Hi,
I need to :
1. Inline an assembly code that modifies Stack pointer directly (__asm directive is not allowed to modify stack pointer) in a C++ file.
What is the best option? A function call to a label is not an option since I need to manually update Stack Pointer. I need to inline.
I read I can create SRC file. Can I create SRC from the C++ compiler ? if so what is the Directive/Flag? --SRC didn't work.
#prama asm was unrecognized pragma. perhaps because I'm not creating SRC.
Thanks.
Thanks Robert,
You are correct. LR was not mentioned. I will be using intrinsic to manipulate SP and such.
www.keil.com/.../armcc_chr1359124993137.htm
How about pushing R0-R7 into Stack? I need to do that manually as well. Didn't see a intrinsic for that.
What I did was wrote a function to push a single register (specified as an argument) and call it eight times for all eight registers.
It all compiled and linked fine.
didn't work though. Then I realised it was a dumb idea and I didn't have sufficient of understanding what was required.
When I did acquire the knowledge, I found it was totally the wrong way to do it. And the added advantage of understanding it was that I then knew how to do it and didn't need to post any cryptic questions on any forums.
Thanks for your useful and very helpful answer Keith...
Regardless , I worked around the problem.
And of course cannot be bothered to explain what that workaround (or, for that matter, the actual problem) was. Do you really think that's the right approach to thanking the public for trying to help you?
Unnecessary comments like yours and Keith are disappointing to see in threads. I appreciate people (other folks that helped on this thread) who genuinely attempt to help instead of mocking. A simple "can you post your findings" would do.
You have to read the whole thread to see what the problem was. In case you don't want to be bothered with it or give you more reason to post comments like before... read below:
GCC allows for inline assembly that modifies Stack(push/pop and SP). ARM RVCT doesn't allow it.
1. I needed to save LR,and content of R0-R7 onto stack. Don't ask "why you need to do that". It was a HW issue work around. 2. Calling an assembly routine will modify LR so I wanted to figure out a way to inline a function in .s file to avoid modifying LR .
What I ended up doing is calling a subroutine with LR passed as a parameter. And that subroutine pushed passed LR and other registers onto stack.