Misplaced Pages

#433566

152-495: When first released in 2001 after a decade of development, Itanium's performance was disappointing compared to better-established RISC and CISC processors. Emulation to run existing x86 applications and operating systems was particularly poor. Itanium-based systems were produced by HP and its successor Hewlett Packard Enterprise (HPE) as the Integrity Servers line, and by several other manufacturers. In 2008, Itanium

304-425: A 32 nm process technology, skipping the 45 nm process. This was necessary for catching up after Itanium's delays left it at 90 nm competing against 65 nm and 45 nm processors. At ISSCC 2011, Intel presented a paper called "A 32nm 3.1 Billion Transistor 12-Wide-Issue Itanium Processor for Mission Critical Servers." Analyst David Kanter speculated that Poulson would use a new microarchitecture, with

456-572: A 32-bit ALU , and "floating-point or graphics" instructions which operate on a floating-point adder, a floating-point multiplier, or a 64-bit integer graphics unit. The system had separate pipelines for the ALU, floating-point adder, floating-point multiplier, and graphics unit. It can fetch and decode one "core" instruction and one "floating-point or graphics" instruction per clock. When using dual-operation floating-point instructions (which transfer values between subsequent dual-operation instructions), it

608-606: A Harvard memory model , where the instruction stream and the data stream are conceptually separated; this means that modifying the memory where code is held might not have any effect on the instructions executed by the processor (because the CPU has a separate instruction and data cache ), at least until a special synchronization instruction is issued; CISC processors that have separate instruction and data caches generally keep them synchronized automatically, for backwards compatibility with older processors. Many early RISC designs also shared

760-443: A switch-on-event multithreading and split 256 KB + 1 MB L2 caches that roughly doubled the performance and decreased the energy consumption by about 20 percent. At 596 mm² die size and 1.72 billion transistors it was the largest microprocessor at the time. It was supposed to feature Foxton Technology , a very sophisticated frequency regulator, which failed to pass validation and was thus not enabled for customers. Intel released

912-557: A 130 nm process and were the basis of all new Itanium processors until Montecito was released in July 2006, specifically Deerfield being a low wattage Madison , and Fanwood being a version of Madison 9M for lower-end servers with one or two CPU sockets. In November 2005, the major Itanium server manufacturers joined with Intel and a number of software vendors to form the Itanium Solutions Alliance to promote

1064-750: A 24-bit high-speed processor to use as the basis for a digital telephone switch . To reach their goal of switching 1 million calls per hour (300 per second) they calculated that the CPU required performance on the order of 12 million instructions per second (MIPS), compared to their fastest mainframe machine of the time, the 370/168 , which performed at 3.5 MIPS. The design was based on a study of IBM's extensive collection of statistics gathered from their customers. This demonstrated that code in high-performance settings made extensive use of processor registers , and that they often ran out of them. This suggested that additional registers would improve performance. Additionally, they noticed that compilers generally ignored

1216-459: A 5-bit number, for 15 bits. If one of these registers is replaced by an immediate, there is still lots of room to encode the two remaining registers and the opcode. Common instructions found in multi-word systems, like INC and DEC , which reduce the number of words that have to be read before performing the instruction, are unnecessary in RISC as they can be accomplished with a single register and

1368-524: A barebones core sufficient for a small embedded processor to supercomputer and cloud computing use with standard and chip designer–defined extensions and coprocessors. It has been tested in silicon design with the ROCKET SoC , which is also available as an open-source processor generator in the CHISEL language. In the early 1980s, significant uncertainties surrounded the RISC concept. One concern involved

1520-400: A better balancing of pipeline stages than before, making RISC pipelines significantly more efficient and allowing higher clock frequencies . Yet another impetus of both RISC and other designs came from practical measurements on real-world programs. Andrew Tanenbaum summed up many of these, demonstrating that processors often had oversized immediates. For instance, he showed that 98% of all

1672-537: A broader deployment in the second half of the year. By then even Intel publicly acknowledged that many customers would wait for McKinley. During development, Intel, HP, and industry analysts predicted that IA-64 would dominate first in 64-bit servers and workstations, then expand to the lower-end servers, supplanting Xeon, and finally penetrate into the personal computers , eventually to supplant RISC and complex instruction set computing (CISC) architectures for all general-purpose applications, though not replacing x86 "for

SECTION 10

#1732772068434

1824-526: A development vehicle for the Itanium ecosystem. The "wait for McKinley" narrative was becoming prevalent. The same day it was reported that due to the delays, HP would extend its line of PA-RISC PA-8000 series processors from PA-8500 to as far as PA-8900. In October 1998 HP announced its plans for four more generations of PA-RISC processors, with PA-8900 set to reach 1.2 GHz in 2003. By March 1999 some analysts expected Merced to ship in volume only in 2001, but

1976-452: A different opcode. In contrast, a 32-bit machine has ample room to encode an immediate value, and doing so avoids the need to do a second memory read to pick up the value. This is why many RISC processors allow a 12- or 13-bit constant to be encoded directly into the instruction word. Assuming a 13-bit constant area, as is the case in the MIPS and RISC designs, another 19 bits are available for

2128-504: A different stepping, it is functionally identical with the 9500 series, even having exactly the same bugs, the only difference being the 133 MHz higher frequency of 9760 and 9750 over 9560 and 9550 respectively. Intel announced that the 9700 series would be the last Itanium chips produced. The models are: Compared to its Xeon family of server processors, Itanium was never a high-volume product for Intel. Intel does not release production numbers, but one industry analyst estimated that

2280-524: A group of three SHARC DSPs. Good performance was obtained from the i860 by supplying customers with a library of signal processing functions written in assembly language. The hardware packed up to 360 compute nodes in 9U of rack space, making it suitable for mobile applications such as airborne radar processing. During the early 1990s, Stratus Technologies built i860-based servers, the XA/R series, running their proprietary VOS operating system. Also in

2432-405: A key role, as the team was subsequently transferred to Intel's ownership. The original code name for the first Itanium with more than two cores was Tanglewood, but it was changed to Tukwila in late 2003 due to trademark issues. Intel discussed a "middle-of-the-decade Itanium" to succeed Montecito, achieving ten times the performance of Madison. It was being designed by the famed DEC Alpha team and

2584-431: A major update in 2017 (Integrity i6, and HP-UX 11i v3 Update 16). HPE also supports a few other operating systems, including Windows up to Server 2008 R2, Linux , OpenVMS and NonStop . Itanium is not affected by Spectre or Meltdown . Prior to the 9300-series ( Tukwila ), chipsets were needed to connect to the main memory and I/O devices, as the front-side bus to the chipset was the sole operational connection to

2736-491: A more advanced form of multithreading that uses up to two threads, to improve performance for single threaded and multithreaded workloads. Some information was also released at the Hot Chips conference. Information presented improvements in multithreading, resiliency improvements ( Intel Instruction Replay RAS) and few new instructions (thread priority, integer instruction, cache prefetching, and data access hints). Poulson

2888-493: A number of additional points. Among these was the fact that programs spent a significant amount of time performing subroutine calls and returns, and it seemed there was the potential to improve overall performance by speeding these calls. This led the Berkeley design to select a method known as register windows which can significantly improve subroutine performance although at the cost of some complexity. They also noticed that

