162 lines
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162 lines
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<!DOCTYPE html><html lang="en"><head><meta charset="utf-8"><meta name="viewport" content="width=device-width, initial-scale=1.0"><meta name="generator" content="rustdoc"><meta name="description" content="API documentation for the Rust `cortex_m_semihosting` crate."><meta name="keywords" content="rust, rustlang, rust-lang, cortex_m_semihosting"><title>cortex_m_semihosting - Rust</title><link rel="stylesheet" type="text/css" href="../normalize.css"><link rel="stylesheet" type="text/css" href="../rustdoc.css" id="mainThemeStyle"><link rel="stylesheet" type="text/css" href="../dark.css"><link rel="stylesheet" type="text/css" href="../light.css" id="themeStyle"><script src="../storage.js"></script></head><body class="rustdoc mod"><!--[if lte IE 8]><div class="warning">This old browser is unsupported and will most likely display funky things.</div><![endif]--><nav class="sidebar"><div class="sidebar-menu">☰</div><p class='location'>Crate cortex_m_semihosting</p><div class="sidebar-elems"><div class="block items"><ul><li><a href="#modules">Modules</a></li><li><a href="#macros">Macros</a></li><li><a href="#functions">Functions</a></li></ul></div><p class='location'></p><script>window.sidebarCurrent = {name: 'cortex_m_semihosting', ty: 'mod', relpath: '../'};</script></div></nav><div class="theme-picker"><button id="theme-picker" aria-label="Pick another theme!"><img src="../brush.svg" width="18" alt="Pick another theme!"></button><div id="theme-choices"></div></div><script src="../theme.js"></script><nav class="sub"><form class="search-form js-only"><div class="search-container"><input class="search-input" name="search" autocomplete="off" placeholder="Click or press ‘S’ to search, ‘?’ for more options…" type="search"><a id="settings-menu" href="../settings.html"><img src="../wheel.svg" width="18" alt="Change settings"></a></div></form></nav><section id="main" class="content"><h1 class='fqn'><span class='out-of-band'><span id='render-detail'><a id="toggle-all-docs" href="javascript:void(0)" title="collapse all docs">[<span class='inner'>−</span>]</a></span><a class='srclink' href='../src/cortex_m_semihosting/lib.rs.html#1-185' title='goto source code'>[src]</a></span><span class='in-band'>Crate <a class="mod" href=''>cortex_m_semihosting</a></span></h1><div class='docblock'><p>Semihosting for ARM Cortex-M processors</p>
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<h1 id="what-is-semihosting" class="section-header"><a href="#what-is-semihosting">What is semihosting?</a></h1>
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<p>"Semihosting is a mechanism that enables code running on an ARM target to communicate and use
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the Input/Output facilities on a host computer that is running a debugger." - ARM</p>
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<h1 id="interface" class="section-header"><a href="#interface">Interface</a></h1>
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<p>This crate provides implementations of
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<a href="https://doc.rust-lang.org/core/fmt/trait.Write.html"><code>core::fmt::Write</code></a>, so you can use it,
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in conjunction with
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<a href="https://doc.rust-lang.org/core/macro.format_args.html"><code>core::format_args!</code></a> or the <a href="https://doc.rust-lang.org/core/macro.write.html"><code>write!</code> macro</a>, for user-friendly construction and printing of formatted strings.</p>
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<p>Since semihosting operations are modeled as <a href="https://en.wikipedia.org/wiki/System_call">system calls</a>, this crate exposes an untyped
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<code>syscall!</code> interface just like the <a href="https://crates.io/crates/sc"><code>sc</code></a> crate does.</p>
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<h1 id="forewarning" class="section-header"><a href="#forewarning">Forewarning</a></h1>
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<p>Semihosting operations are <em>very</em> slow. Like, each WRITE operation can take hundreds of
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milliseconds.</p>
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<h1 id="example" class="section-header"><a href="#example">Example</a></h1><h2 id="using-hiohstdout" class="section-header"><a href="#using-hiohstdout">Using <code>hio::HStdout</code></a></h2>
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<p>This example will demonstrate how to print formatted strings.</p>
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<pre class="rust rust-example-rendered">
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<span class="kw">extern</span> <span class="kw">crate</span> <span class="ident">cortex_m_semihosting</span>;
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<span class="kw">use</span> <span class="ident">cortex_m_semihosting</span>::<span class="ident">hio</span>;
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<span class="kw">use</span> <span class="ident">core</span>::<span class="ident">fmt</span>::<span class="ident">Write</span>;
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<span class="comment">// This function will be called by the application</span>
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<span class="kw">fn</span> <span class="ident">print</span>() <span class="op">-></span> <span class="prelude-ty">Result</span><span class="op"><</span>(), <span class="ident">core</span>::<span class="ident">fmt</span>::<span class="ident">Error</span><span class="op">></span> {
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<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">stdout</span> <span class="op">=</span> <span class="kw">match</span> <span class="ident">hio</span>::<span class="ident">hstdout</span>() {
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<span class="prelude-val">Ok</span>(<span class="ident">fd</span>) <span class="op">=></span> <span class="ident">fd</span>,
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<span class="prelude-val">Err</span>(()) <span class="op">=></span> <span class="kw">return</span> <span class="prelude-val">Err</span>(<span class="ident">core</span>::<span class="ident">fmt</span>::<span class="ident">Error</span>),
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};
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<span class="kw">let</span> <span class="ident">language</span> <span class="op">=</span> <span class="string">"Rust"</span>;
