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LISA-Machine Description Language and Generic Machine Model for SW/HW Co- Design. -Vojn Zivojnovic Stefen Pees Heinrich Meyr. Introduction. L-chart Instruction Set Architecture Language(LISA)
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LISA-Machine Description Language and Generic Machine Model for SW/HW Co- Design -Vojn Zivojnovic • Stefen Pees • Heinrich Meyr
Introduction • L-chart Instruction Set Architecture Language(LISA) • Improved work over HDL (Verilog,VHDL) and Machine Model Languages( Ptolemy,PIXIE,Sable, MARIL,VLIW ) • Generic machine model to cover difference between standard ISA Models and description languages.
Advantages of LISA • Abstract • Reduce Complexity • Improve runtime over other HDL and Machine Model Languages • Common solution for Processor Architecture
Characteristics of LISA • Application Domain: • Real time Software design ( Word Length analysis, memory optimization, Speed, DSP/Embedded system ,HW/SW co verification, architecture explorations) • Processor Class: • DSP and micro controllers of low or medium complexity with pipeline and RISC processors • Model Accuracy: • Selectable instructions,clock/phase accurate timing,bit accurate register transfer, exact pipeline with wait and interrupts • State visibility: • Complete state visibility at selected control steps
Partitioned into basic scheduled units Transition function Ft change machine state Transition take place in control step at t Precedence and Resource constraint determine next function Operation Sequencer:
Operation Sequencing • Reservation Table • Two dimensional representation of resource allocation in the resource time • A mark in a table indicating corresponding Processor resource etc. bus,functional units • Gantt chart-Uniquely specify operations • Instruction scheduling • Reservation table give details • Clock accurately model • Covert Time axis into precedence axis
01 (R1) | 02(R2) | 03(R3) | 04(R4),05(R5) | 06(R6) Vertical Lines : Precedence Commas: Parallelism Parenthesized: Resources Gannt’s Chart Sequencing&LISA Style
Gannt’s Concept for Hazards • Data & Control Hazard • Access storage has to specified for Read or Write • Access storage has to be acknowledged before operation Hazard: IF | ID (!w=R0) | IA | IE(w=R0)| %Inst set #1 IF | ID(r=R0)| IA | IE %Inst set #2 Solution IF | ID(!w=R0)|IA |IE(w=R0) | IF | NOP | NOP | ID(ro=R0) | IE
Continued… • Stall (wait state by memory or cache) • Resource Reservation for external events • Flushing (permits) • Descriptor of Operation k:03 • Dynamic scheduling to avoid Hazard • Rearrange instructions set
Conclusion: • LISA enable fast and comfortable solution for embedded & processors • Supports design, verification and co design environments • L-charts supports data hazards and pipeline flushing,interlocking bypassing • Model use ASAP to obey Time & Resource Constraints