lwcpu/src/lib.rs

@@ -18,10 +18,12 @@ const TEXT_DISPLAY_POINTER: *mut u8 = (BASE_POINTER + TEXT_DISPLAY_OFFSET) as *m
 const KEYBOARD_POINTER       : *mut u32 = (BASE_POINTER + KEYBOARD_OFFSET)       as *mut u32;
 const SCREEN_POINTER         : *mut u32 = (BASE_POINTER + SCREEN_OFFSET)         as *mut u32;
 
+
 pub struct Screen {}
 impl Screen {
     #[inline]
-    pub fn clear() {}
+    pub fn clear() {
+    }
     #[inline]
     pub fn turn_pixel_on(x: u8, y: u8) {
         unsafe {
@@ -55,17 +57,6 @@ impl TextDisplay {
         }
     }
 }
-impl core::fmt::Write for TextDisplay {
-    #[inline]
-    fn write_str(&mut self, s: &str) -> core::fmt::Result {
-        for ch in s.bytes() {
-            unsafe {
-                write_volatile(TEXT_DISPLAY_POINTER, ch);
-            }
-        }
-        return Ok(());
-    }
-}
 
 pub struct NumberDisplay {}
 impl NumberDisplay {

test/Cargo.toml

@@ -5,7 +5,7 @@ edition = "2021"
 
 [dependencies]
 riscv = "0.12.1"
-riscv-rt = { version = "0.13.0", features=["single-hart"] }
+riscv-rt = "0.13.0"
 lwcpu = { path = "../lwcpu" }
 
 # https://docs.rust-embedded.org/book/unsorted/speed-vs-size.html

test/Makefile

@@ -12,7 +12,7 @@ extract: build
 size: extract
 	cargo size --release -- -A
 
-disassemble: extract
+disassemble: build
 	riscv32-elf-objdump -Cd "target/riscv32i-unknown-none-elf/release/${NAME}" | less
 
 clean:

test/src/main.rs

@@ -1,8 +1,8 @@
 #![no_std]
 #![no_main]
 
-use core::{fmt::Write, panic::PanicInfo};
+use core::panic::PanicInfo;
-use lwcpu::{NumberDisplay, Screen, TextDisplay};
+use lwcpu::{self, NumberDisplay, Screen, TextDisplay};
 use riscv_rt::entry;
 
 #[panic_handler]
@@ -11,15 +11,16 @@ fn panic_handler(_info: &PanicInfo) -> ! {
     loop {}
 }
 
-const HELLO_WORLD: &str = " Hello world!";
+const HELLO_WORLD: &[u8; 13] = b" Hello world!";
 
 #[entry]
 fn main() -> ! {
-    let mut text = TextDisplay{};
     for i in 0..31 {
         Screen::set_line(i, 1 << i);
     }
     loop {
-        let _ = text.write_str(HELLO_WORLD);
+        for ch in HELLO_WORLD {
+            TextDisplay::put_char(*ch);
+        }
     }
 }