65 lines
1.5 KiB
Rust
65 lines
1.5 KiB
Rust
use crate::driver::tty::Tty;
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use core::arch::asm;
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/// A TTY attached via a serial port.
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///
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/// Serial ports don't commonly exist on physical devices anymore,
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/// but many emulators support them and can map them to the host's TTY/terminal emulator,
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/// which makes them useful for debugging in a VM.
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pub struct SerialTty {
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port: u16,
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}
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/// The port used by COM1 on x86 devices.
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#[cfg(target_arch = "x86_64")]
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pub const COM1_PORT: u16 = 0x3F8;
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impl SerialTty {
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/// Creates a new serial TTY which will use the provided port for output.
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///
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/// Unsafe because it is up to the caller to make sure
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/// that the port is actually the port for a TTY device.
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pub unsafe fn new(port: u16) -> SerialTty {
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SerialTty {
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port: port,
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}
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}
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#[cfg(target_arch = "x86_64")]
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fn outb(&self, cmd: u8) {
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unsafe {
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asm!("out dx, al", in("dx") self.port, in("al") cmd);
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}
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}
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fn outc(&self, c: char) {
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let len = c.len_utf8();
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let bytes = (c as u32).to_le_bytes();
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for i in 0..len {
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self.outb(bytes[i]);
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}
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}
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}
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impl Tty for SerialTty {
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fn putc(&mut self, c: char) {
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self.outc(c);
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}
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fn puts(&mut self, s: &str) {
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for c in s.chars() {
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self.putc(c);
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}
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}
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fn clear(&mut self) {
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// VT100 escape code to reset the terminal: `ESC C`.
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self.puts("\u{1B}c");
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}
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fn flush(&mut self) {
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// This TTY doesn't use buffering.
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}
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}
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