13

如何添加ctr0.o？

我收到此错误：

yagarto-4.7.2/bin/arm-none-eabi-ld: cannot find crt0.o: No such file or directory
collect2: error: ld returned 1 exit status`

从这里编译非常简单的程序时：

/* -- first.s */
/* This is a comment */
.global main /* 'main' is our entry point and must be global */
.func main   /* 'main' is a function */

main:          /* This is main */
    mov r0, #2 /* Put a 2 inside the register r0 */
    bx lr      /* Return from main */

我已经看过这 2 个线程，但没有得到任何完整而直接的答案：

  1. http://www.raspberrypi.org/phpBB3/viewtopic.php?t=50046
  2. 从 gcc4.7.x 中删除 crt0.o 的基本原理是什么？

我有这些文件，crt0和crtn有什么区别不能用吗？

./yagarto-4.7.2/lib/gcc/arm-none-eabi/4.7.2/crtbegin.o
./yagarto-4.7.2/lib/gcc/arm-none-eabi/4.7.2/crtend.o
./yagarto-4.7.2/lib/gcc/arm-none-eabi/4.7.2/crti.o
./yagarto-4.7.2/lib/gcc/arm-none-eabi/4.7.2/crtn.o
./yagarto-4.7.2/lib/gcc/arm-none-eabi/4.7.2/thumb/crtbegin.o
./yagarto-4.7.2/lib/gcc/arm-none-eabi/4.7.2/thumb/crtend.o
./yagarto-4.7.2/lib/gcc/arm-none-eabi/4.7.2/thumb/crti.o
./yagarto-4.7.2/lib/gcc/arm-none-eabi/4.7.2/thumb/crtn.o
./yagarto-4.7.2/lib/gcc/arm-none-eabi/4.7.2/thumb/v6m/crtbegin.o
./yagarto-4.7.2/lib/gcc/arm-none-eabi/4.7.2/thumb/v6m/crtend.o
./yagarto-4.7.2/lib/gcc/arm-none-eabi/4.7.2/thumb/v6m/crti.o
./yagarto-4.7.2/lib/gcc/arm-none-eabi/4.7.2/thumb/v6m/crtn.o
./yagarto-4.7.2/lib/gcc/arm-none-eabi/4.7.2/thumb/v7m/crtbegin.o
./yagarto-4.7.2/lib/gcc/arm-none-eabi/4.7.2/thumb/v7m/crtend.o
./yagarto-4.7.2/lib/gcc/arm-none-eabi/4.7.2/thumb/v7m/crti.o
./yagarto-4.7.2/lib/gcc/arm-none-eabi/4.7.2/thumb/v7m/crtn.o

SO解决方案提供了一个也不起作用的解决方法：

arm-none-eabi-gcc -o first assembler_tutorial/chapter01/first.o -nostartfiles
./yagarto-4.7.2/bin/arm-none-eabi-ld: warning: cannot find entry symbol _start; defaulting to 0000000000008000
4

2 回答 2

13

向量.s

.globl _start
_start:
    mov sp,#0x8000
    bl main
hang: b hang

电源

.globl main
main:
    mov r0,#2
    bx lr

memmap（链接描述文件）

MEMORY
{
    ram : ORIGIN = 0x8000, LENGTH = 0x10000
}
SECTIONS
{
    .text : { *(.text*) } > ram
    .bss : { *(.bss*) } > ram
}

命令

arm-none-eabi-as vectors.s -o vectors.o
arm-none-eabi-as main.s -o main.o
arm-none-eabi-ld vectors.o main.o -T memmap -o main.elf
arm-none-eabi-objdump -D main.elf > main.list
arm-none-eabi-objcopy main.elf -O binary main.bin

结果

main.elf:     file format elf32-littlearm


Disassembly of section .text:

00008000 <_start>:
    8000:   e3a0d902    mov sp, #32768  ; 0x8000
    8004:   eb000000    bl  800c <main>

00008008 <hang>:
    8008:   eafffffe    b   8008 <hang>

0000800c <main>:
    800c:   e3a00002    mov r0, #2
    8010:   e12fff1e    bx  lr

如果你想使用 C 而不是 asm 作为 main 然后

主程序

int main ( void )
{
    return(2);
}

命令

arm-none-eabi-as vectors.s -o vectors.o
arm-none-eabi-gcc -Wall -Werror -O2 -nostdlib -nostartfiles -ffreestanding -c main.c -o main.o
arm-none-eabi-ld vectors.o main.o -T memmap -o main.elf
arm-none-eabi-objdump -D main.elf > main.list
arm-none-eabi-objcopy main.elf -O binary main.bin

结果

main.elf:     file format elf32-littlearm


Disassembly of section .text:

00008000 <_start>:
    8000:   e3a0d902    mov sp, #32768  ; 0x8000
    8004:   eb000000    bl  800c <main>

00008008 <hang>:
    8008:   eafffffe    b   8008 <hang>

0000800c <main>:
    800c:   e3a00002    mov r0, #2
    8010:   e12fff1e    bx  lr

我更喜欢使用除 main 之外的函数名，因为某些编译器在看到该函数名时会添加额外的包袱。

向量.s

.globl _start
_start:
    mov sp,#0x8000
    bl notmain
hang: b hang

主程序

int notmain ( void )
{
    return(2);
}

结果

main.elf:     file format elf32-littlearm


Disassembly of section .text:

00008000 <_start>:
    8000:   e3a0d902    mov sp, #32768  ; 0x8000
    8004:   eb000000    bl  800c <notmain>

00008008 <hang>:
    8008:   eafffffe    b   8008 <hang>

0000800c <notmain>:
    800c:   e3a00002    mov r0, #2
    8010:   e12fff1e    bx  lr
于 2013-08-24T13:16:50.760 回答
0

I had the same problem with trying to compile for STM32F4xx (Cortex M4).

I ditched Yagarto and switched to using GNU Tools ARM Embedded - toolchain (4.8_2014q2):

https://launchpad.net/gcc-arm-embedded

Seems to work for me.

于 2014-08-24T13:47:35.083 回答