-mem</code><dt><code>-mlarge-mem</code><dd><a name="index-msmall_002dmem-2562"></a><a name="index-mlarge_002dmem-2563"></a>
|
|
By default, GCC generates code assuming that addresses are never larger
|
|
than 18 bits. With <samp><span class="option">-mlarge-mem</span></samp> code is generated that assumes
|
|
a full 32-bit address.
|
|
|
|
<br><dt><code>-mstdmain</code><dd><a name="index-mstdmain-2564"></a>
|
|
By default, GCC links against startup code that assumes the SPU-style
|
|
main function interface (which has an unconventional parameter list).
|
|
With <samp><span class="option">-mstdmain</span></samp>, GCC links your program against startup
|
|
code that assumes a C99-style interface to <code>main</code>, including a
|
|
local copy of <code>argv</code> strings.
|
|
|
|
<br><dt><code>-mfixed-range=</code><var>register-range</var><dd><a name="index-mfixed_002drange-2565"></a>Generate code treating the given register range as fixed registers.
|
|
A fixed register is one that the register allocator cannot use. This is
|
|
useful when compiling kernel code. A register range is specified as
|
|
two registers separated by a dash. Multiple register ranges can be
|
|
specified separated by a comma.
|
|
|
|
<br><dt><code>-mea32</code><dt><code>-mea64</code><dd><a name="index-mea32-2566"></a><a name="index-mea64-2567"></a>Compile code assuming that pointers to the PPU address space accessed
|
|
via the <code>__ea</code> named address space qualifier are either 32 or 64
|
|
bits wide. The default is 32 bits. As this is an ABI-changing option,
|
|
all object code in an executable must be compiled with the same setting.
|
|
|
|
<br><dt><code>-maddress-space-conversion</code><dt><code>-mno-address-space-conversion</code><dd><a name="index-maddress_002dspace_002dconversion-2568"></a><a name="index-mno_002daddress_002dspace_002dconversion-2569"></a>Allow/disallow treating the <code>__ea</code> address space as superset
|
|
of the generic address space. This enables explicit type casts
|
|
between <code>__ea</code> and generic pointer as well as implicit
|
|
conversions of generic pointers to <code>__ea</code> pointers. The
|
|
default is to allow address space pointer conversions.
|
|
|
|
<br><dt><code>-mcache-size=</code><var>cache-size</var><dd><a name="index-mcache_002dsize-2570"></a>This option controls the version of libgcc that the compiler links to an
|
|
executable and selects a software-managed cache for accessing variables
|
|
in the <code>__ea</code> address space with a particular cache size. Possible
|
|
options for <var>cache-size</var> are ‘<samp><span class="samp">8</span></samp>’, ‘<samp><span class="samp">16</span></samp>’, ‘<samp><span class="samp">32</span></samp>’, ‘<samp><span class="samp">64</span></samp>’
|
|
and ‘<samp><span class="samp">128</span></samp>’. The default cache size is 64KB.
|
|
|
|
<br><dt><code>-matomic-updates</code><dt><code>-mno-atomic-updates</code><dd><a name="index-matomic_002dupdates-2571"></a><a name="index-mno_002datomic_002dupdates-2572"></a>This option controls the version of libgcc that the compiler links to an
|
|
executable and selects whether atomic updates to the software-managed
|
|
cache of PPU-side variables are used. If you use atomic updates, changes
|
|
to a PPU variable from SPU code using the <code>__ea</code> named address space
|
|
qualifier do not interfere with changes to other PPU variables residing
|
|
in the same cache line from PPU code. If you do not use atomic updates,
|
|
such interference may occur; however, writing back cache lines is
|
|
more efficient. The default behavior is to use atomic updates.
|
|
|
|
<br><dt><code>-mdual-nops</code><dt><code>-mdual-nops=</code><var>n</var><dd><a name="index-mdual_002dnops-2573"></a>By default, GCC inserts nops to increase dual issue when it expects
|
|
it to increase performance. <var>n</var> can be a value from 0 to 10. A
|
|
smaller <var>n</var> inserts fewer nops. 10 is the default, 0 is the
|
|
same as <samp><span class="option">-mno-dual-nops</span></samp>. Disabled with <samp><span class="option">-Os</span></samp>.
|
|
|
|
<br><dt><code>-mhint-max-nops=</code><var>n</var><dd><a name="index-mhint_002dmax_002dnops-2574"></a>Maximum number of nops to insert for a branch hint. A branch hint must
|
|
be at least 8 instructions away from the branch it is affecting. GCC
|
|
inserts up to <var>n</var> nops to enforce this, otherwise it does not
|
|
generate the branch hint.
|
|
|
|
<br><dt><code>-mhint-max-distance=</code><var>n</var><dd><a name="index-mhint_002dmax_002ddistance-2575"></a>The encoding of the branch hint instruction limits the hint to be within
|
|
256 instructions of the branch it is affecting. By default, GCC makes
|
|
sure it is within 125.
|
|
|
|
<br><dt><code>-msafe-hints</code><dd><a name="index-msafe_002dhints-2576"></a>Work around a hardware bug that causes the SPU to stall indefinitely.
|
|
By default, GCC inserts the <code>hbrp</code> instruction to make sure
|
|
this stall won't happen.
|
|
|
|
</dl>
|
|
|
|
</body></html>
|
|
|