Re: freebsd, binutils-2.9.1 and arm-aout

[Richard Earnshaw <rearnsha at arm dot com>]

I'm sorry, but I don't fully understand what your problem is.

When you have BEFORE set to 1, the first symbol in your object file is 
_start, so the entry point to your file is the same as the load address.

When you have BEFORE set to 0, the first symbol in your object file is 
_main, and _start follows it.  So while the load address of the file 
remains at 0x8000 (the default load address), the entry point has changed 
to 0x8044.

Richard.

> 
> Hi, 
> 
> I had built  a set of tools implementing arm-unknown-aout from
> binutils-2.9.1, newlib-1.8.2 and gcc-2.95.2 and a few patches
> found on the net. 
> 
> It seems like linker has a bug. I am using following command
> to build a test program:
> 
>         $(CC) $(CFLAGS) -o tst -nostartfiles -Wl,-e,_start tst.c
> 
> Test program is below:
> 
> 
> #include <stdio.h>
> 
> #define BEFORE 1
> 
> #if BEFORE
> void
> start(void)
> {
> }
> #endif
> 
> int
> main(int argc, char *argv[])
> {
>    printf("Hello, world\n");
> 
>    return 0;
> }
> 
> #if !BEFORE
> void
> start(void)
> {
> }
> #endif
> 
> 
> It has OK file header:
> 
> tst:     file format a.out-arm-little
> tst
> architecture: arm, flags 0x000001be:
> EXEC_P, HAS_LINENO, HAS_DEBUG, HAS_SYMS, HAS_LOCALS, WP_TEXT, D_PAGED
> start address 0x00008000
> 
> Sections:
> Idx Name          Size      VMA       LMA       File off  Algn
>   0 .text         00010000  00008000  00008000  00008000  2**4
>                   CONTENTS, ALLOC, LOAD, CODE
>   1 .data         00008000  00018000  00018000  00018000  2**4
>                   CONTENTS, ALLOC, LOAD, DATA
>   2 .bss          00000000  00020000  00020000  00000000  2**4
>                   ALLOC
> 
> However,once I change BEFORE to 0, the file header will beecome
> 
> tst:     file format a.out-arm-little
> tst
> architecture: arm, flags 0x000001be:
> EXEC_P, HAS_LINENO, HAS_DEBUG, HAS_SYMS, HAS_LOCALS, WP_TEXT, D_PAGED
> start address 0x00008044
> 
> Sections:
> Idx Name          Size      VMA       LMA       File off  Algn
>   0 .text         0000ffe0  00008000  00008000  00000020  2**4
>                   CONTENTS, ALLOC, LOAD, CODE
>   1 .data         00008000  00018000  00018000  00010000  2**4
>                   CONTENTS, ALLOC, LOAD, DATA
>   2 .bss          00000000  00020000  00020000  00000000  2**4
>                   ALLOC
> 
> Which is incorrect because text will still be located at offset
> 0x8000 in the file.
> 
> So, I am quite puzzled to say the least, is it a known bug ?
> 
> Thanks,
> 
> Aleksey
> 
> 
>  
> 
> 
> 
> 
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