From ee452e816e83cbf96387c760c4c6a17577ae1d3b Mon Sep 17 00:00:00 2001
From: steve <jscrane@gmail.com>
Date: Tue, 26 Sep 2023 10:41:35 +0100
Subject: [PATCH] PIA cleanup

---
 io.cpp  | 10 +++++-----
 io.h    |  8 +++++---
 pia.cpp | 17 ++++++++---------
 pia.h   |  9 +++++----
 4 files changed, 23 insertions(+), 21 deletions(-)

diff --git a/io.cpp b/io.cpp
index 16b9a48..4b5ac88 100644
--- a/io.cpp
+++ b/io.cpp
@@ -28,7 +28,7 @@ void io::reset() {
 			screen[j][i] = ' ';
 
 	_loading = false;
-	pia::reset();
+	PIA::reset();
 }
 
 void io::load() {
@@ -142,11 +142,11 @@ void io::display(uint8_t b) {
 void io::write_portb(uint8_t b) {
 	b &= 0x7f;
 	display(b);
-	pia::write_portb(b);
+	PIA::write_portb(b);
 }
 
 uint8_t io::read_porta_cr() {
-	uint8_t b = pia::read_porta_cr();
+	uint8_t b = PIA::read_porta_cr();
 	if (b != 0xa7)
 		return b;
 
@@ -160,7 +160,7 @@ uint8_t io::read_porta_cr() {
 }
 
 void io::checkpoint(Stream &s) {
-	pia::checkpoint(s);
+	PIA::checkpoint(s);
 	s.write(r);
 	s.write(c);
 	for (int j = 0; j < ROWS; j++)
@@ -169,7 +169,7 @@ void io::checkpoint(Stream &s) {
 }
 
 void io::restore(Stream &s) {
-	pia::restore(s);
+	PIA::restore(s);
 	r = s.read();
 	c = s.read();
 	for (int j = 0; j < ROWS; j++)
diff --git a/io.h b/io.h
index 9d19df9..e11a40e 100644
--- a/io.h
+++ b/io.h
@@ -1,15 +1,17 @@
 #ifndef _IO_H
 #define _IO_H
 
-// http://mamedev.org/source/src/mess/machine/apple1.c.html
-class io: public Display, Keyboard, public pia {
+class io: public Memory::Device, public Display, Keyboard, public PIA {
 public:
-	io(filer &files): files(files) {}
+	io(filer &files): Memory::Device(Memory::page_size), files(files) {}
 
 	virtual void reset();
 	virtual void down(uint8_t scan);
 	virtual void up(uint8_t scan);
 
+	virtual void operator=(uint8_t b) { PIA::write(_acc, b); }
+	virtual operator uint8_t() { return PIA::read(_acc); }
+
 	virtual void checkpoint(Stream &);
 	virtual void restore(Stream &);
 
diff --git a/pia.cpp b/pia.cpp
index a5e06fb..82fa487 100644
--- a/pia.cpp
+++ b/pia.cpp
@@ -2,15 +2,15 @@
 #include <memory.h>
 #include "pia.h"
 
-void pia::operator=(uint8_t b) {
+void PIA::write(Memory::address a, uint8_t b) {
 #if defined(DEBUGGING)
 	Serial.print(millis());
 	Serial.print(" > ");
-	Serial.print(_acc, 16);
+	Serial.print(a, 16);
 	Serial.print(' ');
 	Serial.println(b, 16);
 #endif
-	switch(_acc % 4) {
+	switch(a % 4) {
 	case 0:
 		write_porta(b);
 		break;
@@ -26,13 +26,13 @@ void pia::operator=(uint8_t b) {
 	}
 }
 
-pia::operator uint8_t() {
+uint8_t PIA::read(Memory::address a) {
 #if defined(DEBUGGING)
 	Serial.print(millis());
 	Serial.print(" < ");
-	Serial.println(_acc, 16);
+	Serial.println(a, 16);
 #endif
-	switch (_acc % 4) {
+	switch (a % 4) {
 	case 0:
 		return read_porta();
 	case 1:
@@ -45,17 +45,16 @@ pia::operator uint8_t() {
 	return 0xff;
 }
 
-void pia::checkpoint(Stream &s) {
+void PIA::checkpoint(Stream &s) {
 	s.write(portb_cr);
 	s.write(portb);
 	s.write(porta_cr);
 	s.write(porta);
 }
 
-void pia::restore(Stream &s) {
+void PIA::restore(Stream &s) {
 	portb_cr = s.read();
 	portb = s.read();
 	porta_cr = s.read();
 	porta = s.read();
 }
-
diff --git a/pia.h b/pia.h
index 1818429..3e0906f 100644
--- a/pia.h
+++ b/pia.h
@@ -1,13 +1,14 @@
 #ifndef __PIA_H__
 #define __PIA_H__
 
-class pia: public Memory::Device {
+// https://en.wikipedia.org/wiki/Peripheral_Interface_Adapter
+class PIA {
 public:
-	pia(): Memory::Device(256), portb_cr(0), porta_cr(0) {}
+	PIA(): portb_cr(0), porta_cr(0) {}
 	virtual void reset() { portb_cr = porta_cr = 0; }
 
-	void operator=(uint8_t);
-	operator uint8_t();
+	void write(Memory::address, uint8_t);
+	uint8_t read(Memory::address);
 
 	void checkpoint(Stream &);
 	void restore(Stream &);