最近在看嵌入式C编程时，用到GCC编译器的IDE直接在链接器脚本文件中定义变量， 一开始有些摸不着头脑，毕竟不经常使用这种GCC编译器的IDE，在网上查到相关资料。具体原文链接如下：
STM32中的链接器脚本文件(.ld文件)
摘要部分内容如下: 一、链接器脚本文件.ld文件的作用
设置堆空间大小、栈空间大小、然后根据应用的请求设置栈的位置如果使用了外部内存，则设置内存块的区域和大小
二、 .ld文件讲解
/* Entry Point */
ENTRY(Reset_Handler)
//1、设置了用户ram的最高地址
/* Highest address of the user mode stack */
_estack = 0x20020000; /* end of RAM */
//2、设置用户栈空间以及堆空间的大小
/* Generate a link error if heap and stack don't fit into RAM */
_Min_Heap_Size = 0x4000; /* required amount of heap */
_Min_Stack_Size = 0x1000; /* required amount of stack */
//3、指定了RAM与ROM的起始地址，以及大小
/* Specify the memory areas */
MEMORY
{
RAM (xrw) : ORIGIN = 0x20000000, LENGTH = 128K
CCMRAM (rw) : ORIGIN = 0x10000000, LENGTH = 64K
FLASH (rx) : ORIGIN = 0x8000000, LENGTH = 1024K
}
//4、将相关内容放到对应段中
/* Define output sections */
SECTIONS
{
//中断向量表放在.isr_vector段中
/* The startup code goes first into FLASH */
.isr_vector :
{
. = ALIGN(4);
KEEP(*(.isr_vector)) /* Startup code */
. = ALIGN(4);
} >FLASH
//程序代码和其他部分数据存放在.text段中
/* The program code and other data goes into FLASH */
.text :
{
. = ALIGN(4);
*(.text) /* .text sections (code) */
*(.text*) /* .text* sections (code) */
*(.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
//.rodata 存放常量(只读数据)
/* Constant data goes into FLASH */
.rodata :
{
. = ALIGN(4);
*(.rodata) /* .rodata sections (constants, strings, etc.) */
*(.rodata*) /* .rodata* sections (constants, strings, etc.) */
. = ALIGN(4);
} >FLASH
.ARM.extab : { *(.ARM.extab* .gnu.linkonce.armextab.*) } >FLASH
.ARM : {
__exidx_start = .;
*(.ARM.exidx*)
__exidx_end = .;
} >FLASH
//.preinit_array 和 .init_array 保存程序或共享对象加载时的初始化函数指针
.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 保存程序或共享对象退出时的退出函数地址
.fini_array :
{
PROVIDE_HIDDEN (__fini_array_start = .);
KEEP (*(SORT(.fini_array.*)))
KEEP (*(.fini_array*))
PROVIDE_HIDDEN (__fini_array_end = .);
} >FLASH
/* used by the startup to initialize data */
_sidata = LOADADDR(.data);
//.data 存放了经过初始化的全局变量和静态变量
/* Initialized data sections goes into RAM, load LMA copy after code */
.data :
{
. = 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 AT> FLASH
_siccmram = LOADADDR(.ccmram);
/* CCM-RAM section
*
* IMPORTANT NOTE!
* If initialized variables will be placed in this section,
* the startup code needs to be modified to copy the init-values.
*/
//.ccmram 是STM32中只允许内核访问的空间，可以将一些内核放在这里使用
.ccmram :
{
. = ALIGN(4);
_sccmram = .; /* create a global symbol at ccmram start */
*(.ccmram)
*(.ccmram*)
. = ALIGN(4);
_eccmram = .; /* create a global symbol at ccmram end */
} >CCMRAM AT> FLASH
//.bss 保存了那些用到但未被初始化的数据
/* 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
//._user_heap_stack 用户的堆栈段
/* User_heap_stack section, used to check that there is enough RAM left */
._user_heap_stack :
{
. = ALIGN(4);
PROVIDE ( end = . );
PROVIDE ( _end = . );
. = . + _Min_Heap_Size;
. = . + _Min_Stack_Size;
. = ALIGN(4);
} >RAM
/* Remove information from the standard libraries */
/DISCARD/ :
{
libc.a ( * )
libm.a ( * )
libgcc.a ( * )
}
.ARM.attributes 0 : { *(.ARM.attributes) }
}