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<span class="kw">let</span> <span class="ident">ranking</span> <span class="op">=</span> <span class="number">1</span>;
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<span class="macro">write</span><span class="macro">!</span>(<span class="ident">stdout</span>, <span class="string">"{} on embedded is #{}!"</span>, <span class="ident">language</span>, <span class="ident">ranking</span>)<span class="question-mark">?</span>;
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<span class="prelude-val">Ok</span>(())
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}</pre>
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<p>On the host side:</p>
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<pre><code class="language-text">$ openocd -f $INTERFACE -f $TARGET -l /tmp/openocd.log
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Open On-Chip Debugger 0.9.0 (2016-04-27-23:18)
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Licensed under GNU GPL v2
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For bug reports, read
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http://openocd.org/doc/doxygen/bugs.html
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# the command will block at this point
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</code></pre>
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<p>The OpenOCD logs will be redirected to <code>/tmp/openocd.log</code>. You can view those logs in "real
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time" using <code>tail</code></p>
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<pre><code class="language-text">$ tail -f /tmp/openocd.log
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Info : Unable to match requested speed 1000 kHz, using 950 kHz
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Info : Unable to match requested speed 1000 kHz, using 950 kHz
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Info : clock speed 950 kHz
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Info : STLINK v1 JTAG v11 API v2 SWIM v0 VID 0x0483 PID 0x3744
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Info : using stlink api v2
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Info : nrf51.cpu: hardware has 4 breakpoints, 2 watchpoints
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</code></pre>
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<p>Alternatively you could omit the <code>-l</code> flag from the <code>openocd</code> call, and the <code>tail -f</code> command
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but the OpenOCD output will have intermingled in it logs from its normal operation.</p>
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<p>Then, we run the program:</p>
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<pre><code class="language-text">$ arm-none-eabi-gdb hello-world
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(gdb) # Connect to OpenOCD
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(gdb) target remote :3333
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(gdb) # Enable OpenOCD's semihosting support
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(gdb) monitor arm semihosting enable
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(gdb) # Flash the program
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(gdb) load
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(gdb) # Run the program
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(gdb) continue
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</code></pre>
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<p>And you'll see the output under OpenOCD's terminal</p>
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<pre><code class="language-text"># openocd -f $INTERFACE -f $TARGET -l /tmp/openocd.log
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(..)
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Rust on embedded is #1!
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</code></pre>
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<h2 id="using-the-syscall-interface" class="section-header"><a href="#using-the-syscall-interface">Using the syscall interface</a></h2>
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<p>This example will show how to print "Hello, world!" on the host.</p>
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<p>Target program:</p>
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<pre class="rust rust-example-rendered">
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<span class="kw">extern</span> <span class="kw">crate</span> <span class="ident">cortex_m_semihosting</span>;
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<span class="comment">// This function will be called by the application</span>
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<span class="kw">fn</span> <span class="ident">print</span>() {
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<span class="comment">// File descriptor (on the host)</span>
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<span class="kw">const</span> <span class="ident">STDOUT</span>: <span class="ident">usize</span> <span class="op">=</span> <span class="number">1</span>; <span class="comment">// NOTE the host stdout may not always be fd 1</span>
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<span class="kw">static</span> <span class="ident">MSG</span>: <span class="kw-2">&</span><span class="lifetime">'static</span> [<span class="ident">u8</span>] <span class="op">=</span> <span class="string">b"Hello, world!\n"</span>;
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<span class="comment">// Signature: fn write(fd: usize, ptr: *const u8, len: usize) -> usize</span>
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<span class="kw">let</span> <span class="ident">r</span> <span class="op">=</span> <span class="kw">unsafe</span> { <span class="macro">syscall</span><span class="macro">!</span>(<span class="ident">WRITE</span>, <span class="ident">STDOUT</span>, <span class="ident">MSG</span>.<span class="ident">as_ptr</span>(), <span class="ident">MSG</span>.<span class="ident">len</span>()) };
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}</pre>
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<p>Output and monitoring proceed as in the above example.</p>
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<h1 id="optional-features" class="section-header"><a href="#optional-features">Optional features</a></h1><h2 id="inline-asm" class="section-header"><a href="#inline-asm"><code>inline-asm</code></a></h2>
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<p>When this feature is enabled semihosting is implemented using inline assembly (<code>asm!</code>) and
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compiling this crate requires nightly.</p>
