Fix spells (#17)

Author: AsaiYusuke

include/emulation/cpu_device.h

@@ -30,11 +30,6 @@ class cpu_device
     exec_mos6502 *cpu;
     uint64_t max_cycle_count;
     uint64_t cycle_count;
-    enum class inst_type
-    {
-        call,
-        retern
-    };
     call_stack_filter *call_stack;
     register_counter_filter *register_counter;
     vector<i_cpu_filter *> filters;
@@ -57,7 +52,7 @@ class cpu_device
     uint8_t get_read_count(status_flag_type type);
     uint8_t get_write_count(status_flag_type type);
     bool is_illegal_instruction();
-    bool is_call_instrunction();
+    bool is_call_instruction();
     bool is_return_instruction();
     bool is_read_register_instruction(register_type type);
     bool is_write_register_instruction(register_type type);

include/emulation/cpu_filter/call_stack_filter.h

@@ -13,11 +13,11 @@ class call_stack_filter : public i_cpu_filter
     enum class inst_type
     {
         call,
-        retern
+        return_back
     };
     cpu_device *cpu;
     bool isCallInstr;
-    bool isReternInstr;
+    bool isReturnInstr;
     bool isInterruptInstr;
     bool isReturned;
     bool willReturn;

src/emulation/cpu_device.cpp

@@ -192,7 +192,7 @@ bool cpu_device::is_illegal_instruction()
     return cpu->isIllegalInstr();
 }
 
-bool cpu_device::is_call_instrunction()
+bool cpu_device::is_call_instruction()
 {
     return cpu->isCallInstr();
 }

src/emulation/cpu_filter/call_stack_filter.cpp

@@ -17,12 +17,12 @@ void call_stack_filter::clear()
 bool call_stack_filter::pre()
 {
     isCallInstr = false;
-    isReternInstr = false;
+    isReturnInstr = false;
     isInterruptInstr = false;
 
     pre_pc = cpu->get_register16(register_type::PC);
 
-    if (cpu->is_call_instrunction())
+    if (cpu->is_call_instruction())
     {
         call_stack.push_back(make_pair(inst_type::call, pre_pc));
         isCallInstr = true;
@@ -36,8 +36,8 @@ bool call_stack_filter::pre()
         }
         else
         {
-            call_stack.push_back(make_pair(inst_type::retern, pre_pc));
-            isReternInstr = true;
+            call_stack.push_back(make_pair(inst_type::return_back, pre_pc));
+            isReturnInstr = true;
         }
     }
 
@@ -58,9 +58,9 @@ bool call_stack_filter::post()
     {
         call_stack.push_back(make_pair(inst_type::call, cpu->get_register16(register_type::PC)));
     }
-    if (isReternInstr)
+    if (isReturnInstr)
     {
-        call_stack.push_back(make_pair(inst_type::retern, cpu->get_register16(register_type::PC)));
+        call_stack.push_back(make_pair(inst_type::return_back, cpu->get_register16(register_type::PC)));
     }
     if (!isReturned && isInterruptInstr)
     {