Obscure names

Obscure names

[Pavel Baranov]

I'm trying to understand how CGEN works and thanks to CGEN manual
the overall picture is more or less clear. One thing which is not described
in this manual (or I couldn't find the description) is the names like
'src1', 'src2,
'sr', 'dr' in .cpu files in Model/Unit descriptions (for example in
m32r.cpu). I can guess
that these are some kind of register names but I haven't seen list of
possible names
and their descriptions. Can you help me with this information?

Regards,
Pavel

Re: Obscure names

[Dave Brolley]

These are the names of operands in the instructions which use those 
particular units. These in turn are usually named to correspond directly 
with the names used in the instruction set manual of the cpu.

I hope this helps,
Dave

Pavel Baranov wrote:

> I'm trying to understand how CGEN works and thanks to CGEN manual
> the overall picture is more or less clear. One thing which is not described
> in this manual (or I couldn't find the description) is the names like
> 'src1', 'src2,
> 'sr', 'dr' in .cpu files in Model/Unit descriptions (for example in
> m32r.cpu). I can guess
> that these are some kind of register names but I haven't seen list of
> possible names
> and their descriptions. Can you help me with this information?
> 
> Regards,
> Pavel
> 
> 
> 
> 
> 

Obscure names

[Doug Evans]

Pavel Baranov writes:
 > I'm trying to understand how CGEN works and thanks to CGEN manual
 > the overall picture is more or less clear. One thing which is not described
 > in this manual (or I couldn't find the description) is the names like
 > 'src1', 'src2,
 > 'sr', 'dr' in .cpu files in Model/Unit descriptions (for example in
 > m32r.cpu). I can guess
 > that these are some kind of register names but I haven't seen list of
 > possible names
 > and their descriptions. Can you help me with this information?

These are register operand names that are invented by the person doing
the port.  Generally one tries to pick identical names to what's in the
architecture reference manual.  The m32r manual uses dr and sr,
hence m32r.cpu uses dr and sr.  The fr30 manual uses Rj and Ri
thus fr30.cpu uses Rj and Ri.

If you look in m32r.cpu you'll see this:

(dnop sr     "source register"              () h-gr   f-r2)
(dnop dr     "destination register"         () h-gr   f-r1)

Those are what's refered to in

  (unit u-exec "Execution Unit" ()
	1 1 ; issue done
	() ; state
	((sr INT -1) (dr INT -1)) ; inputs
	((dr INT -1)) ; outputs
	() ; profile action (default)
	)

[and so on for all the other names/registers]

Re: Obscure names

[Frank Ch. Eigler]

Hi -

On Mon, Apr 23, 2001 at 11:02:39AM -0700, Pavel Baranov wrote:
: [...]
: One thing which is not described in this manual (or I couldn't find
: the description) is the names like 'src1', 'src2, 'sr', 'dr' in .cpu
: files in Model/Unit descriptions (for example in m32r.cpu). [...]

In the m32r.cpu file, you will see all those names defined as operands
(via the "dnop" macro).  If you see those strings in other target ports,
then they are there only as a placeholder and cannot be used as is.


- FChE
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Re: Obscure names

[Nitin Gupta]

sr and dr are source register and target registers
src1 and src2 are sources for various functional units

You are not required to use the same names, If you are using *.cpu as an
skeleton for your own port.

I will suggest that if you are not sure of any variable defined in xyz.cpu,
try to see its usage in xyz.c. Or just use a source browsing tool like CSCOPE.

Nitin

nitin@mobilygen.com
www.mobilygen.com

Pavel Baranov wrote:

> I'm trying to understand how CGEN works and thanks to CGEN manual
> the overall picture is more or less clear. One thing which is not described
> in this manual (or I couldn't find the description) is the names like
> 'src1', 'src2,
> 'sr', 'dr' in .cpu files in Model/Unit descriptions (for example in
> m32r.cpu). I can guess
> that these are some kind of register names but I haven't seen list of
> possible names
> and their descriptions. Can you help me with this information?
>
> Regards,
> Pavel

--
--------------------------------------------------------------------------
Nitin Gupta                          Mobilygen Corp.
Email: nitin@mobilygen.com           2520 Mission College Blvd., Suite 201
Phone: (408) 869-4049(direct)        Santa Clara, CA  95054
Fax  : (408) 980-8044                www.mobilygen.com

RE: Obscure names

[Doug Evans]

Pavel Baranov writes:
 > Wow! I didn't expect so many responses as I thought cgen is
 > a rather small community :) Any ideas how big it is?

Not that big.  10?

RE: Obscure names

[Pavel Baranov]

Wow! I didn't expect so many responses as I thought cgen is
a rather small community :) Any ideas how big it is?

Thanks,
Pavel