ApplicationSpecific InstructionSet Processor ASIP

1
ApplicationSpecific Instruction-Set Processor (
ASIP )

• 2004 . 10. 2
• Supercomputing Lab Seminar
• By Kim Byoung Gil

2
Concept of ASIP

• A processor designed for particular
  application(s).
• Exploits special characteristics of
  application(s) to meet the desired performance,
  cost and power requirements.
• Balance between ASIC and general programmable
  processor (GPP)
• ASIC is specially designed for one behavior. Hard
  to change
• ASIP offer the required flexibility at lower cost
  than GPP

3
ASICs

• Strength
• Offers the ultimate in tailored hardware
• Performance, energy efficiency, cost/performance
• Integration to match the product requirements
• Vast architectural options
• Weaknesses
• Large development costs and risks vs.
  off-the-shelf hardware mask costs increasing
• Long developments cycles
• Inflexibility

4
ASIPs

• Off-the-shelf, fixed-function chips specialzed
  for an application
• Similar to an ASIC in design
• Many architecture possibilities
• May contain one or more processor cores
• May be a SoC with memory, peripherals ,.etc
• ASIC designed by application system designer
  for their usage
• ASIP designed by chip designer to sell
  application system designer

5
ASIPs

• Strength
• Often very well matched to the application
• SoCs with extensive integration
• Architecture turned for the application
• Ease of use
• Reduce system development costs
• Reduce required implementation experties
• Weaknesses
• Often inflexible
• Limited differentiation opportunities for system
  designer
• Usually single-source
• Roadmap often unclear

6
Example ASIP (Micronas MDE9500)

• High-integration digital TV receiver
• Analog decode, DVB decryption, decode
• On-chip MPEG-2 video decoder
• Interfaces to other DTV components, VCRs, HDD
• Multi-layer software architecture

7
Point of ASIP Design

• Design starts with the application behavior
• Evaluate several architectural options.
• Identify hardware functionalities to speed up the
  application
• Introduce hardware resources for frequently used
  operations only if it can be supported during
  compilation

8
Steps of ASIP Design
9
Application Analysis

• An application written in a high level language
  is analyzed
• To get the desired characteristics/requirements
  which can guide the hardware definition
• Analyzed information is stored in some suitable
  intermediate format.
• Application Program Analyzer (APA) helps to gain
  application information
• Average basic block size
• ration of address computation/data computation
• ratio of I/O inst./ total inst.
• Number of Multiply-Accumulate (MAC) operations
  ,.etc

10
Architectural Exploration

• Design several candidate architectures based on
  application analysis
• Performance of possible architecture is estimated
  and suitable architecture satisfying the
  requirements is selected
• Using retargetable simulator for an architecture
  template
• The simulator, by using pre-defined modules and
  architecture description, reports performance and
  power consumption

11
Instruction-set generation

• On the foundation of selected architecture,
  instruction set is defined
• The fucntionality of instruction is classified by
  frequency and reliability, as follow
• primary
• basic
• extended
• Generated ASIP will include hardware module
  corresponding all primary instruction, a part of
  basic and extended instruction

12
Summary

• ASIC vs. ASIP
• Steps of ASIP design
• application alalysis
• architecture exploraton
• instruction-set generation