First cut of bare metal GOS layer. Only requires gfxGetSystemTicks() and gfxMilliseconds2Ticks() to be defined by the user.

6 files changed, 878 insertions, 2 deletions

diff --git a/include/gfx_rules.h b/include/gfx_rules.h
index 534c2cc9..54fe3a1a 100644
--- a/include/gfx_rules.h
+++ b/include/gfx_rules.h
@@ -26,14 +26,14 @@
 	#define GFX_DISPLAY_RULE_WARNINGS	FALSE
 #endif
 
-#if !GFX_USE_OS_CHIBIOS && !GFX_USE_OS_WIN32 && !GFX_USE_OS_LINUX && !GFX_USE_OS_OSX
+#if !GFX_USE_OS_CHIBIOS && !GFX_USE_OS_WIN32 && !GFX_USE_OS_LINUX && !GFX_USE_OS_OSX && !GFX_USE_OS_RAW32
 	#if GFX_DISPLAY_RULE_WARNINGS
 		#warning "GOS: No Operating System has been defined. ChibiOS (GFX_USE_OS_CHIBIOS) has been turned on for you."
 	#endif
 	#undef GFX_USE_OS_CHIBIOS
 	#define GFX_USE_OS_CHIBIOS	TRUE
 #endif
-#if GFX_USE_OS_CHIBIOS + GFX_USE_OS_WIN32 + GFX_USE_OS_LINUX + GFX_USE_OS_OSX != 1 * TRUE
+#if GFX_USE_OS_CHIBIOS + GFX_USE_OS_WIN32 + GFX_USE_OS_LINUX + GFX_USE_OS_OSX + GFX_USE_OS_RAW32 != 1 * TRUE
 	#error "GOS: More than one operation system has been defined as TRUE."
 #endif
 
diff --git a/include/gos/gos.h b/include/gos/gos.h
index 8e7840e3..37335fbb 100644
--- a/include/gos/gos.h
+++ b/include/gos/gos.h
@@ -435,6 +435,8 @@
 	#include "gos/linux.h"
 #elif GFX_USE_OS_OSX
 	#include "gos/osx.h"
+#elif GFX_USE_OS_RAW32
+	#include "gos/raw32.h"
 #else
 	#error "Your operating system is not supported yet"
 #endif
diff --git a/include/gos/options.h b/include/gos/options.h
index f1762134..4edb35d8 100644
--- a/include/gos/options.h
+++ b/include/gos/options.h
@@ -48,6 +48,13 @@
 	#ifndef GFX_USE_OS_OSX
 		#define GFX_USE_OS_OSX			FALSE
 	#endif
+	/**
+	 * @brief   Use a Raw 32 bit CPU based system
+	 * @details	Defaults to FALSE
+	 */
+	#ifndef GFX_USE_OS_RAW32
+		#define GFX_USE_OS_RAW32		FALSE
+	#endif
 /**
  * @}
  *
diff --git a/include/gos/raw32.h b/include/gos/raw32.h
new file mode 100644
index 00000000..165bc606
--- /dev/null
+++ b/include/gos/raw32.h
@@ -0,0 +1,124 @@
+/*
+ * This file is subject to the terms of the GFX License. If a copy of
+ * the license was not distributed with this file, you can obtain one at:
+ *
+ *              http://ugfx.org/license.html
+ */
+
+/**
+ * @file    include/gos/raw32.h
+ * @brief   GOS - Operating System Support header file for any 32 bit processor in bare-metal mode
+ */
+
+/**
+ * The raw32 GOS implementation supports any 32 bit processor with or without an
+ * 	underlying operating system. It uses cooperative multi-tasking. Be careful
+ * 	when writing device drivers not to disturb the assumptions this creates by performing
+ * 	call-backs to uGFX code unless you define the INTERRUPTS_OFF() and INTERRUPTS_ON() macros.
+ * 	It still requires some C runtime library support...
+ * 		enough startup to initialise the stack, interrupts, static data etc and call main().
