世界您好，裸机的BeagleBoard [英] Hello world, bare metal Beagleboard

问题描述

我试图让我的BeagleBoard-XM REV运行的'Hello World类型的程序。 C，通过调用C 看跌功能从组装。

I'm trying to get a 'hello world' type program running on my Beagleboard-xm rev. C, by calling a C puts function from assembly.

到目前为止，我一直在使用这个作为参考： http://wiki.osdev.org/ARM_Beagleboard

So far I've been using this as a reference: http://wiki.osdev.org/ARM_Beagleboard

下面是我到目前为止，但没有输出。

Here's what I have so far, but there's no output.

的hello.c

volatile unsigned int * const UART3DR = (unsigned int *)0x49020000;

void puts(const char *s) {
  while(*s != '\0') { 
    *UART3DR = (unsigned int)(*s); 
    s++; 
  }
}

void hello() {
  puts("Hello, Beagleboard!\n");
}

boot.asm

.global start
start:
   ldr sp, =stack_bottom
   bl hello
   b .

linker.ld

ENTRY(start)

MEMORY
{
    ram : ORIGIN = 0x80200000, LENGTH = 0x10000
}

SECTIONS
{
    .hello : { hello.o(.text) } > ram
    .text : { *(.text) } > ram
    .data : { *(.data) } > ram
    .bss : { *(.bss) } > ram
     . = . + 0x5000; /* 4kB of stack memory */
    stack_bottom = .;

}

的Makefile

ARMGNU = arm-linux-gnueabi

AOPS = --warn --fatal-warnings
COPS = -Wall -Werror -O2 -nostdlib -nostartfiles -ffreestanding

boot.bin: boot.asm
   $(ARMGNU)-as boot.asm -o boot.o
   $(ARMGNU)-gcc-4.6 -c $(COPS) hello.c -o hello.o
   $(ARMGNU)-ld -T linker.ld hello.o boot.o -o boot.elf
   $(ARMGNU)-objdump -D boot.elf > boot.list
   $(ARMGNU)-objcopy boot.elf -O srec boot.srec
   $(ARMGNU)-objcopy boot.elf -O binary boot.bin

只需使用ASM文件中像这样的作品。

Using just the asm file like this works.

.equ UART3.BASE,        0x49020000
start:
   ldr r0,=UART3.BASE
   mov r1,#'c'

下面是一些的BeagleBoard /小型机相关信息： http://paste.ubuntu.com/829072/

Here are some Beagleboard/minicom related info: http://paste.ubuntu.com/829072/

任何指针？ ：）

我也试过

void hello() {
  *UART3DR = 'c';
}

我使用的小型机，并通过了ymodem发送的文件，然后我试图与运行：

I'm using minicom and send the file via ymodem, then I try to run it with:

go 0x80200000

Minicom中

硬件和软件控制流程都关闭。

Hardware and software control flow in minicom are off.

推荐答案

这应该为你工作过。下面是一些code，我从回来的路上时，没有尝试，只是做一个肯定的BeagleBoard今晚挖出它编译，它在同一时间工作过...

that should have worked for you. Here is some code I dug up from way back when, did not try it on a beagleboard tonight just made sure it compiled, it had worked at one time...

的Startup.s：

startup.s:

    .code 32

.globl _start
_start:

    bl main
hang: b hang

.globl PUT32
PUT32:
    str r1,[r0]
    bx lr

.globl GET32
GET32:
    ldr r0,[r0]
    bx lr

hello.c的：

hello.c :

extern void PUT32 ( unsigned int, unsigned int );
extern unsigned int GET32 ( unsigned int );
void uart_send ( unsigned char x )
{
    while((GET32(0x49020014)&0x20)==0x00) continue;
    PUT32(0x49020000,x);
}
void hexstring ( unsigned int d )
{
    //unsigned int ra;
    unsigned int rb;
    unsigned int rc;

    rb=32;
    while(1)
    {
        rb-=4;
        rc=(d>>rb)&0xF;
        if(rc>9) rc+=0x37; else rc+=0x30;
        uart_send(rc);
        if(rb==0) break;
    }
    uart_send(0x0D);
    uart_send(0x0A);
}
int main ( void )
{
    hexstring(0x12345678);
    return(0);
}

MEMMAP（链接脚本）：

memmap (linker script):

MEMORY
{
    ram : ORIGIN = 0x82000000, LENGTH = 256K
}

SECTIONS
{
    ROM : { startup.o } > ram
}

的Makefile：

Makefile :

CROSS_COMPILE = arm-none-eabi

AOPS = --warn --fatal-warnings 
COPS = -Wall -Werror -O2 -nostdlib -nostartfiles -ffreestanding 

all : hello.bin

hello.bin : startup.o hello.o memmap
    $(CROSS_COMPILE)-ld startup.o hello.o -T memmap -o hello.elf  
    $(CROSS_COMPILE)-objdump -D hello.elf > hello.list
    $(CROSS_COMPILE)-objcopy hello.elf -O binary hello.bin

startup.o : startup.s
    $(CROSS_COMPILE)-as $(AOPS) startup.s -o startup.o

hello.o : hello.c 
    $(CROSS_COMPILE)-gcc -c $(COPS) hello.c -o hello.o

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

看起来像我刚离开堆栈指针的地方引导程序有它。同样，如你，承担了引导程序已经初始化串口。

Looks like I just left the stack pointer wherever the bootloader had it. Likewise, as you, assumed the bootloader had initialized the serial port.

我假设你有串行端口访问的工作，你看uboot的，你可以以下载这个程序（XMODEM，或其他）进入议会RAM中输入命令？如果你不能做到这一点则可能是您没有连接到串口的权利。在beagleboards串口扭曲，可能需要使自己的电缆。

I assume you have serial port access working, you see uboot and you are able to type commands in order to download this program (xmodem, or whatever) into the boards ram? If you cant do that then it may be you are not connected to the serial port right. the beagleboards serial port is screwy, might need to make your own cable.

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