RE: test app

[Vanalme Filip <F.Vanalme@TELEVIC.com>]

> -----Original Message-----
> From: Baruch Siach [mailto:baruch@tkos.co.il]
> Sent: dinsdag 8 maart 2011 12:22
> To: Vanalme Filip
> Cc: barebox@lists.infradead.org
> Subject: Re: test app
> 
> Hi Vanalme,
> 
> On Tue, Mar 08, 2011 at 11:09:57AM +0100, Vanalme Filip wrote:
> > As a start, I just took over your Makefile and a minimal source file :
> >
> > __asm__ (".text\n"
> >         ".globl _start\n"
> >         "_start:\n"
> >         "ldr    sp, =0xA7E00000\n"
> >         "bl     main\n"
> >         "stop:\n"
> >         "b      stop\n"
> >         );
> >
> > int main (int argc, char *argv[])
> > {
> > 	return 0;
> > }
> >
> > I think I might still miss something because the assembler part gives me errors
> e.g.
> > 	" Error: no such instruction: 'ldr sp,=0xA7E00000' "
> > 	" Error: no such instruction: 'bl main' "
> > 	" Error: no such instruction: 'b stop' "
> >
> > Maybe a tab/space related issue ?
> 
> Works for me (using the CodeSourcery toolchain):
> 
> $ cat baretest.c
> __asm__ (".text\n"
>         ".globl _start\n"
>         "_start:\n"
>         "ldr    sp, =0xA7E00000\n"
>         "bl     main\n"
>         "stop:\n"
>         "b      stop\n"
>         );
> 
> int main (int argc, char *argv[])
> {
>         return 0;
> }
> $ arm-none-linux-gnueabi-gcc -Wall -Os -nostdlib baretest.c -o baretest.elf -Wl,-
> Ttext=0x78000000
> $ arm-none-linux-gnueabi-objdump -S baretest.elf
> 
> baretest.elf:     file format elf32-littlearm
> 
> 
> Disassembly of section .text:
> 
> 78000000 <_start>:
> 78000000:   e59fd00c    ldr sp, [pc, #12]   ; 78000014 <main+0x8>
> 78000004:   eb000000    bl  7800000c <main>
> 
> 78000008 <stop>:
> 78000008:   eafffffe    b   78000008 <stop>
> 
> 7800000c <main>:
> 7800000c:   e3a00000    mov r0, #0
> 78000010:   e12fff1e    bx  lr
> 78000014:   a7e00000    .word   0xa7e00000
> 
> baruch
> 

[Filip] 

Baruch,

Compiling and linking seems to work well now. When I dump the .elf, I see that the start address is 0xA7E00000. That's what I wanted.
However, when loading the app in ram and executing it, I see that it tries to start from 0xA0000000 (this is the base address of the RAM section) :

barebox:/test tftp testapp.bin
TFTP from server 10.0.48.80 ('testapp.bin' -> 'testapp.bin')

barebox:/test cp testapp.bin /dev/ram0
barebox:/test go /dev/ram0
## Starting application at 0xA0000000 ...
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Should I specify an address when executing 'go' or 'cp' ? Isn't it loading the app always at the beginning of the RAM space, i.e. 0xA0000000 ?

Filip

> --
>                                                      ~. .~   Tk Open Systems
> =}------------------------------------------------ooO--U--Ooo------------{=
>    - baruch@tkos.co.il - tel: +972.2.679.5364, http://www.tkos.co.il -

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