add breakpoints

gb-emu/src/debug.rs

@@ -18,6 +18,7 @@ pub enum CommandErr {
 
 pub enum Commands {
     Watch(u16),
+    Break(u16),
     Step,
     Continue,
 }
@@ -38,6 +39,13 @@ impl FromStr for Commands {
                     Err(CommandErr::InvalidArgument)
                 }
             }
+            _ if let Some(addr) = lower.strip_prefix("break") => {
+                if let Ok(addr) = u16::from_str_radix(addr.trim().trim_start_matches("0x"), 16) {
+                    Ok(Self::Break(addr))
+                } else {
+                    Err(CommandErr::InvalidArgument)
+                }
+            }
             _ => Err(CommandErr::InvalidCommand),
         }
     }
@@ -49,6 +57,7 @@ pub struct Debugger {
     stepping: bool,
     last_command: String,
     watches: HashMap<u16, u8>,
+    breakpoints: Vec<u16>,
 }
 
 impl Debugger {
@@ -62,6 +71,7 @@ impl Debugger {
             stepping: true,
             last_command: String::from(""),
             watches: HashMap::new(),
+            breakpoints: Vec::new(),
         }
     }
 
@@ -95,6 +105,11 @@ impl Debugger {
                     }
                     Commands::Step => self.stepping = true,
                     Commands::Continue => self.stepping = false,
+                    Commands::Break(address) => {
+                        if !self.breakpoints.contains(&address) {
+                            self.breakpoints.push(address)
+                        }
+                    }
                 }
             } else {
                 println!("Invalid command");
@@ -117,6 +132,12 @@ impl Debugger {
                 *data = new_data;
             }
         }
+        for address in &self.breakpoints {
+            if self.core.pc() == *address {
+                println!("Breakpoint at 0x{address:0>4X} reached");
+                should_pause = true;
+            }
+        }
         should_pause
     }
 }

lib/src/lib.rs

@@ -134,6 +134,10 @@ where
         self.cpu.cycle_count
     }
 
+    pub fn pc(&self) -> u16 {
+        self.cpu.reg.pc
+    }
+
     pub fn print_reg(&self) -> String {
         format!(
             "A:{:0>2X}, F:{}, BC:{:0>4X}, DE:{:0>4X}, HL:{:0>4X}, SP:{:0>4X}, PC:{:0>4X}\nLast instruction: {:0>2X} from 0x{:0>4X}",