/*
*********************************************************************************************************
*                                               uC/OS-II
*                                         The Real-Time Kernel
*
*                        (c) Copyright 1992-2002, Jean J. Labrosse, Weston, FL
*                                          All Rights Reserved
*
*                                          80x86 Specific code
*                                 LARGE MEMORY MODEL WITH FLOATING-POINT
*                                          Borland C/C++ V4.51
*
*
* File         : OS_CPU_C.C
* By           : Jean J. Labrosse
*********************************************************************************************************
*/

#define  OS_CPU_GLOBALS
#include "includes.h"

/*$PAGE*/
/*
*********************************************************************************************************
*                                             LOCAL CONSTANTS
*
* Note(s) : 1) OS_NTASKS_FP  establishes the number of tasks capable of supporting floating-point.  One
*              task is removed for the idle task because it doesn't do floating-point at all.
*           2) OS_FP_STORAGE_SIZE  currently allocates 128 bytes of storage even though the 80x86 FPU 
*              only require 108 bytes to save the FPU context.  I decided to allocate 128 bytes for 
*              future expansion.  
*********************************************************************************************************
*/


/*
*********************************************************************************************************
*                                             LOCAL VARIABLES
*********************************************************************************************************
*/


                                       /* I used INT32U to ensure that storage is aligned on a ...     */
                                       /* ... 32-bit boundary.                                         */

/*$PAGE*/
/*
*********************************************************************************************************
*                                        INITIALIZE FP SUPPORT
*
* Description: This function is called to initialize the memory partition needed to support context
*              switching the Floating-Point registers.  This function MUST be called AFTER calling
*              OSInit().
*
* Arguments  : none
*
* Returns    : none
*
* Note(s)    : 1) Tasks that are to use FP support MUST be created with OSTaskCreateExt().
*              2) For the 80x86 FPU, 108 bytes are required to save the FPU context.  I decided to
*                 allocate 128 bytes for future expansion.  Also, I used INT32U to ensure that storage 
*                 is aligned on a 32-bit boundary.
*              3) I decided to 'change' the 'Options' attribute for the statistic task in case you
*                 use OSTaskStatHook() and need to perform floating-point operations in this function.
*                 This only applies if OS_TaskStat() was created with OSTaskCreateExt().
*********************************************************************************************************
*/



/*$PAGE*/
/*
*********************************************************************************************************
*                                       OS INITIALIZATION HOOK
*                                            (BEGINNING)
*
* Description: This function is called by OSInit() at the beginning of OSInit().
*
* Arguments  : none
*
* Note(s)    : 1) Interrupts should be disabled during this call.
*********************************************************************************************************
*/
#if OS_CPU_HOOKS_EN > 0 && OS_VERSION > 203
void  OSInitHookBegin (void)
{
}
#endif

/*
*********************************************************************************************************
*                                       OS INITIALIZATION HOOK
*                                               (END)
*
* Description: This function is called by OSInit() at the end of OSInit().
*
* Arguments  : none
*
* Note(s)    : 1) Interrupts should be disabled during this call.
*********************************************************************************************************
*/
#if OS_CPU_HOOKS_EN > 0 && OS_VERSION > 203
void  OSInitHookEnd (void)
{
   
}
#endif

/*$PAGE*/
/*
*********************************************************************************************************
*                                          TASK CREATION HOOK
*
* Description: This function is called when a task is created.
*
* Arguments  : ptcb   is a pointer to the task control block of the task being created.
*
* Note(s)    : 1) Interrupts are disabled during this call.
*              2) I decided to change the options on the statistic task to allow for floating-point in
*                 case you decide to do math. in OSTaskStatHook().
*********************************************************************************************************
*/
#if OS_CPU_HOOKS_EN > 0
void OSTaskCreateHook (OS_TCB *ptcb)
{
    ptcb = ptcb; 
}
#endif

/*
*********************************************************************************************************
*                                           TASK DELETION HOOK
*
* Description: This function is called when a task is deleted.
*
* Arguments  : ptcb   is a pointer to the task control block of the task being deleted.
*
* Note(s)    : 1) Interrupts are disabled during this call.
*********************************************************************************************************
*/
#if OS_CPU_HOOKS_EN > 0
void OSTaskDelHook (OS_TCB *ptcb)
{
   ptcb = ptcb; 
}
#endif

/*$PAGE*/
/*
*********************************************************************************************************
*                                             IDLE TASK HOOK
*
* Description: This function is called by the idle task.  This hook has been added to allow you to do  
*              such things as STOP the CPU to conserve power.
*
* Arguments  : none
*
* Note(s)    : 1) Interrupts are enabled during this call.
*********************************************************************************************************
*/
#if OS_CPU_HOOKS_EN && OS_VERSION >= 251
void  OSTaskIdleHook (void)
{
}
#endif

