as: MSP430 Profiling Capability
9.28.6 Profiling Capability
---------------------------
It is a performance hit to use gcc's profiling approach for this tiny
target. Even more - jtag hardware facility does not perform any
profiling functions. However we've got gdb's built-in simulator where
we can do anything.
We define new section '.profiler' which holds all profiling
information. We define new pseudo operation '.profiler' which will
instruct assembler to add new profile entry to the object file. Profile
should take place at the present address.
Pseudo operation format:
'.profiler flags,function_to_profile [, cycle_corrector, extra]'
where:
'flags' is a combination of the following characters:
's'
function entry
'x'
function exit
'i'
function is in init section
'f'
function is in fini section
'l'
library call
'c'
libc standard call
'd'
stack value demand
'I'
interrupt service routine
'P'
prologue start
'p'
prologue end
'E'
epilogue start
'e'
epilogue end
'j'
long jump / sjlj unwind
'a'
an arbitrary code fragment
't'
extra parameter saved (a constant value like frame size)
'function_to_profile'
a function address
'cycle_corrector'
a value which should be added to the cycle counter, zero if
omitted.
'extra'
any extra parameter, zero if omitted.
For example:
.global fxx
.type fxx,@function
fxx:
.LFrameOffset_fxx=0x08
.profiler "scdP", fxx ; function entry.
; we also demand stack value to be saved
push r11
push r10
push r9
push r8
.profiler "cdpt",fxx,0, .LFrameOffset_fxx ; check stack value at this point
; (this is a prologue end)
; note, that spare var filled with
; the farme size
mov r15,r8
...
.profiler cdE,fxx ; check stack
pop r8
pop r9
pop r10
pop r11
.profiler xcde,fxx,3 ; exit adds 3 to the cycle counter
ret ; cause 'ret' insn takes 3 cycles
Info Catalog
as: MSP430 Opcodes
as: MSP430-Dependent