Messages in this thread | | | Date | Tue, 1 Mar 2011 08:59:11 +0000 | From | Russell King - ARM Linux <> | Subject | Re: [RFC PATCH] ARM: Use generic BUG() handler |
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On Tue, Mar 01, 2011 at 08:49:49AM +0000, Russell King - ARM Linux wrote: > On Mon, Feb 28, 2011 at 04:27:43PM -0800, Simon Glass wrote: > > + asm volatile("1:\t.word %c3\n" \ > > + ".pushsection __bug_table,\"a\"\n" \ > > + "2:\t.word 1b, %c0\n" \ > > + "\t.hword %c1, 0\n" \ > > + "\t.org 2b+%c2\n" \ > > %c doesn't work on lots of versions of gcc, which is why we can't use > the generic bug support. There's no way to reliably generate constants > without many compiler versions spitting out a '#' before them.
gcc 4.3.2:
asm(".word %c0" : : "i" (0));
produces:
.word #0
which gas chokes on:
/tmp/cc2hGOHd.s:12: Error: bad expression /tmp/cc2hGOHd.s:12: Error: junk at end of line, first unrecognized character is `0'
So what this means is that it's impossible to generate constants in assembly with GCC targetting ARM without having them prefixed by '#', which in turn makes it impossible to use the generic BUG support.
I reported this bug to gcc folk many years ago. I've no idea which version it has been fixed in or if it's even been fixed.
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