From 3e908415008db1cfe090bb12956c406a59bb28c8 Mon Sep 17 00:00:00 2001
From: Stephen Crane <jscrane@gmail.com>
Date: Wed, 27 Sep 2023 15:38:16 +0100
Subject: [PATCH] acia updates (#22)

---
 acia.cpp | 48 ++++++++++++++++++++++++++++++------------------
 acia.h   | 11 +++++++++--
 timed.h  |  4 ++++
 3 files changed, 43 insertions(+), 20 deletions(-)

diff --git a/acia.cpp b/acia.cpp
index bfd9ab1..5555ab6 100644
--- a/acia.cpp
+++ b/acia.cpp
@@ -5,46 +5,58 @@
 #include "acia.h"
 
 void ACIA::write(Memory::address a, uint8_t b) {
-	if (a & 1) {
-		_device->write(b);
-		return;
-	}
+	if (a & 1)
+		write_data(b);
+	else
+		write_control(b);
+}
+
+void ACIA::write_control(uint8_t b) {
 	if ((b & cd_mask) == reset) {
-		_device->reset();
+		_serial->reset();
 		return;
 	}
 	switch (b & ws_mask) {
 	case ws7e2:
-		_device->framing(7, 2, even);
+		_serial->framing(7, 2, even);
 		break;
 	case ws7o2:
-		_device->framing(7, 2, odd);
+		_serial->framing(7, 2, odd);
 		break;
 	case ws7e1:
-		_device->framing(7, 1, even);
+		_serial->framing(7, 1, even);
 		break;
 	case ws7o1:
-		_device->framing(7, 1, odd);
+		_serial->framing(7, 1, odd);
 		break;
 	case ws8n2:
-		_device->framing(8, 2, none);
+		_serial->framing(8, 2, none);
 		break;
 	case ws8n1:
-		_device->framing(8, 1, none);
+		_serial->framing(8, 1, none);
 		break;
 	case ws8e1:
-		_device->framing(8, 1, even);
+		_serial->framing(8, 1, even);
 		break;
 	case ws8o1:
-		_device->framing(8, 1, odd);
+		_serial->framing(8, 1, odd);
 		break;
 	};
 	// FIXME: more
 }
 
-uint8_t ACIA::read(Memory::address a) {
-	if (a & 1)
-		return _device->read();
-
-	return _device->more()? rdrf | tdre: tdre;
+void ACIA::write_data(uint8_t b) {
+	_serial->write(b);
+}
+
+uint8_t ACIA::read(Memory::address a) {
+	return (a & 1)? read_data(): read_status();
+}
+
+uint8_t ACIA::read_data() {
+	return _serial->read();
+}
+
+uint8_t ACIA::read_status() {
+	return _serial->more()? rdrf | tdre: tdre;
 }
diff --git a/acia.h b/acia.h
index b20cec9..96f7def 100644
--- a/acia.h
+++ b/acia.h
@@ -8,7 +8,7 @@ public:
 	void write(Memory::address, uint8_t);
 	uint8_t read(Memory::address);
 
-	ACIA(serialio &d): _device(&d) {}
+	ACIA(serialio &s): _serial(&s) {}
 
 	// status bits
 	//
@@ -47,7 +47,14 @@ public:
 
 	static const uint8_t eri = 1 << 7;	// enable receive interrupt
 
+protected:
+	// overrideable device memory interface
+	virtual uint8_t read_status();
+	virtual uint8_t read_data();
+	virtual void write_control(uint8_t);
+	virtual void write_data(uint8_t);
+
 private:
-	class serialio *_device;
+	class serialio *_serial;
 };
 #endif
diff --git a/timed.h b/timed.h
index 1d73720..246aadb 100644
--- a/timed.h
+++ b/timed.h
@@ -5,4 +5,8 @@ typedef void (*handler_t)(void);
 
 void timer_create(unsigned freq, handler_t handler);
 
+#if !defined(ESP32) && !defined(ESP8266)
+#define IRAM_ATTR
+#endif
+
 #endif