Possible fixed for issue #22 One line more then expected

Stopped both cores sending I2C data at the same time.

Makefile

@@ -3,7 +3,7 @@ OBJS	= armc-start.o armc-cstartup.o armc-cstubs.o armc-cppstubs.o \
 	rpi-gpio.o rpi-interrupts.o cache.o ff.o interrupt.o Keyboard.o performance.o \
 	Drive.o Pi1541.o DiskImage.o iec_bus.o iec_commands.o m6502.o m6522.o \
 	gcr.o prot.o lz.o emmc.o diskio.o options.o Screen.o SSD1306.o ScreenLCD.o \
-	Timer.o FileBrowser.o DiskCaddy.o ROMs.o InputMappings.o xga_font_data.o m8520.o wd177x.o Pi1581.o
+	Timer.o FileBrowser.o DiskCaddy.o ROMs.o InputMappings.o xga_font_data.o m8520.o wd177x.o Pi1581.o SpinLock.o
 
 SRCDIR   = src
 OBJS    := $(addprefix $(SRCDIR)/, $(OBJS))

src/SpinLock.cpp

@@ -0,0 +1,76 @@
+//
+// spinlock.cpp
+//
+// Circle - A C++ bare metal environment for Raspberry Pi
+// Copyright (C) 2015  R. Stange <rsta2@o2online.de>
+// 
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+//
+#include "SpinLock.h"
+
+//#ifdef HAS_MULTICORE
+
+bool SpinLock::s_bEnabled = true;
+
+SpinLock::SpinLock()
+	: m_bLocked(false)
+{
+}
+
+SpinLock::~SpinLock(void)
+{
+}
+
+void SpinLock::Acquire(void)
+{
+	if (s_bEnabled)
+	{
+		// See: ARMv7-A Architecture Reference Manual, Section D7.3
+		asm volatile
+			(
+			"mov r1, %0\n"
+			"mov r2, #1\n"
+			"1: ldrex r3, [r1]\n"
+			"cmp r3, #0\n"
+			"wfene\n"
+			"strexeq r3, r2, [r1]\n"
+			"cmpeq r3, #0\n"
+			"bne 1b\n"
+			"dmb\n"
+
+			: : "r" ((u32)&m_bLocked)
+			);
+	}
+}
+
+void SpinLock::Release(void)
+{
+	if (s_bEnabled)
+	{
+		// See: ARMv7-A Architecture Reference Manual, Section D7.3
+		asm volatile
+			(
+			"mov r1, %0\n"
+			"mov r2, #0\n"
+			"dmb\n"
+			"str r2, [r1]\n"
+			"dsb\n"
+			"sev\n"
+
+			: : "r" ((u32)&m_bLocked)
+			);
+	}
+}
+
+//#endif

src/SpinLock.h

@@ -0,0 +1,46 @@
+//
+// spinlock.h
+//
+// Circle - A C++ bare metal environment for Raspberry Pi
+// Copyright (C) 2015  R. Stange <rsta2@o2online.de>
+// 
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+//
+#ifndef SPINLOCK_H
+#define SPINLOCK_H
+
+#include "types.h"
+
+//#ifdef HAS_MULTICORE
+
+class SpinLock
+{
+public:
+	SpinLock();
+	~SpinLock(void);
+
+	void Acquire(void);
+	void Release(void);
+
+	static void Enable(void);
+
+private:
+	boolean m_bLocked;
+
+	static bool s_bEnabled;
+};
+
+//#endif
+#endif
+

src/main.cpp

@@ -41,13 +41,14 @@ extern "C"
 #include "Pi1581.h"
 #include "FileBrowser.h"
 #include "ScreenLCD.h"
+#include "SpinLock.h"
 
 #include "logo.h"
 #include "sample.h"
 #include "ssd_logo.h"
 
 unsigned versionMajor = 1;
-unsigned versionMinor = 18;
+unsigned versionMinor = 19;
 
 // When the emulated CPU starts we execute the first million odd cycles in non-real-time (ie as fast as possible so the emulated 1541 becomes responsive to CBM-Browser asap)
 // During these cycles the CPU is executing the ROM self test routines (these do not need to be cycle accurate)
@@ -115,6 +116,8 @@ bool USBKeyboardDetected = false;
 bool selectedViaIECCommands = false;
 u16 pc;
 
+SpinLock core0RefreshingScreen;
+
 unsigned int screenWidth = 1024;
 unsigned int screenHeight = 768;
 int i2cLcdUseCBMChar = 0;
@@ -504,14 +507,21 @@ void UpdateScreen()
 
 				if (screenLCD)
 				{
+					core0RefreshingScreen.Acquire();
+
+					IEC_Bus::WaitMicroSeconds(100);
+
 					screenLCD->PrintText(false, 0, 0, tempBuffer, 0, RGBA(0xff, 0xff, 0xff, 0xff));
 					//				screenLCD->SetContrast(255.0/79.0*track);
 					screenLCD->RefreshRows(0, 1);
+
+					IEC_Bus::WaitMicroSeconds(100);
+					core0RefreshingScreen.Release();
 				}
 
 			}
 		}
-		else
+		else if (emulating == EMULATING_1581)
 		{
 			track = pi1581.wd177x.GetCurrentTrack();
 			if (track != oldTrack)
@@ -523,9 +533,13 @@ void UpdateScreen()
 
 				if (screenLCD)
 				{
+					core0RefreshingScreen.Acquire();
+					IEC_Bus::WaitMicroSeconds(100);
 					screenLCD->PrintText(false, 0, 0, tempBuffer, 0, RGBA(0xff, 0xff, 0xff, 0xff));
 					//				screenLCD->SetContrast(255.0/79.0*track);
 					screenLCD->RefreshRows(0, 1);
+					IEC_Bus::WaitMicroSeconds(100);
+					core0RefreshingScreen.Release();
 				}
 
 			}
@@ -1069,6 +1083,9 @@ void emulator()
 
 			IEC_Bus::LetSRQBePulledHigh();
 
+			core0RefreshingScreen.Acquire();
+			IEC_Bus::WaitMicroSeconds(100);
+
 // workaround for occasional oled curruption
 			if (screenLCD)
 				screenLCD->ClearInit(0);
@@ -1085,6 +1102,8 @@ void emulator()
 //			else
 				fileBrowser->RefeshDisplay(); // Just redisplay the current folder.
 
+			core0RefreshingScreen.Release();
+
 //			resetWhileEmulating = false;
 			selectedViaIECCommands = false;
 
@@ -1215,8 +1234,6 @@ void emulator()
 			//					if (screenLCD)
 			//						screenLCD->ClearInit(0);
 
-			fileBrowser->ClearSelections();
-			fileBrowser->RefeshDisplay(); // Just redisplay the current folder.
 
 			IEC_Bus::WaitUntilReset();
 			//DEBUG_LOG("6502 resetting\r\n");