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diff --git a/share/doc/gcc/MSP430-Options.html b/share/doc/gcc/MSP430-Options.html new file mode 100644 index 0000000..13b14dd --- /dev/null +++ b/share/doc/gcc/MSP430-Options.html @@ -0,0 +1,296 @@ +<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> +<html> +<!-- This file documents the use of the GNU compilers. + +Copyright (C) 1988-2023 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. 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Normally such +constants are signed decimals, but this option is available for +testsuite and/or aesthetic purposes. +</p> +<a name="index-mmcu_003d"></a> +</dd> +<dt><code>-mmcu=</code></dt> +<dd><p>Select the MCU to target. This is used to create a C preprocessor +symbol based upon the MCU name, converted to upper case and pre- and +post-fixed with ‘<samp>__</samp>’. This in turn is used by the +<samp>msp430.h</samp> header file to select an MCU-specific supplementary +header file. +</p> +<p>The option also sets the ISA to use. If the MCU name is one that is +known to only support the 430 ISA then that is selected, otherwise the +430X ISA is selected. A generic MCU name of ‘<samp>msp430</samp>’ can also be +used to select the 430 ISA. Similarly the generic ‘<samp>msp430x</samp>’ MCU +name selects the 430X ISA. +</p> +<p>In addition an MCU-specific linker script is added to the linker +command line. The script’s name is the name of the MCU with +<samp>.ld</samp> appended. Thus specifying <samp>-mmcu=xxx</samp> on the <code>gcc</code> +command line defines the C preprocessor symbol <code>__XXX__</code> and +cause the linker to search for a script called <samp>xxx.ld</samp>. +</p> +<p>The ISA and hardware multiply supported for the different MCUs is hard-coded +into GCC. However, an external ‘<samp>devices.csv</samp>’ file can be used to +extend device support beyond those that have been hard-coded. +</p> +<p>GCC searches for the ‘<samp>devices.csv</samp>’ file using the following methods in the +given precedence order, where the first method takes precendence over the +second which takes precedence over the third. +</p> +<dl compact="compact"> +<dt>Include path specified with <code>-I</code> and <code>-L</code></dt> +<dd><p>‘<samp>devices.csv</samp>’ will be searched for in each of the directories specified by +include paths and linker library search paths. +</p></dd> +<dt>Path specified by the environment variable ‘<samp>MSP430_GCC_INCLUDE_DIR</samp>’</dt> +<dd><p>Define the value of the global environment variable +‘<samp>MSP430_GCC_INCLUDE_DIR</samp>’ +to the full path to the directory containing devices.csv, and GCC will search +this directory for devices.csv. If devices.csv is found, this directory will +also be registered as an include path, and linker library path. Header files +and linker scripts in this directory can therefore be used without manually +specifying <code>-I</code> and <code>-L</code> on the command line. +</p></dd> +<dt>The ‘<samp>msp430-elf{,bare}/include/devices</samp>’ directory</dt> +<dd><p>Finally, GCC will examine ‘<samp>msp430-elf{,bare}/include/devices</samp>’ from the +toolchain root directory. This directory does not exist in a default +installation, but if the user has created it and copied ‘<samp>devices.csv</samp>’ +there, then the MCU data will be read. As above, this directory will +also be registered as an include path, and linker library path. +</p> +</dd> +</dl> +<p>If none of the above search methods find ‘<samp>devices.csv</samp>’, then the +hard-coded MCU data is used. +</p> + +<a name="index-mwarn_002dmcu"></a> +<a name="index-mno_002dwarn_002dmcu"></a> +</dd> +<dt><code>-mwarn-mcu</code></dt> +<dt><code>-mno-warn-mcu</code></dt> +<dd><p>This option enables or disables warnings about conflicts between the +MCU name specified by the <samp>-mmcu</samp> option and the ISA set by the +<samp>-mcpu</samp> option and/or the hardware multiply support set by the +<samp>-mhwmult</samp> option. It also toggles warnings about unrecognized +MCU names. This option is on by default. +</p> +<a name="index-mcpu_003d-4"></a> +</dd> +<dt><code>-mcpu=</code></dt> +<dd><p>Specifies the ISA to use. Accepted values are ‘<samp>msp430</samp>’, +‘<samp>msp430x</samp>’ and ‘<samp>msp430xv2</samp>’. This option is deprecated. The +<samp>-mmcu=</samp> option should be used to select the ISA. +</p> +<a name="index-msim-5"></a> +</dd> +<dt><code>-msim</code></dt> +<dd><p>Link to the simulator runtime libraries and linker script. Overrides +any scripts that would be selected by the <samp>-mmcu=</samp> option. +</p> +<a name="index-mlarge"></a> +</dd> +<dt><code>-mlarge</code></dt> +<dd><p>Use large-model addressing (20-bit pointers, 20-bit <code>size_t</code>). +</p> +<a name="index-msmall"></a> +</dd> +<dt><code>-msmall</code></dt> +<dd><p>Use small-model addressing (16-bit pointers, 16-bit <code>size_t</code>). +</p> +<a name="index-mrelax-3"></a> +</dd> +<dt><code>-mrelax</code></dt> +<dd><p>This option is passed to the assembler and linker, and allows the +linker to