uCOS-II在ARM上的移植（1）

平台：

CentOS 5.4

arm-linux-gcc 3.4.1

uC/OS V2.52

CPU：s3c2410（arm9）

 

要使uC/OS-II正常运行，处理器必须满足以下要求：

（1）处理器的C编译器能产生可重入型代码；

（2）处理器支持中断，并且能产生定时中断（通常10-100Hz）；

（3）用C语言可以开/关中断；

（4）处理器能支持一定数量的数据存储硬件堆栈（可能是几千字节）；

（5）处理器有将堆栈指针以及其他CPU寄存器的内容读出、并存储到堆栈或内存中去的指令。

 

 

为了移植uC/OS-II，需要提供几个文件：

os_cpu.h

os_cpu_a.S

os_cpu_c.c

os_cfg.h

includes.h

 

1、os_cpu.h

主要包括与编译器有关的数据类型定义；

处理器开关中断函数定义

堆栈方向定义；

任务切换函数定义；

其他函数声明。

 

//全局变量定义

#ifndef __OS_CPU_H__
#define __OS_CPU_H__

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

 

typedef unsigned char  BOOLEAN;
typedef unsigned char  INT8U;

typedef signed   char  INT8S;
typedef unsigned int   INT16U;
typedef signed   int   INT16S;
typedef unsigned long  INT32U;
typedef signed   long  INT32S;
typedef float          FP32;
typedef double         FP64;

typedef unsigned int   OS_STK;    //堆栈入口宽度16位
typedef unsigned int   OS_CPU_SR; //CPU状态寄存器的宽度16位

 

#define BYTE           INT8S      //与1.x版兼容

#define UBYTE          INT8U
#define WORD           INT16S
#define UWORD          INT16U
#define LONG           INT32S
#define ULONG          INT32U

 

/*
*                              ARM
*
* 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.
*
*/

#define OS_CRITICAL_METHOD 3 //我们使用方式3

#if      OS_CRITICAL_METHOD == 3
#define  OS_ENTER_CRITICAL()  (cpu_sr = OSCPUSaveSR())    /* Disable interrupts                        */
#define  OS_EXIT_CRITICAL()   (OSCPURestoreSR(cpu_sr))    /* Restore  interrupts                       */
#endif

 

#define  OS_STK_GROWTH        1 /* 堆栈：向下递减 */

#define  OS_TASK_SW()         OSCtxSw() //任务切换函数定义

 

//其他函数声明

void UCOS_IRQHandler(void);
void OSCtxSw(void);
void OSIntCtxSw(void);

#if OS_CRITICAL_METHOD == 3 /* Allocate storage for CPU status register           */
OS_CPU_SR  OSCPUSaveSR(void);
void       OSCPURestoreSR(OS_CPU_SR cpu_sr);
#endif