/*
*********************************************************************************************************
* 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
*********************************************************************************************************
*/
//系统内核的各种服务文件
#define OS_CPU_GLOBALS
#include "includes.h"
/*$PAGE*/
/*
*********************************************************************************************************
* LOCAL CONSTANTS
*
* Note(s) : 1) OS_NTASKS_FP establishes the number of tasks capable of supporting floating-point. One
* task is removed for the idle task because it doesn‘t do floating-point at all.
* 2) OS_FP_STORAGE_SIZE currently allocates 128 bytes of storage even though the 80x86 FPU
* only require 108 bytes to save the FPU context. I decided to allocate 128 bytes for
* future expansion.
*********************************************************************************************************
*/
#define OS_NTASKS_FP (OS_MAX_TASKS + OS_N_SYS_TASKS - 1)
#define OS_FP_STORAGE_SIZE 128
/*
*********************************************************************************************************
* LOCAL VARIABLES
*********************************************************************************************************
*/
static OS_MEM *OSFPPartPtr; /* Pointer to memory partition holding FPU storage areas */
/* I used INT32U to ensure that storage is aligned on a ... */
/* ... 32-bit boundary. */
static INT32U OSFPPart[OS_NTASKS_FP][OS_FP_STORAGE_SIZE / sizeof(INT32U)];
/*$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().
*********************************************************************************************************
*/
void OSFPInit (void)
{
INT8U err;
#if OS_TASK_STAT_EN && OS_TASK_CREATE_EXT_EN
OS_TCB *ptcb;
void *pblk;
#endif
OSFPPartPtr = OSMemCreate(&OSFPPart[0][0], OS_NTASKS_FP, OS_FP_STORAGE_SIZE, &err);
#if OS_TASK_STAT_EN && OS_TASK_CREATE_EXT_EN /* CHANGE ‘OPTIONS‘ for OS_TaskStat() */
ptcb = OSTCBPrioTbl[OS_STAT_PRIO];
ptcb->OSTCBOpt |= OS_TASK_OPT_SAVE_FP; /* Allow floating-point support for Statistic task */
pblk = OSMemGet(OSFPPartPtr, &err); /* Get storage for FPU registers */
if (pblk != (void *)0) { /* Did we get a memory block? */
ptcb->OSTCBExtPtr = pblk; /* Yes, Link to task‘s TCB */
OSFPSave(pblk); /* Save the FPU registers in block */
}
#endif
}
/*$PAGE*/
/*
*********************************************************************************************************
* OS INITIALIZATION HOOK
* (BEGINNING)
*
* Description: This function is called by OSInit() at the beginning of OSInit().
*
* Arguments : none
*
* Note(s) : 1) Interrupts should be disabled during this call.
*********************************************************************************************************
*/
#if OS_CPU_HOOKS_EN > 0 && OS_VERSION > 203
void OSInitHookBegin (void)
{
}
#endif
/*
*********************************************************************************************************
* OS INITIALIZATION HOOK
* (END)
*
* Description: This function is called by OSInit() at the end of OSInit().
*
* Arguments : none
*
* Note(s) : 1) Interrupts should be disabled during this call.
*********************************************************************************************************
*/
#if OS_CPU_HOOKS_EN > 0 && OS_VERSION > 203
void OSInitHookEnd (void)
{
OSFPInit();
}
#endif
/*$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)
{
INT8U err;
void *pblk;
if (ptcb->OSTCBOpt & OS_TASK_OPT_SAVE_FP) { /* See if task needs FP support */
pblk = OSMemGet(OSFPPartPtr, &err); /* Yes, Get storage for FPU registers */
if (pblk != (void *)0) { /* Did we get a memory block? */
ptcb->OSTCBExtPtr = pblk; /* Yes, Link to task‘s TCB */
OSFPSave(pblk); /* Save the FPU registers in block */
}
}
}
#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)
{
if (ptcb->OSTCBOpt & OS_TASK_OPT_SAVE_FP) { /* See if task had FP support */
if (ptcb->OSTCBExtPtr != (void *)0) { /* Yes, OSTCBExtPtr must not be NULL */
OSMemPut(OSFPPartPtr, ptcb->OSTCBExtPtr); /* Return memory block to free pool */
}
}
}
#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)FP_SEG(pdata); /* Simulate call to function with argument */
*stk-- = (INT16U)FP_OFF(pdata);
*stk-- = (INT16U)FP_SEG(task);
*stk-- = (INT16U)FP_OFF(task);
*stk-- = (INT16U)0x0202; /* SW = Interrupts enabled */
*stk-- = (INT16U)FP_SEG(task); /* Put pointer to task on top of stack */
*stk-- = (INT16U)FP_OFF(task);
*stk-- = (INT16U)0xAAAA; /* AX = 0xAAAA */
*stk-- = (INT16U)0xCCCC; /* CX = 0xCCCC */
*stk-- = (INT16U)0xDDDD; /* DX = 0xDDDD */
*stk-- = (INT16U)0xBBBB; /* BX = 0xBBBB */
*stk-- = (INT16U)0x0000; /* SP = 0x0000 */
*stk-- = (INT16U)0x1111; /* BP = 0x1111 */
*stk-- = (INT16U)0x2222; /* SI = 0x2222 */
*stk-- = (INT16U)0x3333; /* DI = 0x3333 */
*stk-- = (INT16U)0x4444; /* ES = 0x4444 */
*stk = _DS; /* DS = Current value of DS */
return ((OS_STK *)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)
{
INT8U err;
void *pblk;
/* Save FPU context of preempted task */
if (OSRunning == TRUE) { /* Don‘t save on OSStart()! */
if (OSTCBCur->OSTCBOpt & OS_TASK_OPT_SAVE_FP) { /* See if task used FP */
pblk = OSTCBCur->OSTCBExtPtr; /* Yes, Get pointer to FP storage area */
if (pblk != (void *)0) { /* Make sure we have storage */
OSFPSave(pblk); /* Save the FPU registers in block */
}
}
}
/* Restore FPU context of new task */
if (OSTCBHighRdy->OSTCBOpt & OS_TASK_OPT_SAVE_FP) { /* See if new task uses FP */
pblk = OSTCBHighRdy->OSTCBExtPtr; /* Yes, Get pointer to FP storage area */
if (pblk != (void *)0) { /* Make sure we have storage */
OSFPRestore(pblk); /* Get contents of FPU registers */
}
}
}
#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