/* File **********THREAD.C***********
   Simulator example for the MC68HC11EVB

   This example accompanies the book
     "Embedded Microcomputer Systems: Real Time Interfacing", Brooks-Cole, copyright (c) 2000,
      Jonathan W. Valvano 7/6/99

   Interface between the TExaS simulator running a MC68HC11 EVB
      with ICC11 freeware compiler 
   TExaS Copyright 1999 by Jonathan W. Valvano 
   for more information about ICC11 
      see http://www.imagecraft.com
   You may use this file without restrictions
 
   Statically allocated thread example with spin lock semaphores
   PortB bits 0,1,2,3 specify which thread is running
   PortC bit program
          0  Put
		  1  Get
		  2  Producer
		  3  Consumer
		  4  Wait
		  5  Signal
*/
#include "HC11.h"
#include "SCI11a.h"
#include "SPIN.H"
#include "SFIFO.H"
/* global variables */
unsigned int ElapsedTime;  /* in timeslices */
int DisplayFree;           /* Semaphore used to share Display */
#define timeslice 1000
#define stacksize 75
/* stacksize must be odd */
struct	TCB
{   struct TCB *Next;      /* Link to Next TCB */
    unsigned char *Spt;     /* Stack Pointer  */
    unsigned char Id;      /* 1,2 or 4 */
    unsigned char MoreStack[stacksize-9];  /* additional stack */
    unsigned char CCR;     /* Initial CCR */
    unsigned char RegB;    /* Initial RegB */
    unsigned char RegA;    /* Initial RegA */
    unsigned int RegX;     /* Initial RegX */
    unsigned int RegY;     /* Initial RegY */
    void (*PC)(void);      /* Initial Program Counter */
};
typedef struct TCB TCBType;
typedef TCBType * TCBPtr;
TCBPtr RunPt;   /* Pointer to thread currently running */

unsigned int last;
unsigned int CreateData(void){ unsigned int i;
/* will generate the data stream 1,2,3,4,...,99 */
    asm(" sei");     /* read modify write nonreentrant code */
    if((last++)==100){
       OutString("done"); 
       OutChar(13);
       asm(" stop");} /* halt execution */
    asm(" cli");
    return(last);}
void pseudo(unsigned int loopcnt){ unsigned int i;
    for(i=0;i<loopcnt;i++);}

void Message( unsigned int threadId, char *NamePt, unsigned int data){
    Wait(&DisplayFree);
    OutUDec(threadId);
    OutString(NamePt);
    OutUDec(data);
    OutChar(CR);
    Signal(&DisplayFree);
}
void Producer(void){ unsigned int x; unsigned int myId;
    myId=RunPt->Id;
    while(1) {
       PORTC=4;
       x=CreateData();
       pseudo(x);
       Message(myId," puts ",x);
       Put(x); }
}
void Consumer(void){ unsigned int x; unsigned int myId;
    myId=RunPt->Id;
    while(1) {
       PORTC=8;
       x=Get();
       pseudo(x);
       Message(myId," gets ",x);
}}
TCBType sys[4]={
  {	&sys[1],           /* Pointer to Next */
	 &sys[0].MoreStack[stacksize-10],  /* Initial SP */
	 1,                 /* Id */
	 { 0},
	 0x40,0,0,0,0,      /* CCR,B,A,X,Y */
	 Producer, },       /* Initial PC */
  {	&sys[2],            /* Pointer to Next */
	 &sys[1].MoreStack[stacksize-10],  /* Initial SP */
	 2,                 /* Id */
	 { 0},
	 0x40,0,0,0,0,      /* CCR,B,A,X,Y */
	 Producer, },       /* Initial PC */
  {  	&sys[3],            /* Pointer to Next */
	 &sys[2].MoreStack[stacksize-10],  /* Initial SP */
	 4,                 /* Id */
	 { 0},
	 0x40,0,0,0,0,      /* CCR,B,A,X,Y */
	 Consumer, },       /* Initial PC */
  {  	&sys[0],            /* Pointer to Next */
	 &sys[3].MoreStack[stacksize-10],  /* Initial SP */
	 8,                 /* Id */
	 { 0},
	 0x40,0,0,0,0,      /* CCR,B,A,X,Y */
	 Consumer, }};      /* Initial PC */
void IncTime(void){
   if((ElapsedTime++)==0)
      ElapsedTime=65535;
}
void ThreadSwitch(void){ /* suspend current tread */
asm(" ldx _RunPt\n"  
    " sts 2,x");
   IncTime();
   RunPt=RunPt->Next; /* find next thread to watch */
   PORTB=RunPt->Id;   /* PortB shows which thread is running */
asm(" ldx _RunPt\n"
    " lds 2,x");
   TOC3=TCNT+timeslice;  /* Thread runs for fixed amount of time */
   TFLG1=0x20;           /* acknowledge by clearing OC3F */
asm(" rti");
}

void main(void){
   InitSCI();
   DDRC=0xFF; DisplayFree=1; last=0; ElapsedTime=0;
   OutString("Fixed allocation spinlock semaphore system"); OutChar(CR);
   RunPt=&sys[0];   /* Specify first thread to run */
asm("  sei");
   InitFifo();
   TFLG1 = 0x20;   /* Clear OC3F */
   TMSK1 = 0x20;   /* Arm TOC3 */
   TOC3=TCNT+timeslice;  /* time slice for first thread */
   PORTB=RunPt->Id;
asm("  ldx _RunPt\n"
    "  lds 2,x\n"
    "  cli\n"
    "  rti");}    /* Launch First Thread */

#include "SCI11a.C"
#include "SPIN.C"
#include "SFIFO.C"

void resetVectors(void){
/* not really a function, 
   but this must be last */
  asm(" org $FFD6");
  asm(" FDB _SciHandler");
  asm(" org $FFE4");
  asm(" FDB _ThreadSwitch");
  asm(" org $FFFE");
  asm(" FDB __start");
  asm(" org $FC00"); /* puts rts in a harmless place */
/* string constants also placed here */
/* the value FC00 means you can have up to 1000 characters of strings  */
}