3040-598: A paper on ways to improve microcoding, but later changed his mind and decided microcode itself was the problem. With funding from the DARPA VLSI Program , Patterson started the Berkeley RISC effort. The Program, practically unknown today, led to a huge number of advances in chip design, fabrication, and even computer graphics. Considering a variety of programs from their BSD Unix variant, the Berkeley team found, as had IBM, that most programs made no use of

3192-484: A particular strategy for implementing some RISC designs, and modern RISC designs generally do away with it (such as PowerPC and more recent versions of SPARC and MIPS). Some aspects attributed to the first RISC- labeled designs around 1975 include the observations that the memory-restricted compilers of the time were often unable to take advantage of features intended to facilitate manual assembly coding, and that complex addressing modes take many cycles to perform due to

SECTION 20

#1732772068434

3344-413: A pipelined processor and for code generation by an optimizing compiler. A common misunderstanding of the phrase "reduced instruction set computer" is that instructions are simply eliminated, resulting in a smaller set of instructions. In fact, over the years, RISC instruction sets have grown in size, and today many of them have a larger set of instructions than many CISC CPUs. Some RISC processors such as

3496-469: A reasonably sized constant in a 32-bit instruction word. Since many real-world programs spend most of their time executing simple operations, some researchers decided to focus on making those operations as fast as possible. The clock rate of a CPU is limited by the time it takes to execute the slowest sub-operation of any instruction; decreasing that cycle-time often accelerates the execution of other instructions. The focus on "reduced instructions" led to

3648-506: A sequence of simpler internal instructions. In the 68k, a full 1 ⁄ 3 of the transistors were used for this microcoding. In 1979, David Patterson was sent on a sabbatical from the University of California, Berkeley to help DEC's west-coast team improve the VAX microcode. Patterson was struck by the complexity of the coding process and concluded it was untenable. He first wrote

3800-503: A sequence of simpler operations doing the same thing. This was in part an effect of the fact that many designs were rushed, with little time to optimize or tune every instruction; only those used most often were optimized, and a sequence of those instructions could be faster than a less-tuned instruction performing an equivalent operation as that sequence. One infamous example was the VAX 's INDEX instruction. The Berkeley work also turned up

3952-457: A single complex instruction such as STRING MOVE , but hide those details from the compiler. The internal operations of a RISC processor are "exposed to the compiler", leading to the backronym 'Relegate Interesting Stuff to the Compiler'. Most RISC architectures have fixed-length instructions and a simple encoding, which simplifies fetch, decode, and issue logic considerably. This is among

4104-482: A single data memory cycle—compared to the "complex instructions" of CISC CPUs that may require dozens of data memory cycles in order to execute a single instruction. The term load–store architecture is sometimes preferred. Another way of looking at the RISC/CISC debate is to consider what is exposed to the compiler. In a CISC processor, the hardware may internally use registers and flag bit in order to implement

4256-576: A small number of supercomputers such as the Intel iPSC/860 . Intel later marketed the i860 as a workstation microprocessor for a time, where it competed with microprocessors based on the MIPS and SPARC architectures, among others. The Oki Electric OKI Station 7300/30 and Stardent Vistra 800 Unix workstations were based on a 40 MHz i860 XR running UNIX System V /i860. The Hauppauge 4860 and Olivetti CP486 featured an Intel 80486 and i860 on

4408-613: A very small set of instructions—but these designs are very different from classic RISC designs, so they have been given other names such as minimal instruction set computer (MISC) or transport triggered architecture (TTA). RISC architectures have traditionally had few successes in the desktop PC and commodity server markets, where the x86 -based platforms remain the dominant processor architecture. However, this may change, as ARM-based processors are being developed for higher performance systems. Manufacturers including Cavium , AMD, and Qualcomm have released server processors based on

4560-500: Is 6 MB, 512 I  KB , 256 D KB per core. Die size is 544 mm², less than its predecessor Tukwila (698.75 mm²). Intel's Product Change Notification (PCN) 111456-01 lists four models of Itanium 9500 series CPU , which was later removed in a revised document. The parts were later listed in Intel's Material Declaration Data Sheets (MDDS) database. Intel later posted Itanium 9500 reference manual. The models are

4712-423: Is able to execute up to three operations (one ALU, one floating-point multiply, and one floating-point add-or-subtract) per clock. All of the data buses were at least 64 bits wide. The internal memory bus to the cache, for instance, was 128 bits wide. The "core" class instructions use thirty-two 32-bit integer registers. But the "floating-point or graphics" instructions use a register file that can be accessed by

Itanium - Misplaced Pages Continue

4864-728: Is excluded from the L1 cache, because the L2 cache's higher bandwidth is more beneficial to typical floating-point applications than low latency. The L3 cache is now integrated on-chip rather than on a separate die, tripling in associativity and doubling in bus width. McKinley also greatly increases the number of possible instruction combinations in a VLIW-bundle and reaches 25% higher frequency, despite having only eight pipeline stages versus Merced's ten. McKinley contains 221 million transistors (of which 25 million are for logic and 181 million for L3 cache), measured 19.5 mm by 21.6 mm (421 mm) and

5016-460: Is finally dead: The Itanic sunken by the x86 juggernaut" Techspot declared "Itanium's promise ended up sunken by a lack of legacy 32-bit support and difficulties in working with the architecture for writing and maintaining software" while the dream of a single dominant ISA would be realized by the AMD64 extensions. In 1989, HP started to research an architecture that would exceed the expected limits of

5168-537: The 32-bit x86 architecture continued to grow into the enterprise space, building on the economies of scale fueled by its enormous installed base. Only a few thousand systems using the original Merced Itanium processor were sold, due to relatively poor performance, high cost and limited software availability. Recognizing that the lack of software could be a serious problem for the future, Intel made thousands of these early systems available to independent software vendors (ISVs) to stimulate development. HP and Intel brought

5320-550: The Adapteva Epiphany , have an optional short, feature-reduced compressed instruction set . Generally, these instructions expose a smaller number of registers and fewer bits for immediate values, and often use a two-operand format to eliminate one register number from instructions. A two-operand format in a system with 16 registers requires 8 bits for register numbers, leaving another 8 for an opcode or other uses. The SH5 also follows this pattern, albeit having evolved in

5472-536: The Chivano project. In September 2004 Intel demonstrated a working Montecito system, and claimed that the inclusion of hyper-threading increases Montecito's performance by 10-20% and that its frequency could reach 2 GHz. After a delay to "mid-2006" and reduction of the frequency to 1.6 GHz, on July 18 Intel delivered Montecito (marketed as the Itanium ;2 9000 series), a dual-core processor with

5624-623: The DEC Alpha , AMD Am29000 , Intel i860 and i960 , Motorola 88000 , IBM POWER , and, slightly later, the IBM/Apple/Motorola PowerPC . Many of these have since disappeared due to them often offering no competitive advantage over others of the same era. Those that remain are often used only in niche markets or as parts of other systems; of the designs from these traditional vendors, only SPARC and POWER have any significant remaining market. The ARM architecture has been

5776-577: The Itanium 9100 series, codenamed Montvale , in November 2007, retiring the "Itanium 2" brand. Originally intended to use the 65 nm process , it was changed into a fix of Montecito, enabling the demand-based switching (like EIST ) and up to 667 MT/s front-side bus , which were intended for Montecito, plus a core-level lockstep . Montecito and Montvale were the last Itanium processors in which design Hewlett-Packard 's engineering team at Fort Collins had

