arm framepointer stacktrace

arm_fp_stacktrace.txt

prologue:
mov ip, sp
stmdb sp!, {fp, ip, lr, pc}
sub fp, ip, #4

epilogue:
ldm sp, {fp, sp, pc}
======

==stack====
prologue:
  ...         <-----pre_sp
  pre_pc,     <-----fp
  pre_lr      // lr of last frame's return address
  pre_sp      // sp of last frame's sp
  pre_fp      // fp of last frame's fp
              <-----sp


epilogue:
  fp = pre_fp
  sp = pre_sp
  pc = pre_lr