Hi Dmitry!
[the following holds for IAR C-compiler - not MSP430-GCC]
>>I will decribe the mechanism of "__low_level_init" in detail:
>>Every program written in C starts with the initialisation of the stack
>>pointer SP. Short after this the function "__low_level_init" is
>>CALLed.
>>In default case this function just gives back a return value, but the
>>user can redefine this function for own purpose. After the RETurn, the
>>normal C-preamble is computed (initialisation of global variables,
>>heap...).
actually, there is no stack initialization in __reset_vector.
ACK - the first in the C prologue of the MSP430-GCC is the HOLD command
to the watchdog timer.
stack being initialized in the 'main' prologue and can be avoided with
'-mno-stack-init' option.
I don't care about stack initialisazions... Maybe you misunderstood me.
My problem ist, that I would like to have some user-specific
initialisazions before the automatical generated function
_reset_vector__ is executed.
1. use gcc-3.4 and put some code into '.initX' sections
Could you explain in short words, what do you mean?
(I am only a C-newbie. I am a hardware engineer, who knows a possible
architecture of the MSP430 and the assembler very well.)
2. make your 'main' doing low_level_init then branch to real main.
This would lead to the fact, that _reset_vector__ is computed first.
Then a CALL to a initialisation function would be done and after this,
the real body of main would be executed
This is not what I would like to have.
Let me describe in assembler, what I want:
_reset_vector__:
MOV #0x5A80,&0x0120 ;hold watchdog (optional)
MOV #0x0A00,R1 ;initialize SP
CALL #__low_level_init
;do all the other stuff
;what has to be done
;in the C prologue
;NOTE:
;this should be automatical generated
;by the C-compiler
JMP main
main:
;main program
;...
__low_level_init:
;do specific low level init
;before the C-prologue is computed
RET
My intention is, to have specific initialisazion at the very first time,
because the C-prologue may be too time consuming to do it afterwards (or
there are some other reasons...). To achieve this, I don't want to write
my own _reset_vector__, because this should be automatically made by the
compiler (that can do this better than me).
This mechanism is offered by IARs C-Compiler and called
"__low_level_init". So I am asking if there is a similar solution for
MSP430-GCC.
Ralf
