|
SPARC (from "scalable processor architecture") is a RISC instruction set architecture (ISA) developed by Sun Microsystems and introduced in mid-1987. SPARC is a registered trademark of SPARC International, Inc., an organization established in 1989 to promote the SPARC architecture, manage SPARC trademarks, and provide conformance testing. Implementations of the original 32-bit SPARC architecture were initially designed and used in Sun's Sun-4 workstation and server systems, replacing their earlier Sun-3 systems based on the Motorola 68000 series of processors. Later, SPARC processors were used in SMP and CC-NUMA servers produced by Sun, Solbourne and Fujitsu, among others, and designed for 64-bit operation. SPARC International was intended to open the SPARC architecture to make a larger ecosystem for the design, which has been licensed to several manufacturers, including Texas Instruments, Atmel, Cypress Semiconductor, and Fujitsu. As a result of SPARC International, the SPARC architecture is fully open, non-proprietary and royalty free. In March 2006, the complete design of Sun's UltraSPARC T1 microprocessor was released in open-source form at (OpenSPARC.net ) and named the OpenSPARC T1. In 2007 the design of Sun's UltraSPARC T2 microprocessor was also released in open-source form as OpenSPARC T2.〔 The most recent commercial iterations of the SPARC processor design are the Fujitsu Laboratories Ltd.'s 34 core SPARC64 XIfx 2.2 GHz of 1.1 TFLOPS introduced 2015, which is used in the supercomputer PRIMEHPC FX100; the Fujitsu Laboratories Ltd.'s 16 core SPARC64 X+ introduced in 2014,〔 running at 3.2 GHz; the 32 core SPARC M7 introduced by Oracle Corporation in October 2015 running at 4.133 GHz. ==Features== The SPARC architecture was heavily influenced by the earlier RISC designs including the RISC I and II from the University of California, Berkeley and the IBM 801. These original RISC designs were minimalist, including as few features or op-codes as possible and aiming to execute instructions at a rate of almost one instruction per clock cycle. This made them similar to the MIPS architecture in many ways, including the lack of instructions such as multiply or divide. Another feature of SPARC influenced by this early RISC movement is the branch delay slot. The SPARC processor usually contains as many as 160 general purpose registers. At any point, only 32 of them are immediately visible to software – 8 are a set of global registers (one of which, g0, is hard-wired to zero, so only 7 of them are usable as registers) and the other 24 are from the stack of registers. These 24 registers form what is called a register window, and at function call/return, this window is moved up and down the register stack. Each window has 8 local registers and shares 8 registers with each of the adjacent windows. The shared registers are used for passing function parameters and returning values, and the local registers are used for retaining local values across function calls. The "Scalable" in SPARC comes from the fact that the SPARC specification allows implementations to scale from embedded processors up through large server processors, all sharing the same core (non-privileged) instruction set. One of the architectural parameters that can scale is the number of implemented register windows; the specification allows from 3 to 32 windows to be implemented, so the implementation can choose to implement all 32 to provide maximum call stack efficiency, or to implement only 3 to reduce cost and complexity of the design, or to implement some number between them. Other architectures that include similar register file features include Intel i960, IA-64, and AMD 29000. The architecture has gone through several revisions. It gained hardware multiply and divide functionality in Version 8. 64-bit (addressing and data) were added to the version 9 SPARC specification published in 1994.〔 In SPARC Version 8, the floating point register file has 16 double precision registers. Each of them can be used as two single precision registers, providing a total of 32 single precision registers. An odd-even number pair of double precision registers can be used as a quad precision register, thus allowing 8 quad precision registers. SPARC Version 9 added 16 more double precision registers (which can also be accessed as 8 quad precision registers), but these additional registers can not be accessed as single precision registers. No SPARC CPU implements quad-precision operations in hardware as of 2004. Tagged add and subtract instructions perform adds and subtracts on values checking that the bottom two bits of both operands are 0 and reporting overflow if they are not. This can be useful in the implementation of the run time for ML, Lisp, and similar languages that might use a tagged integer format. The endianness of the 32-bit SPARC V8 architecture is purely big-endian. The 64-bit SPARC V9 architecture uses big-endian instructions, but can access data in either big-endian or little-endian byte order, chosen either at the application instruction (load/store) level or at the memory page level (via an MMU setting). The latter is often used for accessing data from inherently little-endian devices, such as those on PCI buses. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「SPARC」の詳細全文を読む スポンサード リンク
|