Allow instruction trace from any stage

In reality this internally allows us to see stages even it we are not
using pipelining but that is hidden from outside simply to not confuse
user.

1 files changed, 1 insertions, 1 deletions

diff --git a/qtmips_machine/instruction.h b/qtmips_machine/instruction.h
index 6232d3e..d84b0cb 100644
--- a/qtmips_machine/instruction.h
+++ b/qtmips_machine/instruction.h
@@ -29,7 +29,7 @@ public:
     bool operator!=(const Instruction &c) const;
     Instruction &operator=(const Instruction &c);
 
-    QString to_str();
+    QString to_str() const;
 
 private:
     std::uint32_t dt;