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.orgmailto:zhenqiang.chen@linaro.org> wrote: On 19 December 2013 13:36, Parimala Baggiri <baggiriparimala@gmail.commailto: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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