From 78e3fff5c3faa18ed03a9d106c5231dd3fdae9f0 Mon Sep 17 00:00:00 2001
From: steve <jscrane@gmail.com>
Date: Sat, 30 Sep 2023 12:51:46 +0100
Subject: [PATCH] minor change

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

diff --git a/pia.cpp b/pia.cpp
index d35ea9b..c1612b9 100644
--- a/pia.cpp
+++ b/pia.cpp
@@ -27,7 +27,7 @@ void PIA::write(Memory::address a, uint8_t b) {
 	Serial.print(' ');
 	Serial.println(b, 16);
 #endif
-	switch(a % 4) {
+	switch(a & 3) {
 	case 0:
 		output_selected(cra)? write_porta(b): write_ddra(b);
 		break;
@@ -49,7 +49,7 @@ uint8_t PIA::read(Memory::address a) {
 	Serial.print(" < ");
 	Serial.println(a, 16);
 #endif
-	switch (a % 4) {
+	switch (a & 3) {
 	case 0:
 		return output_selected(cra)? read_porta(): read_ddra();
 	case 1:
@@ -59,7 +59,6 @@ uint8_t PIA::read(Memory::address a) {
 	case 3:
 		return read_crb();
 	}
-	return 0xff;
 }
 
 void PIA::checkpoint(Stream &s) {