s5pv210 汇编开栈 C语言流水灯

makefile

final.bin: start.o led.o
    arm-linux-ld -Ttext 0x0 -o start.elf $^
    arm-linux-objcopy -O binary start.elf final.bin
    
%.o : %.S
    arm-linux-gcc -o $@ $< -c -nostdlib    //不连接系统标准启动文件和标准库文件,只把指定的文件传递给连接器

%.o : %.c
    arm-linux-gcc -o $@ $< -c -nostdlib

clean:
    rm *.o *.elf *.bin   -f

 

start.S

#define WTCON        0xE2700000
#define SVC_STACK    0xd0037d80

.global _start
_start:

    // 第1步:关看门狗(向WTCON的bit5写入0即可)
    ldr r0, =WTCON
    ldr r1, =0x0
    str r1, [r0]
    
    // 第2步:设置SVC栈    满减栈,满的意思是入栈先移动指针再填入数据,减的意思是栈从高到低用
    ldr sp, =SVC_STACK
    
    // 第3步:开/关icache
    mrc p15,0,r0,c1,c0,0;            // 读出cp15的c1到r0中  mrc和mcr是协处理器的相关汇编指令
    //bic r0, r0, #(1<<12)            // bit12 置0  关icache
    orr r0, r0, #(1<<12)            // bit12 置1  开icache
    mcr p15,0,r0,c1,c0,0;
    
    
    bl led_blink        //跳转到C语言函数
    
    b .

 

led.c

#define GPJ0CON        0xE0200240
#define GPJ0DAT        0xE0200244
void delay(void)
{
    unsigned int cnt = 900000;
    while(cnt)
    {
        cnt--;
    }
}

void led_blink(void)
{
    unsigned int *p1 = (unsigned int *)GPJ0CON;
    unsigned int *p2 = (unsigned int *)GPJ0DAT;
    *p1 = 0x11111111;
    
    while(1)
    {
        *p2 = ~(1<<3);
        delay();
        *p2 = ~(1<<4);
        delay();
        *p2 = ~(1<<5);
        delay(); 
    }  
}

 

上一篇:STM32 RTTHREAD线程编写知识


下一篇:python中出现 IndentationError:unindent does not match any outer indentation level