1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
|
use crate::*;
use std::collections::VecDeque;
use std::io::{BufRead, Stdout, Write};
use std::sync::mpsc::{self, TryRecvError};
pub struct StreamDevice {
/// True if a source is connected to stdin.
stdin_connected: bool,
/// True if a transmission is in progress.
stdin_control: bool,
stdin_rx: mpsc::Receiver<Vec<u8>>,
/// Bytes received in the current transmission.
stdin_queue: VecDeque<u8>,
/// Bytes received since stdin end-of-transmission.
stdin_excess: VecDeque<u8>,
stdout: Stdout,
/// True if a sink is connected to stdout.
stdout_connected: bool,
/// True if stdin is transmission-encoded.
decode_stdin: bool,
/// True if stdout should be transmission-encoded.
encode_stdout: bool,
/// Half-byte buffer for decoding stdin.
decode_buffer: Option<u8>,
wake: bool,
}
impl Device for StreamDevice {
fn read(&mut self, port: u8) -> u8 {
match port {
0x0 => read_b!(self.stdin_connected),
0x1 => read_b!(self.stdout_connected),
0x2 => read_b!(self.stdin_control),
0x3 => 0xff,
0x4 => self.stdin_length(),
0x5 => 0xff,
0x6 => self.stdin_read(),
0x7 => self.stdin_read(),
0x8 => todo!(),
0x9 => todo!(),
0xa => todo!(),
0xb => todo!(),
0xc => todo!(),
0xd => todo!(),
0xe => todo!(),
0xf => todo!(),
_ => unreachable!(),
}
}
fn write(&mut self, port: u8, value: u8) -> Option<Signal> {
match port {
0x0 => (),
0x1 => (),
0x2 => self.stdin_enable(),
0x3 => self.stdout_disable(),
0x4 => (),
0x5 => (),
0x6 => self.stdout_write(value),
0x7 => self.stdout_write(value),
0x8 => todo!(),
0x9 => todo!(),
0xa => todo!(),
0xb => todo!(),
0xc => todo!(),
0xd => todo!(),
0xe => todo!(),
0xf => todo!(),
_ => unreachable!(),
};
return None;
}
fn wake(&mut self) -> bool {
self.fetch_stdin_data();
std::mem::take(&mut self.wake)
}
}
impl StreamDevice {
pub fn new(config: &EmulatorConfig) -> Self {
// Spawn a thread to enable non-blocking reads of stdin.
let (stdin_tx, stdin_rx) = std::sync::mpsc::channel();
std::thread::spawn(move || loop {
let mut stdin = std::io::stdin().lock();
match stdin.fill_buf() {
Ok(buf) if !buf.is_empty() => {
let length = buf.len();
stdin_tx.send(buf.to_vec()).unwrap();
stdin.consume(length);
}
_ => break,
};
});
Self {
stdin_connected: true,
stdin_control: false,
stdin_rx,
stdin_queue: VecDeque::new(),
stdin_excess: VecDeque::new(),
stdout: std::io::stdout(),
stdout_connected: true,
decode_stdin: config.decode_stdin,
encode_stdout: config.encode_stdout,
decode_buffer: None,
wake: true,
}
}
pub fn stdin_length(&mut self) -> u8 {
self.fetch_stdin_data();
self.stdin_queue.len().try_into().unwrap_or(u8::MAX)
}
pub fn stdin_enable(&mut self) {
self.stdin_control = true;
}
pub fn stdin_read(&mut self) -> u8 {
self.fetch_stdin_data();
self.stdin_queue.pop_front().unwrap_or(0)
}
pub fn stdout_write(&mut self, value: u8) {
macro_rules! hex {
($value:expr) => { match $value {
0x0..=0x9 => $value + b'0',
0xa..=0xf => $value - 0x0a + b'a',
_ => unreachable!("Cannot encode value as hex digit: 0x{:02x}", $value),
} };
}
if self.encode_stdout {
let encoded = [hex!(value >> 4), hex!(value & 0xf), b' '];
self.stdout_write_raw(&encoded);
} else {
self.stdout_write_raw(&[value]);
};
}
fn stdout_write_raw(&mut self, bytes: &[u8]) {
if let Err(_) = self.stdout.write_all(bytes) {
if self.stdout_connected {
self.stdout_connected = false;
self.wake = true; // wake because stdout was disconnected.
}
}
}
pub fn stdout_disable(&mut self) {
if self.encode_stdout {
self.stdout_write_raw(&[b'\n']);
}
}
/// Fetch all pending data from stdin.
pub fn fetch_stdin_data(&mut self) {
while self.stdin_control {
match self.stdin_excess.pop_front() {
Some(byte) => self.fetch_byte(byte),
None => break,
}
}
loop {
match self.stdin_rx.try_recv() {
Ok(tx) => {
for byte in tx {
match self.stdin_control {
true => self.fetch_byte(byte),
false => self.stdin_excess.push_back(byte),
}
}
}
Err(TryRecvError::Empty) => {
break;
}
Err(TryRecvError::Disconnected) => {
self.stdin_control = false;
if self.stdin_connected {
self.stdin_connected = false;
self.wake = true; // wake because stdin was disconnected.
}
break;
}
}
}
}
fn fetch_byte(&mut self, byte: u8) {
if self.decode_stdin {
let decoded = match byte {
b'0'..=b'9' => byte - b'0',
b'a'..=b'f' => byte - b'a' + 0x0a,
b'A'..=b'F' => byte - b'A' + 0x0a,
b'\n' => {
self.decode_buffer = None;
self.stdin_control = false;
self.wake = true; // wake because a transmission ended.
return;
},
_ => return,
};
if let Some(high) = std::mem::take(&mut self.decode_buffer) {
self.stdin_queue.push_back((high << 4) | decoded);
self.wake = true; // wake because a byte was received.
} else {
self.decode_buffer = Some(decoded);
}
} else {
self.stdin_queue.push_back(byte);
self.wake = true; // wake because a byte was received.
}
}
pub fn flush(&mut self) {
let _ = self.stdout.flush();
}
}
impl Drop for StreamDevice {
fn drop(&mut self) {
self.flush();
}
}
|
