Sony Emotion Engine

Sony Emotion Engine
architectural overview
2002.5.20
Kim L. Vu
Acronyms
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ALU
COP
DMAC
DSP
EE
EFU
GIF
IPU
MAC
RDRAM
SPRAM
VPU
Arithmetic Logic Unit
Coprocessor
Direct Memory Access Controller
Digital Sound Processing
Emotion Engine
Elementary Functional Unit
Graphics Interface
Image Processing Unit
Multiply-Accumulate
Rambus Dynamic RAM
Scratch-Pad RAM
Vector Processing Unit
Overview (ps2 architecture)
Emotion Engine
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VU0
VU1
 CPU + FPU
 IPU
thought simulation, AI, physics calculations
SIMD, VLIW architecture
fixed geometry calculations
program control
real-time image data decompression
Emotion Engine Features
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300Mhz MIPS III CPU
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Two-issue superscalar,128-bit multimedia extensions
16k, 2-way instruction cache
8k, 2-way data cache
16k “scratch pad” RAM
Vector Units
– Both have 4 FMACS + 1 FDIV
– EFP (Elementary function unit) in VU1
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1 FMAC + 1 FDIV
128-bit data bus
IPU – MPEG2 decoder unit
10-channel DMA Controller
CPU Core Features
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MIPS III Instruction Set architecture
6 stage pipeline
- PC Select | Fetch | Register | Exec | Cache Access | Write Back
Two 64-bit integers ALUs
– ALUs can be combined in”lock step” to execute 128-bit SIMD operations
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Load/Store Unit
Branch Execution Unit
– 64-entry two-branch prediction mechanism
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32 128-bit registers
Vector unit performance
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Microarchitecturally identical
4 FMACS
1 FDIV
1 Load/Store Unit
1 ALU
1 random number generator
2 issue VLIW (64-bit bundle)
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Two operating modes
VLIW and Coprocessor mode
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Throughput
FMAC operation – 1 cycle
FDIV operation – 7 cycles
4x4 matrix * vector – 4 cycles
4x4 matrix * matrix – 16 cycles
VU Features
VU0
Features
VU1
Flexible calculations
Fixed 3D calculations
VLIW mode
Yes
Yes
Coprocessor mode
Yes
No
VPU components
4k instruction RAM
4k data RAM
VIF
16k instruction RAM
16k data RAM
VIF
GIF
EFU
4 FMACS (2.4 Gflops)
1 FDIV (0.04 Gflops)
4 FMACS (2.4 Gflops)
1 FDIV (0.04 Gflops)
1 EFU (0.64 Gflops)
Job
Performance
VPU0 Design Strategy
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2-modes : VLIW and coprocessor
- Runs mainly in coprocessor mode
Lower opcode always NOP
- Controlled by CPU
- Executes 32-bit MIPS coprocessor instructions
- Processes 4 parallel FP instructions
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VPU1 Design Strategy
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Can only run in VLIW mode
 Executes 64-bit VLIW bundle
 Accessed by 3D display list
– 3D display list contain boht instruction and data in
same structure
VU Instruction Formats
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Instruction bundle has 2 parts
– “upper” (SIMD) + “lower”
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“Lower” execution unit
FP div/sqrt/reverse sqrt
Load/store
EFU(1 FMAC + 1FDIV)
Jump/branch
Random number generator
“Upper” execution unit
4 parallel FP add/sub
4 parallel FP mul
4 parallel FP add/msub
EE Teams
Team 1
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Handles physics, program control, AI and
behavior calculations
 Members work closely together with each other
 Ease of communication through
– 128-bit dedicated busses from CPU to FPU and VU0
– SPRAM – acts as CPU and VU0’s shared workspace
Team 2
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Handles simple geometric
calculations
 Members act as equal
partners
 Dedicated 128-bit bus from
VPU1 to GIF
Team Interoperation
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Serial connection
– VPU0 acts as VPU1’s coprocessor
– SPRAM is used to transfer data to
VPU1
– VPU1 renders final image
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Parallel connection
– GIF monitors the status of the
graphics synthesizer
– Both teams independently and
asynchronously sends display lists
References
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Atsushi Kunimatsu, et. al., “Vector Unit Architecture for Emotion
Synthesis”, IEEE Micro, Vol. 20, No. 2, March/April 2000, pp. 40-47
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K. Kutaragie et. al., “A Microprocessor with 128b CPU, 10 Floating-Point
MACS, 4 Floating-Point Dividers, and MPEG2 Decoder,” ISSCC (Int’l SolidStates Circuit Conf.) Digest Tech. Papers, IEEE Press, Piscatawey, New
Jersey, Feb. 1999, pp. 256-257
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F. Micheal Raam, et. al., “A High-Bandwidth Superscalar Microprocessor
for Multimedia Applications,” ISSCC Digest Tech. Papers, IEEE Press, Feb.
1999, pp. 258-259
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Sound and Vision: A Technical Overview of the Emotion Engine by John
Stokes, Ars Technica
– http://arstechnica.com/reviews/1q00/playstation2/ee-1.html
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The Playstation2 vs. the PC: A System-level Comparison of Two 3D
Platforms by John Stokes, Ars Technica
– http://arstechnica.com/cpu/2q00/ps2/ps2vspc-1.html