本文是 zynq 7000 AMP模式 双裸核CPU同时运行 的继续。本文主要是上文的基础上增加通过共享内存的方式，演示2个裸核的交互。

共享内存前先看看内存地址分布，这个图取自 ug585 4.1 节 address map 的表4-1

本文定义OCM  为共享内存，地址为0xffff_0000。 

在2个文件的头部都这样定义共享内存

#include "xil_mmu.h"
#define COM_VAL (*(volatile unsigned int*)(0xffff0000))
#define COM_VAL1 (*(volatile unsigned int*)(0xffff0004))

在程序中定义0xffff0000 这段内存没有cache，防止写在cache ，另一方看不到。同时初始化变量为0，代码如下：

Xil_SetTlbAttributes(0xffff0000,0x14de2);
	COM_VAL=0;
	COM_VAL1=0;

在cpu0 中（helloworld工程中）COM_VAL=i， 在cpu1 中显示这个数据

printf("led=%x, cpu0 count=%d\n\r",1<<Ledwidth,COM_VAL);

在cpu1 中 COM_VAL1=1<<Ledwidth; 在cpu0 中显示 

printf("%d: Hello World! led=%d\n\r",i,COM_VAL1);

2个完整的程序分别是：

cpu0（helloworld 工程）中程序代码

#include <stdio.h>
#include "xil_printf.h"
#include "sleep.h"
#include "xil_mmu.h"
#define COM_VAL (*(volatile unsigned int*)(0xffff0000))
#define COM_VAL1 (*(volatile unsigned int*)(0xffff0004))
int main()
{
    int i=0;
    Xil_SetTlbAttributes(0xffff0000,0x14de2);
    COM_VAL=0;
    COM_VAL1=0;
    while (1)
    {
    	i++;
    	COM_VAL=i;
      printf("%d: Hello World! led=%d\n\r",i,COM_VAL1);
      sleep(2);
    }
    return 0;
}

cpu1 中程序代码

#include <stdio.h>
#include "platform.h"
#include "xil_printf.h"
#include "xparameters.h"
#include "xil_io.h"
#include "sleep.h"
#define MY_IP 0x41200000

#include "xil_mmu.h"
#define COM_VAL (*(volatile unsigned int*)(0xffff0000))
#define COM_VAL1 (*(volatile unsigned int*)(0xffff0004))

int main()
{
	u32 Ledwidth;
	Xil_SetTlbAttributes(0xffff0000,0x14de2);
	COM_VAL=0;
	COM_VAL1=0;
    while (1)
    	{
    	for (Ledwidth = 0x0; Ledwidth < 4; Ledwidth++)
    		{
    		  Xil_Out32(MY_IP,1 << Ledwidth);
    		  COM_VAL1=1<<Ledwidth;
    		  printf("led=%x, cpu0 count=%d\n\r",1<<Ledwidth,COM_VAL);
    		  sleep(1);
    		}
       	}
    return 0;
}

按照上文介绍的方法调试(debug) 运行，结果如下：

。。。

led=1, cpu0 count=1317
led=2, cpu0 count=1317
1318: Hello World! led=2
led=4, cpu0 count=1318
led=8, cpu0 count=1318
1319: Hello World! led=8
led=1, cpu0 count=1319
led=2, cpu0 count=1319
1320: Hello World! led=2
led=4, cpu0 count=1320
led=8, cpu0 count=1320
1321: Hello World! led=8
led=1, cpu0 count=1321
led=2, cpu0 count=1321
1322: Hello World! led=2
led=4, cpu0 count=1322
led=8, cpu0 count=1322
1323: Hello World! led=8
led=1, cpu0 count=1323
led=2, cpu0 count=1323
1324: Hello World! led=2
led=4, cpu0 count=1324
led=8, cpu0 count=1324
1325: Hello World! led=8

可以看到数据通过共享内存在cpu0 和cpu1 间交互了。介绍结束。