REX Prefix
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REX Prefix
The VEX prefix (from "vector extensions") and VEX coding scheme are an extension to the x86 and x86-64 instruction set architecture for microprocessors from Intel, AMD and others. Features The VEX coding scheme allows the definition of new instructions and the extension or modification of previously existing instruction codes. This serves the following purposes: * The opcode map is extended to make space for future instructions. * It allows instruction codes to have up to four operands (plus immediate), where the original scheme allows only two operands (plus immediate). * It allows the size of SIMD vector registers to be extended from the 128-bits XMM registers to 256-bits registers named YMM. There is room for further extensions of the register size. * It allows existing two-operand instructions to be modified into non-destructive three-operand forms where the destination register is different from both source registers. For example, instead of (where register ''a'' is chan ...
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X86-64
x86-64 (also known as x64, x86_64, AMD64, and Intel 64) is a 64-bit version of the x86 instruction set, first released 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 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, is used. (Each register can store one or two double-preci ...
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Advanced Vector Extensions
Advanced Vector Extensions (AVX) are extensions to the x86 instruction set architecture for microprocessors from Intel and Advanced Micro Devices (AMD). They were proposed by Intel in March 2008 and first supported by Intel with the Sandy Bridge processor shipping in Q1 2011 and later by AMD with the Bulldozer processor shipping in Q3 2011. AVX provides new features, new instructions and a new coding scheme. AVX2 (also known as Haswell New Instructions) expands most integer commands to 256 bits and introduces new instructions. They were first supported by Intel with the Haswell processor, which shipped in 2013. AVX-512 expands AVX to 512-bit support using a new EVEX prefix encoding proposed by Intel in July 2013 and first supported by Intel with the Knights Landing co-processor, which shipped in 2016. In conventional processors, AVX-512 was introduced with Skylake server and HEDT processors in 2017. Advanced Vector Extensions AVX uses sixteen YMM registers to perform a sin ...
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FMA3 Instruction Set
The FMA instruction set is an extension to the 128 and 256-bit Streaming SIMD Extensions instructions in the x86 microprocessor instruction set to perform fused multiply–add (FMA) operations."FMA3 and FMA4 are not instruction sets, they are individual instructions -- fused multiply add. They could be quite useful depending on how Intel and AMD implement them" There are two variants: * FMA4 is supported in AMD processors starting with the Bulldozer architecture. FMA4 was performed in hardware before FMA3 was. Support for FMA4 has been removed since Zen 1. * FMA3 is supported in AMD processors starting with the Piledriver architecture and Intel starting with Haswell processors and Broadwell processors since 2014. Instructions FMA3 and FMA4 instructions have almost identical functionality, but are not compatible. Both contain fused multiply–add (FMA) instructions for floating-point scalar and SIMD operations, but FMA3 instructions have three operands, while FMA4 ones have ...
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FMA4 Instruction Set
The FMA instruction set is an extension to the 128 and 256-bit Streaming SIMD Extensions instructions in the x86 microprocessor instruction set to perform fused multiply–add (FMA) operations."FMA3 and FMA4 are not instruction sets, they are individual instructions -- fused multiply add. They could be quite useful depending on how Intel and AMD implement them" There are two variants: * FMA4 is supported in AMD processors starting with the Bulldozer architecture. FMA4 was performed in hardware before FMA3 was. Support for FMA4 has been removed since Zen 1. * FMA3 is supported in AMD processors starting with the Piledriver architecture and Intel starting with Haswell processors and Broadwell processors since 2014. Instructions FMA3 and FMA4 instructions have almost identical functionality, but are not compatible. Both contain fused multiply–add (FMA) instructions for floating-point scalar and SIMD operations, but FMA3 instructions have three operands, while FMA4 ones h ...
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Sandy Bridge (microarchitecture)
Sandy Bridge is the codename for Intel's 32 nm microarchitecture used in the second generation of the Intel Core processors (Core i7, i5, i3). The Sandy Bridge microarchitecture is the successor to Nehalem and Westmere microarchitecture. Intel demonstrated a Sandy Bridge processor in 2009, and released first products based on the architecture in January 2011 under the Core brand. Sandy Bridge is manufactured in the 32 nm process and has a soldered contact with the die and IHS (Integrated Heat Spreader), while Intel's subsequent generation Ivy Bridge uses a 22 nm die shrink and a TIM (Thermal Interface Material) between the die and the IHS. Technology Intel demonstrated a Sandy Bridge processor with A1 stepping at 2 GHz during the Intel Developer Forum in September 2009. Upgraded features from Nehalem include: CPU * Intel Turbo Boost 2.0 * 32 KB data + 32 KB instruction L1 cache and 256 KB L2 cache per core * Shared L3 cache which includes ...
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XOP Instruction Set
The XOP (''eXtended Operations'') instruction set, announced by AMD on May 1, 2009, is an extension to the 128-bit SSE core instructions in the x86 and AMD64 instruction set for the Bulldozer processor core, which was released on October 12, 2011. However AMD removed support for XOP from Zen (microarchitecture) onward. The XOP instruction set contains several different types of vector instructions since it was originally intended as a major upgrade to SSE. Most of the instructions are integer instructions, but it also contains floating point permutation and floating point fraction extraction instructions. See the index for a list of instruction types. History XOP is a revised subset of what was originally intended as SSE5. It was changed to be similar but not overlapping with AVX, parts that overlapped with AVX were removed or moved to separate standards such as FMA4 (floating-point vector multiply–accumulate) and CVT16 (Half-precision floating-point conversion implement ...
