关于SDRAM指定地址空间分配使用的问题

youwei · 发表于 2021-11-1 11:14:27

1.首先ICF分配如下：
/*###ICF### Section handled by ICF editor, don't touch! ****/
/*-Editor annotation file-*/
/* IcfEditorFile="$TOOLKIT_DIR$\config\ide\IcfEditor\cortex_v1_0.xml" */
/*-Specials-*/
define symbol __ICFEDIT_intvec_start__ = 0x08020000;
/*-Memory Regions-*/
define symbol __ICFEDIT_region_ROM_start__ = 0x08020000;
define symbol __ICFEDIT_region_ROM_end__    = 0x081FFFFF;
define symbol __ICFEDIT_region_RAM_start__ = 0x20000000;
define symbol __ICFEDIT_region_RAM_end__    = 0x2004FFFF;
define symbol __ICFEDIT_region_CCMRAM_start__ = 0x10000000;
define symbol __ICFEDIT_region_CCMRAM_end__ = 0x1000FFFF;
define symbol __region_SDRAM_RAM_start__    = 0xC0000000;
define symbol __region_SDRAM_RAM_end__       = 0xCFFFFFFF;
/*define symbol __region_NORFLASH_RAM_start__ = 0x90000000;*/
/*define symbol __region_NORFLASH_RAM_end__ = 0x9FFFFFFF;*/
/*-Sizes-*/
define symbol __ICFEDIT_size_cstack__ = 0x400;
define symbol __ICFEDIT_size_heap__ = 0x200;
/**** End of ICF editor section. ###ICF###*/

define memory mem with size = 4G;
define region ROM_region    = mem:[from __ICFEDIT_region_ROM_start__    to __ICFEDIT_region_ROM_end__];
define region RAM_region    = mem:[from __ICFEDIT_region_RAM_start__    to __ICFEDIT_region_RAM_end__];
define region CCMRAM_region = mem:[from __ICFEDIT_region_CCMRAM_start__ to __ICFEDIT_region_CCMRAM_end__];
define region SDRAM_region = mem:[from __region_SDRAM_RAM_start__       to __region_SDRAM_RAM_end__];
/*define region NORFLASH_region = mem:[from __region_NORFLASH_RAM_start__    to __region_NORFLASH_RAM_end__];*/

define block CSTACK with alignment = 8, size = __ICFEDIT_size_cstack__ { };
define block HEAP    with alignment = 8, size = __ICFEDIT_size_heap__    { };

initialize by copy { readwrite };
do not initialize  { section .noinit };

place at address mem:__ICFEDIT_intvec_start__ { readonly section .intvec };

place in ROM_region       { readonly };
place in RAM_region       { readwrite,
                           block CSTACK, block HEAP };
place in SDRAM_region    { readwrite data section SDRAM };
/*place in NORFLASH_region { readwrite data section NORFLASH };*/

2.模拟情况如下：
2.1 首先有3个文件，a.c、 b.c和b.h文件
2.2 测试：
测试1：a.c内容如下：
#include <b.h>
main()
{
  for(int a=0;a<12;a++)
   buf[a] = 0;
}

b.c内容如下：
#include <b.h>
#pragma location=0xC0000000
__no_init int buf[12];

b.h内容如下：
#include <stdio.h>
#include <stdlib.h>
extern int buf[12];

测试结果：Error[Li005]: no definition for "buf" [referenced from D:\IarTest\Debug\Obj\main.o]

测试2：将测试1的b.c内容修改为
#include <b.h>
#pragma location=0xC0000000
int buf[12];

测试结果：通过

测试3：将测试1的b.c修改为
#include <b.h>
#pragma location=0xC0000000
__no_init int buf[12];
void test(void)
{
  for(int a=0;a<12;a++)
   buf[a] = 0;
}

测试结果：通过

问题：是什么原因导致测试1的编译不通过。具体内在原因是什么？