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Re: [PATCH] fix dcbt operand order for "server" category


On Thu, 2009-02-05 at 17:14 -0600, Peter Bergner wrote:
> On Fri, 2009-02-06 at 08:30 +1030, Alan Modra wrote:
> > On Thu, Feb 05, 2009 at 02:29:54PM -0600, Peter Bergner wrote:
> > > The dcbt instruction that supports the TH operand used to be optional but
> > > now is part of the base ISA.  However, Embdedded and Server categories use
> > > different operand ordering, with Embedded having TH being the first operand
> > > and Server having TH being the last/3rd operand.  Ditto for dcbtst.
> > 
> > Horrible.  This patch will break the linux kernel, won't it?
> 
> Or were you worried that I was changing the binary bit pattern with
> this change?  All I'm trying to do is change the asm syntax accepted,
> not the bit pattern we produce...  Hmmm, looking at the hex bits in
> the objdumps, something looks wrong (ie, they're not matching).
> Let me check into that and report back.

Actually, it was just a luser error on my part, using the wrong asm
syntax with the wrong assembler options.  I've confirmed that I get
the same exact bit patterns either way.

Peter


bergner@etna:~/> cat dcbt-old.s 
	.section	".text"
old:
	dcbt     1,2
	dcbt     0,1,2
	dcbt     8,1,2
bergner@etna:~/> cat dcbt-p7.s 
	.section	".text"
power7:
	dcbt     1,2
	dcbt     1,2,0
	dcbt     1,2,8
bergner@etna:~/> /home/bergner/binutils/build/binutils-dcbt/gas/as-new -mppc dcbt-old.s -o dcbt-old.o
bergner@etna:~/> /home/bergner/binutils/build/binutils-dcbt/gas/as-new -mpower7 dcbt-p7.s -o dcbt-p7.o 
bergner@etna:~/> /home/bergner/binutils/build/binutils-dcbt/binutils/objdump -d -Mppc dcbt-old.o 

dcbt-old.o:     file format elf32-powerpc


Disassembly of section .text:

00000000 <old>:
   0:	7c 01 12 2c 	dcbt    r1,r2
   4:	7c 01 12 2c 	dcbt    r1,r2
   8:	7d 01 12 2c 	dcbt    8,r1,r2

bergner@etna:~/> /home/bergner/binutils/build/binutils-dcbt/binutils/objdump -d -Mpower7 dcbt-p7.o 

dcbt-p7.o:     file format elf32-powerpc


Disassembly of section .text:

00000000 <power7>:
   0:	7c 01 12 2c 	dcbt    r1,r2
   4:	7c 01 12 2c 	dcbt    r1,r2
   8:	7d 01 12 2c 	dcbt    r1,r2,8



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