diff --git a/InstructionSets/x86/Implementation/PerformImplementation.hpp b/InstructionSets/x86/Implementation/PerformImplementation.hpp
index dfbcfd72d..d1e4c0810 100644
--- a/InstructionSets/x86/Implementation/PerformImplementation.hpp
+++ b/InstructionSets/x86/Implementation/PerformImplementation.hpp
@@ -610,6 +610,9 @@ void cwd(IntT &dx, IntT ax) {
 inline void clc(Status &status) {	status.carry = 0;				}
 inline void cld(Status &status) {	status.direction = 0;			}
 inline void cli(Status &status) {	status.interrupt = 0;			}	// TODO: quite a bit more in protected mode.
+inline void stc(Status &status) {	status.carry = 1;				}
+inline void std(Status &status) {	status.direction = 1;			}
+inline void sti(Status &status) {	status.interrupt = 1;			}	// TODO: quite a bit more in protected mode.
 inline void cmc(Status &status) {	status.carry = !status.carry;	}
 
 }
@@ -731,6 +734,9 @@ template <
 		case Operation::CLC:	Primitive::clc(status);				return;
 		case Operation::CLD:	Primitive::cld(status);				return;
 		case Operation::CLI:	Primitive::cli(status);				return;
+		case Operation::STC:	Primitive::stc(status);				return;
+		case Operation::STD:	Primitive::std(status);				return;
+		case Operation::STI:	Primitive::sti(status);				return;
 		case Operation::CMC:	Primitive::cmc(status);				return;
 	}
 
diff --git a/InstructionSets/x86/Instruction.hpp b/InstructionSets/x86/Instruction.hpp
index d948fd88f..9c93e53e2 100644
--- a/InstructionSets/x86/Instruction.hpp
+++ b/InstructionSets/x86/Instruction.hpp
@@ -195,7 +195,7 @@ enum class Operation: uint8_t {
 	CLI,
 	/// Set carry flag.
 	STC,
-	/// Set decimal flag.
+	/// Set direction flag.
 	STD,
 	/// Set interrupt flag.
 	STI,
diff --git a/OSBindings/Mac/Clock SignalTests/8088Tests.mm b/OSBindings/Mac/Clock SignalTests/8088Tests.mm
index d9bf0bdaa..c8d68a34b 100644
--- a/OSBindings/Mac/Clock SignalTests/8088Tests.mm	
+++ b/OSBindings/Mac/Clock SignalTests/8088Tests.mm	
@@ -330,6 +330,9 @@ struct FailedExecution {
 		@"F8.json.gz",	// CLC
 		@"FC.json.gz",	// CLD
 		@"FA.json.gz",	// CLI
+		@"F9.json.gz",	// STC
+		@"FD.json.gz",	// STD
+		@"FB.json.gz",	// STI
 		@"F5.json.gz",	// CMC
 	]];