perform certain optimizations that cannot be done until +the final link. +</p> +<a name="index-mhwmult_003d"></a> +</dd> +<dt><code>mhwmult=</code></dt> +<dd><p>Describes the type of hardware multiply supported by the target. +Accepted values are ‘<samp>none</samp>’ for no hardware multiply, ‘<samp>16bit</samp>’ +for the original 16-bit-only multiply supported by early MCUs. +‘<samp>32bit</samp>’ for the 16/32-bit multiply supported by later MCUs and +‘<samp>f5series</samp>’ for the 16/32-bit multiply supported by F5-series MCUs. +A value of ‘<samp>auto</samp>’ can also be given. This tells GCC to deduce +the hardware multiply support based upon the MCU name provided by the +<samp>-mmcu</samp> option. If no <samp>-mmcu</samp> option is specified or if +the MCU name is not recognized then no hardware multiply support is +assumed. <code>auto</code> is the default setting. +</p> +<p>Hardware multiplies are normally performed by calling a library +routine. This saves space in the generated code. When compiling at +<samp>-O3</samp> or higher however the hardware multiplier is invoked +inline. This makes for bigger, but faster code. +</p> +<p>The hardware multiply routines disable interrupts whilst running and +restore the previous interrupt state when they finish. This makes +them safe to use inside interrupt handlers as well as in normal code. +</p> +<a name="index-minrt"></a> +</dd> +<dt><code>-minrt</code></dt> +<dd><p>Enable the use of a minimum runtime environment - no static +initializers or constructors. This is intended for memory-constrained +devices. The compiler includes special symbols in some objects +that tell the linker and runtime which code fragments are required. +</p> +<a name="index-mtiny_002dprintf"></a> +</dd> +<dt><code>-mtiny-printf</code></dt> +<dd><p>Enable reduced code size <code>printf</code> and <code>puts</code> library functions. +The ‘<samp>tiny</samp>’ implementations of these functions are not reentrant, so +must be used with caution in multi-threaded applications. +</p> +<p>Support for streams has been removed and the string to be printed will +always be sent to stdout via the <code>write</code> syscall. The string is not +buffered before it is sent to write. +</p> +<p>This option requires Newlib Nano IO, so GCC must be configured with +‘<samp>--enable-newlib-nano-formatted-io</samp>’. +</p> +<a name="index-mmax_002dinline_002dshift_003d"></a> +</dd> +<dt><code>-mmax-inline-shift=</code></dt> +<dd><p>This option takes an integer between 0 and 64 inclusive, and sets +the maximum number of inline shift instructions which should be emitted to +perform a shift operation by a constant amount. When this value needs to be +exceeded, an mspabi helper function is used instead. The default value is 4. +</p> +<p>This only affects cases where a shift by multiple positions cannot be +completed with a single instruction (e.g. all shifts >1 on the 430 ISA). +</p> +<p>Shifts of a 32-bit value are at least twice as costly, so the value passed for +this option is divided by 2 and the resulting value used instead. +</p> +<a name="index-mcode_002dregion"></a> +<a name="index-mdata_002dregion"></a> +</dd> +<dt><code>-mcode-region=</code></dt> +<dt><code>-mdata-region=</code></dt> +<dd><p>These options tell the compiler where to place functions and data that +do not have one of the <code>lower</code>, <code>upper</code>, <code>either</code> or +<code>section</code> attributes. Possible values are <code>lower</code>, +<code>upper</code>, <code>either</code> or <code>any</code>. The first three behave +like the corresponding attribute. The fourth possible value - +<code>any</code> - is the default. It leaves placement entirely up to the +linker script and how it assigns the standard sections +(<code>.text</code>, <code>.data</code>, etc) to the memory regions. +</p> +<a name="index-msilicon_002derrata"></a> +</dd> +<dt><code>-msilicon-errata=</code></dt> +<dd><p>This option passes on a request to assembler to enable the fixes for +the named silicon errata. +</p> +<a name="index-msilicon_002derrata_002dwarn"></a> +</dd> +<dt><code>-msilicon-errata-warn=</code></dt> +<dd><p>This option passes on a request to the assembler to enable warning +messages when a silicon errata might need to be applied. +</p> +<a name="index-mwarn_002ddevices_002dcsv"></a> +<a name="index-mno_002dwarn_002ddevices_002dcsv"></a> +</dd> +<dt><code>-mwarn-devices-csv</code></dt> +<dt><code>-mno-warn-devices-csv</code></dt> +<dd><p>Warn if ‘<samp>devices.csv</samp>’ is not found or there are problem parsing it +(default: on). +</p> +</dd> +</dl> + +<hr> +<div class="header"> +<p> +Next: <a href="NDS32-Options.html#NDS32-Options" accesskey="n" rel="next">NDS32 Options</a>, Previous: <a href="Moxie-Options.html#Moxie-Options" accesskey="p" rel="previous">Moxie Options</a>, Up: <a href="Submodel-Options.html#Submodel-Options" accesskey="u" rel="up">Submodel Options</a> [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Indices.html#Indices" title="Index" rel="index">Index</a>]</p> +</div> + + + +</body> +</html> |