+ * 		setjmp() and longjmp()			- for threading
+ * 		memcpy()						- for heap and threading
+ * 		malloc(), realloc and free()	- if GOS_RAW_HEAP_SIZE == 0
+ *
+ * 	You must also define the following routines in your own code so that timing functions will work...
+ * 		systemticks_t gfxSystemTicks(void);
+ *		systemticks_t gfxMillisecondsToTicks(delaytime_t ms);
+ */
+#ifndef _GOS_RAW32_H
+#define _GOS_RAW32_H
+
+#if GFX_USE_OS_RAW32
+
+/*===========================================================================*/
+/* Special Macros just for a Raw implementation                              */
+/*===========================================================================*/
+
+/**
+ * @brief	Set the maximum size of the heap.
+ * @note	If set to 0 then the C runtime library malloc() and free() are used.
+ */
+#ifndef GOS_RAW_HEAP_SIZE
+	#define GOS_RAW_HEAP_SIZE	0
+#endif
+
+/*===========================================================================*/
+/* Type definitions                                                          */
+/*===========================================================================*/
+
+typedef unsigned char	bool_t;
+typedef char			int8_t;
+typedef unsigned char	uint8_t;
+typedef short			int16_t;
+typedef unsigned short	uint16_t;
+typedef int				int32_t;
+typedef unsigned int	uint32_t;
+
+typedef uint32_t		size_t;
+typedef uint32_t		delaytime_t;
+typedef uint32_t		systemticks_t;
+typedef short			semcount_t;
+typedef int				threadreturn_t;
+typedef int				threadpriority_t;
+
+#define DECLARE_THREAD_FUNCTION(fnName, param)	threadreturn_t fnName(void *param)
+#define DECLARE_THREAD_STACK(name, sz)			uint8_t name[sz];
+
+#define TIME_IMMEDIATE				0
+#define TIME_INFINITE				((delaytime_t)-1)
+#define MAX_SEMAPHORE_COUNT			((semcount_t)(((unsigned long)((semcount_t)(-1))) >> 1))
+#define LOW_PRIORITY				0
+#define NORMAL_PRIORITY				1
+#define HIGH_PRIORITY				2
+
+typedef struct {
+	semcount_t		cnt;
+	semcount_t		limit;
+	} gfxSem;
+
+typedef uint32_t		gfxMutex;
+typedef void *			gfxThreadHandle;
+
+#define gfxThreadClose(thread)
+#define gfxMutexDestroy(pmutex)
+#define gfxSemDestroy(psem)
+#define gfxSemCounter(psem)			((psem)->cnt)
+#define gfxSemCounterI(psem)		((psem)->cnt)
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+	#if GOS_RAW_HEAP_SIZE != 0
+		void gfxAddHeapBlock(void *ptr, size_t sz);
+	#endif
+
+	void gfxHalt(const char *msg);
+	void gfxExit(void);
+	void *gfxAlloc(size_t sz);
+	void *gfxRealloc(void *ptr, size_t oldsz, size_t newsz);
+	void gfxFree(void *ptr);
+	void gfxYield(void);
+	void gfxSleepMilliseconds(delaytime_t ms);
+	void gfxSleepMicroseconds(delaytime_t ms);
+	systemticks_t gfxSystemTicks(void);
+	systemticks_t gfxMillisecondsToTicks(delaytime_t ms);
+	void gfxSystemLock(void);
+	void gfxSystemUnlock(void);
+	void gfxMutexInit(gfxMutex *pmutex);
+	void gfxMutexEnter(gfxMutex *pmutex);
+	void gfxMutexExit(gfxMutex *pmutex);
+	void gfxSemInit(gfxSem *psem, semcount_t val, semcount_t limit);
+	bool_t gfxSemWait(gfxSem *psem, delaytime_t ms);
+	void gfxSemSignal(gfxSem *psem);
+	void gfxSemSignalI(gfxSem *psem);
