[U-Boot-Users] Hush shell and simple calculations

Robin Gilks robin.gilks at tait.co.nz
Tue May 23 02:08:37 CEST 2006

Antonio Di Bacco wrote:
> I don't manage to do some simple calculations like:
> echo $((1+1))
> Bye,
> Antonio

I've solved this with a new command 'eval' which is used to set a 
variable based on an expression. For example, I wanted to determine the 
start address of the kernel in flash for both 4 and 8meg parts but since 
its sits above U-Boot in the memory map (and U-Boot has to be 1M down 
from the top for high boot), it has to be calculated depending on the 
flash size. In this case, the new variable 'kb' contains the address of 
the beginning of the kernel of either 40340000 or 40740000 for either 4M 
or 8M devices.
     "eval kb $flash - c00c0000;"		\

This is work I did a couple of years ago and I'm no longer on the 
project so I'm not able to provide a 'formal' patch. To use it, put the 
file cmd_eval.c into ...uboot/common/ and make the following mods

in cmd_confdefs.h add
#define CFG_CMD_EVAL	0x0080000000000000U	/* Eval arithmetics             */

in your board config add
                   | CFG_CMD_EVAL		\
in ..../uboot/common/Makefile
COBJS	= main.o ACEX1K.o altera.o bedbug.o \

And that should be it.

I hope it helps...

Robin Gilks
Senior Design Engineer          Phone: (+64)(3) 357 1569
Tait Electronics                Fax  :  (+64)(3) 359 4632
PO Box 1645 Christchurch        Email : robin.gilks at tait.co.nz
New Zealand

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