From 5c6bbab8fef65c565e52dd2e579aaefc97a7a358 Mon Sep 17 00:00:00 2001 From: Nick Clifton Date: Tue, 22 Jun 1999 11:23:06 +0000 Subject: [PATCH] document behaviour of dot inside sections. --- ld/ChangeLog | 5 +++++ ld/ld.texinfo | 33 +++++++++++++++++++++++++++++++++ 2 files changed, 38 insertions(+) diff --git a/ld/ChangeLog b/ld/ChangeLog index 3e2235d..70572de 100644 --- a/ld/ChangeLog +++ b/ld/ChangeLog @@ -1,3 +1,8 @@ +1999-06-22 Nick Clifton + + * ld.texinfo (Location Counter): Describe behaviour of + location counter inside section statements. + 1999-06-20 Mark Mitchell * scripttempl/elf.sc (WRITABLE_RODATA): New variable for diff --git a/ld/ld.texinfo b/ld/ld.texinfo index 9e720de..73dc816 100644 --- a/ld/ld.texinfo +++ b/ld/ld.texinfo @@ -3410,6 +3410,39 @@ followed by a 1000 byte gap. Then the @samp{.text} section from @samp{.text} section from @file{file3}. The notation @samp{= 0x1234} specifies what data to write in the gaps (@pxref{Output Section Fill}). +@cindex dot inside sections +Note: @code{.} actually refers to the byte offset from the start of the +current containing object. Normally this is the @code{SECTIONS} +statement, whoes start address is 0, hence @code{.} can be used as an +absolute address. If @code{.} is used inside a section description +however, it refers to the byte offset from the start of that section, +not an absolute address. Thus in a script like this: + +@smallexample +SECTIONS +@{ + . = 0x100 + .text: @{ + *(.text) + . = 0x200 + @} + . = 0x500 + .data: @{ + *(.data) + . += 0x600 + @} +@} +@end smallexample + +The @samp{.text} section will be assigned a starting address of 0x100 +and a size of exactly 0x200 bytes, even if there is not enough data in +the @samp{.text} input sections to fill this area. (If there is too +much data, an error will be produced because this would be an attempt to +move @code{.} backwards). The @samp{.data} section will start at 0x500 +and it will have an extra 0x600 bytes worth of space after the end of +the values from the @samp{.data} input sections and before the end of +the @samp{.data} output section itself. + @need 2000 @node Operators @subsection Operators -- 2.7.4