2022-09-26 08:03 PM
The optimization options for GCC compilation are: Optimize for size(-Os),The compiled result is as follows:
The size of MCU Flash resources occupied is: text+data = 47264 Byte
The.ld link script is shown below:
Question: In my program, the.data segment data (initialized variable) can not be 15K, in theory only 0x44 bytes size, this can be seen from the map file, as shown below:
I compiled the same project program using Keil and everything worked fine. What is the problem with me, or the GCC compiler?
Thanks.
Below is the complete linked script file.
/*
******************************************************************************
**
** @file : LinkerScript.ld
**
** @author : Auto-generated by STM32CubeIDE
**
** @brief : Linker script for STM32L451CEUx Device from STM32L4 series
** 512Kbytes FLASH
** 160Kbytes RAM
** 32Kbytes RAM2
**
** 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
**
** Distribution: The file is distributed as is, without any warranty
** of any kind.
**
******************************************************************************
** @attention
**
** Copyright (c) 2022 STMicroelectronics.
** All rights reserved.
**
** This software is licensed under terms that can be found in the LICENSE file
** in the root directory of this software component.
** If no LICENSE file comes with this software, it is provided AS-IS.
**
******************************************************************************
*/
/* Entry Point */
ENTRY(Reset_Handler)
/* Highest address of the user mode stack */
_estack = ORIGIN(RAM) + LENGTH(RAM); /* end of "RAM" Ram type memory */
_Min_Heap_Size = 0x200; /* required amount of heap */
_Min_Stack_Size = 0x400; /* required amount of stack */
_RAM2_START_ADDR = 0x10000000;
_RAM2_Size = 32K - 4;
_RAM2_BOOT_START_ADDR = 0x10000000 + _RAM2_Size;
/* Memories definition */
MEMORY
{
RAM (xrw) : ORIGIN = 0x20000000, LENGTH = 128K
RAM2 (xrw) : ORIGIN = _RAM2_START_ADDR, LENGTH = _RAM2_Size
RAM2_BOOT (xrw) : ORIGIN = _RAM2_BOOT_START_ADDR, LENGTH = 4
FLASH (rx) : ORIGIN = 0x8008000, LENGTH = 80K
}
/* Sections */
SECTIONS
{
/* The startup code into "FLASH" Rom type memory */
.isr_vector :
{
. = ALIGN(4);
KEEP(*(.isr_vector)) /* Startup code */
. = ALIGN(4);
} >FLASH
/* The program code and other data into "FLASH" Rom type memory */
.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
/* Constant data into "FLASH" Rom type memory */
.rodata :
{
. = ALIGN(4);
*(.rodata) /* .rodata sections (constants, strings, etc.) */
*(.rodata*) /* .rodata* sections (constants, strings, etc.) */
. = ALIGN(4);
} >FLASH
.ARM.extab : {
. = ALIGN(4);
*(.ARM.extab* .gnu.linkonce.armextab.*)
. = ALIGN(4);
} >FLASH
.ARM : {
. = ALIGN(4);
__exidx_start = .;
*(.ARM.exidx*)
__exidx_end = .;
. = ALIGN(4);
} >FLASH
.preinit_array :
{
. = ALIGN(4);
PROVIDE_HIDDEN (__preinit_array_start = .);
KEEP (*(.preinit_array*))
PROVIDE_HIDDEN (__preinit_array_end = .);
. = ALIGN(4);
} >FLASH
.init_array :
{
. = ALIGN(4);
PROVIDE_HIDDEN (__init_array_start = .);
KEEP (*(SORT(.init_array.*)))
KEEP (*(.init_array*))
PROVIDE_HIDDEN (__init_array_end = .);
. = ALIGN(4);
} >FLASH
.fini_array :
{
. = ALIGN(4);
PROVIDE_HIDDEN (__fini_array_start = .);
KEEP (*(SORT(.fini_array.*)))
KEEP (*(.fini_array*))
PROVIDE_HIDDEN (__fini_array_end = .);
. = ALIGN(4);
} >FLASH
