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From: Richard Henderson <rth@cygnus.com>
To: Cort Dougan <cort@attis.cs.nmt.edu>
Cc: gas2@sourceware.cygnus.com
Subject: Re: ppc instructions in gas
Date: Thu, 06 May 1999 16:56:00 -0000	[thread overview]
Message-ID: <19990506165624.A24549@cygnus.com> (raw)
In-Reply-To: <19990506171639.A26711@attis.cs.nmt.edu>

On Thu, May 06, 1999 at 05:16:40PM -0600, Cort Dougan wrote:
> Ah-ha!  The problem is this:
> 
> We do immediate loads of (for example) 0xffff.  Even with lis (which takes
> a signed 16-bit value) this works with 32-bit.  It shouldn't since 0xffff
> is > +32k.  When I assemble with -Wa,-mppc64 it doesn't work and complains
> that 0xffff is > +32k.
> 
> Eh?  Any idea what's going on?

In gas/config/tc-ppc.c --

1067              if ((operand->flags & PPC_OPERAND_SIGNOPT) != 0
1068                  && ppc_size == PPC_OPCODE_32)
1069                max = (1 << operand->bits) - 1;

Looks like there's some backward compatibility thing going on. 

You said lis takes a signed value?  Meaning that the register
gets 0xffffffffffff0000?  If so, in my opinion the assembler is
correct to bitch at you for 0xffff as an operand.


r~

  parent reply	other threads:[~1999-05-06 16:56 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <19990504180843.A31050@attis.cs.nmt.edu>
     [not found] ` <19990505145806.H9469@cygnus.com>
     [not found]   ` <19990505165232.A8594@attis.cs.nmt.edu>
1999-05-06 15:07     ` Richard Henderson
     [not found]       ` <19990506161159.A27229@attis.cs.nmt.edu>
1999-05-06 15:35         ` Richard Henderson
     [not found]           ` <19990506171639.A26711@attis.cs.nmt.edu>
1999-05-06 16:56             ` Richard Henderson [this message]
     [not found]               ` <19990506180806.A5113@attis.cs.nmt.edu>
1999-05-06 17:49                 ` Richard Henderson
     [not found]                   ` <19990506185754.A12025@attis.cs.nmt.edu>
1999-05-06 18:43                     ` Richard Henderson
1999-05-06 20:06       ` Ian Lance Taylor
1999-05-06 20:13         ` Richard Henderson
1999-05-06 20:43           ` Ian Lance Taylor

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