FW: GCC ARM Cross Linker Problem

[Richard Earnshaw]

The following works fine for me:

sym.s:
	.global	tfunc
	.type tfunc %function
	.equ	tfunc, 0x1235
main.c:
extern void tfunc(void);
int main()
{
    tfunc();
    return 0;
}

arm-elf-as sym.s -o sym.o
arm-elf-gcc main.c sym.o -o main.exe
arm-elf-objdump -xd main.exe
...
00008224 <main>:
    8224:       e1a0c00d        mov     ip, sp
    8228:       e92dd800        stmdb   sp!, {fp, ip, lr, pc}
    822c:       e24cb004        sub     fp, ip, #4      ; 0x4
    8230:       eb0007f8        bl      a218 <__tfunc_from_arm>
    8234:       e3a03000        mov     r3, #0  ; 0x0
    8238:       e1a00003        mov     r0, r3
    823c:       e89da800        ldmia   sp, {fp, sp, pc}
...
0000a218 <__tfunc_from_arm>:
    a218:       e59fc000        ldr     ip, [pc, #0]    ; a220
<__tfunc_from_arm
+0x8>
    a21c:       e12fff1c        bx      ip
    a220:       00001235        andeq   r1, r0, r5, lsr r2
...

Notice that __tfunc_from_arm loads the value 0x1235 into a register and
issues a bx instruction, which will then correctly switch to Thumb
state.

R.

On Tue, 2006-08-29 at 14:47, Kanwal Preet Singh CHANANA wrote:
> Hi Vinayak,
> Kindly refer to below mail. I am already using this following method but it is not working.
> 
> Regards,
> Kanwal
> 
> -----Original Message-----
> From: gcc-help-owner@gcc.gnu.org [mailto:gcc-help-owner@gcc.gnu.org] On Behalf Of Vinayak Bhalkar
> Sent: Tuesday, August 29, 2006 5:42 PM
> To: kanwalpreet.singh@st.com
> Cc: gcc-help@gcc.gnu.org; crossgcc@sources.redhat.com
> Subject: Re: FW: GCC ARM Cross Linker Problem
> 
> 
> 
> Try following-
> 
> MaskInterrupt	=	0x00c008f9; 
> 
> Regards,
> vinayak
> 
> --- kanwalpreet.singh@st.com wrote:
> 
> From: Kanwal Preet Singh CHANANA <kanwalpreet.singh@st.com>
> To: <gcc-help@gcc.gnu.org>, <crossgcc@sources.redhat.com>
> Subject: FW: GCC ARM Cross Linker Problem
> Date: Tue, 29 Aug 2006 14:59:35 +0530
> 
> Hi all,
> 
> I am able to compile & Link my source files with a workaround mentioned below:
> 
> The absolute symbols defined in symbols.o are
> 
> 0x000002a8 D CurTask
> 0x00c008f8 T MaskInterrupt
> Where Curtask is data located in RoM & MaskInterrupt is function in Thumb Mode.
> 
> I used following definations in Linker Script
> 
> pCurTask		=	0x000002a8; 
> MaskInterrupt	=	0x00c008f8; 
> 
> With this I am able to link & built Image.axf file. But when running on target,the image crashes at a point when it jumps to MaskInterrupt(shown above) . The reason is that the Linker assumes MaskInterrupt function to be in ARM mode.When it jumps there, it expects 4 byte ARM instruction but the code at this location has 2 Byte Thumb Instruction.
> 
> The Thumb Interwork option is enabled in Build options.
> 
> Can anyone suggest me a method to Link above symbols in a way so that GCC-ARMv4.0.3 knows whether the symbols is Data or Thumb Function or ARM function? If there is a way, then Image will run correctly on Target. Also if anyone needs any help on Project porting from ADS to GCC-ARM,then I can help him out.
> 
> Please suggest a wayout to fix the above problem.
> Regards,
> Kanwal
> 
> 
> 
> 
> -----Original Message-----
> From: gcc-help-owner@gcc.gnu.org [mailto:gcc-help-owner@gcc.gnu.org] On Behalf Of Kanwal Preet Singh CHANANA
> Sent: Monday, August 21, 2006 3:48 PM
> To: gcc-help@gcc.gnu.org
> Subject: GCC ARM Cross Linker Problem
> 
> 
> Hi all,
> 
> I am porting my project from ADS from ARM to GCC ARM Tool chain. I am able to compile my source files but fail to link. I have a symbols file (symbols.o) with absolute symbols addresses in format 
> Symboladdress SymbolType Symbolname e.g
> 
> 0x000002a8 D CurTask
> 0x00c008f8 T MaskInterrupt
> 
> These symbols are located in ROM( code built with ADS) & project image will be in flash. When I use this same file during build with ARM ADS, it works fine but with GCC ARM tool chain,I get following error message
> 
> "./symbols.o: file not recognized: File format not recognized"
> 
> Can anybody please tell me the solution to this error? Can I link objects built with ADS with GCC ARM ?
> 
> Regards,
> Kanwal
> 
> 
> 
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Richard Earnshaw             Email: Richard.Earnshaw@arm.com
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