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RISC/DSP cores gain Linux development support

Jun 24, 2010 — by Eric Brown — from the LinuxDevices Archive — 2 views

Semiconductor IP vendor Virage Logic, which is soon to be acquired by Synopsis, released Linux toolchains for its 32-bit RISC/DSP ARC processor cores. The ARC GNU 2.3 Toolchain suite is available for the company's ARC cores, and the ARC Linux 1.3 distribution is available for its high-end, ARC 750D RISC/DSP processor core, which targets consumer electronics devices.

Virage Logic develops configurable, licensable CPU/DSP core IP (intellectual property) for system-on-chip (SoC) processors. The company acquired ARC International and its ARC cores in November, and is now itself set to be acquired by Synopsis (see farther below).

ARC International announced that its ARC 700 processor cores would be available with a Linux distribution from Codito Technologies back in 2004. ARC added SIMD (single-instruction, multiple-data) instruction support to the ARC 700 line in 2005, and added support subscriptions for the Codito Linux tools in 2007.

Now, Virage Logic is offering a full Linux development package of its own. Virage Logic's GCC 4.2.1 based ARC GNU Toolchain for the ARC supports the company's complete range of ARC processor cores, says the company.

Optimized for the ARC processor architecture, the open source ARC GNU Linux distribution and ARC Linux Toolchains are supported with ARC Instruction Set Simulators, which enable software development long before silicon is available, says the company. The ARC Linux distribution for the high-end ARC 750D is said to be based on a Linux 2.6.30 kernel, and is said to include BusyBox, uboot, and InitRamFS.

ARC's cores are equipped with the ARCompact ISA (instruction set architecture), enabling 16- and 32-bit instructions to be freely mixed without overhead. This is said to deliver memory footprint savings of up to 40 percent.

The cores can be configured with three different execution blocks, such as cache, FPU (floating point unit), and DSP (digital signal processor), says Virage Logic. Designers can then tune the parameters of the blocks, such as altering cache size and CPU register file size. Designers can define custom instructions, additional core and auxiliary registers, custom condition codes, and co-processor interfaces, the company says.

ARC 700 processor cores

The ARC 750D is the high-end version of a three-product ARC 700 family which includes the ARC 710D and ARC 725D. The 32-bit RISC processor cores offer a seven-stage pipeline, and are touted for small die size, low power consumption, and performance of over 1.5 DMIPS/MHz.

ARC 750D block architecture
(Click to enlarge)

The ARC 700 processor cores are supported by Virage Logic's own ARC MQX real-time operating system (RTOS), as well as Linux, Express Logic's ThreadX, Micrium's uC/OS-II, and uITRON, says the company.

The cores are also supported by the ARC MetaWare Development Toolkit, which is said to include a C/C++ compiler, advanced debugger, integrated profiler, and an Eclipse IDE (integrated development environment). A GNU suite, including gcc and gdb, is also available.

The ARC 750D core is designed for "complex SoCs running Linux or other high-end operating systems," says Virage Logic. It is billed as being a complete application processor for home entertainment systems, portable devices such as smartphones and PDAs, and automotive telematics systems.

The ARC 750D core requires less than half the die area and half the power compared to ARM1136 and MIPS32 24Kc cores with similar configuration and speed, claims the company.

The processor design features a built-in DSP with instruction and register extensions that accelerate signal processing algorithms. An optional "ARC XY Advanced DSP subsystem," meanwhile, delivers the performance of dedicated DSP cores, allowing external logic and DSP blocks to be eliminated, says the company.

A JTAG debug port and optional embedded hardware breakpoints are available, and options include integrated timers, interrupt controllers, and bit manipulation instructions, says Virage Logic. The processor is also said to feature built-in inter-processor communications capabilities for multicore designs.

Stated Mike Thompson, director of product marketing for Processor and SoC Solutions at Virage Logic, "Linux and GNU have seen renewed interest among software developers thanks to the exploding popularity of Android. Virage Logic is committed to supporting GNU and Linux for its ARC processor cores to give customers a broad choice in the selection of development tools for their specific application." 

Synopsis to buy Virage Logic for $315 million

On June 10, Synopsis announced it was acquiring Virage Logic for approximately $315 million. Virage Logic's products will complement Synopsys' DesignWare interface and analog IP portfolio by adding embedded memories with test and repair, non-volatile memories (NVMs), standard cell libraries, and programmable cores for control and multimedia sub-systems, says Synopsis. The transaction is said to be subject to regulatory and Virage Logic shareholder approval, as well as other customary closing conditions.

Stated Aart de Geus, chairman and CEO at Synopsys, "With more functionality being integrated into a single device, high-quality IP continues to be key for enabling designers to reduce integration risk and speed time-to-market. Bringing Synopsys and Virage Logic together broadens our portfolio and builds on two very strong technical teams."


The ARC GNU 2.3 Toolchain suite and ARC Linux 1.3 distribution are available now, free of charge, and may be downloaded at SourceForge, here, says Virage Logic. More information about the ARC 700 processor family may be found here, and should eventually be available at Synopsis' website, here.

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