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65-487: The DLX is essentially a cleaned up (and modernized) simplified Stanford MIPS CPU. The DLX has a simple 32-bit load/store architecture, somewhat unlike the modern MIPS architecture CPU. As the DLX was intended primarily for teaching purposes, the DLX design is widely used in university -level computer architecture courses. There are two known " softcore " hardware implementations: ASPIDA and VAMP. The ASPIDA project resulted in

130-405: A HPE EPYC -based supercomputer called Frontier is number one. The first ARM-based supercomputer appeared on the list in 2018 and, in recent years, non-CPU architecture co-processors ( GPGPU ) have also played a big role in performance. Intel's Xeon Phi "Knights Corner" coprocessors, which implement a subset of x86-64 with some vector extensions, are also used, along with x86-64 processors, in

195-484: A 32-bit address bus , permitting up to 4 GB of RAM to be accessed, far more than previous generations of system architecture allowed. 32-bit designs have been used since the earliest days of electronic computing, in experimental systems and then in large mainframe and minicomputer systems. The first hybrid 16/32-bit microprocessor , the Motorola 68000 , was introduced in the late 1970s and used in systems such as

260-650: A 64-bit OS. A CPU would no longer have legacy mode , and start directly in 64-bit long mode . There will be a way to switch to 5-level paging without going through the unpaged mode. Specific removed features include: Intel believes the change follows logically after the removal of the A20 gate in 2008 and the removal of 16-bit and 32-bit OS support in Intel firmware in 2020. Support for legacy operating systems would be accomplished via hardware-accelerated virtualization and/or ring 0 emulation. Advanced Performance Extensions

325-707: A behaviour that was an unintended consequence. The DLX architecture does not force single clock cycle execution, and is therefore immune to this problem. In the DLX design a more modern approach to handling long instructions was used: data-forwarding and instruction reordering. In this case the longer instructions are "stalled" in their functional units, and then re-inserted into the instruction stream when they can complete. Externally this design behaviour makes it appear as if execution had occurred linearly. DLX instructions can be broken down into three types, R-type , I-type and J-type . R-type instructions are pure register instructions, with three register references contained in

390-434: A bit more than 512  GiB of memory (about 0.195% of the 256 TiB virtual space). Intel has implemented a scheme with a 5-level page table , which allows Intel 64 processors to support a 57-bit virtual address space. Further extensions may allow full 64-bit virtual address space and physical memory with 12-bit page table descriptors and 16- or 21-bit memory offsets for 64 KiB and 2 MiB page allocation sizes;

455-774: A completely new design, the Isaiah architecture was built with support for features like the x86-64 instruction set and x86 virtualization which were unavailable on its predecessors, the VIA C7 line, while retaining their encryption extensions. In 2020, through a collaboration between AMD, Intel, Red Hat , and SUSE , three microarchitecture levels (or feature levels) on top of the x86-64 baseline were defined: x86-64-v2, x86-64-v3, and x86-64-v4. These levels define specific features that can be targeted by programmers to provide compile-time optimizations. The features exposed by each level are as follows: baseline for all x86-64 CPUs matches

520-544: A core with many nice features: it is open source, supports Wishbone , has an asynchronous design, supports multiple ISAs , and is ASIC proven. VAMP is a DLX-variant that was mathematically verified as part of Verisoft project. It was specified with PVS , implemented in Verilog , and runs on a Xilinx FPGA . A full stack from compiler to kernel to TCP/IP was built on it. In the Stanford MIPS architecture, one of

585-499: A mirror surface. HDR imagery allows for the reflection of highlights that can still be seen as bright white areas, instead of dull grey shapes. A 32-bit file format is a binary file format for which each elementary information is defined on 32 bits (or 4 bytes ). An example of such a format is the Enhanced Metafile Format . X86-64 x86-64 (also known as x64 , x86_64 , AMD64 , and Intel 64 )

650-467: A number of VIA-specific x86 extensions designed to boost efficiency in low-power appliances. It is expected that the Isaiah architecture will be twice as fast in integer performance and four times as fast in floating-point performance as the previous-generation VIA Esther at an equivalent clock speed . Power consumption is also expected to be on par with the previous-generation VIA CPUs, with thermal design power ranging from 5 W to 25 W. Being

