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FAST CPU SIMULATION METHOD AVOIDING THE CALCULATION OF RESULTS WHICH ARE NOT FURTHER USED

IP.com Disclosure Number: IPCOM000009530D
Original Publication Date: 1999-Sep-01
Included in the Prior Art Database: 2002-Aug-30
Document File: 1 page(s) / 69K

Publishing Venue

Motorola

Related People

Vassily Nikolaevitch Soloviev: AUTHOR

Abstract

The proposal relates to simulating central pro- cessing units (CPUs). A CPU is a hardware arrange- ment with operand register (OR), flag' register (FR) and instruction decoder (ID). The CPU is usually coupled to a memory (M). A simulator is a computer (hardware) which represents the CPU (CPU': OR', IX', ID') and the memory (M') virtually by execut- ing simulation software called model. Usually, the simulator operates CPU' by executing an application program designed for hardware CPU and simulates ID' using a look-up table.

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MOTOROLA Technical Developmenfs

@

FAST CPU SIMULATION METHOD AVOIDING THE CALCULATION

OF RESULTS WHICH ARE NOT FURTHER USED

by Vassily Nikolaevitch Soloviev

INTRODUCTION

  The proposal relates to simulating central pro- cessing units (CPUs). A CPU is a hardware arrange- ment with operand register (OR), flag' register (FR) and instruction decoder (ID). The CPU is usually coupled to a memory (M). A simulator is a computer (hardware) which represents the CPU (CPU': OR', IX', ID') and the memory (M') virtually by execut- ing simulation software called model. Usually, the simulator operates CPU' by executing an application program designed for hardware CPU and simulates ID' using a look-up table.

PROBLEM

  When the CPU executes an instruction, the CPU substantially simultaneously provides results by changing the states of OR, FR and M. The results are classified into main (in OR and M) and side (in FR) results. The side result depends on the main result. Later, when the CPU executes further instruc- tions, the CPU usually uses the main result, and, alternatively, uses the side result ("USE") or does not use the side result ("VOID"). Providing a VOID does not slow down the operation of the CPU.

  Similar as above, the simulator simulates the execution of the instruction (of application program) and provides virtual results by changing the states of OR', FR', and M'. However, the simulator provides the results consecutively, and not simultaneously. Similar as above, when the...