Wolfgang Denk wrote:
All examples that i have found uses static addresses. Also using google i have not found any answers.
You will either have to use PIC (which is not what U-Boot does), or use a static link address (which is what U-Boot does for standalone applications), or use relocatable code that you can (manually) relocate to a target address of your choice (which is what U-Boot does for the U-Boot code itself).
The thing that i like to use is PIC and PID ( position independent data and code ). U-boot allows to load my code in any address and i really don't like to manually relocate it. I like to have ready compiled code parts in mass media ( flash ) and i like to to allow load them to any free address.
There is this same problem allways if you use non-mmu processor like MPC555 and you like to load more than just one fixed program into memory. You should remember that the applications loaded with u-boot are not allways just "stand-alone" apps or Linux. Based on my knowledge there is not even Linux for mpc555. I our case i like to load my open source rtos kernel ( Katix ) and then applications for it.
Becouse u-boot runs in many non-mmu processors i was just thinking that some u-boot user has had same problem and find already answer.
I have searched all around internet to find answer but not yet find one. -fpic should make program code position independent and -msdata=eabi -G20000 should put all static data smaller than 20000 bytes to relative to r2(const data) or r13 . For some reason gcc says that -msdata=eabi and -fpic are incompatible and even -msdata=eabi does not make data references as register relative.
Kate