From 93e90b09a01a4da09057d1c39110673d1ff15a3b Mon Sep 17 00:00:00 2001
From: Thomas Harte <thomas.harte@gmail.com>
Date: Fri, 20 Oct 2023 21:46:47 -0400
Subject: [PATCH] Implement MOVS, STOS, revealing an issue in the memory
 handler.

---
 .../Implementation/PerformImplementation.hpp  | 38 +++++++++++++++++++
 OSBindings/Mac/Clock SignalTests/8088Tests.mm |  8 +++-
 2 files changed, 45 insertions(+), 1 deletion(-)

diff --git a/InstructionSets/x86/Implementation/PerformImplementation.hpp b/InstructionSets/x86/Implementation/PerformImplementation.hpp
index 1160b2aaf..57343b294 100644
--- a/InstructionSets/x86/Implementation/PerformImplementation.hpp
+++ b/InstructionSets/x86/Implementation/PerformImplementation.hpp
@@ -1417,6 +1417,38 @@ void lods(const InstructionT &instruction, AddressT &eCX, AddressT &eSI, IntT &e
 	repeat<AddressT>(instruction, eCX, flow_controller);
 }
 
+template <typename IntT, typename AddressT, typename InstructionT, typename MemoryT, typename FlowControllerT>
+void movs(const InstructionT &instruction, AddressT &eCX, AddressT &eSI, AddressT &eDI, MemoryT &memory, Status &status, FlowControllerT &flow_controller) {
+	if(repetition_over<AddressT>(instruction, eCX)) {
+		return;
+	}
+
+	Source source_segment = instruction.segment_override();
+	if(source_segment == Source::None) source_segment = Source::DS;
+
+	memory.template access<IntT>(Source::ES, eDI) = memory.template access<IntT>(source_segment, eSI);
+
+	eSI += status.direction<AddressT>() * sizeof(IntT);
+	eDI += status.direction<AddressT>() * sizeof(IntT);
+
+	repeat<AddressT>(instruction, eCX, flow_controller);
+}
+
+template <typename IntT, typename AddressT, typename InstructionT, typename MemoryT, typename FlowControllerT>
+void stos(const InstructionT &instruction, AddressT &eCX, AddressT &eDI, IntT &eAX, MemoryT &memory, Status &status, FlowControllerT &flow_controller) {
+	if(repetition_over<AddressT>(instruction, eCX)) {
+		return;
+	}
+
+	Source destination_segment = instruction.segment_override();
+	if(destination_segment == Source::None) destination_segment = Source::DS;
+
+	memory.template access<IntT>(destination_segment, eDI) = eAX;
+
+	eDI += status.direction<AddressT>() * sizeof(IntT);
+
+	repeat<AddressT>(instruction, eCX, flow_controller);
+}
 
 }
 
@@ -1664,6 +1696,12 @@ template <
 		case Operation::LODS:
 			Primitive::lods<IntT, AddressT>(instruction, eCX(), eSI(), pair_low(), memory, status, flow_controller);
 		break;
+		case Operation::MOVS:
+			Primitive::movs<IntT, AddressT>(instruction, eCX(), eSI(), eDI(), memory, status, flow_controller);
+		break;
+		case Operation::STOS:
+			Primitive::stos<IntT, AddressT>(instruction, eCX(), eDI(), pair_low(), memory, status, flow_controller);
+		break;
 	}
 
 	// Write to memory if required to complete this operation.
diff --git a/OSBindings/Mac/Clock SignalTests/8088Tests.mm b/OSBindings/Mac/Clock SignalTests/8088Tests.mm
index b4086eff4..e63655c66 100644
--- a/OSBindings/Mac/Clock SignalTests/8088Tests.mm	
+++ b/OSBindings/Mac/Clock SignalTests/8088Tests.mm	
@@ -401,13 +401,19 @@ struct FailedExecution {
 		@"C4.json.gz",	// LES
 		@"8D.json.gz",	// LEA
 
-		// TODO: MOVS, SCAS, STOS
+		// TODO: SCAS, INS, OUTS
 */
+		// MOVS
+		@"A4.json.gz",	@"A5.json.gz",
+
 		// CMPS
 		@"A6.json.gz",	@"A7.json.gz",
 
 		// LODS
 		@"AC.json.gz",	@"AD.json.gz",
+
+		// STOS
+		@"AA.json.gz",	@"AB.json.gz",
 /*
 		@"E0.json.gz",	// LOOPNE
 		@"E1.json.gz",	// LOOPE