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Author Topic: Of FPGAs and the way forward  (Read 6681 times)

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Offline SamuraiCrowTopic starter

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Re: Of FPGAs and the way forward
« Reply #29 from previous page: August 10, 2008, 08:19:55 PM »
Update from the Natami website regarding how the memory busses are connected:

Quote

Just like the original AMIGA, the NATAMI has two fully separate memory busses.

1) The CHIP-memory bus
2) The Fast memory bus.

The SuperAGA chipset has in addition to this a very small 3rd memory block inside the chipset. This 3rd memory block is a Sprite/3D cache and can be used to accelerate blitting and 3D operations.

The two buses are independent and the NATAMI can do two memory operation at the same time, one to each of the buses.
In addition to these two memory access on the two external buses, the NATAMI Blitter can do several memory operations per clock inside his local store.

The CHIP-memory is 64bit wide and is build from very fast pipelined, syncrones external SRAM.
The fast memory on the Natami60 is regular SDRAM.

A major strength of the original AMIGA design is its DMA capabilities. The Natami is fully compatible to this.
But of course the SuperAGA chipset is faster and can do 100 times more DMA than the original AMIGA chipset.

The original AMIGA could do Audio and Sprite DMA into Chip memory only. The original AMIGA could do SCSI DMA into fast memory.
This means the original AMIGA could do DMA to both memory busses but not fully freely.

The Natami improves this design. The Natami can do all types DMA to both memory banks.

From a programming point of view you can program the Natami liek any other AMIGA.
It good to use the chip memory as always to keep your audio and video data in it.

For best performance you should always store your heavy accessed video data in chip memory. But as  the Blitter can read from fats-memory as well you are more flexible in creating huge games as you can as well store information inside the bigger fast memory.

SuperAGA is many times faster than normal AGA out of several reasons.

a) Blitter and Chipmemory are 64bit wide.
AGA was 16bit wide.

b) Blitter and Chipmemory is much higher clocks. Natami Chipmemory can be clocked to 200 MHz. While the original AMIGA was only working at 3.7 MHz.

c) The Natami Blitter has a local store inside the chip which means if you blit the same sprite many times or draw the same texture several time you only need to read it once. Depending on your game engine this can up to quadruple the overall performance.


So the chip bus is off of the FPGA but there is a 32Kbyte local store for the 3D and vector acceleration portion of the new SuperAGA Chipset.
 

Offline shoggoth

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Re: Of FPGAs and the way forward
« Reply #30 on: August 13, 2008, 08:05:57 PM »
Quote

Atheist wrote:
AOS is so streamlined, that even games that need 1 GHz P4s may actually be able to run on NatAmi60s!


Even though AOS doesn't impose much overhead compared to Windows, there's a physical limit to everything. You won't get P4 performance from a 060.

When porting stuff to another 680x0-based platform, I've concluded that stuff intended for ~300Mhz Pentium machines often runs well on a 100Mhz 060. This comparison assumes low OS overhead (well, virtually none in fact) and slow chipram for graphics, which means it's most problably applicable on the Amiga as well.

Quote

Atheist wrote:
Look at, just how big is DirectX?!? Can't tell me that doesn't use tons of Hz.


On the other hand, DirectX provides tons of accelleration features. I think size is a bad comparison here.
 

Offline wawrzon

Re: Of FPGAs and the way forward
« Reply #31 on: August 13, 2008, 09:48:13 PM »
yet again i stumble upon a thread where uncorrect statemnents by supporters of the natami project are made. gunnar v.b. has never stated that the 16mb chip ram is going to be included into the fpga. i dont know if this project is going to work out but it is unfair to criticize something or someone on account of hearsay.
also the dev team has never stated that the natami's computing speed is going to be comparable to p4 clocked @ some ghz.

 
 

Offline SamuraiCrowTopic starter

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Re: Of FPGAs and the way forward
« Reply #32 on: August 14, 2008, 03:31:09 AM »
I posted that quote from the Natami website as a correction for my previous bad information.

What they said on the Natami website about the speed of it is that it should be comparable to the Wii or the Playstation 2.
 

Offline wawrzon

Re: Of FPGAs and the way forward
« Reply #33 on: August 14, 2008, 04:01:40 AM »
@SamuraiCrow:
apologies, sir. once more ive been too careless reading.