This page provides detailed information about the Imperas Instruction Set Simulator for the ARM Cortex-M4F processor core.
Processor IP owner is ARM Holdings. More information is available from them here.
The Imperas Instruction Set Simulator (ISS) is a product of Imperas Software Ltd. It is a binary licensed by Imperas as a commercial product. It is also available in OVP packages for evaluation and demonstration.
The Imperas ISS uses the OVP Fast Processor Models and dynamically loads them as selected.The OVP Fast Processor Models are written using the OVP VMI API that provides a Virtual Machine Interface that defines the behavior of the processor.The VMI API makes a clear line between model and simulator allowing very good optimization and world class high speed performance.
The processor models are provided as a binary shared object and are also available as source (different models have different licensing conditions). This allows the download and use of the model binary or the use of the source to explore and modify the model.
The models have been run through an extensive QA and regression testing process.
If you develop your own processor models using the OVP VMI APIs then they can be used with the Imperas ISS.
Traditionally, processor models and simulators make use of one thread on the host PC. Imperas have developed a technology, called QuantumLeap, that makes use of the many host cores found in modern PC/workstations to achieve industry leading simulation performance. To find out about the Imperas parallel simulation lookup Imperas QuantumLeap. There are videos of QuantumLeap on ARM here, and MIPS here. For press information related to QuantumLeap for ARM click here or for MIPS click here. Many of the OVP Fast Processor Models have been qualified to work with QuantumLeap - this is indicated for this model below.
This ISS executes instructions of the target architecture and provides an interface for debug access. An interface to GDB is provided and this allows the connection of many industry standard debuggers that use the GDB/RSP interface. For more information watch the OVP video here.
The ISS also works with the Imperas Multicore Debugger and advanced Verification, Analysis and Profiling tools.
The ISS is downloadable (needs registration and to be logged in) in package Demo_Processors for Windows32 and for Linux32. Note that the ISS is also available for 64 bit hosts as part of the commercial products from Imperas.
This ISS uses the CPU with Model Variant name: Cortex-M4F
ARMM Processor Model
Usage of binary model under license governing simulator usage.
Note that for models of ARM CPUs the license includes the following terms:
Licensee is granted a non-exclusive, worldwide, non-transferable, revocable licence to:
If no source is being provided to the Licensee: use and copy only (no modifications rights are granted) the model for the sole purpose of designing, developing, analyzing, debugging, testing, verifying, validating and optimizing software which: (a) (i) is for ARM based systems; and (ii) does not incorporate the ARM Models or any part thereof; and (b) such ARM Models may not be used to emulate an ARM based system to run application software in a production or live environment.
If source code is being provided to the Licensee: use, copy and modify the model for the sole purpose of designing, developing, analyzing, debugging, testing, verifying, validating and optimizing software which: (a) (i) is for ARM based systems; and (ii) does not incorporate the ARM Models or any part thereof; and (b) such ARM Models may not be used to emulate an ARM based system to run application software in a production or live environment.
In the case of any Licensee who is either or both an academic or educational institution the purposes shall be limited to internal use.
Except to the extent that such activity is permitted by applicable law, Licensee shall not reverse engineer, decompile, or disassemble this model. If this model was provided to Licensee in Europe, Licensee shall not reverse engineer, decompile or disassemble the Model for the purposes of error correction.
The License agreement does not entitle Licensee to manufacture in silicon any product based on this model.
The License agreement does not entitle Licensee to use this model for evaluating the validity of any ARM patent.
The License agreement does not entitle Licensee to use the model to emulate an ARM based system to run application software in a production or live environment.
Source of model available under separate Imperas Software License Agreement.
Performance Monitors are not implemented.
Debug Extension and related blocks are not implemented.
Models have been extensively tested by Imperas. ARM Cortex-M models have been successfully used by customers to simulate the Micrium uC/OS-II kernel and FreeRTOS.
The model is configured with 16 interrupts and 3 priority bits (use override_numInterrupts and override_priorityBits parameters to change these).
Thumb-2 instructions are supported.
MPU is present. Use parameter override_MPU_TYPE to disable it or change the number of MPU regions if required.