+	gfxThreadHandle gfxThreadCreate(void *stackarea, size_t stacksz, threadpriority_t prio, DECLARE_THREAD_FUNCTION((*fn),p), void *param);
+	threadreturn_t gfxThreadWait(gfxThreadHandle thread);
+	gfxThreadHandle gfxThreadMe(void);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* GFX_USE_OS_RAW32 */
+#endif /* _GOS_RAW32_H */
diff --git a/src/gos/gos.mk b/src/gos/gos.mk
index 14193883..9db29fe2 100644
--- a/src/gos/gos.mk
+++ b/src/gos/gos.mk
@@ -2,4 +2,5 @@ GFXSRC +=   $(GFXLIB)/src/gos/chibios.c	\
 			$(GFXLIB)/src/gos/win32.c \
 			$(GFXLIB)/src/gos/linux.c \
 			$(GFXLIB)/src/gos/osx.c \
+			$(GFXLIB)/src/gos/raw32.c \
 
diff --git a/src/gos/raw32.c b/src/gos/raw32.c
new file mode 100644
index 00000000..7dd15c27
--- /dev/null
+++ b/src/gos/raw32.c
@@ -0,0 +1,742 @@
+/*
+ * This file is subject to the terms of the GFX License. If a copy of
+ * the license was not distributed with this file, you can obtain one at:
+ *
+ *              http://ugfx.org/license.html
+ */
+
+/**
+ * @file    src/gos/raw32.c
+ * @brief   GOS Raw (bare metal) support.
+ */
+#include "gfx.h"
+
+#if GFX_USE_OS_RAW32
+
+#include <string.h>				// Prototype for memcpy()
+
+
+#if GOS_RAW_HEAP_SIZE != 0
+	static void _gosHeapInit(void);
+#else
+	#define _gosHeapInit()
+#endif
+static void _gosThreadsInit(void);
+
+/*********************************************************
+ * Initialise
+ *********************************************************/
+
+void _gosInit(void) {
+	// Set up the heap allocator
+	_gosHeapInit();
+
+	// Start the scheduler
+	_gosThreadsInit();
+}
+
+/*********************************************************
+ * For WIn32 emulation - automatically add the tick functions
+ * the user would normally have to provide for bare metal.
+ *********************************************************/
+
+#if defined(WIN32)
+	#undef Red
+	#undef Green
+	#undef Blue
+	#define WIN32_LEAN_AND_MEAN
+	#include <stdio.h>
+	#include <windows.h>
+	systemticks_t gfxSystemTicks(void)						{ return GetTickCount(); }
+	systemticks_t gfxMillisecondsToTicks(delaytime_t ms)	{ return ms; }
+#endif
+
+/*********************************************************
+ * Exit everything functions
+ *********************************************************/
+
+void gfxHalt(const char *msg) {
+	#if defined(WIN32)
+		fprintf(stderr, "%s\n", msg);
+		ExitProcess(1);
+	#else
+		volatile uint32_t	dummy;
+		(void)				msg;
+
+		while(1)
+			dummy++;
+	#endif
+}
+
+void gfxExit(void) {
+	#if defined(WIN32)
+		ExitProcess(0);
+	#else
+		volatile uint32_t	dummy;
+
+		while(1)
+			dummy++;
+	#endif
+}
+
+/*********************************************************
+ * Head allocation functions
+ *********************************************************/
+
+#if GOS_RAW_HEAP_SIZE == 0
+	#include <stdlib.h>				// Prototype for malloc(), realloc() and free()
+
+	void *gfxAlloc(size_t sz) {
+		return malloc(sz);
+	}
+
+	void *gfxRealloc(void *ptr, size_t oldsz, size_t newsz) {
+		(void) oldsz;
+		return realloc(ptr, newsz);
+	}
+
+	void gfxFree(void *ptr) {
+		free(ptr);
+	}
+
+#else
+
+	// Slot structure - user memory follows
+	typedef struct memslot {
+		struct memslot *next;		// The next memslot
+		size_t			sz;			// Includes the size of this memslot.
