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From: Dave Brolley <brolley@redhat.com>
To: Joern Rennecke <joernr@arc.com>
Cc: "Frank Ch. Eigler" <fche@redhat.com>, cgen@sources.redhat.com
Subject: Re: delayed branches and zero overhead loops
Date: Fri, 16 Feb 2007 20:54:00 -0000	[thread overview]
Message-ID: <45D619DD.7010602@redhat.com> (raw)
In-Reply-To: <20070214201406.GD18550@elsdt-razorfish.arc.com>

Joern Rennecke wrote:
> On Wed, Feb 14, 2007 at 02:51:50PM -0500, Dave Brolley wrote:
>   
>> Joern Rennecke wrote:
>>     
>>> That is indeed the case.  The only format differences are in the
>>> RC-ilink / RC-noilink operand and in the F0 / F1F operand.
>>>
>>>
>>>       
>> If so, then there must be more bits which are constant in each of the 
>> two forms of the insn, otherwise, how does the hardware decode them?
>>     
>
> ilink1 is core register 29, ilink2 is core register 30 .
> Thus, you could describe the upper four bits of RC-ilink as 7,
> but that would still not disambiguate it from RC-noilink for core registers
> 28 and 31.
>   
I would merge the two insns into one and handle the difference in the 
semantic code by checking (index-of <operand>)
>   
>>> It's the same situation with long immediates.  They are indicated by a
>>> special value in any one of three operand fields.
>>>       
This could be handled in the same way by checking the values of the 
immediate operands.

Dave

  reply	other threads:[~2007-02-16 20:54 UTC|newest]

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-02-13 15:37 Joern Rennecke
2007-02-13 18:51 ` Frank Ch. Eigler
2007-02-13 21:00   ` Joern Rennecke
2007-02-13 21:12     ` Frank Ch. Eigler
2007-02-13 22:21       ` Joern Rennecke
2007-02-14 17:09         ` Dave Brolley
2007-02-14 18:30           ` Joern Rennecke
2007-02-14 19:52             ` Dave Brolley
2007-02-14 20:15               ` Joern Rennecke
2007-02-16 20:54                 ` Dave Brolley [this message]
2007-02-19  3:39                   ` Joern Rennecke
     [not found]                     ` <45D9C06A.4030903@redhat.com>
2007-02-19 15:56                       ` Joern Rennecke
2007-02-19 16:07                         ` Frank Ch. Eigler
2007-02-19 18:14                           ` Joern Rennecke
2007-02-19 18:19                             ` Dave Brolley
2007-02-22 15:50                               ` Joern Rennecke
2007-02-22 16:08                               ` insert evaluation for multi-ifields broken Joern Rennecke
2007-02-22 16:56                                 ` Dave Brolley
2007-02-22 18:14                                   ` Joern Rennecke
2007-02-23 17:45                                     ` Dave Brolley
2007-02-15 16:54               ` delayed branches and zero overhead loops Joern Rennecke
2007-02-14 18:58       ` decode-bitsize (Was: Re: delayed branches and zero overhead loops) Joern Rennecke
2007-02-13 19:25 ` delayed branches and zero overhead loops Doug Evans
2007-02-13 20:38   ` Joern Rennecke
2007-02-14 18:30     ` Doug Evans
2007-02-14 19:22       ` Joern Rennecke

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