diff --git a/bus.cpp b/bus.cpp
index ca066e9..d66dbc6 100644
--- a/bus.cpp
+++ b/bus.cpp
@@ -743,6 +743,8 @@ void bus::write(const uint16_t addr_in, const word_mode_t word_mode, uint16_t va
 				else
 					v = (v & 0x00ff) | (value << 8);
 
+				v |= 0377;
+
 				c->setStackLimitRegister(v);
 
 				return;
diff --git a/cpu.h b/cpu.h
index 6eca542..2d9023f 100644
--- a/cpu.h
+++ b/cpu.h
@@ -32,7 +32,7 @@ private:
 	uint16_t pc    { 0 };
 	uint16_t psw   { 0 };
 	uint16_t fpsr  { 0 };
-	uint16_t stackLimitRegister { 0 };
+	uint16_t stackLimitRegister { 0377 };
 	uint64_t instruction_count { 0 };
 	uint64_t running_since     { 0 };