initial commit

.gitignore

@@ -0,0 +1,2 @@
+target
+Cargo.lock

Cargo.toml

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+[package]
+authors = ["Jorge Aparicio <japaricious@gmail.com>"]
+description = "Semihosting for ARM Cortex-M processors"
+documentation = "https://docs.rs/cortex-m-semihosting"
+keywords = ["semihosting", "arm", "cortex-m"]
+license = "MIT OR Apache-2.0"
+name = "cortex-m-semihosting"
+repository = "https://github.com/japaric/cortex-m-semihosting"
+version = "0.1.0"
+
+[dependencies]

LICENSE-APACHE

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LICENSE-MIT

@@ -0,0 +1,25 @@
+Copyright (c) 2017 Jorge Aparicio
+
+Permission is hereby granted, free of charge, to any
+person obtaining a copy of this software and associated
+documentation files (the "Software"), to deal in the
+Software without restriction, including without
+limitation the rights to use, copy, modify, merge,
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+the Software, and to permit persons to whom the Software
+is furnished to do so, subject to the following
+conditions:
+
+The above copyright notice and this permission notice
+shall be included in all copies or substantial portions
+of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF
+ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED
+TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
+PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT
+SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR
+IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+DEALINGS IN THE SOFTWARE.

README.md

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+[![crates.io](https://img.shields.io/crates/v/cortex-m-semihosting.svg)](https://crates.io/crates/cortex-m-semihosting)
+[![crates.io](https://img.shields.io/crates/d/cortex-m-semihosting.svg)](https://crates.io/crates/cortex-m-semihosting)
+
+# `cortex-m-semihosting`
+
+> Semihosting for ARM Cortex-M processors
+
+## [Documentation](https://docs.rs/cortex-m-semihosting)
+
+## License
+
+Licensed under either of
+
+- Apache License, Version 2.0 ([LICENSE-APACHE](LICENSE-APACHE) or
+  http://www.apache.org/licenses/LICENSE-2.0)
+- MIT license ([LICENSE-MIT](LICENSE-MIT) or http://opensource.org/licenses/MIT)
+
+at your option.
+
+### Contribution
+
+Unless you explicitly state otherwise, any contribution intentionally submitted
+for inclusion in the work by you, as defined in the Apache-2.0 license, shall be
+dual licensed as above, without any additional terms or conditions.

src/io.rs

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+//! Host I/O
+
+use core::{fmt, slice};
+use core::fmt::Write;
+
+/// File descriptor
+const STDOUT: usize = 1;
+
+/// Host's standard output
+struct Stdout;
+
+impl Stdout {
+    fn write_all(&mut self, mut buffer: &[u8]) {
+        while !buffer.is_empty() {
+            match unsafe {
+                syscall!(WRITE, STDOUT, buffer.as_ptr(), buffer.len())
+            } {
+                // Done
+                0 => return,
+                // `n` bytes were not written
+                n => {
+                    buffer = unsafe {
+                        slice::from_raw_parts(buffer.as_ptr(), buffer.len() - n)
+                    }
+                }
+            }
+        }
+    }
+}
+
+impl Write for Stdout {
+    fn write_str(&mut self, s: &str) -> fmt::Result {
+        self.write_all(s.as_bytes());
+        Ok(())
+    }
+}
+
+pub fn _write_str(s: &str) {
+    Stdout.write_str(s).ok();
+}
+
+pub fn _write_fmt(args: fmt::Arguments) {
+
+    Stdout.write_fmt(args).ok();
+}

