[rfc] For mips, sign-extended ecoff offsets

Ian Lance Taylor ian@zembu.com
Mon Jun 19 20:41:00 GMT 2000


   Date: Mon, 19 Jun 2000 20:07:59 -0700
   From: Geoff Keating <geoffk@cygnus.com>

   > From: Ulf Carlsson <ulfc@calypso.engr.sgi.com>
   > Date: Mon, 19 Jun 2000 18:45:44 -0700 (PDT)

   > On a 64-bit MIPS processor 32-bit addresses are of course sign
   > extended, but this shouldn't concern the 32-bit BFD backend for MIPS
   > in any way.  Whether we sign extend the addresses or not shouldn't
   > make any difference except in our internal representation of the
   > bfd_vma.  I may be wrong though!

   The 64-bit MIPS machines often use the 32-bit ELF format, typically
   because they have 32-bit memory addresses (I forget whether trying to
   access 0x0000000087654321 gives you 0xffffffff87654321 or a trap).

I think the real reason this happens is historical--because we didn't
have a 64-bit MIPS format when we started supporting 64-bit MIPS
chips.  I don't think there is any particularly legitimate reason to
use a 32-bit format for a 64-bit chip.

Ian


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