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发表于 2009-12-1 22:27 · 内蒙古
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显示全部楼层
楼上的大概都说了,我也摘一小段英文资料,有闲的可以看看:
The RSX is a graphical processor unit (GPU) based off of the nVidia 7800GTX graphics processor, and is a G70/G71 hybrid with some modifications. The RSX has separate vertex and pixel shader pipelines. The chip model number is CXD2982 GB for PS3 Fat. CDX2991 EGB for Slim. The following are relevant facts about the RSX...
Little Endian
8 vertex shaders at 500Mhz
28 pixel shaders (4 redundant, 24 active) at 550Mhz
28 texture units (4 redundant, 24 active)
8 Raster Operations Pipeline units (ROPs)
Includes 256MB GDDR3 650Mhz clocked graphics memory
Earlier PS3 Models: Samsung K4J52324QC-SC14 rated at 700Mhz
Later PS3 Models: Qimonda HYB18H512322AF-14
GDDR3 Memory interface bus width: 128bit
Rambus XDR Memory interface bus width: 56bit out of 64bit (serial)
258mm2 die size 90nm technology (earlier models)
65nm (later models) technology
More features are revealed in the following chart delineating the differences between the RSX and the nVidia 7800 GTX.
Difference RSX nVidia 7800GTX
GDDR3 Memory bus width 128bit 256bit
ROPs 8 16
Post Transform and Lighting Cache 63 max vertices 45 max vertices
Total Texture Cache Per Quad of Pixel Pipes (L1 and L2) 96kB 48kB
CPU interface FlexIO PCI-Express 16x
Technology 65nm/90nm 110nm
Other RSX features/differences include:
More shader instructions
Extra texture lookup logic (helps RSX transport data from XDR)
Fast vector normalize
Note that the cache (Post Transform and Lighting Vertext Cache) is located between the vector shader and the triangle setup.
A sample flow of data inside the RSX would see them first processed by 8 vertex shaders. The output are then sent to the 24 active pixel shaders, which can involve the 24 active texture units. Finally, the data is passed to the 8 Raster Operation Pipeline units (ROPs), and on out to the GDDR3. Note that the pixel shaders are grouped into groups of four (called Quads). There are 7 Quads, with 1 redundant, leaving 6 Quads active, which provides us with the 24 active pixel shaders listed above (6 times 4 equals 24). Since each Quad has 96kB of L1 and L2 cache, the total RSX texture cache is 576kB. General RSX features include 2x and 4x hardware anti-aliasing, and support for Shader Model 3.0.
Although the RSX has 256MB of GDDR3 RAM, not all of it is useable. The last 4MB is reserved for keeping track of the RSX internal state and issued commands. The 4MB of GPU Data contains RAMIN, RAMHT, RAMFC, DMA Objects, Graphic Objects, and the Graphic Context. The following is a breakdown of the address within 256MB of the RSX.
Address Range Size Comment
0000000-FBFFFFF 252 MB Framebuffer
FC00000-FFFFFFF 4 MB GPU Data
FF80000-FFFFFFF 512KB RAMIN: Instance Memory
FF90000-FF93FFF 16KB RAMHT: Hash Table
FFA0000-FFA0FFF 4KB/s RAMFC: FIFO Context
FFC0000-FFCFFFF 64KB DMA Objects
FFD0000-FFDFFFF 64KB Graphic Objects
FFE0000-FFFFFFF 128KB GRAPH: Graphic Context
RSX Libraries
The RSX is dedicated to 3D graphics, and developers are able to use different API libraries to access its features. The easiest way is to use high level PSGL, which is bascially OpenGL|ES with programmable pipeline added in. At a lower level developers can use LibGCM, which is an API that talks to the RSX at a lower level. PSGL is actually implemented on top of LibGCM. For the advanced programmer, you can program the RSX by sending commands to it directly using C or assembly. This can be done by setting up commands (via FIFO Context) and DMA Objects and issuing them to the RSX via DMA calls. |
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