Date: Sat, 22 Oct 2011 03:26:02 +0530 From: Rohit J <mipsjunkie@gmail.com> To: Juli Mallett <jmallett@freebsd.org> Cc: freebsd-mips <freebsd-mips@freebsd.org> Subject: Re: Assembler complains about use of $at after ".set noat" on sd instr Message-ID: <CAPJ9Q0W4MggQ-BumAkNRXpR618JZPESyUWbLw8porD-J0ayeXQ@mail.gmail.com> In-Reply-To: <CACVs6=8F=QfEKtr5%2BsNrC3cn%2BK6fA%2BOKsHEu7fixLqsO3dUnuA@mail.gmail.com> References: <CAPJ9Q0U%2BJ9U46XuAAi0p7X0wkDazRRN5aUKgpFYU7bPCEj_H5A@mail.gmail.com> <CACVs6=8F=QfEKtr5%2BsNrC3cn%2BK6fA%2BOKsHEu7fixLqsO3dUnuA@mail.gmail.com>
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>> 2. Why does it complain about ld instr so far up in the file away f=
rom
>> the place new code was inserted?
Hi Juli,
thanks for taking time to respond and so quickly and nicely.
the "ld" error happened because I fat fingered the operand in vi! ;-p
(yes i need to smack myself on the head!!)
>> octeon_asm.S:440: Error: illegal operands `ld T3,8($7)'
which should have referenced the "t3" register (in small case)
>> octeon_asm.S:440: Error: illegal operands `ld t3,8($7)'
the big picture story is that
as a partial fix to using octeon specific very large mult instructions
in our freebsd kernel
(for crypto related ops), we had initially disabled
interrupts=3D>context switches
during these large mult ops as the code wasnt saving the mult related
registers/info
and if it were to context switch in the middle of these multiplication rout=
ines,
bad things happened.
Need to see if there is a better way to do it.
am now trying to see if it makes sense to save those registers and
remove the disable interrupt constraint for running these large multiplicat=
ion
instructions.
will be adapting the (multiplication context save/restore)
in the octeon HRM and will revert if i have any further questions.
thanks a ton
rohit
ps:got all excited to see that some of the files I am working on now have
you as the original author/contributor!
On Fri, Oct 21, 2011 at 12:43 PM, Juli Mallett <jmallett@freebsd.org> wrote=
:
> On Thu, Oct 20, 2011 at 23:38, Rohit J <mipsjunkie@gmail.com> wrote:
>> Hi FreeBSD MIPS Gurus,
>>
>> Am just starting on MIPS assembly in FreeBSD.
>>
>> The code that I have was building just fine.
>> Then I added an line to a .S file @line# 513
>>
>> =A0 =A0 sd =A0k0, mpl(sp)
>>
>> which on make gives an error that says :
>>
>> =A0Assembler messages:
>> octeon_asm.S:440: Error: illegal operands `ld T3,8($7)'
>> octeon_asm.S:513: Error: Macro used $at after ".set noat"
>>
>> The .S file has a noat directive
>> =A0.set noat
>>
>> Silly Questions
>> 1. =A0 =A0 =A0Why does sd instruction (store double word) end up using a=
t ?
>> I checked the particular manual (Cavium Octeon H/w reference Manual)
>> and didn=92t find anything about sd instr using register at.
>
> Probably you are using a symbol/macro that is not locally defined, and
> so assembler assumes it's an external data reference, and tries to
> turn sd into a series of instructions using the assembler temporary to
> load a linker-resolved address into a register to be used in the sd
> instruction. =A0Try running just the C preprocessor and looking at the
> resulting assembly to see what's not being resolved properly.
>
>> 2. =A0 =A0 =A0Why does it complain about ld instr so far up in the file =
away from
>> the place
>> new code was inserted?
>
> Can you send the source inline? =A0I suspect you're missing an include
> or something. =A0Did you change that line? =A0Are you compiling it as it'=
s
> built on stock FreeBSD, or are you, say, copying the file from the
> kernel and then trying to build it in userland?
>
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