SkyEye Introduction:
Tianmu all-digital real-time simulation software SkyEye, as a hardware behavior-level simulation platform based on visual modeling, can provide a virtualized operating environment for embedded software. Developers and testers can conduct software development, software testing and software verification on this virtual operating environment Activity. From small chips to large systems, SkyEye can simulate them.
01. Background introduction
In 1936, Alan Turing, known as the "father of computer science and artificial intelligence", proved the feasibility of a general-purpose computer capable of executing any computable sequence in his book [1], which established the foundation of computer simulation technology. theoretical basis. In the 1950s, the world's first "commercial program built-in electronic computer" EDSAC project used this theory, and the "STEP-BY-STEP" technology used in the error diagnosis technology already has the current processor The "interpret-execute" feature commonly used in simulation [2].
With the rapid improvement of computer hardware performance and the continuous progress of software technology, computer simulation technology has also made great progress and entered a broad and practical stage. It has been applied to transplant heterogeneous computers, develop processors, develop and test operating systems and applications. Software, virus detection, virtualization server and other fields.
Among the many fields of application simulation, embedded software development and testing is particularly prominent in the applicability of simulation technology due to the following characteristics:
(1) Complex cross-development environment: simulation can avoid the download operation of executable files;
(2) Relatively low-speed embedded processor: the performance loss caused by simulation can be overcome by the running speed of the PC, even exceeding the running speed of the real target machine;
(3) Embedded software with high reliability requirements: avoid the lack of physical test environment and its inherent defects.
The method of using simulation technology to construct virtual verification system of embedded software has been paid more and more attention.
02. Full digital real-time simulation
As the most suitable type of simulation technology for embedded software, all-digital real-time simulation technology refers to the pure software simulation of the simulation target on the basis of meeting the real-time requirements of the simulation target hardware platform.
All-digital real-time simulation in the embedded field refers to modeling the SoC and various peripherals of the embedded board through software , and realizing functional-level simulation, and its real-time performance can be comparable to that of real hardware. Its main value is that it can be separated from the hardware, and the function development and non-intervention verification can be carried out in time or even in advance, and the simulation results are consistent with the running results of the hardware platform.
03.SkyEye simulates Loongson 2K1000 processor
Loongson Zhongke, as a well-known independent CPU design supplier in China, has launched three series (Loongson No. 1, No. 2, and No. 3) CPUs and self-developed LoongArch instruction set to meet the needs of national informatization construction. This article mainly focuses on the Loongson-2 series products: Loongson 2K1000 processor.
The Loongson 2K1000 processor is mainly oriented to network applications, taking into account both tablet applications and industrial control applications. Using 40nm technology, it integrates two GS264 processor cores on-chip, compatible with MIPS64 architecture, with a main frequency of 1GHz, a 64-bit DDR3 controller, and various system IO interfaces.
Loongson 2K1000 structure diagram is as follows:
▲ Loongson 2K1000 structure diagram
Using the SkyEye platform to simulate the Loongson 2K1000 is divided into three steps:
Step 1: Based on SkyEye's device modeling tool, complete the functional-level modeling of the CPU and peripherals on the Loongson 2K1000 board, and form a dynamic link library for the SkyEye simulation engine to use.
Step 2: According to the Loongson 2K1000 structure diagram, in the modeling area of SkyEye Workstation, drag and drop the basic module (completed in the first step), configure peripherals and bus properties to complete the Loongson 2K1000 board-level modeling, at this time A full digital simulation board has been obtained.
Step 3: Create the startup script of SkyEye, which corresponds to the burning process of the physical board.
SkyEye already supports Loongson 2K1000, and successfully runs Linux3.10 (compiled with gcc4.9) on this emulation board, and you can enter Shell commands to interact with Linux through the serial port. The following is the running process:
references
[1] Turing A M. On Computable Numbers, with an Application to the Entscheidungsproblem[J]. Proceedings of the London Mathematical Society, 1936, 42(1):230-265.
[2] Gill S. The Diagnosis of Mistakes in Programmes on the EDSAC[J]. Proceedings of the Royal Society A Mathematical Physical & Enginee ring Sciences, 1951, 206(1087):538-554.