From a87f6a28c9e5b1e45bf009ee66e3c51cc8d098b2 Mon Sep 17 00:00:00 2001
From: Thomas Harte <thomas.harte@gmail.com>
Date: Mon, 23 May 2022 10:43:17 -0400
Subject: [PATCH] Fix LINK A7.

---
 .../Clock SignalTests/68000ComparativeTests.mm   |  2 +-
 .../Implementation/68000Mk2Implementation.hpp    | 16 ++++++++++++++--
 2 files changed, 15 insertions(+), 3 deletions(-)

diff --git a/OSBindings/Mac/Clock SignalTests/68000ComparativeTests.mm b/OSBindings/Mac/Clock SignalTests/68000ComparativeTests.mm
index 8608babd3..2f63c38e6 100644
--- a/OSBindings/Mac/Clock SignalTests/68000ComparativeTests.mm	
+++ b/OSBindings/Mac/Clock SignalTests/68000ComparativeTests.mm	
@@ -156,7 +156,7 @@ struct TestProcessor: public CPU::MC68000Mk2::BusHandler {
 
 	// To limit tests run to a subset of files and/or of tests, uncomment and fill in below.
 //	_fileSet = [NSSet setWithArray:@[@"abcd_sbcd.json"]];
-//	_testSet = [NSSet setWithArray:@[@"UNLK 0007"]];
+//	_testSet = [NSSet setWithArray:@[@"LINK.w 0007"]];
 }
 
 - (void)testAll {
diff --git a/Processors/68000Mk2/Implementation/68000Mk2Implementation.hpp b/Processors/68000Mk2/Implementation/68000Mk2Implementation.hpp
index 0f5e71a31..108cf781a 100644
--- a/Processors/68000Mk2/Implementation/68000Mk2Implementation.hpp
+++ b/Processors/68000Mk2/Implementation/68000Mk2Implementation.hpp
@@ -2120,8 +2120,20 @@ void Processor<BusHandler, dtack_is_implicit, permit_overrun, signal_will_perfor
 		//
 		BeginState(LINK):
 			Prefetch();
-			Push(registers_[8 + instruction_.reg(0)]);
-			registers_[8 + instruction_.reg(0)].l = registers_[15].l + uint32_t(int16_t(prefetch_.high.w));
+
+			// Ensure that the stack pointer is [seemingly] captured after
+			// having been decremented by four, if it's what should be captured.
+			registers_[15].l -= 4;
+			temporary_address_ = registers_[8 + instruction_.reg(0)];
+			registers_[15].l += 4;
+
+			// Push will actually decrement the stack pointer.
+			Push(temporary_address_);
+
+			// Make the exchange.
+			registers_[8 + instruction_.reg(0)].l = registers_[15].l;
+			registers_[15].l += uint32_t(int16_t(prefetch_.high.w));
+
 			Prefetch();
 		MoveToStateSpecific(Decode);