I am working on an IAR project. In its linker configuration file, a block is defined as the following
define block MY_BLOCK with alignment = 32 { section myblock };
place in CODE_RAM { block MY_BLOCK };
This created a MY_BLOCK memory object with 32 byte alignment， which is linked into physical memory CODE_RAM.
What I want to achieve is, leaving some extra padding area (say 64 bytes) in the end of the block. The block definition directive have the size parameter, if I want the MY_BLOCK size to grow to 1024, I can use
define block MY_BLOCK with alignment = 32, size = 1024 { section myblock };
And it works well.
However, I want the size to be relative to the original size. So I use
define block MY_BLOCK with alignment = 32, size = __section_size(section myblock) + 64 { section myblock };
This time linker report a error
Error[Lc009]: "__section_size" undefined
Looks like __section_size can be only used in C instead of linker configuration file.
In comparision, ARMGCC we can simply use
. = . + 64
in linker file to achieve this purpose. I am wondering if it is achievable in IAR.
Can someone help me out?
The way to achieve this is to create an empty block with the padding and add it to MY_BLOCK. To ensure that the content and the padding are placed in the order listed in the file we add the attribute fixed order to MY_BLOCK. We also need to add keep { block MY_PADDING }; to the configuration file to tell the linker to include MY_PADDING even though its content is not referenced from the application. The result looks something like this:
define block MY_PADDING with size = 64 {};
define block MY_BLOCK with alignment = 32, fixed order { section myblock,
block MY_PADDING };
keep { block MY_PADDING };
place in CODE_RAM { block MY_BLOCK };