715-413: A total of 96 bits per pixel. 32-bit-per-channel images are used to represent values brighter than what sRGB color space allows (brighter than white); these values can then be used to more accurately retain bright highlights when either lowering the exposure of the image or when it is seen through a dark filter or dull reflection. For example, a reflection in an oil slick is only a fraction of that seen in

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780-406: A virtual processor running in the desired mode. Since the basic instruction set is the same, there is almost no performance penalty for executing protected mode x86 code. This is unlike Intel's IA-64 , where differences in the underlying instruction set mean that running 32-bit code must be done either in emulation of x86 (making the process slower) or with a dedicated x86 coprocessor. However, on

845-496: Is a 64-bit version of the x86 instruction set , first announced in 1999. It introduced two new modes of operation, 64-bit mode and compatibility mode, along with a new 4-level paging mode. With 64-bit mode and the new paging mode, it supports vastly larger amounts of virtual memory and physical memory than was possible on its 32-bit predecessors, allowing programs to store larger amounts of data in memory. x86-64 also expands general-purpose registers to 64-bit, and expands

910-479: Is a 2023 Intel proposal for new instructions and an additional 16 general-purpose registers. VIA Technologies introduced their first implementation of the x86-64 architecture in 2008 after five years of development by its CPU division, Centaur Technology . Codenamed "Isaiah", the 64-bit architecture was unveiled on January 24, 2008, and launched on May 29 under the VIA Nano brand name. The processor supports

975-402: Is a 32-bit machine, with 32-bit registers and instructions that manipulate 32-bit quantities, but the external address bus is 36 bits wide, giving a larger address space than 4 GB, and the external data bus is 64 bits wide, primarily in order to permit a more efficient prefetch of instructions and data. Prominent 32-bit instruction set architectures used in general-purpose computing include

1040-467: Is made into a submode of legacy mode. It is the submode that 32-bit operating systems and 16-bit protected mode operating systems operate in when running on an x86-64 CPU. Real mode is the initial mode of operation when the processor is initialized, and is a submode of legacy mode. It is backwards compatible with the original Intel 8086 and Intel 8088 processors. Real mode is primarily used today by operating system bootloaders, which are required by

1105-588: Is that a processor with 32-bit memory addresses can directly access at most 4  GiB of byte-addressable memory (though in practice the limit may be lower). The world's first stored-program electronic computer , the Manchester Baby , used a 32-bit architecture in 1948, although it was only a proof of concept and had little practical capacity. It held only 32 32-bit words of RAM on a Williams tube , and had no addition operation, only subtraction. Memory, as well as other digital circuits and wiring,

1170-723: Is the Merom version of the Core 2 processor, which was released on July 27, 2006. None of Intel's earlier notebook CPUs ( Core Duo , Pentium M , Celeron M , Mobile Pentium 4 ) implement Intel 64. Intel's processors implementing the Intel64 architecture include the Pentium 4 F-series/5x1 series, 506, and 516, Celeron D models 3x1, 3x6, 355, 347, 352, 360, and 365 and all later Celerons , all models of Xeon since " Nocona ", all models of Pentium Dual-Core processors since " Merom-2M ",

1235-568: Is used by 64-bit operating systems. Under a 64-bit operating system, 64-bit programs run under 64-bit mode, and 32-bit and 16-bit protected mode applications (that do not need to use either real mode or virtual 8086 mode in order to execute at any time) run under compatibility mode. Real-mode programs and programs that use virtual 8086 mode at any time cannot be run in long mode unless those modes are emulated in software. However, such programs may be started from an operating system running in long mode on processors supporting VT-x or AMD-V by creating

1300-400: Is used. (Each register can store one or two double-precision numbers or one to four single-precision numbers, or various integer formats.) In 64-bit mode, instructions are modified to support 64-bit operands and 64-bit addressing mode . The compatibility mode defined in the architecture allows 16-bit and 32-bit user applications to run unmodified, coexisting with 64-bit applications if

1365-480: The 8086 , as x86 processors supporting protected mode have done since the 80286 . The original specification, created by AMD and released in 2000, has been implemented by AMD, Intel , and VIA . The AMD K8 microarchitecture , in the Opteron and Athlon 64 processors, was the first to implement it. This was the first significant addition to the x86 architecture designed by a company other than Intel. Intel

