diff --git a/InstructionSets/x86/Implementation/PerformImplementation.hpp b/InstructionSets/x86/Implementation/PerformImplementation.hpp
index 780cac885..0101d1fd2 100644
--- a/InstructionSets/x86/Implementation/PerformImplementation.hpp
+++ b/InstructionSets/x86/Implementation/PerformImplementation.hpp
@@ -344,6 +344,58 @@ inline void daa(uint8_t &al, Status &status) {
 	status.zero = status.parity = al;
 }
 
+inline void das(uint8_t &al, Status &status) {
+	/*
+		(as modified by https://www.felixcloutier.com/x86/daa ...)
+
+        old_AL ← AL;
+        old_CF ← CF;
+        CF ← 0;
+
+		IF (((AL AND 0FH) > 9) or AF = 1)
+			THEN
+				AL ← AL - 6;
+				CF ← old_CF OR CarryFromLastAddition; (* CF OR borrow from AL ← AL - 6 *)
+				AF ← 1;
+			ELSE
+				AF ← 0;
+		FI;
+		IF ((old_AL > 99H) or old_CF = 1)
+			THEN
+				AL ← AL - 60H;
+				CF ← 1;
+			ELSE
+				CF ← 0;
+		FI;
+	*/
+	/*
+		The CF and AF flags are set if the adjustment of the value results in a
+		decimal carry in either digit of the result (see the “Operation” section above).
+		The SF, ZF, and PF flags are set according to the result. The OF flag is undefined.
+	*/
+	const uint8_t old_al = al;
+	const auto old_carry = status.carry;
+	status.carry = 0;
+
+	if((al & 0x0f) > 0x09 || status.auxiliary_carry) {
+		status.carry = old_carry | (al < 0x06);
+		al -= 0x06;
+		status.auxiliary_carry = 1;
+	} else {
+		status.auxiliary_carry = 0;
+	}
+
+	if(old_al > 0x99 || old_carry) {
+		al -= 0x60;
+		status.carry = 1;
+	} else {
+		status.carry = 0;
+	}
+
+	status.sign = al & 0x80;
+	status.zero = status.parity = al;
+}
+
 template <typename IntT>
 void adc(IntT &destination, IntT source, Status &status) {
 	/*
@@ -508,6 +560,7 @@ template <
 		case Operation::AAM:	Primitive::aam(registers.axp(), instruction.operand(), status, flow_controller);	return;
 		case Operation::AAS:	Primitive::aas(registers.axp(), status);											return;
 		case Operation::DAA:	Primitive::daa(registers.al(), status);												return;
+		case Operation::DAS:	Primitive::das(registers.al(), status);												return;
 
 		case Operation::ADC:	Primitive::adc(destination(), source(), status);		break;
 		case Operation::ADD:	Primitive::add(destination(), source(), status);		break;
diff --git a/OSBindings/Mac/Clock SignalTests/8088Tests.mm b/OSBindings/Mac/Clock SignalTests/8088Tests.mm
index 2c7ff5344..1d5d8ea0f 100644
--- a/OSBindings/Mac/Clock SignalTests/8088Tests.mm	
+++ b/OSBindings/Mac/Clock SignalTests/8088Tests.mm	
@@ -280,6 +280,9 @@ struct FailedExecution {
 		@"D4.json.gz",	// AAM
 		@"D5.json.gz",	// AAD
 		@"27.json.gz",	// DAA
+		@"2F.json.gz",	// DAS
+
+		@"98.json.gz",	// CBW
 
 		// ADC
 		@"10.json.gz",	@"11.json.gz",	@"12.json.gz",	@"13.json.gz",	@"14.json.gz",	@"15.json.gz",
@@ -297,7 +300,6 @@ struct FailedExecution {
 		@"E8.json.gz",	@"FF.2.json.gz",
 		@"9A.json.gz",	@"FF.3.json.gz",
 
-		@"98.json.gz",	// CBW
 		@"F8.json.gz",	// CLC
 		@"FC.json.gz",	// CLD
 		@"FA.json.gz",	// CLI