Re: [ECOS] File Size Problem??

[Gary Thomas <gthomas at redhat dot com>]

On Tue, 2001-12-11 at 10:35, HuangQiang wrote:
> Hi all:
> 
> hello.c ---  int main(void) { return (0);}
> 
> gcc hello.c
> size a.exe
> text	data	bss	dec	hex	filename
> 1024	1024	12	2060	80c	a.exe
> 
> arm-elf-gcc xxxxxxx    hello.c xxxxxx  (no debug option -g not listed)
> arm-elf-size a.out
> text	data	bss	dec	hex	filename
> 206540	7484	180644	394668	605ac	a.out
> 
> Why so much different??? It seems that the arm-elf-gcc output is much larger
> that the gcc output. How can I get the actual size of the app for the arm? I
> convert it to binary by using arm-elf-objcopy -O binary a.out b, I got b
> 200KB , how come? Is it possible for just for a plain main function? Is
> there any way to get the size of each section for the binary file?

For more detailed information, use 'arm-elf-objdump -h'  However, the
reason for the disparity is that the Linux application only contains
the code for your program.  The eCos application needs to be stand-alone
and thus contains the eCos kernel, etc.

Let's be fair.  On Linux (or any other OS), the 'a.exe' file that you 
quote only has the code+data for "hello.c", whereas your eCos 
application contains that plus the eCos kernel (which may include 
a networking stack and lots of other things).

If you were to compare apples to apples, you'd need to add in all
of these things as well:

[root@hermes parted]# size /boot/vmlinux-2.2.16-22 
   text    data     bss     dec     hex filename
1121911  220968  244092 1586971  18371b /boot/vmlinux-2.2.16-22
[root@hermes parted]# size /lib/libc.so.6 
   text    data     bss     dec     hex filename
1259785   18212   16872 1294869  13c215 /lib/libc.so.6
  ...