+		} memslot;
+
+	// Free Slot - immediately follows the memslot structure
+	typedef struct freeslot {
+		memslot *nextfree;			// The next free slot
+	}
+
+	#define GetSlotSize(sz)		((((sz) + (sizeof(freeslot) - 1)) & ~(sizeof(freeslot) - 1)) + sizeof(memslot))
+	#define NextFree(pslot)		((freeslot *)Slot2Ptr(pslot))->nextfree
+	#define Ptr2Slot(p)			((memslot *)(p) - 1)
+	#define Slot2Ptr(pslot)		((pslot)+1)
+
+	static memslot *			firstSlot, *lastSlot, *freeSlots;
+	static char					heap[GOS_RAW_HEAP_SIZE];
+
+	static void _gosHeapInit(void) {
+		lastSlot = 0;
+		gfxAddHeapBlock(heap, GOS_RAW_HEAP_SIZE);
+	}
+
+	void gfxAddHeapBlock(void *ptr, size_t sz) {
+		if (sz < sizeof(memslot)+sizeof(freeslot))
+			return;
+
+		if (lastSlot)
+			lastSlot->next = (memslot *)ptr;
+		else
+			firstSlot = lastSlot = freeSlot = (memslot *)ptr;
+
+		lastSlot->next = 0;
+		lastSlot->sz = sz;
+		NextFree(lastSlot) = 0;
+	}
+	void *gfxAlloc(size_t sz) {
+		register memslot *prev, *p, *new;
+
+		if (!sz) return 0;
+		sz = GetSlotSize(sz);
+		for (prev = 0, p = freeSlots; p != 0; prev = p, p = NextFree(p)) {
+			// Loop till we have a block big enough
+			if (p->sz < sz)
+				continue;
+			// Can we save some memory by splitting this block?
+			if (p->sz >= sz + sizeof(memslot)+sizeof(freeslot)) {
+				new = (memslot *)((char *)p + sz);
+				new->next = p->next;
+				p->next = new;
+				new->sz = p->sz - sz;
+				p->sz = sz;
+				if (lastSlot == p)
+					lastSlot = new;
+				NextFree(new) = freeSlots;
+				freeSlots = new;
+			}
+			// Remove it from the free list
+			if (prev)
+				NextFree(prev) = NextFree(p);
+			else
+				freeSlots = NextFree(p);
+			// Return the result found
+			return Slot2Ptr(p);
+		}
+		// No slots large enough
+		return 0;
+	}
+
+	void *gfxRealloc(void *ptr, size_t oldsz, size_t sz) {
+		register memslot *prev, *p, *new;
+		(void) oldsz;
+
+		if (!ptr)
+			return gfxAlloc(sz);
+		if (!sz) {
+			gfxFree(ptr);
+			return 0;
+		}
+
+		p = Ptr2Slot(ptr);
+		sz = GetSlotSize(sz);
+
+		// If the next slot is free (and contiguous) merge it into this one
+		if ((char *)p + p->sz == (char *)p->next) {
+			for (prev = 0, new = freeSlots; new != 0; prev = new, new = NextFree(new)) {
+				if (new == p->next) {
+					p->next = new->next;
+					p->sz += new->sz;
+					if (prev)
+						NextFree(prev) = NextFree(new);
+					else
+						freeSlots = NextFree(new);
+					if (lastSlot == new)
+						lastSlot = p;
+					break;
+				}
+			}
+		}
+
+		// If this block is large enough we are nearly done
+		if (sz < p->sz) {
+			// Can we save some memory by splitting this block?
