From 44738e191f4fa00e00d21fb8a07507751a0200e9 Mon Sep 17 00:00:00 2001
From: Ariejan de Vroom <ariejan@ariejan.net>
Date: Sun, 17 Aug 2014 22:36:01 +0200
Subject: [PATCH] WIP

---
 acia6551.go      | 49 ++++++++++++++++++++++++++++++++++++++++--------
 acia6551_test.go |  3 +++
 2 files changed, 44 insertions(+), 8 deletions(-)

diff --git a/acia6551.go b/acia6551.go
index 3bdbe2f..6f04540 100644
--- a/acia6551.go
+++ b/acia6551.go
@@ -14,8 +14,9 @@ type Acia6551 struct {
 	Rx chan byte // Reading (Acia Input) line
 	Tx chan byte // Transmitting (Acia Output) line
 
-	rxData      byte
-	txData      byte
+	rxData byte
+	txData byte
+
 	commandData byte
 	controlData byte
 
@@ -24,6 +25,8 @@ type Acia6551 struct {
 
 	rxIrqEnabled bool
 	txIrqEnabled bool
+
+	overrun bool
 }
 
 func NewAcia6551(rx chan byte, tx chan byte) (*Acia6551, error) {
@@ -46,6 +49,7 @@ func (a *Acia6551) Size() uint16 {
 	return 0x04
 }
 
+// Emulates a hardware reset
 func (a *Acia6551) Reset() {
 	a.rxData = 0
 	a.rxFull = false
@@ -55,14 +59,43 @@ func (a *Acia6551) Reset() {
 
 	a.rxIrqEnabled = false
 	a.txIrqEnabled = false
+
+	a.overrun = false
+
+	a.setControl(0)
+	a.setCommand(0)
 }
 
-/*
-func (r *Rom) Read(address uint16) byte {
-	return r.data[address]
+func (a *Acia6551) setControl(data byte) {
 }
 
-func (r *Rom) Write(address uint16, data byte) {
-	panic(fmt.Errorf("Trying to write to ROM at 0x%04X", address))
+func (a *Acia6551) setCommand(data byte) {
+}
+
+func (a *Acia6551) Read(address uint16) byte {
+	switch address {
+	case aciaData:
+		// Read Rx
+	case aciaStatus:
+		// Read Status reg.
+	case aciaCommand:
+		// Read command
+	case aciaControl:
+		// Read control
+	}
+
+	return 0x00
+}
+
+func (a *Acia6551) Write(address uint16, data byte) {
+	switch address {
+	case aciaData:
+		// Write Tx
+	case aciaStatus:
+		// Reset
+	case aciaCommand:
+		// Write command
+	case aciaControl:
+		// Write control
+	}
 }
-*/
diff --git a/acia6551_test.go b/acia6551_test.go
index 8763d79..d62f86d 100644
--- a/acia6551_test.go
+++ b/acia6551_test.go
@@ -34,6 +34,9 @@ func TestAciaReset(t *testing.T) {
 
 	assert.False(t, a.txIrqEnabled)
 	assert.False(t, a.rxIrqEnabled)
+
+	assert.False(t, a.overrun)
+	assert.Equal(t, 0, a.controlData)
 }
 
 func TestAciaCommand(t *testing.T) {