Added stack tracer and fixed bug with CMPA instruction

src/cpus/m68k/debugger.rs

@@ -5,19 +5,43 @@ use crate::memory::{Address, AddressSpace};
 use super::execute::{MC68010};
 use super::decode::{Instruction, Target, Size, Direction, Condition, ControlRegister, RegisterType};
 
+pub struct StackTracer {
+    pub calls: Vec<u32>,
+}
+
+impl StackTracer {
+    pub fn new() -> StackTracer {
+        StackTracer {
+            calls: vec![],
+        }
+    }
+
+    pub fn push_return(&mut self, addr: u32) {
+        self.calls.push(addr);
+    }
+
+    pub fn pop_return(&mut self) {
+        self.calls.pop();
+    }
+}
+
+
 pub struct M68kDebugger {
     pub breakpoints: Vec<u32>,
     pub use_tracing: bool,
     pub use_debugger: bool,
+    pub step_until_return: bool,
+    pub stack_tracer: StackTracer,
 }
 
-
 impl M68kDebugger {
     pub fn new() -> M68kDebugger {
         M68kDebugger {
             breakpoints: vec!(),
             use_tracing: false,
             use_debugger: false,
+            step_until_return: false,
+            stack_tracer: StackTracer::new(),
         }
     }
 }
@@ -45,6 +69,17 @@ impl MC68010 {
     pub fn run_debugger(&mut self, space: &mut AddressSpace) {
         self.dump_state(space);
 
+        if self.debugger.step_until_return {
+            match self.decoder.instruction {
+                Instruction::RTS | Instruction::RTE | Instruction::RTR => {
+                    self.debugger.step_until_return = false;
+                }
+                _ => {
+                    return;
+                },
+            }
+        }
+
         loop {
             let mut buffer = String::new();
             std::io::stdin().read_line(&mut buffer).unwrap();
@@ -83,6 +118,16 @@ impl MC68010 {
                     space.dump_memory(self.state.msp as Address, 0x40 as Address);
                 }
             },
+            "ds" | "stack" | "dumpstack" => {
+                println!("Stack:");
+                for addr in &self.debugger.stack_tracer.calls {
+                    println!("  {:08x}", space.read_beu32(*addr as Address)?);
+                }
+            },
+            "so" | "stepout" => {
+                self.debugger.step_until_return = true;
+                return Ok(true);
+            },
             "c" | "continue" => {
                 self.debugger.use_debugger = false;
                 return Ok(true);

src/cpus/m68k/execute.rs

@@ -227,6 +227,8 @@ impl MC68010 {
             },
             Instruction::BSR(offset) => {
                 self.push_long(space, self.state.pc)?;
+                let sp = *self.get_stack_pointer_mut();
+                self.debugger.stack_tracer.push_return(sp);
                 self.state.pc = (self.decoder.start + 2).wrapping_add(offset as u32);
             },
             Instruction::BTST(bitnum, target, size) => {
@@ -267,10 +269,10 @@ impl MC68010 {
                 self.set_compare_flags(result, size, carry, get_overflow(existing, value, result, size));
             },
             Instruction::CMPA(src, reg, size) => {
-                let value = self.get_target_value(space, src, size)?;
+                let value = sign_extend_to_long(self.get_target_value(space, src, size)?, size) as u32;
-                let existing = sign_extend_to_long(*self.get_a_reg_mut(reg), size) as u32;
+                let existing = *self.get_a_reg_mut(reg);
                 let (result, carry) = overflowing_sub_sized(existing, value, Size::Long);
-                self.set_compare_flags(result, size, carry, get_overflow(existing, value, result, Size::Long));
+                self.set_compare_flags(result, Size::Long, carry, get_overflow(existing, value, result, Size::Long));
             },
             Instruction::DBcc(cond, reg, offset) => {
                 let condition_true = self.get_current_condition(cond);
@@ -326,6 +328,8 @@ impl MC68010 {
             },
             Instruction::JSR(target) => {
                 self.push_long(space, self.state.pc)?;
+                let sp = *self.get_stack_pointer_mut();
+                self.debugger.stack_tracer.push_return(sp);
                 self.state.pc = self.get_target_address(target)?;
             },
             Instruction::LEA(target, reg) => {
@@ -493,6 +497,7 @@ impl MC68010 {
             //Instruction::RTR => {
             //},
             Instruction::RTS => {
+                self.debugger.stack_tracer.pop_return();
                 self.state.pc = self.pop_long(space)?;
             },
             Instruction::Scc(cond, target) => {

src/main.rs

@@ -30,7 +30,8 @@ fn main() {
     //cpu.enable_tracing();
 
     //cpu.add_breakpoint(0x0c94);
-    cpu.add_breakpoint(0x103220);
+    //cpu.add_breakpoint(0x103234);
+    //cpu.add_breakpoint(0x106e6a);
 
     while cpu.is_running() {
         match cpu.step(&mut space) {

src/memory.rs

@@ -143,7 +143,7 @@ impl AddressSpace {
     pub fn read(&mut self, addr: Address, count: usize) -> Result<Vec<u8>, Error> {
         let mut seg = self.get_segment_mut(addr)?;
         let relative_addr = addr - seg.base;
-        if relative_addr as usize + count >= seg.contents.len() {
+        if relative_addr as usize + count > seg.contents.len() {
             Err(Error::new(&format!("Error reading address {:#010x}", addr)))
         } else {
             Ok(seg.contents.read(relative_addr, count))