5928-529: The RT PC —was less competitive than others, but the success of SPARC renewed interest within IBM, which released new RISC systems by 1990 and by 1995 RISC processors were the foundation of a $ 15 billion server industry. By the later 1980s, the new RISC designs were easily outperforming all traditional designs by a wide margin. At that point, all of the other vendors began RISC efforts of their own. Among these were

6080-455: The laser printer , the router , and similar products. In the minicomputer market, companies that included Celerity Computing , Pyramid Technology , and Ridge Computers began offering systems designed according to RISC or RISC-like principles in the early 1980s. Few of these designs began by using RISC microprocessors . The varieties of RISC processor design include the ARC processor,

6232-409: The load–store approach. The term RISC was coined by David Patterson of the Berkeley RISC project, although somewhat similar concepts had appeared before. The CDC 6600 designed by Seymour Cray in 1964 used a load–store architecture with only two addressing modes (register+register, and register+immediate constant) and 74 operation codes, with the basic clock cycle being 10 times faster than

Itanium - Misplaced Pages Continue

6384-622: The reduced instruction set computer (RISC) architectures caused by the great increase in complexity needed for executing multiple instructions per cycle due to the need for dynamic dependency checking and precise exception handling . HP hired Bob Rau of Cydrome and Josh Fisher of Multiflow , the pioneers of very long instruction word (VLIW) computing. One VLIW instruction word can contain several independent instructions , which can be executed in parallel without having to evaluate them for independence. A compiler must attempt to find valid combinations of instructions that can be executed at

6536-538: The "first half of 2001". Server makers had largely forgone spending on the R&;D for the Merced-based systems, instead using motherboards or whole servers of Intel's design. To foster a wide ecosystem, by mid-2000 Intel had provided 15,000 Itaniums in 5,000 systems to software developers and hardware designers. In March 2001 Intel said Itanium systems would begin shipping to customers in the second quarter, followed by

6688-557: The 1980s as the MIPS and SPARC systems. IBM eventually produced RISC designs based on further work on the 801 concept, the IBM POWER architecture , PowerPC , and Power ISA . As the projects matured, many similar designs, produced in the mid-to-late 1980s and early 1990s, such as ARM , PA-RISC , and Alpha , created central processing units that increased the commercial utility of the Unix workstation and of embedded processors in

6840-632: The 1990s, Alliant Computer Systems built their i860-based FX/800 and FX/2800 servers, replacing the FX/80 and FX/8 series that had been based on the Motorola 68000 ISA. Both the Alliant and Mercury compute systems were in heavy use at NASA/JPL for the SIR-C missions. The U.S. military used the i860 for numerous aerospace and digital signal processing applications as a coprocessor, where it saw use up until

6992-472: The 9000-series the bus speeds of over 400 MT/s were limited to up to two processors per bus. As no Itanium chipset could connect to more than four sockets, high-end servers needed multiple interconnected chipsets. The "Tukwila" Itanium processor model had been designed to share a common chipset with the Intel Xeon processor EX (Intel's Xeon processor designed for four processor and larger servers). The goal

7144-455: The ALU and FPU parts) and an interrupt could spill them and require them all to be re-loaded. This took 62 cycles in the best case, and almost 2000 cycles in the worst. The latter is 1/20000th of a second at 40 MHz (50 microseconds), an eternity for a CPU. This largely eliminated the i860 as a general purpose CPU. As the compilers improved, the general performance of the i860 did likewise, but by then most other RISC designs had already passed

7296-707: The ARM architecture. ARM further partnered with Cray in 2017 to produce an ARM-based supercomputer. On the desktop, Microsoft announced that it planned to support the PC version of Windows 10 on Qualcomm Snapdragon -based devices in 2017 as part of its partnership with Qualcomm. These devices will support Windows applications compiled for 32-bit x86 via an x86 processor emulator that translates 32-bit x86 code to ARM64 code . Apple announced they will transition their Mac desktop and laptop computers from Intel processors to internally developed ARM64-based SoCs called Apple silicon ;

7448-597: The Berkeley RISC-II system. The US government Committee on Innovations in Computing and Communications credits the acceptance of the viability of the RISC concept to the success of the SPARC system. By 1989 many RISC CPUs were available; competition lowered their price to $ 10 per MIPS in large quantities, much less expensive than the sole sourced Intel 80386 . The performance of IBM's RISC CPU—only available in

7600-551: The CPU allows RISC computers few simple addressing modes and predictable instruction times that simplify design of the system as a whole. The conceptual developments of the RISC computer architecture began with the IBM 801 project in the late 1970s, but these were not immediately put into use. Designers in California picked up the 801 concepts in two seminal projects, Stanford MIPS and Berkeley RISC . These were commercialized in

7752-638: The DEC Alpha, the AMD Am29000 , the ARM architecture, the Atmel AVR , Blackfin , Intel i860 , Intel i960 , LoongArch , Motorola 88000 , the MIPS architecture, PA-RISC, Power ISA, RISC-V , SuperH , and SPARC. RISC processors are used in supercomputers , such as the Fugaku . A number of systems, going back to the 1960s, have been credited as the first RISC architecture, partly based on their use of

SECTION 50

#1732772068434

7904-640: The HP processor. Intel immediately issued a clarification, saying that P7 is still being defined, and that HP may contribute to its architecture. Later it was confirmed that the P7 codename had indeed passed to the HP-Intel processor. By early 1996 Intel revealed its new codename, Merced . HP believed that it was no longer cost-effective for individual enterprise systems companies such as itself to develop proprietary microprocessors, so it partnered with Intel in 1994 to develop

8056-473: The IA-64 architecture, derived from EPIC. Intel was willing to undertake the very large development effort on IA-64 in the expectation that the resulting microprocessor would be used by the majority of enterprise systems manufacturers. HP and Intel initiated a large joint development effort with a goal of delivering the first product, Merced, in 1998. Merced was designed by a team of 500, which Intel later admitted

8208-457: The IA-64 software. Linley Gwennap of MPR said of Merced that "at this point, everyone is expecting it's going to be late and slow, and the real advance is going to come from McKinley. What this does is puts a lot more pressure on McKinley and for that team to deliver". By then, Intel had revealed that Merced would be initially priced at $ 5000. In August 1999 HP advised some of their customers to skip Merced and wait for McKinley. By July 2000 HP told

8360-448: The ISA, who in partnership with TI, GEC, Sharp, Nokia, Oracle and Digital would develop low-power and embedded RISC designs, and target those market segments, which at the time were niche. With the rise in mobile, automotive, streaming, smart device computing, ARM became the most widely used ISA, the company estimating almost half of all CPUs shipped in history have been ARM. Confusion around

8512-506: The Itanium bus-based architecture. It has a peak interprocessor bandwidth of 96 GB/s and a peak memory bandwidth of 34 GB/s. With QuickPath, the processor has integrated memory controllers and interfaces the memory directly, using QPI interfaces to directly connect to other processors and I/O hubs. QuickPath is also used on Intel x86-64 processors using the Nehalem microarchitecture, which possibly enabled Tukwila and Nehalem to use

