user_lib/
lib.rs

1#![no_std]
2//!
3//! 教程阅读建议：
4//!
5//! - `_start` 展示用户程序最小运行时（初始化控制台、堆、调用 main）；
6//! - 其余辅助函数（sleep/pipe_*）展示了常见 syscall 组合用法。
7
8mod heap;
9
10extern crate alloc;
11
12use tg_console::log;
13
14pub use tg_console::{print, println};
15pub use tg_syscall::*;
16
17#[cfg(feature = "tangram")]
18pub mod tangram;
19
20#[cfg(feature = "snake")]
21pub mod snake;
22
23/// Query framebuffer dimensions from kernel.
24/// Returns (width, height).
25pub fn fb_info() -> (u32, u32) {
26    let packed: usize;
27    unsafe {
28        core::arch::asm!(
29            "ecall",
30            in("a7") 2000usize,
31            lateout("a0") packed,
32        );
33    }
34    let width = (packed >> 32) as u32;
35    let height = packed as u32;
36    (width, height)
37}
38
39/// Write a rectangular BGRA pixel region to the kernel framebuffer.
40/// The kernel copies the data and flushes the display.
41pub fn fb_write(x: u32, y: u32, w: u32, h: u32, data: *const u8) -> isize {
42    let ret: isize;
43    unsafe {
44        core::arch::asm!(
45            "ecall",
46            in("a7") 2001usize,
47            inlateout("a0") x as usize => ret,
48            in("a1") y as usize,
49            in("a2") w as usize,
50            in("a3") h as usize,
51            in("a4") data as usize,
52        );
53    }
54    ret
55}
56
57#[unsafe(no_mangle)]
58#[unsafe(link_section = ".text.entry")]
59pub extern "C" fn _start() -> ! {
60    // 用户态运行时初始化顺序与内核类似：先 I/O，再堆，再进入 main。
61    tg_console::init_console(&Console);
62    tg_console::set_log_level(option_env!("LOG"));
63    heap::init();
64
65    unsafe extern "C" {
66        fn main() -> i32;
67    }
68
69    // SAFETY: main 函数由用户程序提供，链接器保证其存在且符合 C ABI
70    exit(unsafe { main() });
71    unreachable!()
72}
73
74#[panic_handler]
75fn panic_handler(panic_info: &core::panic::PanicInfo) -> ! {
76    let err = panic_info.message();
77    if let Some(location) = panic_info.location() {
78        log::error!("Panicked at {}:{}, {err}", location.file(), location.line());
79    } else {
80        log::error!("Panicked: {err}");
81    }
82    exit(1);
83    unreachable!()
84}
85
86/// File descriptor for buffered keyboard input (timer-polled ring buffer in kernel).
87pub const STDIN_BUFFERED: usize = 3;
88
89pub fn getchar() -> u8 {
90    let mut c = [0u8; 1];
91    read(STDIN, &mut c);
92    c[0]
93}
94
95struct Console;
96
97impl tg_console::Console for Console {
98    #[inline]
99    fn put_char(&self, c: u8) {
100        tg_syscall::write(STDOUT, &[c]);
101    }
102
103    #[inline]
104    fn put_str(&self, s: &str) {
105        tg_syscall::write(STDOUT, s.as_bytes());
106    }
107}
108
109pub fn sleep(period_ms: usize) {
110    // 轮询时钟 + 主动让出 CPU 的教学实现，便于理解 time/yield 系统调用协作。
111    let mut time: TimeSpec = TimeSpec::ZERO;
112    clock_gettime(ClockId::CLOCK_MONOTONIC, &mut time as *mut _ as _);
113    let time = time + TimeSpec::from_millsecond(period_ms);
114    loop {
115        let mut now: TimeSpec = TimeSpec::ZERO;
116        clock_gettime(ClockId::CLOCK_MONOTONIC, &mut now as *mut _ as _);
117        if now > time {
118            break;
119        }
120        sched_yield();
121    }
122}
123
124pub fn get_time() -> isize {
125    let mut time: TimeSpec = TimeSpec::ZERO;
126    clock_gettime(ClockId::CLOCK_MONOTONIC, &mut time as *mut _ as _);
127    (time.tv_sec * 1000 + time.tv_nsec / 1_000_000) as isize
128}
129
130pub fn trace_read(ptr: *const u8) -> Option<u8> {
131    let ret = trace(0, ptr as usize, 0);
132    if ret >= 0 && ret <= 255 {
133        Some(ret as u8)
134    } else {
135        None
136    }
137}
138
139pub fn trace_write(ptr: *const u8, value: u8) -> isize {
140    trace(1, ptr as usize, value as usize)
141}
142
143pub fn count_syscall(syscall_id: usize) -> isize {
144    trace(2, syscall_id, 0)
145}
146
147/// 从管道读取数据
148/// 返回实际读取的总字节数，负数表示错误
149pub fn pipe_read(pipe_fd: usize, buffer: &mut [u8]) -> isize {
150    let mut total_read = 0usize;
151    let len = buffer.len();
152    loop {
153        if total_read >= len {
154            return total_read as isize;
155        }
156        let ret = read(pipe_fd, &mut buffer[total_read..]);
157        if ret == -2 {
158            // 暂时无数据，让出 CPU 后重试
159            sched_yield();
160            continue;
161        } else if ret == 0 {
162            // EOF，写端关闭
163            return total_read as isize;
164        } else if ret < 0 {
165            // 其他错误
166            return ret;
167        } else {
168            total_read += ret as usize;
169        }
170    }
171}
172
173/// 向管道写入数据
174/// 返回实际写入的总字节数，负数表示错误
175pub fn pipe_write(pipe_fd: usize, buffer: &[u8]) -> isize {
176    let mut total_write = 0usize;
177    let len = buffer.len();
178    loop {
179        if total_write >= len {
180            return total_write as isize;
181        }
182        let ret = write(pipe_fd, &buffer[total_write..]);
183        if ret == -2 {
184            // 缓冲区满，让出 CPU 后重试
185            sched_yield();
186            continue;
187        } else if ret < 0 {
188            // 其他错误
189            return ret;
190        } else {
191            total_write += ret as usize;
192        }
193    }
194}
user_lib/lib.rs

user_lib/
lib.rs
