keil 中添加gcc编译 stmf207

一、安装下载arm-gcc 编译器：

二、在keil中配置gcc：

三、配置工程选项

        1.配置gcc编译规则：

Misc Controls :  -mcpu=cortex-m3 -mthumb -fdata-sections -ffunction-sections
注：
1.这里我用的cortex-m3，如果你是m4内核就改成4)
2.-mthumb的意义是：使用这个编译选项生成的目标文件是Thumb的
3.-fdata-sections和-ffunction-sections （-ffunction-sections 和 -fdata-sections 将每个函数或符号创建为一个sections，其中每个sections名与function或data名保持一致）

        2.配置汇编规则：

Misc Controls : -mcpu=cortex-m3 -mthumb

        3配置链接规则：

这里要添加链接脚本，一般可以在官方提供的固件库包找到类似的（链接规则）

Misc Controls : -Wl,--gc-sections
注：
1.-wl, 表示后面的参数 --gc-sections 传递给链接器（ -Wl,--gc-sections 指示链接器去掉不用的section（其中-wl, 表示后面的参数 --gc-sections 传递给链接器），这样就能减少最终的可执行程序的大小了。）

4.找到适合自己芯片的链接文件（在官方例程有）：

其内容：

/*
*****************************************************************************
**
**  File        : stm32_flash.ld
**
**  Abstract    : Linker script for STM32F207IG Device with
**                1MByte FLASH, 128KByte SRAM
**
**                Set heap size, stack size and stack location according
**                to application requirements.
**
**                Set memory bank area and size if external memory is used.
**
**  Target      : STMicroelectronics STM32
**
**  Environment : Atollic TrueSTUDIO(R)
**
**  Distribution: The file is distributed “as is,” without any warranty
**                of any kind.
**
**  (c)Copyright Atollic AB.
**  You may use this file as-is or modify it according to the needs of your
**  project. Distribution of this file (unmodified or modified) is not
**  permitted. Atollic AB permit registered Atollic TrueSTUDIO(R) users the
**  rights to distribute the assembled, compiled & linked contents of this
**  file as part of an application binary file, provided that it is built
**  using the Atollic TrueSTUDIO(R) toolchain.
**
*****************************************************************************
*/

/* Entry Point */
ENTRY(Reset_Handler)

/* Highest address of the user mode stack */
_estack = 0x20020000;    /* end of 128K SRAM */

/* Generate a link error if heap and stack don't fit into RAM */
_Min_Heap_Size = 0;      /* required amount of heap  */
_Min_Stack_Size = 0x200; /* required amount of stack */

/* Specify the memory areas */
MEMORY
{
  FLASH (rx)      : ORIGIN = 0x08000000, LENGTH = 1024K
  RAM (xrw)       : ORIGIN = 0x20000000, LENGTH = 128K
  MEMORY_B1 (rx)  : ORIGIN = 0x60000000, LENGTH = 0K
}

/* Define output sections */
SECTIONS
{
  /* The startup code goes first into FLASH */
  .isr_vector :
  {
    . = ALIGN(4);
    KEEP(*(.isr_vector)) /* Startup code */
    . = ALIGN(4);
  } >FLASH

  /* The program code and other data goes into FLASH */
  .text :
  {
    . = ALIGN(4);
    *(.text)           /* .text sections (code) */
    *(.text*)          /* .text* sections (code) */
    *(.rodata)         /* .rodata sections (constants, strings, etc.) */
    *(.rodata*)        /* .rodata* sections (constants, strings, etc.) */
    *(.glue_7)         /* glue arm to thumb code */
    *(.glue_7t)        /* glue thumb to arm code */
    *(.eh_frame)

    KEEP (*(.init))
    KEEP (*(.fini))

    . = ALIGN(4);
    _etext = .;        /* define a global symbols at end of code */
  } >FLASH

   .ARM.extab   : { *(.ARM.extab* .gnu.linkonce.armextab.*) } >FLASH
    .ARM : {
    __exidx_start = .;
      *(.ARM.exidx*)
      __exidx_end = .;
    } >FLASH

  .preinit_array     :
  {
    PROVIDE_HIDDEN (__preinit_array_start = .);
    KEEP (*(.preinit_array*))
    PROVIDE_HIDDEN (__preinit_array_end = .);
  } >FLASH
  .init_array :
  {
    PROVIDE_HIDDEN (__init_array_start = .);
    KEEP (*(SORT(.init_array.*)))
    KEEP (*(.init_array*))
    PROVIDE_HIDDEN (__init_array_end = .);
  } >FLASH
  .fini_array :
  {
    PROVIDE_HIDDEN (__fini_array_start = .);
    KEEP (*(.fini_array*))
    KEEP (*(SORT(.fini_array.*)))
    PROVIDE_HIDDEN (__fini_array_end = .);
  } >FLASH

  /* used by the startup to initialize data */
  _sidata = .;

  /* Initialized data sections goes into RAM, load LMA copy after code */
  .data : AT ( _sidata )
  {
    . = ALIGN(4);
    _sdata = .;        /* create a global symbol at data start */
    *(.data)           /* .data sections */
    *(.data*)          /* .data* sections */

    . = ALIGN(4);
    _edata = .;        /* define a global symbol at data end */
  } >RAM

  /* Uninitialized data section */
  . = ALIGN(4);
  .bss :
  {
    /* This is used by the startup in order to initialize the .bss secion */
    _sbss = .;         /* define a global symbol at bss start */
    __bss_start__ = _sbss;
    *(.bss)
    *(.bss*)
    *(COMMON)

