From d7a17b10b4ccfa70c3a0dbb51fe7edc6ae435461 Mon Sep 17 00:00:00 2001
From: Harald Barth <haba@kth.se>
Date: Fri, 13 May 2022 00:05:25 +0200
Subject: [PATCH] use ugly macros to make PORTX code portable

---
 MotorDriver.cpp  |  6 +++---
 MotorDriver.h    | 25 +++++++++++++++++++++++++
 TrackManager.cpp | 28 +++++++++++++++-------------
 3 files changed, 43 insertions(+), 16 deletions(-)

diff --git a/MotorDriver.cpp b/MotorDriver.cpp
index 0f5b60e..30dd1be 100644
--- a/MotorDriver.cpp
+++ b/MotorDriver.cpp
@@ -41,15 +41,15 @@ MotorDriver::MotorDriver(VPIN power_pin, byte signal_pin, byte signal_pin2, int8
   getFastPin(F("SIG"),signalPin,fastSignalPin);
   pinMode(signalPin, OUTPUT);
 
-  if (fastSignalPin.inout == &PORTA) {
+  if (HAVE_PORTA(fastSignalPin.inout == &PORTA)) {
     DIAG(F("Found PORTA pin %d"),signalPin);
     fastSignalPin.inout = &fakePORTA;
   }
-  if (fastSignalPin.inout == &PORTB) {
+  if (HAVE_PORTB(fastSignalPin.inout == &PORTB)) {
     DIAG(F("Found PORTB pin %d"),signalPin);
     fastSignalPin.inout = &fakePORTB;
   }
-  if (fastSignalPin.inout == &PORTC) {
+  if (HAVE_PORTC(fastSignalPin.inout == &PORTC)) {
     DIAG(F("Found PORTC pin %d"),signalPin);
     fastSignalPin.inout = &fakePORTC;
   }
diff --git a/MotorDriver.h b/MotorDriver.h
index 61ddf5c..db229d5 100644
--- a/MotorDriver.h
+++ b/MotorDriver.h
@@ -30,6 +30,31 @@
 #define isHIGH(fastpin)   (*fastpin.inout & fastpin.maskHIGH)
 #define isLOW(fastpin)    (!isHIGH(fastpin))
 
+#define TOKENPASTE(x, y) x ## y
+#define TOKENPASTE2(x, y) TOKENPASTE(x, y)
+
+#if defined(ARDUINO_AVR_MEGA) || defined(ARDUINO_AVR_MEGA2560)
+#define HAVE_PORTA(X) X
+#define HAVE_PORTB(X) X
+#define HAVE_PORTC(X) X
+#endif
+#if defined(ARDUINO_AVR_UNO)
+#define HAVE_PORTB(X) X
+#endif
+
+// if macros not defined as pass-through we define
+// them here as someting that is valid as a
+// statement and evaluates to false.
+#ifndef HAVE_PORTA
+#define HAVE_PORTA(X) byte TOKENPASTE2(Unique_, __LINE__) __attribute__((unused)) =0
+#endif
+#ifndef HAVE_PORTB
+#define HAVE_PORTB(X) byte TOKENPASTE2(Unique_, __LINE__) __attribute__((unused)) =0
+#endif
+#ifndef HAVE_PORTC
+#define HAVE_PORTC(X) byte TOKENPASTE2(Unique_, __LINE__) __attribute__((unused)) =0
+#endif
+
 // Virtualised Motor shield 1-track hardware Interface
 
 #ifndef UNUSED_PIN     // sync define with the one in MotorDrivers.h
diff --git a/TrackManager.cpp b/TrackManager.cpp
index 93a92e2..0c5117b 100644
--- a/TrackManager.cpp
+++ b/TrackManager.cpp
@@ -84,19 +84,21 @@ void TrackManager::addTrack(byte t, MotorDriver* driver) {
          lastTrack=t;
          track[t]->setPower(POWERMODE::OFF);
      } 
-}    
+}
+
+// defined in Motordriver.cpp
 extern byte fakePORTA;
 extern byte fakePORTB;
 extern byte fakePORTC;
 
 void TrackManager::setDCCSignal( bool on) {
-  fakePORTA=PORTA;
-  fakePORTB=PORTB;
-  fakePORTC=PORTC;
+  HAVE_PORTA(fakePORTA=PORTA);
+  HAVE_PORTB(fakePORTB=PORTB);
+  HAVE_PORTC(fakePORTC=PORTC);
   APPLY_BY_MODE(TRACK_MODE_MAIN,setSignal(on));
-  PORTA=fakePORTA;
-  PORTB=fakePORTB;
-  PORTC=fakePORTC;
+  HAVE_PORTA(PORTA=fakePORTA);
+  HAVE_PORTB(PORTB=fakePORTB);
+  HAVE_PORTC(PORTC=fakePORTC);
 }
 
 void TrackManager::setCutout( bool on) {
@@ -106,13 +108,13 @@ void TrackManager::setCutout( bool on) {
 }
 
 void TrackManager::setPROGSignal( bool on) {
-  fakePORTA=PORTA;
-  fakePORTB=PORTB;
-  fakePORTC=PORTC;
+  HAVE_PORTA(fakePORTA=PORTA);
+  HAVE_PORTB(fakePORTB=PORTB);
+  HAVE_PORTC(fakePORTC=PORTC);
   APPLY_BY_MODE(TRACK_MODE_PROG,setSignal(on));
-  PORTA=fakePORTA;
-  PORTB=fakePORTB;
-  PORTC=fakePORTC;
+  HAVE_PORTA(PORTA=fakePORTA);
+  HAVE_PORTB(PORTB=fakePORTB);
+  HAVE_PORTC(PORTC=fakePORTC);
 }
 
 void TrackManager::setDCSignal(int16_t cab, byte speedbyte) {