+			if (p->sz >= sz + sizeof(memslot)+sizeof(freeslot)) {
+				new = (memslot *)((char *)p + sz);
+				new->next = p->next;
+				p->next = new;
+				new->sz = p->sz - sz;
+				p->sz = sz;
+				if (lastSlot == p)
+					lastSlot = new;
+				NextFree(new) = freeSlots;
+				freeSlots = new;
+			}
+			return Slot2Ptr(p);
+		}
+
+		// We need to do this the hard way
+		if ((new = gfxAlloc(sz)))
+			return 0;
+		memcpy(new, ptr, p->sz - sizeof(memslot));
+		free(ptr);
+		return new;
+	}
+
+	void gfxFree(void *ptr) {
+		register memslot *prev, *p, *new;
+
+		if (!ptr)
+			return;
+
+		p = Ptr2Slot(ptr);
+
+		// If the next slot is free (and contiguous) merge it into this one
+		if ((char *)p + p->sz == (char *)p->next) {
+			for (prev = 0, new = freeSlots; new != 0; prev = new, new = NextFree(new)) {
+				if (new == p->next) {
+					p->next = new->next;
+					p->sz += new->sz;
+					if (prev)
+						NextFree(prev) = NextFree(new);
+					else
+						freeSlots = NextFree(new);
+					if (lastSlot == new)
+						lastSlot = p;
+					break;
+				}
+			}
+		}
+
+		// Add it into the free chain
+		NextFree(p) = freeSlots;
+		freeSlots = p;
+	}
+#endif
+
+/*********************************************************
+ * Semaphores and critical region functions
+ *********************************************************/
+
+#if !defined(INTERRUPTS_OFF) || !defined(INTERRUPTS_ON)
+	#define INTERRUPTS_OFF()
+	#define INTERRUPTS_ON()
+#endif
+
+void gfxSystemLock(void) {
+	INTERRUPTS_OFF();
+}
+void gfxSystemUnlock(void) {
+	INTERRUPTS_ON();
+}
+
+void gfxMutexInit(gfxMutex *pmutex) {
+	pmutex[0] = 0;
+}
+
+void gfxMutexEnter(gfxMutex *pmutex) {
+	INTERRUPTS_OFF();
+	while (pmutex[0]) {
+		INTERRUPTS_ON();
+		gfxYield();
+		INTERRUPTS_OFF();
+	}
+	pmutex[0] = 1;
+	INTERRUPTS_ON();
+}
+
+void gfxMutexExit(gfxMutex *pmutex) {
+	pmutex[0] = 0;
+}
+
+void gfxSemInit(gfxSem *psem, semcount_t val, semcount_t limit) {
+	psem->cnt = val;
+	psem->limit = limit;
+}
+
+bool_t gfxSemWait(gfxSem *psem, delaytime_t ms) {
+	systemticks_t	starttm, delay;
+
+	// Convert our delay to ticks
+	switch (ms) {
+	case TIME_IMMEDIATE:
+		delay = TIME_IMMEDIATE;
+		break;
+	case TIME_INFINITE:
+		delay = TIME_INFINITE;
+		break;
+	default:
+		delay = gfxMillisecondsToTicks(ms);
+		if (!delay) delay = 1;
+		starttm = gfxSystemTicks();
+	}
+
+	INTERRUPTS_OFF();
+	while (psem->cnt <= 0) {
+		INTERRUPTS_ON();
+		// Check if we have exceeded the defined delay
+		switch (delay) {
+		case TIME_IMMEDIATE:
+			return FALSE;
+		case TIME_INFINITE:
+			break;
+		default:
+			if (gfxSystemTicks() - starttm >= delay)
+				return FALSE;
+			break;
+		}
+		gfxYield();
+		INTERRUPTS_OFF();
+	}
+	psem->cnt--;
+	INTERRUPTS_ON();
+	return TRUE;
+}
+
+void gfxSemSignal(gfxSem *psem) {
+	INTERRUPTS_OFF();
+	gfxSemSignalI(psem);
+	INTERRUPTS_ON();
+}
+
+void gfxSemSignalI(gfxSem *psem) {
+	if (psem->cnt < psem->limit)
+		psem->cnt++;
+}
+
+/*********************************************************
+ * Sleep functions
+ *********************************************************/
+
+void gfxSleepMilliseconds(delaytime_t ms) {
+	systemticks_t	starttm, delay;
+
+	// Safety first
+	switch (ms) {
+	case TIME_IMMEDIATE:
+		return;
+	case TIME_INFINITE:
+		while(1)
+			gfxYield();
+		return;
+	}
+
+	// Convert our delay to ticks
+	delay = gfxMillisecondsToTicks(ms);
+	starttm = gfxSystemTicks();
+
+	do {
+		gfxYield();
+	} while (gfxSystemTicks() - starttm < delay);
+}
+
+void gfxSleepMicroseconds(delaytime_t ms) {
+	systemticks_t	starttm, delay;
+
+	// Safety first
+	switch (ms) {
+	case TIME_IMMEDIATE:
+		return;
+	case TIME_INFINITE:
+		while(1)
+			gfxYield();
+		return;
+	}
+
+	// Convert our delay to ticks
+	delay = gfxMillisecondsToTicks(ms/1000);
+	starttm = gfxSystemTicks();
+
+	do {
+		gfxYield();
+	} while (gfxSystemTicks() - starttm < delay);
+}
+
+/*********************************************************
+ * Threading functions
+ *********************************************************/
+
+/**
+ * There are some compilers we know how they store the jmpbuf. For those
+ * we can use the constant MASK1 and MASK2. For others we have to "auto-detect".
