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From: Renaud Barbier <renaud.barbier@ge.com>
To: barebox@lists.infradead.org
Subject: ARM newbie
Date: Thu, 22 Jan 2015 11:53:56 +0000	[thread overview]
Message-ID: <54C0E4D4.2010402@ge.com> (raw)


I am doing my first port to an ARM CPU (Broadcom chip). For testing I
built the friendlyarm-tiny210 and created an objdump to see what the
code look like:

barebox:     file format elf32-littlearm


Disassembly of section .text:

23e00000 <start>:
23e00000:   ea000012        b       23e00050 <start+0x50>
...
23e00050:   ea000013        b       23e000a4 <barebox_arm_reset_vector>
...

23e000a4 <barebox_arm_reset_vector>:
23e000a4:   e52de004        push    {lr}       ; (str lr, [sp, #-4]!)

I am a bit surprise to see a push to stack as the first instruction of
barebox_arm_reset_vector as the stack pointer has not been defined yet.
Or is there a pre boot loader that is not built as part of the
friendlyarm-tiny210  build.

Other BSP I have built do not produce this push instruction.
Where is the difference coming from in the build?

Are all BSP having a lowlevel.c file assumed to have a pre-bootloader?

Cheers,
R.










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             reply	other threads:[~2015-01-22 11:54 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-01-22 11:53 Renaud Barbier [this message]
2015-01-23  7:09 ` ARM newbie Sascha Hauer

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