/*
*********************************************************************************************************
*                                           STATISTIC TASK HOOK
*
* Description: This function is called every second by uC/OS-II's statistics task.  This allows your 
*              application to add functionality to the statistics task.
*
* Arguments  : none
*********************************************************************************************************
*/
#if OS_CPU_HOOKS_EN > 0
void OSTaskStatHook (void)
{
}
#endif

/*$PAGE*/
/*
*********************************************************************************************************
*                                        INITIALIZE A TASK'S STACK
*
* Description: This function is called by either OSTaskCreate() or OSTaskCreateExt() to initialize the
*              stack frame of the task being created.  This function is highly processor specific.
*
* Arguments  : task          is a pointer to the task code
*
*              pdata         is a pointer to a user supplied data area that will be passed to the task
*                            when the task first executes.
*
*              ptos          is a pointer to the top of stack.  It is assumed that 'ptos' points to
*                            a 'free' entry on the task stack.  If OS_STK_GROWTH is set to 1 then 
*                            'ptos' will contain the HIGHEST valid address of the stack.  Similarly, if
*                            OS_STK_GROWTH is set to 0, the 'ptos' will contains the LOWEST valid address
*                            of the stack.
*
*              opt           specifies options that can be used to alter the behavior of OSTaskStkInit().
*                            (see uCOS_II.H for OS_TASK_OPT_???).
*
* Returns    : Always returns the location of the new top-of-stack' once the processor registers have
*              been placed on the stack in the proper order.
*
* Note(s)    : Interrupts are enabled when your task starts executing. You can change this by setting the
*              PSW to 0x0002 instead.  In this case, interrupts would be disabled upon task startup.  The
*              application code would be responsible for enabling interrupts at the beginning of the task
*              code.  You will need to modify OSTaskIdle() and OSTaskStat() so that they enable 
*              interrupts.  Failure to do this will make your system crash!
*********************************************************************************************************
*/

OS_STK  *OSTaskStkInit (void(*task)(void *pd), void *pdata, OS_STK *ptos, INT16U opt)
{
    INT16U *stk;


    opt    = opt;                           /* 'opt' is not used, prevent warning                      */
    stk    = (INT16U *)ptos;                /* Load stack pointer                                      */
    *stk++ = (INT16U)(pdata);         /* Simulate call to function with argument                 */
    *stk++ = (INT16U)(pdata);         
    *stk++;
    *stk++=0x21ec;
    *stk++=0x2600;                /* SW = Interrupts enabled                                 */
    *stk++=0;          /* Put pointer to task   on top of stack                   */
    *stk++=0xf;
    *stk++=0;                                                  
    *stk++=0;                                  
    *stk++=0;                                            
    *stk++=0;                                            
    *stk++=0;                                   
    *stk++=2;                                                      
    *stk++=3;                                                    
    *stk++=4;                /* DI = 0x3333                                             */
    *stk++=5;                /* ES = 0x4444                                             */
    *stk++=6;
    *stk++=7; 
    *stk++=(INT16U)task; 
    *stk++=(INT16U)task;
    *stk++=5;                         /* DS = Current value of DS                                */
    return ((void *)stk);
}

/*$PAGE*/
/*
*********************************************************************************************************
*                                           TASK SWITCH HOOK
*
* Description: This function is called when a task switch is performed.  This allows you to perform other
*              operations during a context switch.
*
* Arguments  : none
*
* Note(s)    : 1) Interrupts are disabled during this call.
*              2) It is assumed that the global pointer 'OSTCBHighRdy' points to the TCB of the task that
*                 will be 'switched in' (i.e. the highest priority task) and, 'OSTCBCur' points to the 
*                 task being switched out (i.e. the preempted task).
*********************************************************************************************************
*/
#if OS_CPU_HOOKS_EN > 0
void OSTaskSwHook (void)
{
   
}
#endif

/*
*********************************************************************************************************
*                                           OSTCBInit() HOOK
*
* Description: This function is called by OS_TCBInit() after setting up most of the TCB.
*
* Arguments  : ptcb    is a pointer to the TCB of the task being created.
*
* Note(s)    : 1) Interrupts may or may not be ENABLED during this call.
*********************************************************************************************************
*/
#if OS_CPU_HOOKS_EN > 0 && OS_VERSION > 203
void  OSTCBInitHook (OS_TCB *ptcb)
{
    ptcb = ptcb;                                           /* Prevent Compiler warning                 */
}
#endif


/*
*********************************************************************************************************
*                                               TICK HOOK
*
* Description: This function is called every tick.
*
* Arguments  : none
*
* Note(s)    : 1) Interrupts may or may not be ENABLED during this call.
*********************************************************************************************************
*/
#if OS_CPU_HOOKS_EN > 0
void OSTimeTickHook (void)
{
}
#endif