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1430-606: The 8088/8086 or 80286 , 16-bit microprocessors with a segmented address space where programs had to switch between segments to reach more than 64 kilobytes of code or data. As this is quite time-consuming in comparison to other machine operations, the performance may suffer. Furthermore, programming with segments tend to become complicated; special far and near keywords or memory models had to be used (with care), not only in assembly language but also in high level languages such as Pascal , compiled BASIC , Fortran , C , etc. The 80386 and its successors fully support

1495-673: The Atom 230, 330, D410, D425, D510, D525, N450, N455, N470, N475, N550, N570, N2600 and N2800, all versions of the Pentium D , Pentium Extreme Edition , Core 2 , Core i9 , Core i7 , Core i5 , and Core i3 processors, and the Xeon Phi 7200 series processors. X86S is a simplification of x86-64 proposed by Intel in May 2023 for their "Intel 64" products. The new architecture would remove support for 16-bit and 32-bit operating systems, while 32-bit programs will still run under

1560-769: The IBM System/360 , IBM System/370 (which had 24-bit addressing), System/370-XA , ESA/370 , and ESA/390 (which had 31-bit addressing), the DEC VAX , the NS320xx , the Motorola 68000 family (the first two models of which had 24-bit addressing), the Intel IA-32 32-bit version of the x86 architecture, and the 32-bit versions of the ARM , SPARC , MIPS , PowerPC and PA-RISC architectures. 32-bit instruction set architectures used for embedded computing include

1625-551: The IBM System/360 Model 30 had an 8-bit ALU, 8-bit internal data paths, and an 8-bit path to memory, and the original Motorola 68000 had a 16-bit data ALU and a 16-bit external data bus, but had 32-bit registers and a 32-bit oriented instruction set. The 68000 design was sometimes referred to as 16/32-bit . However, the opposite is often true for newer 32-bit designs. For example, the Pentium Pro processor

1690-514: The Tianhe-2 supercomputer. The following operating systems and releases support the x86-64 architecture in long mode . Preliminary infrastructure work was started in February 2004 for a x86-64 port. This development later stalled. Development started again during July 2007 and continued during Google Summer of Code 2008 and SoC 2009. The first official release to contain x86-64 support

1755-526: The Windows NT family) take the higher-addressed half of the address space (named kernel space ) for themselves and leave the lower-addressed half ( user space ) for application code, user mode stacks, heaps, and other data regions. The "canonical address" design ensures that every AMD64 compliant implementation has, in effect, two memory halves: the lower half starts at 00000000'00000000 and "grows upwards" as more virtual address bits become available, while

1820-573: The "AMD64" nomenclature is used. These are used as synonyms with the x86-64-vX nomenclature and are thus functionally identical. E.g. the Go language documentation or the Fedora linux distribution. All levels include features found in the previous levels. Instruction set extensions not concerned with general-purpose computation, including AES-NI and RDRAND , are excluded from the level requirements. Although nearly identical, there are some differences between

1885-533: The 16-bit segments of the 80286 but also segments for 32-bit address offsets (using the new 32-bit width of the main registers). If the base address of all 32-bit segments is set to 0, and segment registers are not used explicitly, the segmentation can be forgotten and the processor appears as having a simple linear 32-bit address space. Operating systems like Windows or OS/2 provide the possibility to run 16-bit (segmented) programs as well as 32-bit programs. The former possibility exists for backward compatibility and

1950-405: The 2013 Intel Haswell architecture, excluding Intel-specific instructions Intel Skylake and newer Intel "big" cores (AVX512 enabled models only) AMD Zen 4 and newer AMD cores features match the 2017 Intel Skylake-X architecture, excluding Intel-specific instructions The x86-64 microarchitecture feature levels can also be found as AMD64-v1, AMD64-v2 .. or AMD64_v1 .. in settings where

2015-450: The 32-bit word. I-type instructions specify two registers, and use 16 bits to hold an immediate value. Finally J-type instructions are jumps , containing a 26-bit address. Opcodes are 6 bits long, for a total of 64 possible basic instructions. To select one of 32 registers 5 bits are needed. The DLX, like the MIPS design, bases its performance on the use of an instruction pipeline . In

DLX - Misplaced Pages Continue

2080-474: The 64-bit operating system supports them. As the full x86 16-bit and 32-bit instruction sets remain implemented in hardware without any intervening emulation, these older executables can run with little or no performance penalty, while newer or modified applications can take advantage of new features of the processor design to achieve performance improvements. Also, a processor supporting x86-64 still powers on in real mode for full backward compatibility with

