My understanding is that your u-boot is built in THUMB mode and also run in THUMB mode now, but your helloworld application is still ARM code. Then under thumb mode u-boot, you issue command “go 82000000 hello” to run an ARM application. Is my understanding correct?

 

If correct, my gut feeling is it might be a problem related to ARM/Thumb mode switch.

 

BR,

Terry

 

From: Parimala Baggiri [mailto:baggiriparimala@gmail.com]
Sent: Friday, December 20, 2013 12:25 PM
To: Zhenqiang Chen
Cc: linaro-toolchain; Terry Guo
Subject: Re: ARM vs THUMB builds

 

When I build hello_world application along with u-boot for ARM mode, it executes fine on target, But, when I build it for THUMB mode, it generates "undefined instruction" exception.

Thank you.

 

 

On Fri, Dec 20, 2013 at 8:38 AM, Zhenqiang Chen <zhenqiang.chen@linaro.org> wrote:

On 19 December 2013 13:36, Parimala Baggiri <baggiriparimala@gmail.com> wrote:
> Hello,
>
> I am using the pre-built toolchain gcc-arm-none-eabi-4_6-2012q2 from linaro
> to compile u-boot (u-boot-linaro-stable) and to compile my standalone
> applications to run on target(PandaBoard ES rev b2)
>
> hello_world standalone application which comes with u-boot is executing fine
> on target when I disable CONFIG_SYS_THUMB_BUILD, but when I enable it,
> target gets reset with following information

How do you build your hello_world? Is it ARM or THUMB?

> Panda # go 82000000 hello
> ## Starting application at 0x82000000 ...
> undefined instruction
> pc : [<8200000c>]          lr : [<bff83147>]
> sp : bfeffe40  ip : bfeffc10     fp : 00000000
> r10: 00000003  r9 : bffac954     r8 : bfefff68
> r7 : bff01d88  r6 : 82000000     r5 : bff01d8c  r4 : 00000003
> r3 : 82000000  r2 : bff01d8c     r1 : bff01d8c  r0 : 00000002
> Flags: nzCv  IRQs off  FIQs off  Mode SVC_32
> Resetting CPU ...
>
> resetting ...
>
> U-Boot SPL 2013.01.-rc1-g0f45941 (Dec 17 2013 - 14:23:41)
> OMAP4460 ES1.1
> OMAP SD/MMC: 0
> reading u-boot.img
> reading u-boot.bin
> reading u-boot.bin
>
> ......
>
> Can anyone please help me why thumb mode build is failing?
>
>
>

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