SysTick timer is present. Use parameter SysTickPresent to disable it if required.
FPU extension is present. Use parameter override_MVFR0 to disable it if required.
DSP extension is present. Use parameter override_InstructionAttributes3 to disable it if required.
Bit-band region is not present. Use parameter BitBandPresent to enable it if required.
Many instruction behaviors are described in the ARM ARM as CONSTRAINED UNPREDICTABLE. This section describes how such situations are handled by this model.
Equal Target Registers:
Some instructions allow the specification of two target registers (for example, double-width SMULL, or some VMOV variants), and such instructions are CONSTRAINED UNPREDICTABLE if the same target register is specified in both positions. In this model, such instructions are treated as UNDEFINED.
Floating Point Load/Store Multiple Lists:
Instructions that load or store a list of floating point registers (e.g. VSTM, VLDM, VPUSH, VPOP) are CONSTRAINED UNPREDICTABLE if either the uppermost register in the specified range is greater than 32 or (for 64-bit registers) if more than 16 registers are specified. In this model, such instructions are treated as UNDEFINED.
If-Then (IT) Block Constraints:
Where the behavior of an instruction in an if-then (IT) block is described as CONSTRAINED UNPREDICTABLE, this model treats that instruction as UNDEFINED.
Use of R13:
Use of R13 is described as CONSTRAINED UNPREDICTABLE in many circumstances. This model allows R13 to be used like any other GPR.
Use of R15:
Use of R15 is described as CONSTRAINED UNPREDICTABLE in many circumstances. This model allows such use to be configured using the parameter "unpredictableR15" as follows:
Value "undefined": any reference to R15 in such a situation is treated as UNDEFINED;
Value "nop": any reference to R15 in such a situation causes the instruction to be treated as a NOP;
Value "raz_wi": any reference to R15 in such a situation causes the instruction to be treated as a RAZ/WI (that is, R15 is read as zero and write-ignored);
Value "execute": any reference to R15 in such a situation is executed using the current value of R15 on read, and writes to R15 are allowed.
Value "assert": any reference to R15 in such a situation causes the simulation to halt with an assertion message (allowing any such unpredictable uses to be easily identified).
In this variant, the default value of "unpredictableR15" is "execute".
The CPU model being used is downloadable (needs registration and to be logged in) in package armm.model for Windows32 and for Linux32. Note that the CPU model is also available for 64 bit hosts as part of the commercial products from Imperas.
OVP simulator downloadable (needs registration and to be logged in) in package OVPsim for Windows32 and for Linux32. Note that the OVP simulator is also available for 64 bit hosts as part of the commercial products from Imperas.
OVP Download page here.
OVP documentation that provides overview information on processor models is available OVP_Guide_To_Using_Processor_Models.pdf.
Full model specific documentation on the variant (Cortex-M4F) being used in this ISS is available OVP_Model_Specific_Information_armm_Cortex-M4F.pdf.
For more information on the Imperas ISS see the Imperas site and on the OVP Fast Processor model see the OVPworld site.
Location: The Fast Processor Model source and object file is found in the installation VLNV tree: arm.ovpworld.org/processor/armm/1.0
Processor Endian-ness: This model can be set to either endian-ness (normally by a pin, or the ELF code).
Processor ELF Code: The ELF code for this model is: 0x28
QuantumLeap Support: The processor model is qualified to run in a QuantumLeap enabled simulator.
Information on the Cortex-M4F OVP Fast Processor Model can also be found on other web sites::
www.ovpworld.org has the library pages http://www.ovpworld.org/library/wikka.php?wakka=CategoryProcessor
www.imperas.com has more information on the model library
http://www.ovpworld.org: Creating Instruction Accurate Processor models using the VMI API
http://www.ovpworld.org: VMI Operating System support (VMI OS) API Reference Guide
http://www.ovpworld.org: Renesas v850 Bare Metal Video Presentation
http://www.ovpworld.org: Altera Nios II Bare Metal & Cyclone III Linux Booting Demo Video
Currently available Instruction Set Simulator (ISS) Families.