/*
*********************************************************************************************************
*                                               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
*                                With Floating-Point Register Support
*
*                                         Borland C/C++ V4.51
*
* File         : OS_CPU.H
* By           : Jean J. Labrosse
*********************************************************************************************************
*/

#ifdef  OS_CPU_GLOBALS
#define OS_CPU_EXT
#else
#define OS_CPU_EXT  extern
#endif

/*$PAGE*/
/*
*********************************************************************************************************
*                                              DATA TYPES
*                                         (Compiler Specific)
                                            定義一些常用的數據類型
*********************************************************************************************************
*/

typedef unsigned char  BOOLEAN;
typedef unsigned char  INT8U;                    /* Unsigned  8 bit quantity                           */
typedef signed   char  INT8S;                    /* Signed    8 bit quantity                           */
typedef unsigned int   INT16U;                   /* Unsigned 16 bit quantity                           */
typedef signed   int   INT16S;                   /* Signed   16 bit quantity                           */
typedef unsigned long  INT32U;                   /* Unsigned 32 bit quantity                           */
typedef signed   long  INT32S;                   /* Signed   32 bit quantity                           */
typedef float          FP32;                     /* Single precision floating point                    */
typedef double         FP64;                     /* Double precision floating point                    */

typedef unsigned int   OS_STK;                   /* Each stack entry is 16-bit wide                    */
//每個堆棧入口是十六位寬
typedef unsigned int   OS_CPU_SR;                /* The CPU Status Word is 16-bit wide                 */
//CPU狀態字是十六位寬

/* 
*********************************************************************************************************
*                              Intel 80x86 (Real-Mode, Large Model)
*
* Method #1:  Disable/Enable interrupts using simple instructions.  After critical section, interrupts
*             will be enabled even if they were disabled before entering the critical section.
*
* Method #2:  Disable/Enable interrupts by preserving the state of interrupts.  In other words, if 
*             interrupts were disabled before entering the critical section, they will be disabled when
*             leaving the critical section.
*
* Method #3:  Disable/Enable interrupts by preserving the state of interrupts.  Generally speaking you
*             would store the state of the interrupt disable flag in the local variable 'cpu_sr' and then
*             disable interrupts.  'cpu_sr' is allocated in all of uC/OS-II's functions that need to 
*             disable interrupts.  You would restore the interrupt disable state by copying back 'cpu_sr'
*             into the CPU's status register.
                                                      實時模式：
方法一：用簡單指針開關中斷，臨界狀態后，即使開始關掉中斷，現在也要
                      開中斷。
方法二：通過保存中斷狀態來開關中斷，即：進入臨界狀態前中斷是關的，
                      離開的時候中斷也是關的。
方法三：通過保存中斷狀態來開關中斷，你保存關中斷標志在局部變量cpu_sr
                      中，變量由ucos調用時需要關中斷，你將要通過復制變量到CPU狀態寄存器
                      再次裝載關中斷狀態
*********************************************************************************************************
*/
#define  OS_CRITICAL_METHOD    2


#define  OS_ENTER_CRITICAL()  asm {PUSHF; CLI}  /* Disable interrupts                        *///關中斷
#define  OS_EXIT_CRITICAL()   asm  POPF      /* Enable  interrupts                        *///開中斷

/*
*********************************************************************************************************
*                           Intel 80x86 (Real-Mode, Large Model) Miscellaneous
*********************************************************************************************************
*/

#define  OS_STK_GROWTH        1   /* Stack grows from HIGH to LOW memory on 80x86  */
//堆棧從高到低存儲

#define  uCOS                 0x80    /* Interrupt vector # used for context switch    */
//中斷向量，用于任務轉換

#define  OS_TASK_SW() asm  INT   uCOS

/*
*********************************************************************************************************
*                                            GLOBAL VARIABLES
                                                    全局變量
*********************************************************************************************************
*/

OS_CPU_EXT  INT8U  OSTickDOSCtr;       /* Counter used to invoke DOS's tick handler every 'n' ticks    */
//每N個節拍調用DOS的時鐘處理器的計數器

/*
*********************************************************************************************************
*                                          FUNCTION PROTOTYPES
*********************************************************************************************************
*/

void       OSFPInit(void);//浮點處理單元初始化
void       OSFPRestore(void *pblk);//裝載浮點處理單元
void       OSFPSave(void *pblk);//保存浮點處理單元