/*
*********************************************************************************************************
*                                                uC/OS-II
*                                          The Real-Time Kernel
*
*
*                              (c) Copyright 2010; Micrium, Inc.; Weston, FL
*                    All rights reserved.  Protected by international copyright laws.
*
*                                           ARM Cortex-M4 Port
*
* File      : OS_CPU.H
* Version   : V2.92
* By        : JJL
*
* LICENSING TERMS:
* ---------------
*           uC/OS-II is provided in source form for FREE short-term evaluation, for educational use or 
*           for peaceful research.  If you plan or intend to use uC/OS-II in a commercial application/
*           product then, you need to contact Micrium to properly license uC/OS-II for its use in your 
*           application/product.   We provide ALL the source code for your convenience and to help you 
*           experience uC/OS-II.  The fact that the source is provided does NOT mean that you can use 
*           it commercially without paying a licensing fee.
*
*           Knowledge of the source code may NOT be used to develop a similar product.
*
*           Please help us continue to provide the embedded community with the finest software available.
*           Your honesty is greatly appreciated.
*
*           You can contact us at www.micrium.com, or by phone at +1 (954) 217-2036.
*
* For       : ARMv7 Cortex-M4
* Mode      : Thumb-2 ISA
* Toolchain : IAR EWARM
*********************************************************************************************************
*/

#ifndef  OS_CPU_H
#define  OS_CPU_H

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

#ifndef  OS_CPU_EXCEPT_STK_SIZE
#define  OS_CPU_EXCEPT_STK_SIZE    128u          /* Default exception stack size is 128 OS_STK entries */
#endif

/*
*********************************************************************************************************
*                                               DEFINES
*********************************************************************************************************
*/

#ifdef __ARMVFP__
#define  OS_CPU_ARM_FP_EN                                 1u
#else
#define  OS_CPU_ARM_FP_EN                                 0u
#endif

/*
*********************************************************************************************************
*                              OS TICK INTERRUPT PRIORITY CONFIGURATION
*
* Note(s) : (1) For systems that don't need any high, real-time priority interrupts; the tick interrupt
*               should be configured as the highest priority interrupt but won't adversely affect system
*               operations.
*
*           (2) For systems that need one or more high, real-time interrupts; these should be configured
*               higher than the tick interrupt which MAY delay execution of the tick interrupt.
*
*               (a) If the higher priority interrupts do NOT continually consume CPU cycles but only
*                   occasionally delay tick interrupts, then the real-time interrupts can successfully
*                   handle their intermittent/periodic events with the system not losing tick interrupts
*                   but only increasing the jitter.
*
*               (b) If the higher priority interrupts consume enough CPU cycles to continually delay the
*                   tick interrupt, then the CPU/system is most likely over-burdened & can't be expected
*                   to handle all its interrupts/tasks. The system time reference gets compromised as a
*                   result of losing tick interrupts.
*********************************************************************************************************
*/

#define  OS_CPU_CFG_SYSTICK_PRIO           0u

/*
*********************************************************************************************************
*                                              DATA TYPES
*                                         (Compiler Specific)
*********************************************************************************************************
*/

typedef unsigned char  BOOLEAN;
typedef unsigned char  INT8U;                    /* Unsigned  8 bit quantity                           */
typedef signed   char  INT8S;                    /* Signed    8 bit quantity                           */
typedef unsigned short INT16U;                   /* Unsigned 16 bit quantity                           */
typedef signed   short INT16S;                   /* Signed   16 bit quantity                           */
typedef unsigned int   INT32U;                   /* Unsigned 32 bit quantity                           */
typedef signed   int   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 32-bit wide                    */
typedef unsigned int   OS_CPU_SR;                /* Define size of CPU status register (PSR = 32 bits) */

/*
*********************************************************************************************************
*                                              Cortex-M4
*                                      Critical Section Management
*
* 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.
*             NOT IMPLEMENTED
*
* 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.
*             NOT IMPLEMENTED
*
* 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.
*********************************************************************************************************
*/

#define  OS_CRITICAL_METHOD   3u

#if OS_CRITICAL_METHOD == 3u
#define  OS_ENTER_CRITICAL()  {cpu_sr = OS_CPU_SR_Save();}
#define  OS_EXIT_CRITICAL()   {OS_CPU_SR_Restore(cpu_sr);}
#endif

/*
*********************************************************************************************************
*                                        Cortex-M4 Miscellaneous
*********************************************************************************************************
*/

#define  OS_STK_GROWTH        1u                  /* Stack grows from HIGH to LOW memory on ARM        */

#define  OS_TASK_SW()         OSCtxSw()

/*
*********************************************************************************************************
*                                          GLOBAL VARIABLES
*********************************************************************************************************
*/

OS_CPU_EXT  OS_STK   OS_CPU_ExceptStk[OS_CPU_EXCEPT_STK_SIZE];
OS_CPU_EXT  OS_STK  *OS_CPU_ExceptStkBase;

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

#if OS_CRITICAL_METHOD == 3u                      /* See OS_CPU_A.ASM                                  */
OS_CPU_SR  OS_CPU_SR_Save(void);
void       OS_CPU_SR_Restore(OS_CPU_SR cpu_sr);
#endif

void  OSCtxSw              (void);
void  OSIntCtxSw           (void);
void  OSStartHighRdy       (void);

void  OS_CPU_PendSVHandler (void);

                                                  /* See OS_CPU_C.C                                    */
void  OS_CPU_SysTickHandler(void);
void  OS_CPU_SysTickInit   (INT32U  cnts);

#if (OS_CPU_ARM_FP_EN > 0u)
void  OS_CPU_FP_Reg_Push   (OS_STK    *stkPtr);
void  OS_CPU_FP_Reg_Pop    (OS_STK    *stkPtr);
#endif
#endif
