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* Can we move location counter backwards?
@ 2006-08-22 18:04 H. J. Lu
  2006-08-22 18:36 ` H. J. Lu
  0 siblings, 1 reply; 2+ messages in thread
From: H. J. Lu @ 2006-08-22 18:04 UTC (permalink / raw)
  To: binutils

The linker manual says "The location counter may never be moved
backwards." But in the same manual, there are

   Note that the `OVERLAY' command is just syntactic sugar, since
everything it does can be done using the more basic commands.  The
above example could have been written identically as follows.

       .text0 0x1000 : AT (0x4000) { o1/*.o(.text) }
       __load_start_text0 = LOADADDR (.text0);
       __load_stop_text0 = LOADADDR (.text0) + SIZEOF (.text0);
       .text1 0x1000 : AT (0x4000 + SIZEOF (.text0)) { o2/*.o(.text) }
       __load_start_text1 = LOADADDR (.text1);
       __load_stop_text1 = LOADADDR (.text1) + SIZEOF (.text1);
       . = 0x1000 + MAX (SIZEOF (.text0), SIZEOF (.text1));

It moves the location counter backwards implicitly. It is the same as

       .text0 0x1000 : AT (0x4000) { o1/*.o(.text) }
       __load_start_text0 = LOADADDR (.text0);
       __load_stop_text0 = LOADADDR (.text0) + SIZEOF (.text0);
       . = 0x1000;
       .text1 : AT (0x4000 + SIZEOF (.text0)) { o2/*.o(.text) }
       __load_start_text1 = LOADADDR (.text1);
       __load_stop_text1 = LOADADDR (.text1) + SIZEOF (.text1);
       . = 0x1000 + MAX (SIZEOF (.text0), SIZEOF (.text1));

Given that linker does allow/support moving the location counter
backwards, should we remove "The location counter may never be moved
backwards." from the linker manual?


H.J.

^ permalink raw reply	[flat|nested] 2+ messages in thread

* Re: Can we move location counter backwards?
  2006-08-22 18:04 Can we move location counter backwards? H. J. Lu
@ 2006-08-22 18:36 ` H. J. Lu
  0 siblings, 0 replies; 2+ messages in thread
From: H. J. Lu @ 2006-08-22 18:36 UTC (permalink / raw)
  To: binutils

On Tue, Aug 22, 2006 at 10:22:52AM -0700, H. J. Lu wrote:
> The linker manual says "The location counter may never be moved
> backwards." But in the same manual, there are
> 
>    Note that the `OVERLAY' command is just syntactic sugar, since
> everything it does can be done using the more basic commands.  The
> above example could have been written identically as follows.
> 
>        .text0 0x1000 : AT (0x4000) { o1/*.o(.text) }
>        __load_start_text0 = LOADADDR (.text0);
>        __load_stop_text0 = LOADADDR (.text0) + SIZEOF (.text0);
>        .text1 0x1000 : AT (0x4000 + SIZEOF (.text0)) { o2/*.o(.text) }
>        __load_start_text1 = LOADADDR (.text1);
>        __load_stop_text1 = LOADADDR (.text1) + SIZEOF (.text1);
>        . = 0x1000 + MAX (SIZEOF (.text0), SIZEOF (.text1));
> 
> It moves the location counter backwards implicitly. It is the same as
> 
>        .text0 0x1000 : AT (0x4000) { o1/*.o(.text) }
>        __load_start_text0 = LOADADDR (.text0);
>        __load_stop_text0 = LOADADDR (.text0) + SIZEOF (.text0);
>        . = 0x1000;
>        .text1 : AT (0x4000 + SIZEOF (.text0)) { o2/*.o(.text) }
>        __load_start_text1 = LOADADDR (.text1);
>        __load_stop_text1 = LOADADDR (.text1) + SIZEOF (.text1);
>        . = 0x1000 + MAX (SIZEOF (.text0), SIZEOF (.text1));
> 
> Given that linker does allow/support moving the location counter
> backwards, should we remove "The location counter may never be moved
> backwards." from the linker manual?

Nevermind. The linker manual has been updated.


H.J.

^ permalink raw reply	[flat|nested] 2+ messages in thread

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