    . = ALIGN(4);
    _ebss = .;         /* define a global symbol at bss end */
    __bss_end__ = _ebss;
  } >RAM

  PROVIDE ( end = _ebss );
  PROVIDE ( _end = _ebss );

  /* User_heap_stack section, used to check that there is enough RAM left */
  ._user_heap_stack :
  {
    . = ALIGN(4);
    . = . + _Min_Heap_Size;
    . = . + _Min_Stack_Size;
    . = ALIGN(4);
  } >RAM

  /* MEMORY_bank1 section, code must be located here explicitly            */
  /* Example: extern int foo(void) __attribute__ ((section (".mb1text"))); */
  .memory_b1_text :
  {
    *(.mb1text)        /* .mb1text sections (code) */
    *(.mb1text*)       /* .mb1text* sections (code)  */
    *(.mb1rodata)      /* read-only data (constants) */
    *(.mb1rodata*)
  } >MEMORY_B1

  /* Remove information from the standard libraries */
  /DISCARD/ :
  {
    libc.a ( * )
    libm.a ( * )
    libgcc.a ( * )
  }

  .ARM.attributes 0 : { *(.ARM.attributes) }
}
 

注意：

编译报错

ld.exe: section .ARM.exidx LMA [08009914,0800991b] overlaps section .data LMA [08009914,08009fe3]

/* 添加.ARM.exidx段 */
.ARM.exidx : {
. = ALIGN(4);
*(.ARM.exidx* .gnu.linkonce.armexidx.*)
. = ALIGN(4);
} >FLASH

能解决报错问题，运行不了程序（需要找到自己的链接文件）

四、启动代码,使用GCC专用的.S文件

使用GCC编译器需要的启动代码不同与AMRCC，不过官方已经有提供了相关代码，如下图：

五、解决编译报错:

sbrkr.c:(.text._sbrk_r+0xc): undefined reference to `_sbrk'

添加 syscall.c

/**
*****************************************************************************
**
**  File        : syscalls.c
**
**  Abstract    : System Workbench Minimal System calls file
**
**                   For more information about which c-functions
**                need which of these lowlevel functions
**                please consult the Newlib libc-manual
**
**  Environment : System Workbench for MCU
**
**  Distribution: The file is distributed ¡°as is,¡± without any warranty
**                of any kind.
**
**  (c)Copyright System Workbench for MCU.
**  You may use this file as-is or modify it according to the needs of your
**  project. Distribution of this file (unmodified or modified) is not
**  permitted. System Workbench for MCU permit registered System Workbench(R) users the
**  rights to distribute the assembled, compiled & linked contents of this
**  file as part of an application binary file, provided that it is built
**  using the System Workbench for MCU toolchain.
**
*****************************************************************************
*/

/* Includes */
#include <sys/stat.h>
#include <stdlib.h>
#include <errno.h>
#include <stdio.h>
#include <signal.h>
#include <time.h>
#include <sys/time.h>
#include <sys/times.h>

/* Variables */
//#undef errno
extern int errno;
extern int __io_putchar(int ch) __attribute__((weak));
extern int __io_getchar(void) __attribute__((weak));

register char * stack_ptr asm("sp");

char *__env[1] = { 0 };
char **environ = __env;

/* Functions */
void initialise_monitor_handles()
{
}

int _getpid(void)
{
    return 1;
}

int _kill(int pid, int sig)
{
    errno = EINVAL;
    return -1;
}

void _exit (int status)
{
    _kill(status, -1);
    while (1) {}        /* Make sure we hang here */
}

int _read (int file, char *ptr, int len)
{
    int DataIdx;

    for (DataIdx = 0; DataIdx < len; DataIdx++)
    {
        *ptr++ = __io_getchar();
    }

return len;
}

int _write(int file, char *ptr, int len)
{
    int DataIdx;

    for (DataIdx = 0; DataIdx < len; DataIdx++)
    {
        __io_putchar(*ptr++);
    }
    return len;
}

caddr_t _sbrk(int incr)
{
    extern char end asm("end");
    static char *heap_end;
    char *prev_heap_end;

    if (heap_end == 0)
        heap_end = &end;

    prev_heap_end = heap_end;
    if (heap_end + incr > stack_ptr)
    {
//        write(1, "Heap and stack collision\n", 25);
//        abort();
        errno = ENOMEM;
        return (caddr_t) -1;
    }

    heap_end += incr;

    return (caddr_t) prev_heap_end;
}

int _close(int file)
{
    return -1;
}

int _fstat(int file, struct stat *st)
{
    st->st_mode = S_IFCHR;
    return 0;
}

int _isatty(int file)
{
    return 1;
}

int _lseek(int file, int ptr, int dir)
{
    return 0;
}

int _open(char *path, int flags, ...)
{
    /* Pretend like we always fail */
    return -1;
}

int _wait(int *status)
{
    errno = ECHILD;
    return -1;
}

int _unlink(char *name)
{
    errno = ENOENT;
    return -1;
}

int _times(struct tms *buf)
{
    return -1;
}

int _stat(char *file, struct stat *st)
{
    st->st_mode = S_IFCHR;
    return 0;
}

int _link(char *old, char *new)
{
    errno = EMLINK;
    return -1;
}

int _fork(void)
{
    errno = EAGAIN;
    return -1;
}

int _execve(char *name, char **argv, char **env)
{
    errno = ENOMEM;
    return -1;
}

编译通过，成功运行：