From 449612ac19a1d7364f7130f6b785b1aebb933694 Mon Sep 17 00:00:00 2001
From: zxq5 <zxq5@zxq5.dev>
Date: Tue, 24 Jun 2025 18:07:11 +0100
Subject: [PATCH] added step(n) feature to emulator, allowing for stepping n
 instructions at a time

---
 emulator/src/emulator/system/emulator.rs      | 50 +++++++++++--------
 emulator/src/emulator/system/model.rs         |  2 +-
 emulator/src/emulator/system/processor/mod.rs |  3 --
 emulator/src/emulator/ui/control_unit.rs      | 34 +++++++++++--
 4 files changed, 59 insertions(+), 30 deletions(-)

diff --git a/emulator/src/emulator/system/emulator.rs b/emulator/src/emulator/system/emulator.rs
index 40e4b57..ff4762c 100644
--- a/emulator/src/emulator/system/emulator.rs
+++ b/emulator/src/emulator/system/emulator.rs
@@ -27,6 +27,7 @@ pub fn run_emulator(
     println!("INFO: Starting emulator.");
 
     let mut running = Running::Paused;
+    let mut step = 0;
     let mut addr;
     let mut history = Vec::<(u32, Instruction)>::new();
     let size = 256;
@@ -39,7 +40,7 @@ pub fn run_emulator(
     let mut update = false;
 
     loop {
-        let cmd = if running == Running::Running {
+        let cmd = if running == Running::Running || step > 0 {
             match cmd_rx.try_recv() {
                 Ok(cmd) => Some(cmd),
                 Err(mpsc::TryRecvError::Empty) => {
@@ -96,26 +97,8 @@ pub fn run_emulator(
 
                     processor.reset();
                 }
-                Command::Step => {
-                    update = true;
-
-                    running = Running::Paused;
-
-                    // Execute one cycle.
-                    match processor.cycle() {
-                        Ok((addr, instruction)) => {
-                            history.push((addr, instruction));
-                        }
-                        Err(why) => {
-                            let pcx = processor.get(Register::Pcx);
-                            eprintln!(
-                                "Could not decode instruction at {pcx:x}. Reason: {why}"
-                            );
-                            continue;
-                        }
-                    }
-
-                    instruction_count += 1;
+                Command::Step(x) => {
+                    step = x;
                 }
                 Command::Write(offset, data) => {
                     update = true;
@@ -200,6 +183,31 @@ pub fn run_emulator(
             }
         }
 
+        if step > 0 {
+            step -= 1;
+            update = true;
+            running = Running::Paused;
+
+            // Execute one cycle.
+            match processor.cycle() {
+                Ok((addr, instruction)) => {
+                    history.push((addr, instruction));
+                }
+                Err(why) => {
+                    let pcx = processor.get(Register::Pcx);
+                    report_err(
+                        state_tx,
+                        &format!(
+                            "Could not decode instruction at {pcx:x}. Reason: {why}"
+                        ),
+                        &mut processor,
+                    );
+                }
+            }
+            instruction_count += 1;
+            continue;
+        }
+
         if running == Running::Running {
             update = true;
 
diff --git a/emulator/src/emulator/system/model.rs b/emulator/src/emulator/system/model.rs
index f31ad12..e674b2a 100644
--- a/emulator/src/emulator/system/model.rs
+++ b/emulator/src/emulator/system/model.rs
@@ -21,7 +21,7 @@ pub enum Command {
     // set emulator state.
     Start,
     Stop,
-    Step,
+    Step(usize),
     Reset(usize),
     Interrupt(Interrupt),
     Write(Address, Vec<u8>),
diff --git a/emulator/src/emulator/system/processor/mod.rs b/emulator/src/emulator/system/processor/mod.rs
index aa4f425..3e9a37a 100644
--- a/emulator/src/emulator/system/processor/mod.rs
+++ b/emulator/src/emulator/system/processor/mod.rs
@@ -64,10 +64,7 @@ impl Processor {
         let instruction = Instruction::decode(val)
             .map_err(|_| ProcessorError::InvalidInstruction(val))?;
 
-        log(&instruction.to_string());
-
         instruction.execute(self)?;
-
         Ok((addr, instruction))
     }
 
diff --git a/emulator/src/emulator/ui/control_unit.rs b/emulator/src/emulator/ui/control_unit.rs
index 75c2c3b..bb32679 100644
--- a/emulator/src/emulator/ui/control_unit.rs
+++ b/emulator/src/emulator/ui/control_unit.rs
@@ -7,12 +7,18 @@ use common::{instructions::Register, prelude::Instruction};
 
 pub struct ControlPanel {
     visible: bool,
+    step_amount_input: String,
+    step_amount: usize,
 }
 
 impl ControlPanel {
     #[allow(clippy::must_use_candidate)]
-    pub const fn new() -> Self {
-        Self { visible: false }
+    pub fn new() -> Self {
+        Self {
+            visible: false,
+            step_amount_input: String::from("1"),
+            step_amount: 1,
+        }
     }
 }
 
@@ -59,9 +65,12 @@ impl Component for ControlPanel {
 
             // Step
             if ui.button("Step").clicked() {
-                state.cmd_sender.send(Command::Step).unwrap_or_else(|_| {
-                    state.error_log.push("Failed to send command".to_string());
-                });
+                state
+                    .cmd_sender
+                    .send(Command::Step(self.step_amount))
+                    .unwrap_or_else(|_| {
+                        state.error_log.push("Failed to send command".to_string());
+                    });
             }
 
             // Resets the emulator and all attached devices
@@ -98,6 +107,21 @@ impl Component for ControlPanel {
 
             state.send(Command::RegisterRequest);
             state.send(Command::RunningRequest);
+            state.send(Command::InstructionCountRequest);
+
+            if ui
+                .text_edit_singleline(&mut self.step_amount_input)
+                .changed()
+            {
+                self.step_amount = if let Ok(amount) = self.step_amount_input.parse() {
+                    amount
+                } else {
+                    state
+                        .error_log
+                        .push("Unable to parse step amount".to_string());
+                    1
+                }
+            }
 
             // Status info
             ui.label(format!(