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<p>When this feature is disabled semihosting is implemented using FFI calls into an external
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assembly file and compiling this crate works on stable and beta.</p>
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<h1 id="reference" class="section-header"><a href="#reference">Reference</a></h1>
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<p>For documentation about the semihosting operations, check:</p>
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<p>'Chapter 8 - Semihosting' of the <a href="http://infocenter.arm.com/help/topic/com.arm.doc.dui0471e/DUI0471E_developing_for_arm_processors.pdf">'ARM Compiler toolchain Version 5.0'</a>
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manual.</p>
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</div><h2 id='modules' class='section-header'><a href="#modules">Modules</a></h2>
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<table>
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<tr class=' module-item'>
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<td><a class="mod" href="debug/index.html"
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title='mod cortex_m_semihosting::debug'>debug</a></td>
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<td class='docblock-short'>
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<p>Interacting with debugging agent</p>
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</td>
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</tr>
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<tr class=' module-item'>
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<td><a class="mod" href="hio/index.html"
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title='mod cortex_m_semihosting::hio'>hio</a></td>
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<td class='docblock-short'>
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<p>Host I/O</p>
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</td>
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</tr>
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<tr class=' module-item'>
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<td><a class="mod" href="nr/index.html"
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title='mod cortex_m_semihosting::nr'>nr</a></td>
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<td class='docblock-short'>
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<p>Semihosting operations</p>
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</td>
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</tr></table><h2 id='macros' class='section-header'><a href="#macros">Macros</a></h2>
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<table>
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<tr class=' module-item'>
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<td><a class="macro" href="macro.syscall.html"
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title='macro cortex_m_semihosting::syscall'>syscall</a></td>
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<td class='docblock-short'>
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<p>Variable argument version of <code>syscall</code></p>
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</td>
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</tr>
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<tr class=' module-item'>
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<td><a class="macro" href="macro.syscall1.html"
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title='macro cortex_m_semihosting::syscall1'>syscall1</a></td>
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<td class='docblock-short'>
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<p>Macro version of <code>syscall1</code></p>
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</td>
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</tr></table><h2 id='functions' class='section-header'><a href="#functions">Functions</a></h2>
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<table>
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<tr class=' module-item'>
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<td><a class="fn" href="fn.syscall.html"
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title='fn cortex_m_semihosting::syscall'>syscall</a><a title='unsafe function' href='#'><sup>⚠</sup></a></td>
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<td class='docblock-short'>
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<p>Performs a semihosting operation, takes a pointer to an argument block</p>
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</td>
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</tr>
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<tr class=' module-item'>
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<td><a class="fn" href="fn.syscall1.html"
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title='fn cortex_m_semihosting::syscall1'>syscall1</a><a title='unsafe function' href='#'><sup>⚠</sup></a></td>
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<td class='docblock-short'>
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<p>Performs a semihosting operation, takes one integer as an argument</p>
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</td>
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</tr></table></section><section id="search" class="content hidden"></section><section class="footer"></section><aside id="help" class="hidden"><div><h1 class="hidden">Help</h1><div class="shortcuts"><h2>Keyboard Shortcuts</h2><dl><dt><kbd>?</kbd></dt><dd>Show this help dialog</dd><dt><kbd>S</kbd></dt><dd>Focus the search field</dd><dt><kbd>↑</kbd></dt><dd>Move up in search results</dd><dt><kbd>↓</kbd></dt><dd>Move down in search results</dd><dt><kbd>↹</kbd></dt><dd>Switch tab</dd><dt><kbd>⏎</kbd></dt><dd>Go to active search result</dd><dt><kbd>+</kbd></dt><dd>Expand all sections</dd><dt><kbd>-</kbd></dt><dd>Collapse all sections</dd></dl></div><div class="infos"><h2>Search Tricks</h2><p>Prefix searches with a type followed by a colon (e.g. <code>fn:</code>) to restrict the search to a given type.</p><p>Accepted types are: <code>fn</code>, <code>mod</code>, <code>struct</code>, <code>enum</code>, <code>trait</code>, <code>type</code>, <code>macro</code>, and <code>const</code>.</p><p>Search functions by type signature (e.g. <code>vec -> usize</code> or <code>* -> vec</code>)</p><p>Search multiple things at once by splitting your query with comma (e.g. <code>str,u8</code> or <code>String,struct:Vec,test</code>)</p></div></div></aside><script>window.rootPath = "../";window.currentCrate = "cortex_m_semihosting";</script><script src="../aliases.js"></script><script src="../main.js"></script><script defer src="../search-index.js"></script></body></html> |