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Message
From: "Damon Brantley" <brantley@m...>
Date: Wed, 23 Apr 2003 21:41:20 -0500
Subject: Re: [openrisc] Re:Getting the size down
I took out the multiplier and it cut the utilization on my gate array from
96% to 72%.
This includes the vga interface I added. With just synthesizing or1200_top,
utilization went from 89% to 70%.
These are just the numbers that xst spits out when the synthesis is done.
Still it is enough for me
to push on.
It did take more than a simple removal of the multiplier. My test c
program, which just bounces a character
around on the display, acted very flaky with just removing the multiplier
instantiation.
I had to chase down the connections to the related modules and def things
out as needed. Possibly there
were some dangling outputs that were generating noise.
Regards,
Damon
At 04:33 PM 4/23/2003 -0700, you wrote:
>Damon,
>
>You can comment (disable) the following assuming you don't need them:
>OR1200_CFGR_IMPLEMENTED (this one most likely you don't need)
>OR1200_TT_IMPLEMENTED (do you need tick timer?)
>OR1200_CASE_DEFAULT (some case defaults will be removed, might confuse some
>synthesis tools)
>
>If you update your sources from the cvs, then you will also be able to
>disable implementations of not needed exceptions. For deeply embedded
>applications running firmware certain exceptions like alignment, illegal
>instruction and bus error are not needed at all.
>
>Also like Michael said you can remove multiplier if you don't needed. Right
>now there is no define to disable multiplier. I can add one if there is
>demand, and even beter is idea of simple small shifting multplier.
>
>regards,
>Damjan
>
>----- Original Message -----
>From: "Damon Brantley" <brantley@m...>
>To: <openrisc@o...>
>Sent: Wednesday, April 23, 2003 4:42 AM
>Subject: [openrisc] Re:Getting the size down
>
>
>>
>> Here it is.
>>
>> Thanks,
>> Damon
>>
>> >Can you send your or1200_defines.v so I can see if you really "removed"
>> >everything possible.
>> >
>> >regards,
>> >Damjan
>>
>> >----- Original Message -----
>> >From: "Damon Brantley" <brantley@m... >
>> >To: <openrisc@o... >
>> >Sent: Tuesday, April 22, 2003 7:52 PM
>> >Subject: [openrisc] Getting the size down
>>
>>
>> >> I am currently working with a board made by Digilent that has a Spartan
>> IIe
>> >> with 300k
>> >> gates. By removing all the cache and debug logic, the openrisc cpu uses
>> >> about 84% of the available space.
>> >> My last test project,which interfaced with the vga display, pushed the
>> >> utilization up to 96%.
>> >> Are there any other places where I can do some pruning and get the size
>> >> down more. To get ucLinux up and
>> >> running I need at least enough space to add the memory controller to
>> access
>> >> some external memory
>> >> and the UART.
>> >>
>> >>
>
>
>----------------------------------------------------------------------------
>----
>
>
>>
>>
>
>
>
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