src/lib.rs

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+//! Semihosting for ARM Cortex-M processors
+//!
+//! # What is semihosting?
+//!
+//! "Semihosting is a mechanism that enables code running on an ARM target to
+//!  communicate and use the Input/Output facilities on a host computer that is
+//!  running a debugger." - ARM
+//!
+//! # Interface
+//!
+//! Since semihosting operations are modeled as [system calls][sc], this crate
+//! exposes an untyped `syscall!` interface just like the [`sc`] crate does.
+//!
+//! [sc]: https://en.wikipedia.org/wiki/System_call
+//! [`sc`]: https://crates.io/crates/sc
+//!
+//! And since the most used semihosting operation is writing to the host's
+//! stdout, convenience `hprint` and `hprintln` macros are provided.
+//!
+//! # Forewarning
+//!
+//! Semihosting operations are *very* slow. Like, each WRITE operation can take
+//! hundreds of milliseconds.
+//!
+//! # Example
+//!
+//! This example will show how to print "Hello, world!" on the host.
+//!
+//! Target program:
+//!
+//! ```
+//! fn main() {
+//!     // File descriptor (on the host)
+//!     const STDOUT: usize = 1;
+//!     static MSG: &'static [u8] = b"Hello, world!\n";
+//!
+//!     // Signature: fn write(fd: usize, ptr: *const u8, len: usize) -> usize
+//!     let r = unsafe { syscall!(WRITE, STDOUT, MSG.as_ptr(), MSG.len()) };
+//!
+//!     // (Or you could have just written `hprintln!("Hello, world!")`)
+//!     // ..
+//! }
+//! ```
+//!
+//! On the host side:
+//!
+//! ``` text
+//! $ openocd -f $INTERFACE -f $TARGET -l /tmp/openocd.log
+//! Open On-Chip Debugger 0.9.0 (2016-04-27-23:18)
+//! Licensed under GNU GPL v2
+//! For bug reports, read
+//!         http://openocd.org/doc/doxygen/bugs.html
+//! # the command will block at this point
+//! ```
+//!
+//! The OpenOCD logs will be redirected to `/tmp/openocd.log`. You can view
+//! those logs in "real time" using `watch` + `tail`
+//!
+//! ``` text
+//! $ watch 'tail /tmp/openocd.log'
+//! Every 2.0s: tail /tmp/openocd.log
+//!
+//! Info : Unable to match requested speed 1000 kHz, using 950 kHz
+//! Info : Unable to match requested speed 1000 kHz, using 950 kHz
+//! Info : clock speed 950 kHz
+//! Info : STLINK v1 JTAG v11 API v2 SWIM v0 VID 0x0483 PID 0x3744
+//! Info : using stlink api v2
+//! Info : nrf51.cpu: hardware has 4 breakpoints, 2 watchpoints
+//! ```
+//!
+//! Then, we run the program:
+//!
+//! ``` text
+//! $ arm-none-eabi-gdb hello-world
+//! # Connect to OpenOCD
+//! (gdb) target remote :3333
+//!
+//! # Enable OpenOCD's semihosting support
+//! (gdb) monitor arm semihosting enable
+//!
+//! # Flash the program
+//! (gdb) load
+//!
+//! # Run the program
+//! (gdb) continue
+//! ```
+//!
+//! And you'll see the output under OpenOCD's terminal
+//!
+//! ``` text
+//! # openocd -f $INTERFACE -f $TARGET -l /tmp/openocd.log
+//! (..)
+//! Hello, world!
+//! ```
+//!
+//! # Reference
+//!
+//! For documentation about the semihosting operations, check:
+//!
+//! 'Chapter 8 - Semihosting' of the ['ARM Compiler toolchain Version 5.0'][pdf]
+//! manual.
+//!
+//! [pdf]: http://infocenter.arm.com/help/topic/com.arm.doc.dui0471e/DUI0471E_developing_for_arm_processors.pdf
+
+#![feature(asm)]
+#![no_std]
+
+#[macro_use]
+mod macros;
+#[doc(hidden)]
+pub mod io;
+
+pub mod nr;
+
+/// Performs a semihosting operation
+#[inline(always)]
+pub unsafe fn syscall<T>(mut nr: usize, arg: &T) -> usize {
+    asm!("bkpt 0xAB"
+         : "+{r0}"(nr)
+         : "{r1}"(arg)
+         : "memory"
+         : "volatile");
+    nr
+}

src/macros.rs

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+/// Variable argument version of `syscall`
+#[macro_export]
+macro_rules! syscall {
+    ($nr:ident, $a1:expr, $a2:expr) => {
+        $crate::syscall($crate::nr::$nr, &($a1 as usize))
+    };
+    ($nr:ident, $a1:expr, $a2:expr) => {
+        $crate::syscall($crate::nr::$nr, &[$a1 as usize, $a2 as usize])
+    };
+    ($nr:ident, $a1:expr, $a2:expr, $a3:expr) => {
+        $crate::syscall($crate::nr::$nr, &[$a1 as usize, $a2 as usize,
+                                           $a3 as usize])
+    };
+    ($nr:ident, $a1:expr, $a2:expr, $a3:expr, $a4:expr) => {
+        $crate::syscall($crate::nr::$nr, &[$a1 as usize, $a2 as usize,
+                                           $a3 as usize, $a4 as usize])
+    };
+}
+/// Macro for printing to the **host's** standard output
+#[macro_export]
+macro_rules! hprint {
+    ($s:expr) => ($crate::io::_write_str($s));
+    ($($arg:tt)*) => ($crate::io::_write_fmt(format_args!($($arg)*)));
+}
+
+/// Macro for printing to the **host's** standard output, with a newline.
+#[macro_export]
+macro_rules! hprintln {
+    () => (print!("\n"));
+    ($fmt:expr) => (hprint!(concat!($fmt, "\n")));
+    ($fmt:expr, $($arg:tt)*) => (hprint!(concat!($fmt, "\n"), $($arg)*));
+}

src/nr.rs

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+//! Semihosting operations
+
+pub const CLOCK: usize = 0x10;
+pub const CLOSE: usize = 0x05;
+pub const ELAPSED: usize = 0x30;
+pub const ERRNO: usize = 0x13;
+pub const FLEN: usize = 0x0c;
+pub const GET_CMDLINE: usize = 0x15;
+pub const HEAPINFO: usize = 0x16;
+pub const ISERROR: usize = 0x08;
+pub const ISTTY: usize = 0x09;
+pub const OPEN: usize = 0x01;
+pub const READ: usize = 0x06;
+pub const READC: usize = 0x07;
+pub const REMOVE: usize = 0x0e;
+pub const RENAME: usize = 0x0f;
+pub const SEEK: usize = 0x0a;
+pub const SYSTEM: usize = 0x12;
+pub const TICKFREQ: usize = 0x31;
+pub const TIME: usize = 0x11;
+pub const TMPNAM: usize = 0x0d;
+pub const WRITE0: usize = 0x04;
+pub const WRITE: usize = 0x05;
+pub const WRITEC: usize = 0x03;