+ * Auto-detection is hairy and there is no guarantee it will work on all architectures.
+ * For those it doesn't - read the compiler manuals and the library source code to
+ * work out the correct MASK values.
+ * Using the debugger to work out the values for your compiler and putting them here
+ * also saves a nice block of RAM.
+ */
+#if 0
+	#define STACK_DIR_UP	FALSE			// usually false as most stacks grow down
+	#define MASK1			somevalue1
+	#define MASK2			somevalue2		// optional
+	#define STACK_BASE		someindex
+#else
+	#define AUTO_DETECT_MASK	TRUE
+	#define STACK_DIR_UP		stackdirup
+	#define MASK1				jmpmask1
+	#define MASK2				jmpmask2
+	#define STACK_BASE			stackbase
+#endif
+
+#include <setjmp.h> /* jmp_buf, setjmp(), longjmp() */
+
+/**
+ * Some compilers define a _setjmp() and a setjmp().
+ * The difference between them is that setjmp() saves the signal masks.
+ * That is of no use to us so prefer to use the _setjmp() methods.
+ * If they don't exist compile them to be the standard setjmp() function.
+ * Similarly for longjmp().
+ */
+#ifndef setjmp
+	#ifndef _setjmp
+		#define _setjmp setjmp
+	#endif
+#endif
+#ifndef longjmp
+	#ifndef _longjmp
+		#define _longjmp longjmp
+	#endif
+#endif
+
+typedef struct thread {
+	struct thread *	next;					// Next thread
+	int				flags;					// Flags
+		#define FLG_THD_ALLOC	0x0001
+		#define FLG_THD_MAIN	0x0002
+		#define FLG_THD_DEAD	0x0004
+		#define FLG_THD_WAIT	0x0008
+	size_t			size;					// Size of the thread stack (including this structure)
+	threadreturn_t	(*fn)(void *param);		// Thread function
+	void *			param;					// Parameter for the thread function
+	jmp_buf			cxt;					// The current thread context.
