Cant write asm in correct adress

[lozzik]

Hi,
i am using the PCWH 3,249
in my project there is some codes that have to be executet at startup before anything others. So i am writing it in the first letter in main function. But CCS generates some other codes before my code (defining variables etc.).
i have contactet with ccs support and they have said that i could it by using the #build, #org and #rom combination. i couldnt use the #rom and there is no examples in ccs
can anybody help me to execute my code before anything other.

Thanks an sorry for my english

[Ttelmah]

#build, is in the manual now. If you have an older compiler (before it was documented here), look in the compiler directory, for the 'readme.txt' file, which documents the 'extras'.
The key is that with this, you can move the start of the _CCS_ code to a point higher in memory. So if you have:
#build(reset=0x100)

CCS, will put _it's_ code, starting at address 0x100.
Then you would need to put your assembler at the bottom of memory, and end it with a jump to this address.
If you are using interrupts, you would need to either reloctate the handler for these as well, or 'jump round' this.
Have a look in the examples, for the bootloader stuff (ex_bootload.c). The bootloader is done, by having the bootloader code at the bottom of memory, where it is run first, and checks to see if particular conditions are met for it to start working. If not, the code then jumps to the relocated 'main' function. Hence the relocation involved, is exactly what you need to do.

Best Wishes

[Guest]

i have looked the example bootloader.c
and i write my code so:

first
#build(reset=0x00020)
then

#org 0,10{} //this adresses will be reserwed by compiling
then

#org 0
a jump to my code that has to be executed first
at the end of my code there is a jump back to main
#org default

with this code i have still a problem
the code that has to be executet first runs without any problems but it doesnt jump to main everytime, it jumps sometimes that shows the adress is true but why not everytime.
in summary the code works sometimes how can this be possible

[Guest]

Without seeing what your code is doing, this sounds like something in the addressing is wrong. Note that your 'org' statement, only allows enough space for five instructions in your code (10 != 0x10).
I'd suggest declaring as:

[lozzik]

here is my code

[Guest]

You are doing so much jumping around, that it is hard to work out what the implications are. I'd suggest tidying things a lot. You do not need two sets of org statements. Use something like this:

[lozzik]

Thank you for your repleys.
This code is much easier than the first.
I have written this one. But i have still the same problem. I cant understand how this can happen code works sometimes and somtimes not.
I am swtiching the circuit on everything is okey the boot program runs then it returns to main. I am switching the circuit off starting again this time the boot program runs again but it doesnt returns to main.
i am gonna try with different adresses and different pic.

[lozzik]

here is the reply from ccs support
do you now using the #rom directive

[Ttelmah]

Read what they say again.
You will see that they say you can do the jump using #org, _or_ #rom. The 'danger' with the ORG approach, is that if you have interrupt vectors in use (remember I asked this, and your sample code does not show this), it uses an extra instruction for the 'return' at the end of the ORG'd function, and this can clash with interrupt vectors. You do not need the ROM approach.
ROM, simply allows you to define individual bytes/words to be written to a particular memory location.
You couldn't use the ROM approach easily, since you are doing something they did not expect, and wanting to call the same routine again inside the main code. This _requires_ the extra return instruction is present...
Seriously, the code as posted works (I checked it did, before I posted it). The behaviour you are seeing is something to do with the enviroment you are testing it in.

Best Wishes

[lozzik]

@Ttelmah

Thank you again for your replys