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//! ThreadX stdio implemented over semihosting
#![no_std]
#[unsafe(no_mangle)]
fn __rust_threadx_stdout_write(buf: &[u8]) -> usize {
use cortex_m_semihosting::hio;
// `write_all` loops until the whole buffer is sent or the host reports an
// error, so a success means every byte was written.
let Ok(mut out) = hio::hstdout() else {
return 0;
};
match out.write_all(buf) {
Ok(()) => buf.len(),
Err(()) => 0,
}
}
#[unsafe(no_mangle)]
fn __rust_threadx_stderr_write(buf: &[u8]) -> usize {
use cortex_m_semihosting::hio;
let Ok(mut out) = hio::hstderr() else {
return 0;
};
match out.write_all(buf) {
Ok(()) => buf.len(),
Err(()) => 0,
}
}
#[unsafe(no_mangle)]
fn __rust_threadx_stdin_read(buf: &mut [u8]) -> usize {
use cortex_m_semihosting::{nr, syscall};
if buf.is_empty() {
return 0;
}
// `hio` only opens the host console for writing, so open it for reading
// directly. `:tt` is the special semihosting path for the console.
let name = b":tt\0";
let fd = match unsafe { syscall!(OPEN, name.as_ptr(), nr::open::R, name.len() - 1) } as isize {
-1 => return 0,
fd => fd as usize,
};
// SYS_READ returns the number of bytes that were *not* read; on error it
// returns a value larger than the request, which `saturating_sub` maps to 0.
let not_read = unsafe { syscall!(READ, fd, buf.as_mut_ptr(), buf.len()) };
let _ = unsafe { syscall!(CLOSE, fd) };
buf.len().saturating_sub(not_read)
}
|
