fox32: Dump RAM if bad opcode

src/cpu.rs

@@ -268,6 +268,8 @@ impl Cpu {
             println!("{:#010X}: bad opcode {:#06X}", self.instruction_pointer, opcode);
             println!("size instr  . cond dest src");
             println!("{:02b}   {:06b} {:01b} {:03b}  {:02b}   {:02b}", size, instruction, empty, condition, destination, source);
+            println!("dumping RAM");
+            self.bus.memory.dump();
             panic!("bad opcode");
         }
     }

src/memory.rs

@@ -5,6 +5,7 @@ use crate::error;
 use std::cell::UnsafeCell;
 use std::sync::Arc;
 use std::io::Write;
+use std::fs::File;
 
 pub const MEMORY_RAM_SIZE: usize = 0x04000000; // 64 MiB
 pub const MEMORY_ROM_SIZE: usize = 0x00080000; // 512 KiB
@@ -54,6 +55,11 @@ impl Memory {
     pub fn ram(&self) -> &mut MemoryRam { &mut self.inner().ram }
     pub fn rom(&self) -> &mut MemoryRom { &mut self.inner().rom }
 
+    pub fn dump(&self) {
+        let mut file = File::create("memory.dump").expect("failed to open memory dump file");
+        file.write_all(self.ram()).expect("failed to write memory dump file");
+    }
+
     pub fn read_8(&self, address: u32) -> u8 {
         let address = address as usize;