this is example is from dwarf document.
How Can I caculate provious sp(r7) pointer,I mean It didnot save sp somewhere since sp is a callee-save register.
The architectural ABI committee specifies that the stack pointer (R7) is the
same as the CFA
what this means? is this means "r7=cfa" , how come this is help to compute previous sp , and call a function may change sp.
In this example is that r8 is virtual? looks is a virtual.
dwarf pdf.
https://dwarfstd.org/doc/DWARF5.pdf page 325