John Farmer <news02@xxxxxxxxxxx> writes: > I had a good look through the ARM-THUMB Procedure Call Standard and it sort > of suggests that R7 could be used as a frame pointer. Looked through the GCC > docs and found the -fabi option but it appears to apply to C++ code. > > I am still wondering what makes the decision to use R7 as the frame pointer. > If its used because of an ABI standard for the ARM Cortex-M3 CPU how is it > specified to GCC? Also if this is the case is there a standard that I could > look through? I have looked on the ARM web site but not found it yet. When gcc needs a frame pointer in Thumb code, it will always use r7. There is no way to change this. I'm not sure why you would want to change it. Ian
