//
// When __PROFILE is called, stack frame looks like this:
//
//   sp+08 Caller's return address
//   sp+04 Address of function name string
//   sp    Return address to start of function
// 
// After we save registers and such, stack frame looks like this:
//
//   sp+28 Caller's return address
//   sp+24 Address of function name string
//   sp+20 Return address to start of function
//   sp+16 saved A0
//   sp+12 saved A1
//   sp+08 saved D0
//   sp+04 saved D1
//   sp    saved D2
//
// Upon returning from __PROFILE, stack frame should look like this:
//
//   sp    Address of __PROFILEEND
//
//

#include <Profiler.h>
#include <Threads.h>
#include <Timer.h>
#include <stdio.h>
#include <string.h>

#pragma profile off

#if defined(powerc) || defined(__powerc)
	extern void Profile_GetTime(UnsignedWide *time);
#else
	#define Profile_GetTime(time) Microseconds(time)
#endif

#define THREAD_OFFSET 100

#define NAME_LENGTH 23
#define MAX_FUNCS 1000
#define MAX_THREADS 50
#define STACK_DEPTH 100

typedef struct {
	char name[NAME_LENGTH+1];
	int calls;
	long address;
	UnsignedWide totalTime;
} FunctionInfo;

typedef struct {
	FunctionInfo *callerFunction;
	long returnAddress;
} StackFrame;

typedef struct {
	StackFrame stack[STACK_DEPTH];
	StackFrame *stackPtr;
	FunctionInfo *currentFunction;
	UnsignedWide startTime;
} ThreadInfo;

static ThreadInfo gThread[MAX_THREADS];
static FunctionInfo gFunction[MAX_FUNCS];
static long gProfilerOn = false;
static ThreadInfo *gCurrentThread;
static FunctionInfo *gCallerFunction;
static long gSaveArea[5];

static FunctionInfo *GetIndex(char *functionName:__A0, long address:__D0):__A0;
static void StartTime(FunctionInfo *function:__A0, int call:__D0);
static void StopTime(int index:__D0);
static void GetThreadInfo(void);
static void PushFrame(long returnAddress:__D0);
static long PopFrame(void):__D0;
static asm pascal void __PROFILEEND(void);

#pragma parameter AddToWide(__A0, __A1)
void AddToWide(UnsignedWide *a, UnsignedWide *b) = {
	0x2011,                   //		move.l	0(a1),d0		;d0 = hi
	0x2229, 0x0004,           // 		move.l	4(a1),d1		;d1 = lo
	0x2410,                   //		move.l	0(a0),d2		;d2 = hi
	0xD2A8, 0x0004,           //   	add.l		4(a0),d1		;add lo parts
	0xD580,                   //		addx.l	d0,d2			;add hi parts with carry
	0x2082,                   //		move.l	d2,0(a0)		;store high result
	0x2141, 0x0004            // 		move.l	d1,4(a0)		;store low result
};

#pragma parameter SubFromWide(__A1, __A0)
void SubFromWide(UnsignedWide *a, UnsignedWide *b) = {
	0x2011,                   //		move.l	0(a1),d0		;d0 = hi
	0x2229, 0x0004,           // 		move.l	4(a1),d1		;d1 = lo
	0x2410,                   //		move.l	0(a0),d2		;d2 = hi
	0x92A8, 0x0004,           //   	sub.l		4(a0),d1		;add lo parts
	0x9580,                   //		subx.l	d0,d2			;add hi parts with carry
	0x2082,                   //		move.l	d2,0(a0)		;store high result
	0x2141, 0x0004            // 		move.l	d1,4(a0)		;store low result
};


pascal OSErr ProfilerInit(ProfilerCollectionMethod method, ProfilerTimeBase timeBase, short numFunctions, short stackDepth)
{
	int i;

	// initialize the function table
	memset(gFunction, 0, sizeof(gFunction));
	strcpy(gFunction[0].name, "Root_Function");
	gFunction[0].address = -1;
	gFunction[0].calls = 1;

	// initialize the thread table
	memset(gThread, 0, sizeof(gThread));
	for (i = 0; i < MAX_THREADS; i++) gThread[i].stackPtr = gThread[i].stack;
	Profile_GetTime(&gThread[0].startTime);
	gThread[0].currentFunction = gFunction;

	// make sure we're turned off
	gProfilerOn = false;
	return noErr;
}

pascal void ProfilerSetStatus(short on)
{
	gProfilerOn = (on) ? true : false;
}

pascal OSErr ProfilerDump(StringPtr filename)
{
/*
	static char cfile[256];
	FunctionInfo *function;
	double temp;
	FILE *f;
	int i;
	
	BlockMoveData(filename + 1, cfile, *filename);
	cfile[*filename] = 0;
	f = fopen(cfile, "w");
	if (f) {
		for (i = 0, function = gFunction; i < MAX_FUNCS; i++, function++)
			if (function->address) {
				temp = ((double)function->totalTime.hi * 65536.0 * 65536.0) + (double)function->totalTime.lo;
				fprintf(f, "%-40s  %15.0lf ticks, %15.2lf ticks/call, %7d calls\n", function->name, 
							temp, temp/function->calls, function->calls);
			}
		fclose(f);
	}
	return noErr;
*/
}

pascal void ProfilerTerm(void)
{
	gProfilerOn = false;
}






static void StartTime(FunctionInfo *function:__A0, int call:__D0)
{
	UnsignedWide thisTime, diff;
	FunctionInfo *last;

	// get the current time
	Profile_GetTime(&thisTime);

	// if there was another function being timed, update that timer
	last = gCurrentThread->currentFunction;
	if (last) {
		diff = gCurrentThread->startTime;
		SubFromWide(&thisTime, &diff);
		AddToWide(&last->totalTime, &diff);
	}
	