+	// size - sizeof(thread) bytes of stack follow here
+	} thread;
+
+typedef struct threadQ {
+	thread *head;
+	thread *tail;
+	} threadQ;
+
+static threadQ		readyQ;					// The list of ready threads
+static threadQ		deadQ;					// Where we put threads waiting to be deallocated
+static thread *		current;				// The current running thread
+static thread		mainthread;				// The main thread context
+
+static void Qinit(threadQ * q) {
+	q->head = q->tail = 0;
+}
+
+static void Qadd(threadQ * q, thread *t) {
+	t->next = 0;
+	if (q->tail) {
+		q->tail->next = t;
+		q->tail = t;
+	} else
+		q->head = q->tail = t;
+}
+
+static thread *Qpop(threadQ * q) {
+	struct thread * t;
+
+	if (!q->head)
+		return 0;
+	t = q->head;
+	q->head = t->next;
+	return t;
+}
+
+#if AUTO_DETECT_MASK
+	static char *	lowptr;			// A pointer to somewhere low in the stack frame
+	static char *	highptr;		// A pointer to somewhere high in the stack frame
+
+	// The saved information on a stack frame
+	typedef struct saveloc {
+		char *		localptr;
+		jmp_buf		cxt;
+	} saveloc;
+
+	static saveloc	infn;			// The saved stack frame info inside a function
+	static saveloc	outfn;			// The saved stack frame info outside a function
+	static saveloc	*saveptr;		// Which saved stack frame variable we are currently using
+
+	// Where we save all the information
+	static bool_t	stackdirup;		// TRUE if the stack grow up instead of down
+	static uint32_t	jmpmask1;		// The 1st mask of jmp_buf elements that need relocation
+	static uint32_t	jmpmask2;		// The 2nd mask of jmp_buf elements that need relocation
+	static size_t	stackbase;		// The base of the stack frame relative to the local variables
+
+	/* These functions are not static to prevent the compiler removing them as functions */
+
+	void get_highptr(void) {
+		char c;
+		highptr = &c;
+	}
+
+	void test_stack(void) {
+		char c;
+		saveptr->localptr = (char *)&c;
+		_setjmp(saveptr->cxt);
+		get_highptr();
+	}
+
+	void get_stack_state(void) {
+		char c;
+		lowptr = &c;
+		test_stack();
+	}
+
+	void get_stack_state_in_fn(void) {
+		get_stack_state();
+	}
+#endif
+
+static void _gosThreadsInit(void) {
+	Qinit(&readyQ);
+	current = &mainthread;
+	current->next = 0;
+	current->size = sizeof(thread);
+	current->flags = FLG_THD_MAIN;
+	current->fn = 0;
+	current->param = 0;
+
+	#if AUTO_DETECT_MASK
+		// Get details of the stack frame from within a function
+		saveptr = &infn;
+		get_stack_state_in_fn();
+
+		// Get details of the stack frame outside the function
+		saveptr = &outfn;
+		get_stack_state();
+
+		/* stack direction */
+		stackdirup =  highptr > lowptr;		// Can we also test infn.localptr > outfn.localptr?
+
+		/* study the jump buffer */
+		{
+			uint32_t	i;
+			char **		pout;
+			char **		pin;
+			size_t		diff = outfn.localptr - infn.localptr;
+			char *		min_frame = outfn.localptr;
+
+			/* following line views jump buffer as array of long int */
+			pout = (char **)outfn.cxt;
+			pin = (char **)infn.cxt;
+
+			jmpmask1 = jmpmask2 = 0;
+			if (diff) {
+				for (i = 0; i < sizeof(jmp_buf)/sizeof(char *); i++, pout++, pin++) {
+					if ((size_t)(*pout - *pin) == diff) {
+						/* record frame dependency */
+						if (i < 32)
+							jmpmask1 |= 1 << i;
+						else
+							jmpmask2 |= 1 << (i-32);
+
+						if (stackdirup) {
+							if (min_frame > *pout) {
+								min_frame = *pout;
+							}
+						} else {
+							if (min_frame < *pout) {
+								min_frame = *pout;
+							}
+						}
+					}
+				}
+			}
+
+			if (stackdirup) {
+				stackbase = outfn.localptr - min_frame;
+			} else {
+				stackbase = min_frame - outfn.localptr;
+			}
+		}
+	#endif
+}
+
+gfxThreadHandle gfxThreadMe(void) {
+	return (gfxThreadHandle)current;
+}
+
+void gfxYield(void) {
+	if (!_setjmp(current->cxt)) {
+		// Add us back to the Queue
+		Qadd(&readyQ, current);
+
+		// Check if there are dead processes to deallocate
+		while ((current = Qpop(&deadQ)))
+			gfxFree(current);
+
+		// Run the next process
+		current = Qpop(&readyQ);
+		_longjmp(current->cxt, 1);
+	}
+}
+
+// This routine is not currently public - but it could be.
