On Mon, 2008-02-04 at 20:14 +0100, Wolfgang Denk wrote:
In message 20080204165640.GC19264@ld0162-tx32.am.freescale.net you wrote:
On Mon, Feb 04, 2008 at 12:32:36AM +0100, Wolfgang Denk wrote:
So far, it is not clear to me what a better choice for a global register variable could be (i. e. which register we can chose for our purpose without causing the same or other problems.
r2 is generally used for this purpose.
Hm... R2 is documented to be the TOC pointer?
It seems we could use R15, but I hesitate a bit...
I think the register approach is needed if we ever want to make u-boot fully relocateable.
There are a few global data accesses that needs to be fixed before that can happen though. There should not be any global data accesses before relocate_code has done its thing. One of the first things that happens in board_init_f is: for (init_fnc_ptr = init_sequence; *init_fnc_ptr; ++init_fnc_ptr) { if ((*init_fnc_ptr) () != 0) { hang (); } } init_sequence is a global variable.
Is this table really needed? Why not move it inside board_init_f and save some bytes?
The next is access is env_get_char, this probably needs to move into GD.
I figured global data accesses wasn't allowed(other than GD) at all before relocate_code()?
Jocke