2145-405: The 64-bit registers. Legacy mode is the mode that the processor is in when it is not in long mode. In this mode, the processor acts like an older x86 processor, and only 16-bit and 32-bit code can be executed. Legacy mode allows for a maximum of 32 bit virtual addressing which limits the virtual address space to 4 GiB. 64-bit programs cannot be run from legacy mode. Protected mode

2210-423: The 68000 family and ColdFire , x86, ARM, MIPS, PowerPC, and Infineon TriCore architectures. On the x86 architecture , a 32-bit application normally means software that typically (not necessarily) uses the 32-bit linear address space (or flat memory model ) possible with the 80386 and later chips. In this context, the term came about because DOS , Microsoft Windows and OS/2 were originally written for

2275-452: The AMD64 architecture include Opteron , Athlon 64 , Athlon 64 X2 , Athlon 64 FX , Athlon II (followed by "X2", "X3", or "X4" to indicate the number of cores, and XLT models), Turion 64 , Turion 64 X2 , Sempron ("Palermo" E6 stepping and all "Manila" models), Phenom (followed by "X3" or "X4" to indicate the number of cores), Phenom II (followed by "X2", "X3", "X4" or "X6" to indicate

2340-483: The AMD64 architecture was positioned by AMD from the beginning as an evolutionary way to add 64-bit computing capabilities to the existing x86 architecture while supporting legacy 32-bit x86 code , as opposed to Intel's approach of creating an entirely new, completely x86-incompatible 64-bit architecture with IA-64. The first AMD64-based processor, the Opteron , was released in April 2003. AMD's processors implementing

2405-498: The DLX design this is a fairly simple one, "classic" RISC in concept. The pipeline contains five stages: 32-bit computing In computer architecture , 32-bit computing refers to computer systems with a processor , memory , and other major system components that operate on data in 32- bit units. Compared to smaller bit widths, 32-bit computers can perform large calculations more efficiently and process more data per clock cycle. Typical 32-bit personal computers also have

2470-611: The OEM market as the Pentium 4, model F. The E0 revision also adds eXecute Disable (XD) (Intel's name for the NX bit ) to Intel 64, and has been included in then current Xeon code-named Irwindale . Intel's official launch of Intel 64 (under the name EM64T at that time) in mainstream desktop processors was the N0 stepping Prescott-2M. The first Intel mobile processor implementing Intel 64

2535-431: The amount of RAM that is usable or supported. Details on this point are given in the " Operating system compatibility and characteristics " section of this article. The architecture has two primary modes of operation: long mode and legacy mode. Long mode is the architecture's intended primary mode of operation; it is a combination of the processor's native 64-bit mode and a combined 32-bit and 16-bit compatibility mode. It

2600-471: The appearance of 64-bit extensions for the x86 architecture enabled 64-bit x86 processors by AMD and Intel to replace most RISC processor architectures previously used in such systems (including PA-RISC , SPARC , Alpha and others), as well as 32-bit x86, even though Intel itself initially tried unsuccessfully to replace x86 with a new incompatible 64-bit architecture in the Itanium processor. As of 2023 ,

2665-529: The architecture to configure virtual memory details before transitioning to higher modes. This mode is also used by any operating system that needs to communicate with the system firmware with a traditional BIOS -style interface. Intel 64 is Intel's implementation of x86-64, used and implemented in various processors made by Intel. Historically, AMD has developed and produced processors with instruction sets patterned after Intel's original designs, but with x86-64, roles were reversed: Intel found itself in

DLX - Misplaced Pages Continue

2730-811: The common capabilities between the 2003 AMD AMD64 and the 2004 Intel EM64T initial implementations in the AMD K8 and the Intel Prescott processor families Intel Nehalem and newer Intel "big" cores Intel (Atom) Silvermont and newer Intel "small" cores AMD Bulldozer and newer AMD "big" cores AMD Jaguar VIA Nano and Eden "C" features match the 2008 Intel Nehalem architecture, excluding Intel-specific instructions Intel Haswell and newer Intel "big" cores (AVX2 enabled models only) Intel (Atom) Gracemont and newer Intel "small" cores AMD Excavator and newer AMD "big" cores QEMU emulation (as of version 7.2) features match

2795-450: The discontinued Intel Itanium architecture (formerly IA-64 ), which was originally intended to replace the x86 architecture. x86-64 and Itanium are not compatible on the native instruction set level, and operating systems and applications compiled for one architecture cannot be run on the other natively. AMD64 (also variously referred to by AMD in their literature and documentation as “AMD 64-bit Technology” and “AMD x86-64 Architecture”)