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Ars Technica
''Ars Technica'' is a website covering news and opinions in technology, science, politics, and society, created by Ken Fisher and Jon Stokes in 1998. It publishes news, reviews, and guides on issues such as computer hardware and software, science, technology policy, and video games. ''Ars Technica'' was privately owned until May 2008, when it was sold to Condé Nast Digital, the online division of Condé Nast Publications. Condé Nast purchased the site, along with two others, for $25 million and added it to the company's ''Wired'' Digital group, which also includes ''Wired'' and, formerly, Reddit. The staff mostly works from home and has offices in Boston, Chicago, London, New York City, and San Francisco. The operations of ''Ars Technica'' are funded primarily by advertising, and it has offered a paid subscription service since 2001. History Ken Fisher, who serves as the website's current editor-in-chief, and Jon Stokes created ''Ars Technica'' in 1998. Its purpose was ...
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Bulldozer (processor)
The AMD Bulldozer Family 15h is a microprocessor microarchitecture for the FX and Opteron line of processors, developed by AMD for the desktop and server markets. Bulldozer is the codename for this family of microarchitectures. It was released on October 12, 2011, as the successor to the K10 microarchitecture. Bulldozer is designed from scratch, not a development of earlier processors. The core is specifically aimed at computing products with TDPs of 10 to 125 watts. AMD claims dramatic performance-per-watt efficiency improvements in high-performance computing (HPC) applications with Bulldozer cores. The ''Bulldozer'' cores support most of the instruction sets implemented by Intel processors (Sandy Bridge) available at its introduction (including SSE4.1, SSE4.2, AES, CLMUL, and AVX) as well as new instruction sets proposed by AMD; ABM, XOP, FMA4 and F16C. Only Bulldozer GEN4 (Excavator) supports AVX2 instruction sets. Overview According to AMD, Bulldozer-based CPUs ...
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SSE5
The SSE5 (short for Streaming SIMD Extensions version 5) was a SIMD instruction set extension proposed by AMD on August 30, 2007 as a supplement to the 128-bit SSE core instructions in the AMD64 architecture. AMD chose not to implement SSE5 as originally proposed. In May 2009, AMD replaced SSE5 with three smaller instruction set extensions named as XOP, FMA4, and F16C, which retain the proposed functionality of SSE5, but encode the instructions differently for better compatibility with Intel's proposed AVX instruction set. The three SSE5-derived instruction sets were introduced in the Bulldozer processor core, released in October 2011 on a 32 nm process. Compatibility AMD's SSE5 extension bundle does not include the full set of Intel's SSE4 instructions, making it a competitor to SSE4 rather than a successor. This complicates software development. It is recommended practice for a program to test for the presence of instruction set extensions by means of the CPUID instruc ...
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AVX-512
AVX-512 are 512-bit extensions to the 256-bit Advanced Vector Extensions SIMD instructions for x86 instruction set architecture (ISA) proposed by Intel in July 2013, and implemented in Intel's Xeon Phi x200 (Knights Landing) and Skylake-X CPUs; this includes the Core-X series (excluding the Core i5-7640X and Core i7-7740X), as well as the new Xeon Scalable Processor Family and Xeon D-2100 Embedded Series. AVX-512 consists of multiple extensions that may be implemented independently. This policy is a departure from the historical requirement of implementing the entire instruction block. Only the core extension AVX-512F (AVX-512 Foundation) is required by all AVX-512 implementations. Besides widening most 256-bit instructions, the extensions introduce various new operations, such as new data conversions, scatter operations, and permutations. The number of AVX registers is increased from 16 to 32, and eight new "mask registers" are added, which allow for variable selection and blendi ...
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Bit Manipulation Instruction Set
Bit manipulation instructions sets (BMI sets) are extensions to the x86 instruction set architecture for microprocessors from Intel and AMD. The purpose of these instruction sets is to improve the speed of bit manipulation. All the instructions in these sets are non-SIMD and operate only on general-purpose registers. There are two sets published by Intel: BMI (now referred to as BMI1) and BMI2; they were both introduced with the Haswell microarchitecture with BMI1 matching features offered by AMD's ABM instruction set and BMI2 extending them. Another two sets were published by AMD: ABM (''Advanced Bit Manipulation'', which is also a subset of SSE4a implemented by Intel as part of SSE4.2 and BMI1), and TBM (''Trailing Bit Manipulation'', an extension introduced with Piledriver-based processors as an extension to BMI1, but dropped again in Zen-based processors). ABM (Advanced Bit Manipulation) AMD was the first to introduce the instructions that now form Intel's BMI1 as part of ...
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Streaming SIMD Extensions
In computing, Streaming SIMD Extensions (SSE) is a single instruction, multiple data (SIMD) instruction set extension to the x86 architecture, designed by Intel and introduced in 1999 in their Pentium III series of Central processing units (CPUs) shortly after the appearance of Advanced Micro Devices (AMD's) 3DNow!. SSE contains 70 new instructions (65 unique mnemonics using 70 encodings), most of which work on single precision floating-point data. SIMD instructions can greatly increase performance when exactly the same operations are to be performed on multiple data objects. Typical applications are digital signal processing and graphics processing. Intel's first IA-32 SIMD effort was the MMX instruction set. MMX had two main problems: it re-used existing x87 floating-point registers making the CPUs unable to work on both floating-point and SIMD data at the same time, and it only worked on integers. SSE floating-point instructions operate on a new independent register set, the ...
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