+void gfxThreadExit(threadreturn_t ret) {
+	// Save the results
+	current->param = (void *)ret;
+	current->flags |= FLG_THD_DEAD;
+
+	// Add us to the dead list if we need deallocation as we can't free ourselves.
+	// If someone is waiting on the thread they will do the cleanup.
+	if ((current->flags & (FLG_THD_ALLOC|FLG_THD_WAIT)) == FLG_THD_ALLOC)
+		Qadd(&deadQ, current);
+
+	// Switch to the next task
+	current = Qpop(&readyQ);
+	if (!current)
+		gfxExit();		// Oops - this should never happen!
+	_longjmp(current->cxt, 1);
+}
+
+gfxThreadHandle gfxThreadCreate(void *stackarea, size_t stacksz, threadpriority_t prio, DECLARE_THREAD_FUNCTION((*fn),p), void *param) {
+	thread *	t;
+	(void)		prio;
+
+	// Ensure we have a minimum stack size
+	if (stacksz < sizeof(thread)+64) {
+		stacksz = sizeof(thread)+64;
+		stackarea = 0;
+	}
+
+	if (stackarea) {
+		t = (thread *)stackarea;
+		t->flags = 0;
+	} else {
+		t = (thread *)gfxAlloc(stacksz);
+		if (!t)
+			return 0;
+		t->flags = FLG_THD_ALLOC;
+	}
+	t->size = stacksz;
+	t->fn = fn;
+	t->param = param;
+	if (_setjmp(t->cxt)) {
+		// This is the new thread - call the function!
+		gfxThreadExit(current->fn(current->param));
+
+		// We never get here
+		return 0;
+	}
+
+	// Move the stack frame and relocate the context data
+	{
+		char **	s;
+		char *	nf;
+		int		diff;
+		uint32_t	i;
+
+		// Copy the stack frame
+		#if AUTO_DETECT_MASK
+			if (STACK_DIR_UP) {					// Stack grows up
+				nf = (char *)(t) + sizeof(thread) + stackbase;
+				memcpy(t+1, (char *)&t - stackbase, stackbase+sizeof(char *));
+			} else {							// Stack grows down
+				nf = (char *)(t) + stacksz - (stackbase + sizeof(char *));
+				memcpy(nf, &t, stackbase+sizeof(char *));
+			}
+		#elif STACK_DIR_UP
+			// Stack grows up
+			nf = (char *)(t) + sizeof(thread) + stackbase;
+			memcpy(t+1, (char *)&t - stackbase, stackbase+sizeof(char *));
+		#else
+			// Stack grows down
+			nf = (char *)(t) + size - (stackbase + sizeof(char *));
+			memcpy(nf, &t, stackbase+sizeof(char *));
+		#endif
+
+		// Relocate the context data
+		s = (char **)(t->cxt);
+		diff = nf - (char *)&t;
+
+		// Relocate the elements we know need to be relocated
+		for (i = 1; i && i < MASK1; i <<= 1, s++) {
+			if ((MASK1 & i))
+				*s += diff;
+		}
+		#ifdef MASK2
+			for (i = 1; i && i < MASK2; i <<= 1, s++) {
+				if ((MASK1 & i))
+					*s += diff;
+			}
+		#endif
+	}
+
+	// Add this thread to the ready queue
+	Qadd(&readyQ, t);
+	return t;
+}
+
+threadreturn_t gfxThreadWait(gfxThreadHandle th) {
+	thread *		t;
+
+	t = th;
+	if (t == current)
+		return -1;
+
+	// Mark that we are waiting
+	t->flags |= FLG_THD_WAIT;
+
+	// Wait for the thread to die
+	while(!(t->flags & FLG_THD_DEAD))
+		gfxYield();
+
+	// Unmark
+	t->flags &= ~FLG_THD_WAIT;
+
+	// Clean up resources if needed
+	if (t->flags & FLG_THD_ALLOC)
+		gfxFree(t);
+
+	// Return the status left by the dead process
+	return (threadreturn_t)t->param;
+}
+
+#endif /* GFX_USE_OS_RAW32 */