2860-448: The first implementations of the architecture, only the least significant 48 bits of a virtual address would actually be used in address translation ( page table lookup). In addition, the AMD specification requires that the most significant 16 bits of any virtual address, bits 48 through 63, must be copies of bit 47 (in a manner akin to sign extension ). If this requirement is not met,

2925-551: The full 256 TiB; they were restricted to just 8 TiB of user space and 8 TiB of kernel space. Windows did not support the entire 48-bit address space until Windows 8.1 , which was released in October 2013. The 64-bit addressing mode (" long mode ") is a superset of Physical Address Extensions (PAE); because of this, page sizes may be 4  KiB (2 bytes) or 2  MiB (2 bytes). Long mode also supports page sizes of 1  GiB (2 bytes). Rather than

2990-433: The higher half is "docked" to the top of the address space and grows downwards. Also, enforcing the "canonical form" of addresses by checking the unused address bits prevents their use by the operating system in tagged pointers as flags, privilege markers, etc., as such use could become problematic when the architecture is extended to implement more virtual address bits. The first versions of Windows for x64 did not even use

3055-412: The latter is usually meant to be used for new software development . In digital images/pictures, 32-bit usually refers to RGBA color space ; that is, 24-bit truecolor images with an additional 8-bit alpha channel . Other image formats also specify 32 bits per pixel, such as RGBE . In digital images, 32-bit sometimes refers to high-dynamic-range imaging (HDR) formats that use 32 bits per channel,

3120-433: The methods used to gain performance was to force all instructions to complete in one clock cycle. This forced compilers to insert " no-ops " in cases where the instruction would definitely take longer than one clock cycle. Thus input and output activities (like memory accesses) specifically forced this behaviour, leading to artificial program bloat. In general MIPS programs were forced to have a lot of wasteful NOP instructions,

3185-612: The mid-2000s with installed memory often exceeding the 32-bit 4G RAM address limits on entry level computers. The latest generation of smartphones have also switched to 64 bits. A 32-bit register can store 2 different values. The range of integer values that can be stored in 32 bits depends on the integer representation used. With the two most common representations, the range is 0 through 4,294,967,295 (2 − 1) for representation as an ( unsigned ) binary number , and −2,147,483,648 (−2 ) through 2,147,483,647 (2 − 1) for representation as two's complement . One important consequence

3250-577: The name Intel 64 for its implementation, paralleling AMD's use of the name AMD64. The first processor to implement Intel 64 was the multi-socket processor Xeon code-named Nocona in June 2004. In contrast, the initial Prescott chips (February 2004) did not enable this feature. Intel subsequently began selling Intel 64-enabled Pentium 4s using the E0 revision of the Prescott core, being sold on

3315-536: The number of cores), FX , Fusion/APU and Ryzen / Epyc . The primary defining characteristic of AMD64 is the availability of 64-bit general-purpose processor registers (for example, rax ), 64-bit integer arithmetic and logical operations, and 64-bit virtual addresses . The designers took the opportunity to make other improvements as well. Notable changes in the 64-bit extensions include: Although virtual addresses are 64 bits wide in 64-bit mode, current implementations (and all chips that are known to be in

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3380-404: The number of them from 8 (some of which had limited or fixed functionality, e.g. for stack management) to 16 (fully general), and provides numerous other enhancements. Floating-point arithmetic is supported via mandatory SSE2 -like instructions , and x87 / MMX style registers are generally not used (but still available even in 64-bit mode); instead, a set of 16 vector registers , 128 bits each,

3445-655: The original Apple Macintosh . Fully 32-bit microprocessors such as the HP FOCUS , Motorola 68020 and Intel 80386 were launched in the early to mid 1980s and became dominant by the early 1990s. This generation of personal computers coincided with and enabled the first mass-adoption of the World Wide Web . While 32-bit architectures are still widely-used in specific applications, the PC and server market has moved on to 64 bits with x86-64 and other 64-bit architectures since

3510-568: The page table entry would be expanded to 128 bits to support additional hardware flags for page size and virtual address space size. The operating system can also limit the virtual address space. Details, where applicable, are given in the " Operating system compatibility and characteristics " section. Current AMD64 processors support a physical address space of up to 2 bytes of RAM, or 256  TiB . However, as of 2020 , there were no known x86-64 motherboards that support 256 TiB of RAM. The operating system may place additional limits on