/* Used by the startup to initialize data */
_sidata = LOADADDR(.data);
/* Initialized data sections into "RAM" Ram type memory */
.data :
{
. = ALIGN(4);
_sdata = .; /* create a global symbol at data start */
*(.data) /* .data sections */
*(.data*) /* .data* sections */
*(.RamFunc) /* .RamFunc sections */
*(.RamFunc*) /* .RamFunc* sections */
. = ALIGN(4);
_edata = .; /* define a global symbol at data end */
} >RAM AT> FLASH
/* Uninitialized data section into "RAM" Ram type memory */
. = ALIGN(4);
.bss :
{
/* This is used by the startup in order to initialize the .bss section */
_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 section, used to check that there is enough "RAM" Ram type memory left */
._user_heap_stack :
{
. = ALIGN(8);
PROVIDE ( end = . );
PROVIDE ( _end = . );
. = . + _Min_Heap_Size;
. = . + _Min_Stack_Size;
. = ALIGN(8);
} >RAM
.ram2_data :
{
. = ALIGN(4);
_sram2 = .;
*(.ram2_data)
*(.ram2_data*)
. = ALIGN(4);
_eram2 = .;
} >RAM2 AT> FLASH
.ram2_boot :
{
. = ALIGN(4);
_sram2_boot = .;
*(.ram2_boot)
*(.ram2_boot*)
. = ALIGN(4);
_eram2_boot = .;
} >RAM2_BOOT AT> FLASH
/* Remove information from the compiler libraries */
/DISCARD/ :
{
libc.a ( * )
libm.a ( * )
libgcc.a ( * )
}
.ARM.attributes 0 : { *(.ARM.attributes) }
}
Solved! Go to Solution.
2022-09-27 01:52 AM
I have just modified the link script, the NOLOAD keyword was added,as follows:
.ram2_data (NOLOAD):
{
. = ALIGN(4);
_sram2 = .;
*(.ram2_data)
*(.ram2_data*)
. = ALIGN(4);
_eram2 = .;
} >RAM2 AT> FLASH
.ram2_boot (NOLOAD):
{
. = ALIGN(4);
_sram2_boot = .;
*(.ram2_boot)
*(.ram2_boot*)
. = ALIGN(4);
_eram2_boot = .;
} >RAM2_BOOT AT> FLASH
The compiled result is as follows:
The compiled results are now almost identical to KEIL.
Thank you for your reply.
2022-09-26 08:21 PM
What is the actual error message?
Even if your text+data is 48k, that's still plenty less than the 128k of RAM, or 80k of FLASH.
2022-09-26 08:44 PM
It is true that the current program size will not exceed the MCU Flash limit, but I want to reduce the Bin file size as much as possible and reduce the time required for firmware upgrade.
Thank you for your reply
2022-09-27 12:05 AM
} >RAM2 AT> FLASH
} >RAM2_BOOT AT> FLASH
JW
2022-09-27 12:36 AM
Sorry,I don't quite understand what you mean.
I forgot to mention that I defined a bunch of global variables into RAM2, about 15k in size, but I didn't initialize them, and they shouldn't be in the .data segment, they should be in the .bss segment. as shown below:
2022-09-27 01:03 AM
>RAM2 AT> FLASH means, they are both in RAM2 and in FLASH.
The attribute mechanism of gcc places those data unconditionally into a given section. The implicit magic of splitting to .data and .bss based on explicit initialization applies only to those variables which are not explicitnly assigned to a given section.
.ram2_datas says, size 15.2kB, does that ring a bell?
JW
2022-09-27 01:52 AM
I have just modified the link script, the NOLOAD keyword was added,as follows:
.ram2_data (NOLOAD):
{
. = ALIGN(4);
_sram2 = .;
*(.ram2_data)
*(.ram2_data*)
. = ALIGN(4);
_eram2 = .;
} >RAM2 AT> FLASH
.ram2_boot (NOLOAD):
{
. = ALIGN(4);
_sram2_boot = .;
*(.ram2_boot)
*(.ram2_boot*)
. = ALIGN(4);
_eram2_boot = .;
} >RAM2_BOOT AT> FLASH
The compiled result is as follows:
The compiled results are now almost identical to KEIL.
Thank you for your reply.