[U-Boot] [U-boot] monitor length question

[Albert ARIBAUD <albert.u.boot@aribaud.net>]

Hi TigerLiu at viatech.com.cn,

On Wed, 3 Jul 2013 11:19:13 +0800, <TigerLiu@viatech.com.cn> wrote:

> Hi, experts:
> I am studying u-boot latest code now.
> I have a question about monitor length.
> 1. in board_init_f() function in arch\arm\lib\board.c
>    Gd->mon_len = _bss_end_ofs;
> 2. in board_init_r() function in arch\arm\lib\board.c
> ??Monitor_flash_len = _end_ofs;
> 
> Because _end_ofs < _bss_end_ofs, so it confused me!
> Why need to discard some data when re-calculating monitor_in board_init_r() function.

Both functions don't compute the same thing.

GD->mon_len computes the monitor length including BSS, because it is
the length in RAM at run time, which matters e.g. for relocating  the
monitor -- relocation copies the text and data but not the BSS.

Monitor_flash_len, as the name implies, computes the monitor length
excluding BSS, because this is the length in FLASH, and BSS does not
exist in the flashed image; even if we know its size at build time,
BSS will only exist after relocation, just before entering board_init_r.

> Best wishes,

Amicalement,
-- 
Albert.