From c7165476b1a399388e41c2b806daf9f4e6ea88ca Mon Sep 17 00:00:00 2001
From: D4VID <d4vid@d4vid.xyz>
Date: Sat, 7 Jun 2025 21:21:51 +0200
Subject: [PATCH] More screen control

---
 lwcpu/src/lib.rs | 35 +++++++++++++++++++++++++++++++----
 test/src/main.rs |  6 +++++-
 2 files changed, 36 insertions(+), 5 deletions(-)

diff --git a/lwcpu/src/lib.rs b/lwcpu/src/lib.rs
index 9142050..bb8ec10 100644
--- a/lwcpu/src/lib.rs
+++ b/lwcpu/src/lib.rs
@@ -30,8 +30,8 @@ pub enum ScreenMode {
 
 pub struct Screen {}
 impl Screen {
-    const SCREEN_CLEAR: u32 = 0x0000_0001;
-    const SCREEN_DISPLAY: u32 = 0x0000_0100;
+    const SCREEN_CLEAR   : u32 = 0x0000_0001;
+    const SCREEN_DISPLAY : u32 = 0x0000_0100;
 
     #[inline]
     pub fn init(mode: ScreenMode) {
@@ -48,6 +48,33 @@ impl Screen {
         }
     }
     #[inline]
+    pub fn clear() {
+        unsafe {
+            // Write a 1 to the screen clear byte
+            write_volatile(SCREEN_CONTROL_POINTER as *mut u8, 1);
+            write_volatile(SCREEN_CONTROL_POINTER as *mut u8, 0);
+        }
+    }
+    #[inline]
+    pub fn display() {
+        unsafe {
+            // Write a 1 to the screen display byte
+            write_volatile((SCREEN_CONTROL_POINTER as *mut u8).byte_offset(1), 1);
+            write_volatile((SCREEN_CONTROL_POINTER as *mut u8).byte_offset(1), 0);
+        }
+    }
+    #[inline]
+    pub fn change_mode(mode: ScreenMode) {
+        match mode {
+            ScreenMode::AlwaysDisplay => unsafe {
+                write_volatile((SCREEN_CONTROL_POINTER as *mut u8).byte_offset(1), 1);
+            },
+            ScreenMode::Buffered => unsafe {
+                write_volatile((SCREEN_CONTROL_POINTER as *mut u8).byte_offset(1), 0);
+            },
+        }
+    }
+    #[inline]
     pub fn turn_pixel_on(x: u8, y: u8) {
         unsafe {
             let mut row = read_volatile(SCREEN_POINTER.offset(y as isize));
@@ -73,8 +100,8 @@ impl Screen {
 
 pub struct TextDisplay {}
 impl TextDisplay {
-    const TEXT_CLEAR: u32 = 0x0000_0001;
-    const TEXT_DISPLAY: u32 = 0x0000_0100;
+    const TEXT_CLEAR   : u32 = 0x0000_0001;
+    const TEXT_DISPLAY : u32 = 0x0000_0100;
 
     #[inline]
     pub fn init(&self) {
diff --git a/test/src/main.rs b/test/src/main.rs
index 29e1031..3fdb759 100644
--- a/test/src/main.rs
+++ b/test/src/main.rs
@@ -18,12 +18,16 @@ const HELLO_WORLD: &str = " Hello world!";
 #[entry]
 fn main() -> ! {
     NumberDisplay::display_number(0);
-    Screen::init(ScreenMode::AlwaysDisplay);
+    Screen::init(ScreenMode::Buffered);
     let mut text = TextDisplay{};
     text.init();
     for i in 0..32 {
         Screen::set_line(i, 1 << i);
     }
+    Screen::display();
+    Screen::clear();
+    Screen::display();
+    Screen::change_mode(ScreenMode::AlwaysDisplay);
     unsafe {
         write_volatile(SCREEN_POINTER, 0x001166ff);
         write_volatile(SCREEN_POINTER.offset(1), 0xAAAAAAAA);