3575-488: The planning stages) do not allow the entire virtual address space of 2 bytes (16  EiB ) to be used. This would be approximately four billion times the size of the virtual address space on 32-bit machines. Most operating systems and applications will not need such a large address space for the foreseeable future, so implementing such wide virtual addresses would simply increase the complexity and cost of address translation with no real benefit. AMD, therefore, decided that, in

3640-573: The position of adopting the ISA that AMD created as an extension to Intel's own x86 processor line. Intel's project was originally codenamed Yamhill (after the Yamhill River in Oregon's Willamette Valley). After several years of denying its existence, Intel announced at the February 2004 IDF that the project was indeed underway. Intel's chairman at the time, Craig Barrett , admitted that this

3705-511: The processor will raise an exception. Addresses complying with this rule are referred to as "canonical form." Canonical form addresses run from 0 through 00007FFF'FFFFFFFF, and from FFFF8000'00000000 through FFFFFFFF'FFFFFFFF, for a total of 256  TiB of usable virtual address space. This is still 65,536 times larger than the virtual 4 GiB address space of 32-bit machines. This feature eases later scalability to true 64-bit addressing. Many operating systems (including, but not limited to,

3770-450: The three-level page table system used by systems in PAE mode, systems running in long mode use four levels of page table: PAE's Page-Directory Pointer Table is extended from four entries to 512, and an additional Page-Map Level 4 (PML4) Table is added, containing 512 entries in 48-bit implementations. A full mapping hierarchy of 4 KiB pages for the whole 48-bit space would take

3835-491: The two instruction sets in the semantics of a few seldom used machine instructions (or situations), which are mainly used for system programming . Compilers generally produce executables (i.e. machine code ) that avoid any differences, at least for ordinary application programs . This is therefore of interest mainly to developers of compilers, operating systems and similar, which must deal with individual and special system instructions. In supercomputers tracked by TOP500 ,

3900-410: The x86-64 platform, many x86 applications could benefit from a 64-bit recompile , due to the additional registers in 64-bit code and guaranteed SSE2-based FPU support, which a compiler can use for optimization. However, applications that regularly handle integers wider than 32 bits, such as cryptographic algorithms, will need a rewrite of the code handling the huge integers in order to take advantage of

3965-534: Was created as an alternative to the radically different IA-64 architecture designed by Intel and Hewlett-Packard , which was backward-incompatible with IA-32 , the 32-bit version of the x86 architecture. AMD originally announced AMD64 in 1999 with a full specification available in August 2000. As AMD was never invited to be a contributing party for the IA-64 architecture and any kind of licensing seemed unlikely,

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4030-595: Was expensive during the first decades of 32-bit architectures (the 1960s to the 1980s). Older 32-bit processor families (or simpler, cheaper variants thereof) could therefore have many compromises and limitations in order to cut costs. This could be a 16-bit ALU , for instance, or external (or internal) buses narrower than 32 bits, limiting memory size or demanding more cycles for instruction fetch, execution or write back. Despite this, such processors could be labeled 32-bit , since they still had 32-bit registers and instructions able to manipulate 32-bit quantities. For example,

4095-425: Was forced to follow suit and introduced a modified NetBurst family which was software-compatible with AMD's specification. VIA Technologies introduced x86-64 in their VIA Isaiah architecture, with the VIA Nano . The x86-64 architecture was quickly adopted for desktop and laptop personal computers and servers which were commonly configured for 16 GiB ( gibibytes ) of memory or more. It has effectively replaced

4160-528: Was one of their worst-kept secrets. Intel's name for this instruction set has changed several times. The name used at the IDF was CT (presumably for Clackamas Technology , another codename from an Oregon river ); within weeks they began referring to it as IA-32e (for IA-32 extensions) and in March 2004 unveiled the "official" name EM64T (Extended Memory 64 Technology). In late 2006 Intel began instead using

4225-481: Was version 2.4. FreeBSD first added x86-64 support under the name "amd64" as an experimental architecture in 5.1-RELEASE in June 2003. It was included as a standard distribution architecture as of 5.2-RELEASE in January 2004. Since then, FreeBSD has designated it as a Tier 1 platform. The 6.0-RELEASE version cleaned up some quirks with running x86 executables under amd64, and most drivers work just as they do on

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