[mc1322x] _rom_data_init_ branch

[Giandomenico Rossi]

Thank you a lot for your precious advices!

> I can't say for sure exactly what rom_data_init does --- unfortunatly
> only Freescale has the answer to that. 
>    .org 0x120
>    ROM_var_start: .word 0
>    .org 0x7ff
>    ROM_var_end:   .word 0
> reserves space for the ROM services and I believe rom_data_init does
> work in this area.
> 

You are right!
I've looked inside, disassembling that part of rom code, and I
discovered that it takes 2 entries ( probably in C language would be an
array of struct) at address 0x11788 and 11798 of the form :
+-----------------------------------------------------+
|   address1 |  address2  | size  | function adddress |
+-----------------------------------------------------+
|  0x40020c  |  0x40020c  | 0x520 |    0x10b2c        |
+-----------------------------------------------------+
|  0x400120  |  0x400120  | 0x97  |    0x10a9c        |
+-----------------------------------------------------+
The second entry point refers to address 0x400120 which is ROM_var_start
as  you  said !
For instance the routine to 0x10b2c set to 0  memory 
from 0x40020c to 0x40020c+0x520.

> You also need to set up the rom patching vectors. 
Sorry ; could you briefly explain me what do you mean when you say 
rom vectors ? Exception Vector Table ?  

> Are you having trouble with calling rom_data_init or with ROM service
> calls in general?
both ! But I solved.
Rom_data_init uses R12 register without save it.
In forth that's a particular register used for DATA stack, so my calls
to Rom_data_init never came back.
ROM service call are coded in Thumb instruction, whereas I use  ARM
assembler instruction  so I simply had to make a BLX jump in place o a
BL .


> > Why add current position ( "." ) -base ?
> 
> The assembler treats the label after the bl command as relative.
Yes, it sound strange to me because my assembler straight code the
relative address.

Thanks
Giandomenico