8664-492: The Merced's performance and would "knock your socks off", while using the same 180 nm process as Merced. Pollack also said that Merced's x86 performance would be lower than the fastest x86 processors, and that x86 would "continue to grow at its historical rates". Intel said that IA-64 won't have much presence in the consumer market for 5 to 10 years. Later it was reported that HP's motivation when starting to design McKinley in 1996

8816-592: The PowerPC have instruction sets as large as the CISC IBM System/370 , for example; conversely, the DEC PDP-8 —clearly a CISC CPU because many of its instructions involve multiple memory accesses—has only 8 basic instructions and a few extended instructions. The term "reduced" in that phrase was intended to describe the fact that the amount of work any single instruction accomplishes is reduced—at most

8968-423: The RISC competitor. At the same time Intel was also looking for ways to make better ISAs. In 1989 Intel had launched the i860 , which it marketed for workstations, servers, and iPSC and Paragon supercomputers. It differed from other RISCs by being able to switch between the normal single instruction per cycle mode, and a mode where pairs of instructions are explicitly defined as parallel so as to execute them in

9120-422: The RISC computer is that each instruction performs only one function (e.g. copy a value from memory to a register). The RISC computer usually has many (16 or 32) high-speed, general-purpose registers with a load–store architecture in which the code for the register-register instructions (for performing arithmetic and tests) are separate from the instructions that access the main memory of the computer. The design of

9272-535: The VAX. They followed this up with the 40,760-transistor, 39-instruction RISC-II in 1983, which ran over three times as fast as RISC-I. As the RISC project began to become known in Silicon Valley , a similar project began at Stanford University in 1981. This MIPS project grew out of a graduate course by John L. Hennessy , produced a functioning system in 1983, and could run simple programs by 1984. The MIPS approach emphasized an aggressive clock cycle and

SECTION 60

#1732772068434

9424-485: The XP (from 1 μm to 0.8 CHMOS V) increased the clock to 40 and 50 MHz. Both microprocessors supported the same instruction set for application programs. The i860 combined a number of features that were unique at the time, most notably its very long instruction word (VLIW) architecture and powerful support for high-speed floating-point operations. The design uses two classes of instructions: "core" instructions which use

9576-435: The XP versions, manually written assembler code managed to get only about up to 40 MFLOPS, and most compilers had difficulty getting even 10 MFLOPs. The later Itanium architecture, also a VLIW design, suffered again from the problem of compilers incapable of delivering sufficiently optimized code. Another serious problem was the lack of any solution to handle context switching quickly. The i860 had several pipelines (for

9728-430: The alliance would impact it, but "it is not clear" whether it would "fully encompass the new architecture". Later the same month, Intel said that some of the first features of the new architecture would start appearing on Intel chips as early as the P7, but the full version would appear sometime later. In August 1994 EE Times reported that Intel told investors that P7 was being re-evaluated and possibly canceled in favor of

9880-414: The architecture and accelerate the software porting effort. The Alliance announced that its members would invest $ 10 billion in the Itanium Solutions Alliance by the end of the decade. In early 2003, due to the success of IBM's dual-core POWER4 , Intel announced that the first 90 nm Itanium processor, codenamed Montecito , would be delayed to 2005 so as to change it into a dual-core, thus merging it with

10032-458: The architecture was ultimately supplanted by competitor AMD's x86-64 (also called AMD64) architecture. x86-64 is a compatible extension to the 32-bit x86 architecture, implemented by, for example, Intel's own Xeon line and AMD 's Opteron line. By 2009, most servers were being shipped with x86-64 processors, and they dominate the low cost desktop and laptop markets which were not initially targeted by Itanium. In an article titled "Intel's Itanium

10184-405: The architecture, including Microsoft Windows , OpenVMS , Linux , HP-UX , Solaris , Tru64 UNIX , and Monterey/64 . The latter three were canceled before reaching the market. By 1997, it was apparent that the IA-64 architecture and the compiler were much more difficult to implement than originally thought, and the delivery timeframe of Merced began slipping. Intel announced the official name of

10336-403: The cache, yet there is no way for the programmer to know if they are or not. If an incorrect guess is made, the entire pipeline will stall, waiting for the data. The entire i860 design was based on the compiler efficiently handling this task, which proved almost impossible in practice. While theoretically capable of peaking at about 60-80 MFLOPS for both single precision and double precision for

10488-472: The characteristic of having a branch delay slot , an instruction space immediately following a jump or branch. The instruction in this space is executed, whether or not the branch is taken (in other words the effect of the branch is delayed). This instruction keeps the ALU of the CPU busy for the extra time normally needed to perform a branch. Nowadays the branch delay slot is considered an unfortunate side effect of

10640-424: The combined POWER/SPARC/Itanium systems market, IDC reports that POWER captured 42% of revenue and SPARC captured 32%, while Itanium-based system revenue reached 26% in the second quarter of 2008. According to an IDC analyst, in 2007, HP accounted for perhaps 80% of Itanium systems revenue. According to Gartner, in 2008, HP accounted for 95% of Itanium sales. HP's Itanium system sales were at an annual rate of $ 4.4Bn at

10792-486: The compilers to get the ordering right. Truevision produced an i860-based accelerator board intended for use with their Targa and Vista framebuffer cards. Pixar produced a custom version of RenderMan to run on the card that ran approximately four times faster than the 386 host. Another example was SGI 's RealityEngine , which used a number of i860XP processors in its geometry engine. This sort of use slowly disappeared as well, as more general-purpose CPUs started to match

10944-486: The computer market was criticized for making it vulnerable to challengers expanding from the lower-end market segments, but many people in the computer industry feared voicing doubts about Itanium in the fear of Intel's retaliation. Compaq and Silicon Graphics decided to abandon further development of the Alpha and MIPS architectures respectively in favor of migrating to IA-64. Several groups ported operating systems for

11096-527: The computer to accomplish tasks. Compared to the instructions given to a complex instruction set computer (CISC), a RISC computer might require more instructions (more code) in order to accomplish a task because the individual instructions are written in simpler code. The goal is to offset the need to process more instructions by increasing the speed of each instruction, in particular by implementing an instruction pipeline , which may be simpler to achieve given simpler instructions. The key operational concept of

11248-441: The constants in a program would fit in 13 bits , yet many CPU designs dedicated 16 or 32 bits to store them. This suggests that, to reduce the number of memory accesses, a fixed length machine could store constants in unused bits of the instruction word itself, so that they would be immediately ready when the CPU needs them (much like immediate addressing in a conventional design). This required small opcodes in order to leave room for

11400-539: The critical paths without disturbing the other circuits' speed. Merced was taped out on 4 July 1999, and in August Intel produced the first complete test chip. The expectations for Merced waned over time as delays and performance deficiencies emerged, shifting the focus and onus for success onto the HP-led second Itanium design, codenamed McKinley . In July 1997 the switch to the 180 nm process delayed Merced into

11552-423: The definition of RISC deriving from the formulation of the term, along with the tendency to opportunistically categorize processor architectures with relatively few instructions (or groups of instructions) as RISC architectures, led to attempts to define RISC as a design philosophy. One attempt to do so was expressed as the following: A RISC processor has an instruction set that is designed for efficient execution by

11704-581: The earlier Intel i960 , which was successful in some niches of embedded systems . The i860 never achieved commercial success and the project was terminated in the mid-1990s. The first implementation of the i860 architecture is the i860 XR microprocessor (code-named N10 ), which ran at 25, 33, or 40 MHz. The second-generation i860 XP microprocessor (code named N11 ) added 4 Mbyte pages, larger on-chip caches, second level cache support, faster buses, and hardware support for bus snooping, for cache consistency in multiprocessor systems. A process shrink for

11856-472: The early 1980s, leading, for example, to the iron law of processor performance . Since 2010, a new open standard instruction set architecture (ISA), Berkeley RISC-V , has been under development at the University of California, Berkeley, for research purposes and as a free alternative to proprietary ISAs. As of 2014, version 2 of the user space ISA is fixed. The ISA is designed to be extensible from

12008-555: The end of 2008, and declined to $ 3.5Bn by the end of 2009, compared to a 35% decline in UNIX system revenue for Sun and an 11% drop for IBM, with an x86-64 server revenue increase of 14% during this period. In December 2012, IDC released a research report stating that Itanium server shipments would remain flat through 2016, with annual shipment of 26,000 systems (a decline of over 50% compared to shipments in 2008). By 2006, HP manufactured at least 80% of all Itanium systems, and sold 7,200 in

12160-599: The enterprise server space because it provided an easy upgrade from x86 . Under the influence of Microsoft, Intel responded by implementing AMD's x86-64 instruction set architecture instead of IA-64 in its Xeon microprocessors in 2004, resulting in a new industry-wide de facto standard. In 2003 Intel released a new Itanium 2 family member, codenamed Madison , initially with up to 1.5 GHz frequency and 6 MB of L3 cache. The Madison 9M chip released in November 2004 had 9 MB of L3 cache and frequency up to 1.6 GHz, reaching 1.67 GHz in July 2005. Both chips used

12312-512: The explicitly parallel execution of multiple bundles and increasing the processors' issue width without the need to recompile; by predication of instructions to reduce the need for branches ; and by full interlocking to eliminate the delay slots . In EPIC the assignment of execution units to instructions and the timing of their issuing can be decided by hardware, unlike in the classic VLIW. HP intended to use these features in PA-WideWord,

12464-649: The first quarter of 2006. The bulk of systems sold were enterprise servers and machines for large-scale technical computing, with an average selling price per system in excess of US$ 200,000. A typical system used eight or more Itanium processors. By 2012, only a few manufacturers offered Itanium systems, including HP , Bull , NEC , Inspur and Huawei . In addition, Intel offered a chassis that could be used by system integrators to build Itanium systems. By 2015, only HP supplied Itanium-based systems. When HP split in late 2015, Itanium systems (branded as Integrity ) were handled by Hewlett Packard Enterprise (HPE), with

12616-535: The first such computers, using the Apple M1 processor, were released in November 2020. Macs with Apple silicon can run x86-64 binaries with Rosetta 2 , an x86-64 to ARM64 translator. Outside of the desktop arena, however, the ARM RISC architecture is in widespread use in smartphones, tablets and many forms of embedded devices. While early RISC designs differed significantly from contemporary CISC designs, by 2000

12768-451: The first time in mid-1996, it turned out to be far too large, "this was a lot worse than anything I'd seen before", said Crawford. The designers had to reduce the complexity (and thus performance) of subsystems, including the x86 unit and cutting the L2 cache to 96 KB. Eventually it was agreed that the size target could only be reached by using the 180 nm process instead of the intended 250 nm . Later problems emerged with attempts to speed up

12920-437: The floating point units as either thirty-two 32-bit, sixteen 64-bit, or eight 128-bit floating-point registers, or that can be accessed by the graphics unit as sixteen 64-bit integer registers. The "core" unit is responsible for fetching instructions, and in the normal "single-instruction" mode can fetch one 32-bit "core" or one 32-bit "floating point or graphics" instruction per cycle. But when executing in dual-instruction mode,

13072-577: The following instruction will be executed prior to transferring control to the branch target instruction. It means the i860 has a single branch delay slot. On paper, performance was impressive for a single-chip solution; however, real-world performance was anything but. One problem, perhaps unrecognized at the time, was that runtime code paths are difficult to predict, meaning that it becomes exceedingly difficult to order instructions properly at compile time . For instance, an instruction to add two numbers will take considerably longer if those numbers are not in

13224-574: The following: Intel had committed to at least one more generation after Poulson, first mentioning Kittson on 14 June 2007. Kittson was supposed to be on a 22 nm process and use the same LGA2011 socket and platform as Xeons . On 31 January 2013 Intel issued an update to their plans for Kittson: it would have the same LGA1248 socket and 32 nm process as Poulson, thus effectively halting any further development of Itanium processors. In April 2015, Intel, although it had not yet confirmed formal specifications, did confirm that it continued to work on

13376-401: The foreseeable future" according to Intel. In 1997-1998, Intel CEO Andy Grove predicted that Itanium would not come to the desktop computers for four of five years after launch, and said "I don't see Merced appearing on a mainstream desktop inside of a decade". In contrast, Itanium was expected to capture 70% of the 64-bit server market in 2002. Already in 1998 Itanium's focus on the high end of

13528-586: The high-end business and HPC computing markets, attempting to duplicate the x86's successful "horizontal" market (i.e., single architecture, multiple systems vendors). The success of this initial processor version was limited to replacing the PA-RISC in HP systems, Alpha in Compaq systems and MIPS in SGI systems, though IBM also delivered a supercomputer based on this processor. POWER and SPARC remained strong, while

13680-509: The highest-performing CPUs in the RISC line were almost indistinguishable from the highest-performing CPUs in the CISC line. RISC architectures are now used across a range of platforms, from smartphones and tablet computers to some of the world's fastest supercomputers such as Fugaku , the fastest on the TOP500 list as of November 2020 , and Summit , Sierra , and Sunway TaihuLight ,

13832-581: The i860 in performance. In the late 1990s, Intel replaced their entire RISC line with ARM -based designs, known as the XScale . Confusingly, the 860 number has since been re-used for a motherboard control chipset for Intel Xeon (high-end Pentium ) systems and a model of the Core i7. Andy Grove suggested that the i860's failure in the marketplace was due to Intel being stretched too thin: We now had two very powerful chips that we were introducing at just about

13984-514: The i860 influenced the MMX functionality later added to Intel's Pentium processors. The pipelines into the functional units are program-accessible ( VLIW ), requiring the compilers to order instructions carefully in the object code to keep the pipelines filled. In traditional architectures these duties were handled at runtime by a scheduler on the CPU itself, but the complexity of these systems limited their application in early RISC designs. The i860

14136-410: The i860's performance, and as Intel turned its focus to Pentium processors for general-purpose computing. Mercury Computer Systems used the i860 in their multicomputer . From 2 to 360 compute nodes would reside in a circuit switched fat tree network, with each node having local memory that could be mapped by any other node. Each node in this heterogeneous system could be an i860, a PowerPC , or

14288-413: The immediate value 1. The original RISC-I format remains a canonical example of the concept. It uses 7 bits for the opcode and a 1-bit flag for conditional codes, the following 5 bits for the destination register, and the next five for the first operand. This leaves 14 bits, the first of which indicates whether the following 13 contain an immediate value or uses only five of them to indicate a register for

14440-601: The instruction cache is accessed as VLIW instructions consisting of a 32-bit "core" instruction paired with a 32-bit "floating-point or graphics" instruction, simultaneously fetched together over a 64-bit bus. Intel referred to the design as the "i860 64-Bit Microprocessor". Intel i860 instructions acted on data sizes from 8-bit through 128-bit. The graphics supports SIMD -like instructions in addition to basic 64-bit integer math. For instance, its 64-bit integer datapath can represent multiple pixels together as either 8-bit pixels, 16-bit pixels, or 32-bit pixels. Experience with

14592-403: The instruction encoding. This leaves ample room to indicate both the opcode and one or two registers. Register-to-register operations, mostly math and logic, require enough bits to encode the two or three registers being used. Most processors use the three-operand format, of the form A = B + C , in which case three registers numbers are needed. If the processor has 32 registers, each one requires

14744-445: The instruction word which could then be used to select among a larger set of registers. The telephone switch program was canceled in 1975, but by then the team had demonstrated that the same design would offer significant performance gains running just about any code. In simulations, they showed that a compiler tuned to use registers wherever possible would run code about three times as fast as traditional designs. Somewhat surprisingly,

14896-428: The large variety of instructions in the 68k. Patterson's early work pointed out an important problem with the traditional "more is better" approach; even those instructions that were critical to overall performance were being delayed by their trip through the microcode. If the microcode was removed, the programs would run faster. And since the microcode ultimately took a complex instruction and broke it into steps, there

15048-482: The late 1970s, the 801 had become well-known in the industry. This coincided with new fabrication techniques that were allowing more complex chips to come to market. The Zilog Z80 of 1976 had 8,000 transistors, whereas the 1979 Motorola 68000 (68k) had 68,000. These newer designs generally used their newfound complexity to expand the instruction set to make it more orthogonal. Most, like the 68k, used microcode to do this, reading instructions and re-implementing them as

15200-494: The main goals of the RISC approach. Some of this is possible only due to the contemporary move to 32-bit formats. For instance, in a typical program, over 30% of all the numeric constants are either 0 or 1, 95% will fit in one byte, and 99% in a 16-bit value. When computers were based on 8- or 16-bit words, it would be difficult to have an immediate combined with the opcode in a single memory word, although certain instructions like increment and decrement did this implicitly by using

15352-422: The majority of mathematical instructions were simple assignments; only 1 ⁄ 3 of them actually performed an operation like addition or subtraction. But when those operations did occur, they tended to be slow. This led to far more emphasis on the underlying arithmetic data unit, as opposed to previous designs where the majority of the chip was dedicated to control and microcode. The resulting Berkeley RISC

15504-512: The memory access time. Partly due to the optimized load–store architecture of the CDC 6600, Jack Dongarra says that it can be considered a forerunner of modern RISC systems, although a number of other technical barriers needed to be overcome for the development of a modern RISC system. Michael J. Flynn views the first RISC system as the IBM 801 design, begun in 1975 by John Cocke and completed in 1980. The 801 developed out of an effort to build

15656-558: The mid-1980s. The Acorn ARM1 appeared in April 1985, MIPS R2000 appeared in January 1986, followed shortly thereafter by Hewlett-Packard 's PA-RISC in some of their computers. In the meantime, the Berkeley effort had become so well known that it eventually became the name for the entire concept. In 1987 Sun Microsystems began shipping systems with the SPARC processor, directly based on

15808-442: The more experimental HP Labs PlayDoh as the source of their joint future architecture. Convinced of the superiority of the new project, in 1994 Intel canceled their existing plans for P7. In June 1994 Intel and HP announced their joint effort to make a new ISA that would adopt ideas of Wide Word and VLIW. Yu declared: "If I were competitors, I'd be really worried. If you think you have a future, you don't." On P7's future, Intel said

15960-563: The most significant characteristics of RISC processors was that external memory was only accessible by a load or store instruction. All other instructions were limited to internal registers. This simplified many aspects of processor design: allowing instructions to be fixed-length, simplifying pipelines, and isolating the logic for dealing with the delay in completing a memory access (cache miss, etc.) to only two instructions. This led to RISC designs being referred to as load–store architectures. Some CPUs have been specifically designed to have

16112-657: The most widely adopted RISC ISA, initially intended to deliver higher-performance desktop computing, at low cost, and in a restricted thermal package, such as in the Acorn Archimedes , while featuring in the Super Computer League tables , its initial, relatively, lower power and cooling implementation was soon adapted to embedded applications, such as laser printer raster image processing. Acorn, in partnership with Apple Inc, and VLSI, creating ARM Ltd, in 1990, to share R&D costs and find new markets for

16264-480: The next Itanium processor after Montvale, to be released in 2007. Tukwila would have four processor cores and would replace the Itanium bus with a new Common System Interface , which would also be used by a new Xeon processor. Tukwila was to have a "common platform architecture" with a Xeon codenamed Whitefield , which was canceled in October 2005, when Intel revised Tukwila's delivery date to late 2008. In May 2009,

16416-435: The next three on that list. Intel i860 The Intel i860 (also known as 80860 ) is a RISC microprocessor design introduced by Intel in 1989. It is one of Intel's first attempts at an entirely new, high-end instruction set architecture since the failed Intel iAPX 432 from the beginning of the 1980s. It was the world's first million-transistor chip. It was released with considerable fanfare, slightly obscuring

16568-468: The next-generation Itanium 2 processor to the market a year later. Few of the microarchitectural features of Merced would be carried over to all the subsequent Itanium designs, including the 16+16 KB L1 cache size and the 6-wide (two-bundle) instruction decoding. The Itanium 2 processor was released in July 2002, and was marketed for enterprise servers rather than for the whole gamut of high-end computing. The first Itanium 2, code-named McKinley ,

16720-540: The opcode was 0 and the last 6 bits contained the actual code; those that used an immediate value used the normal opcode field at the front. One drawback of 32-bit instructions is reduced code density, which is more adverse a characteristic in embedded computing than it is in the workstation and server markets RISC architectures were originally designed to serve. To address this problem, several architectures, such as SuperH (1992), ARM thumb (1994), MIPS16e (2004), Power Variable Length Encoding ISA (2006), RISC-V , and

16872-531: The opposite direction, having added longer 32-bit instructions to an original 16-bit encoding. The most characteristic aspect of RISC is executing at least one instruction per cycle . Single-cycle operation is described as "the rapid execution of simple functions that dominate a computer's instruction stream", thus seeking to deliver an average throughput approaching one instruction per cycle for any single instruction stream. Other features of RISC architectures include: RISC designs are also more likely to feature

17024-500: The partners, Intel launched Itanium on May 29, 2001, with first OEM systems from HP, IBM and Dell shipping to customers in June. By then Itanium's performance was not superior to competing RISC and CISC processors. Itanium competed at the low-end (primarily four- CPU and smaller systems) with servers based on x86 processors, and at the high-end with IBM POWER and Sun Microsystems SPARC processors. Intel repositioned Itanium to focus on

17176-416: The planned successor to their PA-RISC ISA. EPIC was intended to provide the best balance between the efficient use of silicon area and electricity, and general-purpose flexibility. In 1993 HP held an internal competition to design the best (simulated) microarchitectures of a RISC and an EPIC type, led by Jerry Huck and Rajiv Gupta respectively. The EPIC team won, with over double the simulated performance of

17328-460: The press that the first Itanium systems would be for niche uses, and that "You're not going to put this stuff near your data center for several years."; HP expected its Itanium systems to outsell the PA-RISC systems only in 2005. The same July Intel told of another delay, due to a stepping change to fix bugs. Now only "pilot systems" would ship that year, while the general availability was pushed to

17480-589: The processor, Itanium , on October 4, 1999. Within hours, the name Itanic had been coined on a Usenet newsgroup, a reference to the RMS Titanic , the "unsinkable" ocean liner that sank on her maiden voyage in 1912. "Itanic" was then used often by The Register , and others, to imply that the multibillion-dollar investment in Itanium—and the early hype associated with it—would be followed by its relatively quick demise. After having sampled 40,000 chips to

17632-404: The processor. Two generations of buses existed: the original Itanium processor system bus (a.k.a. Merced bus ) had a 64 bit data width and 133 MHz clock with DDR (266 MT/s), being soon superseded by the 128-bit 200 MHz DDR (400 MT/s) Itanium 2 processor system bus (a.k.a. McKinley bus ), which later reached 533 and 667 MT/s. Up to four CPUs per single bus could be used, but prior to

17784-468: The production rate was 200,000 processors per year in 2007. According to Gartner Inc. , the total number of Itanium servers (not processors) sold by all vendors in 2007, was about 55,000 (It is unclear whether clustered servers counted as a single server or not.). This compares with 417,000 RISC servers (spread across all RISC vendors) and 8.4 million x86 servers. IDC reports that a total of 184,000 Itanium-based systems were sold from 2001 through 2007. For

17936-557: The project. Meanwhile, the aggressively multicore Xeon E7 platform displaced Itanium-based solutions in the Intel roadmap. Even Hewlett-Packard , the main proponent and customer for Itanium, began selling x86 -based Superdome and NonStop servers, and started to treat the Itanium-based versions as legacy products. Intel officially launched the Itanium 9700 series processor family on May 11, 2017. Kittson has no microarchitecture improvements over Poulson; despite nominally having

18088-497: The required additional memory accesses. It was argued that such functions would be better performed by sequences of simpler instructions if this could yield implementations small enough to leave room for many registers, reducing the number of slow memory accesses. In these simple designs, most instructions are of uniform length and similar structure, arithmetic operations are restricted to CPU registers and only separate load and store instructions access memory. These properties enable

18240-402: The resulting machine being called a "reduced instruction set computer" (RISC). The goal was to make instructions so simple that they could easily be pipelined, in order to achieve a single clock throughput at high frequencies . This contrasted with CISC designs whose "crucial arithmetic operations and register transfers" were considered difficult to pipeline. Later, it was noted that one of

18392-593: The same chipsets. Tukwila incorporates two memory controllers, each of which has two links to Scalable Memory Buffers, which in turn support multiple DDR3 DIMMs , much like the Nehalem-based Xeon processor code-named Beckton . During the 2012 Hewlett-Packard Co. v. Oracle Corp. support lawsuit, court documents unsealed by a Santa Clara County Court judge revealed that in 2008, Hewlett-Packard had paid Intel around $ 440 million to keep producing and updating Itanium microprocessors from 2009 to 2014. In 2010,

18544-508: The same code would run about 50% faster even on existing machines due to the improved register use. In practice, their experimental PL/8 compiler, a slightly cut-down version of PL/I , consistently produced code that ran much faster on their existing mainframes. A 32-bit version of the 801 was eventually produced in a single-chip form as the IBM ROMP in 1981, which stood for 'Research OPD [Office Products Division] Micro Processor'. This CPU

18696-435: The same cycle without having to do dependency checking. Another distinguishing feature were the instructions for an exposed floating-point pipeline, that enabled the tripling of throughput compared to the conventional floating-point instructions. Both of these features were left largely unused because compilers didn't support them, a problem that later challenged Itanium too. Without them, i860's parallelism (and thus performance)

18848-466: The same motherboard. Microsoft initially developed what was to become Windows NT on internally designed i860XR-based workstations (codenamed Dazzle ), only porting NT to the MIPS ( Microsoft Jazz ), Intel 80386 and other processors later. Some claim the NT designation was a reference to the "N-Ten" codename of the i860XR. The i860 did see some use in the workstation world as a graphics accelerator. It

19000-433: The same time , effectively performing the instruction scheduling that conventional superscalar processors must do in hardware at runtime. HP researchers modified the classic VLIW into a new type of architecture, later named Explicitly Parallel Instruction Computing (EPIC), which differs by: having template bits which show which instructions are independent inside and between the bundles of three instructions, which enables

19152-413: The same time: the 486, largely based on CISC technology and compatible with all the PC software, and the i860, based on RISC technology, which was very fast but compatible with nothing. We didn't know what to do. So we introduced both, figuring we'd let the marketplace decide. ... our equivocation caused our customers to wonder what Intel really stood for, the 486 or i860? At first, the i860 was only used in

19304-565: The schedule for Tukwila, was revised again, with the release to OEMs planned for the first quarter of 2010. The Itanium 9300 series processor, codenamed Tukwila , was released on February 8, 2010, with greater performance and memory capacity. The device uses a 65 nm process, includes two to four cores, up to 24  MB on-die caches, Hyper-Threading technology and integrated memory controllers. It implements double-device data correction , which helps to fix memory errors. Tukwila also implements Intel QuickPath Interconnect (QPI) to replace

19456-609: The second half of 1999. Shortly before the reveal of EPIC at the Microprocessor Forum in October 1997, an analyst of the Microprocessor Report said that Itanium would "not show the competitive performance until 2001. It will take the second version of the chip for the performance to get shown". At the Forum, Intel's Fred Pollack originated the "wait for McKinley" mantra when he said that it would double

19608-475: The second half of the 1980s, and led the designers of the MIPS-X to put it this way in 1987: The goal of any instruction format should be: 1. simple decode, 2. simple decode, and 3. simple decode. Any attempts at improved code density at the expense of CPU performance should be ridiculed at every opportunity. Competition between RISC and conventional CISC approaches was also the subject of theoretical analysis in

19760-408: The second operand. A more complex example is the MIPS encoding, which used only 6 bits for the opcode, followed by two 5-bit registers. The remaining 16 bits could be used in two ways, one as a 16-bit immediate value, or as a 5-bit shift value (used only in shift operations, otherwise zero) and the remaining 6 bits as an extension on the opcode. In the case of register-to-register arithmetic operations,

19912-513: The two companies signed another $ 250 million deal, which obliged Intel to continue making Itanium CPUs for HP's machines until 2017. Under the terms of the agreements, HP had to pay for chips it gets from Intel, while Intel launches Tukwila, Poulson, Kittson, and Kittson+ chips in a bid to gradually boost performance of the platform. Intel first mentioned Poulson on March 1, 2005, at the Spring IDF . In June 2007 Intel said that Poulson would use

20064-403: The use of memory; a single instruction from a traditional processor like the Motorola 68k may be written out as perhaps a half dozen of the simpler RISC instructions. In theory, this could slow the system down as it spent more time fetching instructions from memory. But by the mid-1980s, the concepts had matured enough to be seen as commercially viable. Commercial RISC designs began to emerge in

20216-514: The use of the pipeline, making sure it could be run as "full" as possible. The MIPS system was followed by the MIPS-X and in 1984 Hennessy and his colleagues formed MIPS Computer Systems to produce the design commercially. The venture resulted in a new architecture that was also called MIPS and the R2000 microprocessor in 1985. The overall philosophy of the RISC concept was widely understood by

20368-441: The vast majority of the available instructions, especially orthogonal addressing modes. Instead, they selected the fastest version of any given instruction and then constructed small routines using it. This suggested that the majority of instructions could be removed without affecting the resulting code. These two conclusions worked in concert; removing instructions would allow the instruction opcodes to be shorter, freeing up bits in

20520-424: The volume was widely expected to be low as most customers would wait for McKinley. In May 1999, two months before Merced's tape-out , an analyst said that failure to tape-out before July would result in another delay. In July 1999, upon reports that the first silicon would be made in late August, analysts predicted a delay to late 2000, and came into agreement that Merced would be used chiefly for debugging and testing

20672-495: The window "down" by eight, to the set of eight registers used by that procedure, and the return moves the window back. The Berkeley RISC project delivered the RISC-I processor in 1982. Consisting of only 44,420 transistors (compared with averages of about 100,000 in newer CISC designs of the era), RISC-I had only 32 instructions, and yet completely outperformed any other single-chip design, with estimated performance being higher than

20824-482: The x86 with P7. HP's Gupta recalled: "I looked Albert Yu [Intel's general manager for microprocessors] in the eyes and showed him we could run circles around PowerPC , that we could kill PowerPC, that we could kill the x86." Soon Intel and HP started conducting in-depth technical discussions at an HP office, where each side had six engineers who exchanged and discussed both companies' confidential architectural research. They then decided to use not only PA-WideWord, but also

20976-517: Was an attempt to avoid this entirely by moving this duty off-chip into the compiler. This allowed the i860 to devote more room to functional units, improving performance. As a result of its architecture, the i860 could run certain graphics and floating-point algorithms with exceptionally high speed, but its performance in general-purpose applications suffered and it was difficult to program efficiently (see below). The i860 has both non-delayed and delayed branch instructions. When delayed branches are taken,

21128-498: Was based on gaining performance through the use of pipelining and aggressive use of register windowing. In a traditional CPU, one has a small number of registers, and a program can use any register at any time. In a CPU with register windows, there are a huge number of registers, e.g., 128, but programs can only use a small number of them, e.g., eight, at any one time. A program that limits itself to eight registers per procedure can make very fast procedure calls : The call simply moves

21280-468: Was designed for "mini" tasks, and found use in peripheral interfaces and channel controllers on later IBM computers. It was also used as the CPU in the IBM RT PC in 1986, which turned out to be a commercial failure. Although the 801 did not see widespread use in its original form, it inspired many research projects, including ones at IBM that would eventually lead to the IBM POWER architecture . By

21432-493: Was expected have eight new multithreading-focused cores. Intel claimed "a lot more than two" cores and more than seven times the performance of Madison. In early 2004 Intel told of "plans to achieve up to double the performance over the Intel Xeon processor family at platform cost parity by 2007". By early 2005 Tukwila was redefined, now having fewer cores but focusing on single-threaded performance and multiprocessor scalability. In March 2005, Intel disclosed some details of Tukwila,

21584-502: Was fabricated in a 180 nm, bulk CMOS process with six layers of aluminium metallization. In May 2003 it was disclosed that some McKinley processors can suffer from a critical-path erratum leading to a system's crashing. It can be avoided by lowering the processor frequency to 800 MHz. In 2003, AMD released the Opteron CPU, which implements its own 64-bit architecture called AMD64 . The Opteron gained rapid acceptance in

21736-488: Was jointly developed by HP and Intel, led by the HP team at Fort Collins, Colorado , taping out in December 2000. It relieved many of the performance problems of the original Itanium processor, which were mostly caused by an inefficient memory subsystem by approximately halving the latency and doubling the fill bandwidth of each of the three levels of cache, while expanding the L2 cache from 96 to 256 KB. Floating-point data

21888-473: Was no better than other RISCs, so it failed in the market. Itanium would adopt a more flexible form of explicit parallelism than i860 had. In November 1993 HP approached Intel, seeking collaboration on an innovative future architecture. At the time Intel was looking to extend x86 to 64 bits in a processor codenamed P7, which they found challenging. Later Intel claimed that four different design teams had explored 64-bit extensions, but each of them concluded that it

22040-474: Was no reason the compiler couldn't do this instead. These studies suggested that, even with no other changes, one could make a chip with 1 ⁄ 3 fewer transistors that would run faster. In the original RISC-I paper they noted: Skipping this extra level of interpretation appears to enhance performance while reducing chip size. It was also discovered that, on microcoded implementations of certain architectures, complex operations tended to be slower than

22192-436: Was not economically feasible. At the meeting with HP, Intel's engineers were impressed when Jerry Huck and Rajiv Gupta presented the PA-WideWord architecture they had designed to replace PA-RISC . "When we saw WideWord, we saw a lot of things we had only been looking at doing, already in their full glory", said Intel's John Crawford , who in 1994 became the chief architect of Merced, and who had earlier argued against extending

22344-400: Was released on November 8, 2012, as the Itanium 9500 series processor. It is the follow-on processor to Tukwila. It features eight cores and has a 12-wide issue architecture, multithreading enhancements, and new instructions to take advantage of parallelism, especially in virtualization. The Poulson L3 cache size is 32 MB and common for all cores, not divided like previously. L2 cache size

22496-624: Was the fourth-most deployed microprocessor architecture for enterprise-class systems , behind x86-64 , Power ISA , and SPARC . In February 2017, Intel released the final generation, Kittson, to test customers, and in May began shipping in volume. It was only used in mission-critical servers from HPE. In 2019, Intel announced that new orders for Itanium would be accepted until January 30, 2020, and shipments would cease by July 29, 2021. This took place on schedule. Itanium never sold well outside enterprise servers and high-performance computing systems, and

22648-418: Was to have more control over the project so as to avoid the issues affecting Merced's performance and schedule. The design team finalized McKinley's project goals in 1997. In late May 1998 Merced was delayed to mid-2000, and by August 1998 analysts were questioning its commercial viability, given that McKinley would arrive shortly after with double the performance, as delays were causing Merced to turn into simply

22800-427: Was to streamline system development and reduce costs for server OEMs, many of which develop both Itanium- and Xeon-based servers. However, in 2013, this goal was pushed back to be "evaluated for future implementation opportunities". RISC In electronics and computer science , a reduced instruction set computer ( RISC ) is a computer architecture designed to simplify the individual instructions given to

22952-404: Was too inexperienced, with many recent college graduates. Crawford (Intel) was the chief architect, while Huck (HP) held the second position. Early in the development HP and Intel had a disagreement where Intel wanted more dedicated hardware for more floating-point instructions. HP prevailed upon the discovery of a floating-point hardware bug in Intel's Pentium . When Merced was floorplanned for

23104-573: Was used, for instance, in the NeXTdimension , where it ran a cut-down version of the Mach kernel running a complete PostScript stack. However, the PostScript part of the project was never finished so it ended up just moving color pixels around. In this role, the i860 design worked considerably better, as the core program could be loaded into the cache and made entirely "predictable", allowing

#433566