From 778aacaef66315f39423a7c2b4176df34798bd6c Mon Sep 17 00:00:00 2001
From: Adrian Conlon <adrian.conlon@gmail.com>
Date: Sun, 27 Dec 2020 15:45:14 +0000
Subject: [PATCH] Z80: Better interrupt timing response.

---
 Z80/src/Z80.cpp | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/Z80/src/Z80.cpp b/Z80/src/Z80.cpp
index 0b8c9b9..5072c38 100644
--- a/Z80/src/Z80.cpp
+++ b/Z80/src/Z80.cpp
@@ -114,23 +114,22 @@ void EightBit::Z80::handleNMI() {
 
 void EightBit::Z80::handleINT() {
 	IntelProcessor::handleINT();
+	tick(2);	// 2 extra clock cycles introduced to allow the bus to settle
 	uint8_t data;
 	{
 		_ActivateIORQ iorq(*this);
 		data = readBusDataM1();
 	}
 	di();
-	tick(5);
 	switch (IM()) {
 	case 0:		// i8080 equivalent
 		IntelProcessor::execute(data);
 		break;
 	case 1:
-		tick();
 		restart(7 << 3);
 		break;
 	case 2:
-		tick(7);
+		tick(7);	// How long to allow fetching data from the device...
 		call(MEMPTR() = { data, IV() });
 		break;
 	default: