📄 os_cpu_c.c
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/*
*********************************************************************************************************
* uC/OS-II
* The Real-Time Kernel
*
* (c) Copyright 1992-2002, Jean J. Labrosse, Weston, FL
* All Rights Reserved
*
*
* 80x86/80x88 Specific code
* LARGE MEMORY MODEL
*
* Borland C/C++ V4.51
*
* File : OS_CPU_C.C
* By : Jean J. Labrosse
*********************************************************************************************************
*/
#define OS_CPU_GLOBALS
#include "includes.h"
/*
*********************************************************************************************************
* 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.
*********************************************************************************************************
*/
#if OS_CPU_HOOKS_EN > 0
void OSTaskCreateHook (OS_TCB *ptcb)
{
ptcb = ptcb; /* Prevent compiler warning */
}
#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; /* Prevent compiler warning */
}
#endif
/*
*********************************************************************************************************
* 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 > 0 && 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);
}
/*$PAGE*/
/*
*********************************************************************************************************
* INITIALIZE A TASK'S STACK FOR FLOATING POINT EMULATION
*
* Description: This function MUST be called BEFORE calling either OSTaskCreate() or OSTaskCreateExt() in
* order to initialize the task's stack to allow the task to use the Borland floating-point
* emulation. The returned pointer MUST be used in the task creation call.
*
* Ex.: OS_STK TaskStk[1000];
*
*
* void main (void)
* {
* OS_STK *ptos;
* OS_STK *pbos;
* INT32U size;
*
*
* OSInit();
* .
* .
* ptos = &TaskStk[999];
* pbos = &TaskStk[0];
* psize = 1000;
* OSTaskStkInit_FPE_x86(&ptos, &pbos, &size);
* OSTaskCreate(Task, (void *)0, ptos, 10);
* .
* .
* OSStart();
* }
*
* Arguments : pptos is the pointer to the task's top-of-stack pointer which would be passed to
* OSTaskCreate() or OSTaskCreateExt().
*
* ppbos is the pointer to the new bottom of stack pointer which would be passed to
* OSTaskCreateExt().
*
* psize is a pointer to the size of the stack (in number of stack elements). You
* MUST allocate sufficient stack space to leave at least 384 bytes for the
* floating-point emulation.
*
* Returns : The new size of the stack once memory is allocated to the floating-point emulation.
*
* Note(s) : 1) _SS is a Borland 'pseudo-register' and returns the contents of the Stack Segment (SS)
* 2) The pointer to the top-of-stack (pptos) will be modified so that it points to the new
* top-of-stack.
* 3) The pointer to the bottom-of-stack (ppbos) will be modified so that it points to the new
* bottom-of-stack.
* 4) The new size of the stack is adjusted to reflect the fact that memory was reserved on
* the stack for the floating-point emulation.
*********************************************************************************************************
*/
/*$PAGE*/
void OSTaskStkInit_FPE_x86 (OS_STK **pptos, OS_STK **ppbos, INT32U *psize)
{
INT32U lin_tos; /* 'Linear' version of top-of-stack address */
INT32U lin_bos; /* 'Linear' version of bottom-of-stack address */
INT16U seg;
INT16U off;
INT32U bytes;
seg = FP_SEG(*pptos); /* Decompose top-of-stack pointer into seg:off */
off = FP_OFF(*pptos);
lin_tos = ((INT32U)seg << 4) + (INT32U)off; /* Convert seg:off to linear address */
bytes = *psize * sizeof(OS_STK); /* Determine how many bytes for the stack */
lin_bos = (lin_tos - bytes + 15) & 0xFFFFFFF0L; /* Ensure paragraph alignment for BOS */
seg = (INT16U)(lin_bos >> 4); /* Get new 'normalized' segment */
*ppbos = (OS_STK *)MK_FP(seg, 0x0000); /* Create 'normalized' BOS pointer */
memcpy(*ppbos, MK_FP(_SS, 0), 384); /* Copy FP emulation memory to task's stack */
bytes = bytes - 16; /* Loose 16 bytes because of alignment */
*pptos = (OS_STK *)MK_FP(seg, (INT16U)bytes); /* Determine new top-of-stack */
*ppbos = (OS_STK *)MK_FP(seg, 384); /* Determine new bottom-of-stack */
bytes = bytes - 384;
*psize = bytes / sizeof(OS_STK); /* Determine new stack size */
}
/*$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
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