	// if we have a new function to track, reset the start time and increment the calling count
	if (function) {
		if (call) function->calls++;
		gCurrentThread->startTime = thisTime;
	}
	
	// update the current thread's function pointer
	gCurrentThread->currentFunction = function;
}

static FunctionInfo *GetIndex(char *functionName:__A0, long address:__D0):__A0
{
	FunctionInfo *function;
	register int i;
	
	// loop over all functions, looking for an address match or an empty space
	for (i = 0, function = gFunction; i < MAX_FUNCS; i++, function++) {
		long a = function->address;
		if (!a) break;
		else if (a == address) return function;
	}

	// if we have space for a new function, create an entry
	if (i < MAX_FUNCS) {
		strncpy(function->name, functionName, NAME_LENGTH);
		function->address = address;
		return function;
	}
	
	// return nil if nothing could be found
	return nil;
}

void GetThreadInfo(void)
{
	// get a pointer to the current thread's info
	ThreadID thread;
	GetCurrentThread(&thread);
	gCurrentThread = gThread + thread - THREAD_OFFSET;
}

void PushFrame(long returnAddress:__D0)
{
	// get a pointer to the next empty stack frame, and increment the stack pointer
	StackFrame *sp = gCurrentThread->stackPtr++;

	// save the current function and return address
	sp->callerFunction = gCurrentThread->currentFunction;
	sp->returnAddress = returnAddress;
}

long PopFrame(void):__D0
{
	// get a pointer to the next empty stack frame, and increment the stack pointer
	StackFrame *sp = --gCurrentThread->stackPtr;

	// save the current function and return address
	gCallerFunction = sp->callerFunction;
	return sp->returnAddress;
}




// When __PROFILE is called, stack frame looks like this:
//
//   sp+0c Return space for Pascal function
//   sp+08 Caller's return address
//   sp+04 Address of function name string
//   sp    Return address to start of function
// 
// After we save registers and such, stack frame looks like this:
//
//   sp+32 Return space for Pascal function
//   sp+28 Caller's return address
//   sp+24 Address of function name string
//   sp+20 Return address to start of function
//   sp+16 saved A0
//   sp+12 saved A1
//   sp+08 saved D0
//   sp+04 saved D1
//   sp    saved D2
//
// Upon returning from __PROFILE, stack frame should look like this:
//
//   sp+04 Return space for Pascal function
//   sp    Address of __PROFILEEND

asm pascal void __PROFILE(char *functionName)
{
	tst.l		gProfilerOn						// is the profiler on?
	bne.s		@doProfile						// if so, go do the work
	move.l	(sp),4(sp)						// otherwise, copy return address over parameter
	addq.l	#4,sp								// adjust the stack pointer accordingly
	rts											// return
@doProfile:
_Debugger
	clr.l		gProfilerOn						// clear the profiler flag -- we are not reentrant
	movem.l	a0/a1/d0-d2,-(sp)				// save registers
	jsr		GetThreadInfo					// get the current thread info into a global
	move.l	28(sp),d0						// get the return address in d0
	jsr		PushFrame						// and push it onto the stack
	move.l	24(sp),a0						// now get the function name
	move.l	20(sp),d0						// and the function address
	move.l	d0,24(sp)						// (copy the address onto the stack for later)
	jsr		GetIndex							// and return an index into our function table
	moveq.l	#1,d0								// set the call flag
	jsr		StartTime						// start the timer for this baby (and stop the last one)
	lea		__PROFILEEND,a0				// point a0 to our profile end routine
	move.l	a0,28(sp)						// store that in place of the real return address
	movem.l	(sp)+,a0/a1/d0-d2				// restore the registers
	addq.l	#4,sp								// skip over stack space for the functionName parameter
	move.l	#1,gProfilerOn					// turn the profiler flag back on
	rts											// and return
}

// sequence  of events:
//
// call to __PROFILE
//   clears profilerOn flag to prevent re-entrancy
//   gets a pointer to the current thread info in gCurrentThread
//   saves the currentFunction pointer and the real return address as a stack frame
//   calculates a pointer to the new currentFunction
//   stops the timer for the previous currentFunction and starts it for the new one
//   replaces the real return address with a return into __PROFILEEND
//   resets profilerOn flag
//   returns to the beginning of the function
//
// return to __PROFILEEND
//   clears profilerOn flag to prevent re-entrancy
//   gets a pointer to the current thread info in gCurrentThread
//   pops the stack frame, returning real return address and pointer to caller function
//   saves real return address on the stack for returning
//   stops the timer for the previous function and starts it back up for the caller function
//   resets profilerOn flag
//   returns to the calling function
//   

// When __PROFILEEND is called, stack frame looks like this:
//
//   sp    Return space for Pascal function
// 
// Upon returning from __PROFILE, stack frame should look like this:
//
//   sp    Address of __PROFILEEND

asm pascal void __PROFILEEND(void)
{
_Debugger
	clr.l		gProfilerOn						// clear the profiler flag -- we are not reentrant
	movem.l	a0/d0,gSaveArea				// save a0/d0
	jsr		GetThreadInfo					// get the current thread info into a global
	jsr		PopFrame							// pop the frame, returning the real return address
	move.l	d0,gSaveArea+8					// save return address in a safe place
	move.l	gCallerFunction,a0			// get pointer to new current function
	clr.l		d0									// clear the call flag
	jsr		StartTime						// now start the timer
	movem.l	gSaveArea,a0/d0				// restore a0/d0
	move.l	gSaveArea+8,a1					// get return address in a1
	move.l	#1,gProfilerOn					// turn the profiler flag back on
	jmp		(a1)								// return to the caller
}