1 files changed, 97 insertions, 0 deletions
diff --git a/sw/deps/hd44780-driver/src/entry_mode.rs b/sw/deps/hd44780-driver/src/entry_mode.rs
new file mode 100644
index 0000000..577c5d0
--- /dev/null
+++ b/sw/deps/hd44780-driver/src/entry_mode.rs
@@ -0,0 +1,97 @@
+/// Determines if the cursor should be incremented or decremented on write
+#[derive(Debug, PartialEq, Eq)]
+pub enum CursorMode {
+    Increment,
+    Decrement,
+}
+
+impl Default for CursorMode {
+    fn default() -> CursorMode {
+        CursorMode::Increment
+    }
+}
+
+/// Determines if the screen should be shifted on write
+#[derive(Debug, PartialEq, Eq)]
+pub enum ShiftMode {
+    Enabled,
+    Disabled,
+}
+
+impl From<bool> for ShiftMode {
+    fn from(b: bool) -> ShiftMode {
+        if b {
+            ShiftMode::Enabled
+        } else {
+            ShiftMode::Disabled
+        }
+    }
+}
+
+impl Default for ShiftMode {
+    fn default() -> ShiftMode {
+        ShiftMode::Disabled
+    }
+}
+
+#[derive(Default)]
+pub struct EntryMode {
+    pub cursor_mode: CursorMode,
+    pub shift_mode: ShiftMode,
+}
+
+impl EntryMode {
+    pub fn as_byte(&self) -> u8 {
+        let cursor_bits = match self.cursor_mode {
+            CursorMode::Increment => 0b0000_0010,
+            CursorMode::Decrement => 0,
+        };
+
+        let shift_bits = match self.shift_mode {
+            ShiftMode::Enabled => 0b0000_0001,
+            ShiftMode::Disabled => 0,
+        };
+
+        0b0000_0100 | cursor_bits | shift_bits
+    }
+}
+
+#[cfg(test)]
+mod tests {
+
+    use super::*;
+
+    #[test]
+    fn cursor_mode() {
+        let em = EntryMode {
+            cursor_mode: CursorMode::Increment,
+            shift_mode: Default::default(),
+        };
+
+        assert!(em.as_byte() & 0b0000_0010 != 0);
+
+        let em = EntryMode {
+            cursor_mode: CursorMode::Decrement,
+            shift_mode: Default::default(),
+        };
+
+        assert!(em.as_byte() & 0b0000_0010 == 0);
+    }
+
+    #[test]
+    fn shift_mode() {
+        let em = EntryMode {
+            cursor_mode: Default::default(),
+            shift_mode: ShiftMode::Enabled,
+        };
+
+        assert!(em.as_byte() & 0b0000_0001 != 0);
+
+        let em = EntryMode {
+            cursor_mode: Default::default(),
+            shift_mode: ShiftMode::Disabled,
+        };
+
+        assert!(em.as_byte() & 0b0000_0001 == 0);
+    }
+}