The F16C (previously/informally known as CVT16) instruction set is an x86

instruction set architecture In computer science, an instruction set architecture (ISA), also called computer architecture, is an abstract model of a computer. A device that executes instructions described by that ISA, such as a central processing unit (CPU), is called an ...

extension which provides support for converting between half-precision and standard IEEE

single-precision floating-point format Single-precision floating-point format (sometimes called FP32 or float32) is a computer number format, usually occupying 32 bits in computer memory; it represents a wide dynamic range of numeric values by using a floating radix point. A floatin ...

History

The CVT16 instruction set, announced by AMD on May 1, 2009, is an extension to the 128-bit SSE core instructions in the x86 and

AMD64 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 m ...

instruction set. CVT16 is a revision of part of the SSE5 instruction set proposal announced on August 30, 2007, which is supplemented by the XOP and

FMA4 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 ...

instruction sets. This revision makes the binary coding of the proposed new instructions more compatible with

Intel Intel Corporation is an American multinational corporation and technology company headquartered in Santa Clara, California. It is the world's largest semiconductor chip manufacturer by revenue, and is one of the developers of the x86 ser ...

's AVX instruction extensions, while the functionality of the instructions is unchanged. In recent documents, the name F16C is formally used in both

and AMD

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 ...

architecture specifications.

Technical information

There are variants that convert four floating-point values in an XMM register or 8 floating-point values in a YMM register. The instructions are abbreviations for "vector convert packed half to packed single" and vice versa: * VCVTPH2PS xmmreg,xmmrm64 convert four half-precision floating point values in memory or the bottom half of an XMM register to four single-precision floating-point values in an XMM register. * VCVTPH2PS ymmreg,xmmrm128 convert eight half-precision floating point values in memory or an XMM register (the bottom half of a YMM register) to eight single-precision floating-point values in a YMM register. * VCVTPS2PH xmmrm64,xmmreg,imm8 convert four single-precision floating point values in an XMM register to half-precision floating-point values in memory or the bottom half an XMM register. * VCVTPS2PH xmmrm128,ymmreg,imm8 convert eight single-precision floating point values in a YMM register to half-precision floating-point values in memory or an XMM register. The 8-bit immediate argument to VCVTPS2PH selects the

rounding Rounding means replacing a number with an approximate value that has a shorter, simpler, or more explicit representation. For example, replacing $ with $, the fraction 312/937 with 1/3, or the expression with . Rounding is often done to ob ...

mode. Values 0–4 select nearest, down, up, truncate, and the mode set in MXCSR.RC. Support for these instructions is indicated by bit 29 of ECX after CPUID with EAX=1.

CPUs with F16C

* AMD: ** Jaguar-based processors and newer ** Puma-based processors and newer ** "Heavy Equipment" processors *** Bulldozer-based processors, Q4 2011 *** Piledriver-based processors, Q4 2012 *** Steamroller-based processors, Q1 2014 *** Excavator-based processors and newer, 2015 ** Zen-based processors, Q1 2017 ** Zen+-based processors, Q2 2018 ** Zen2-based processors, Q3 2019 *

: ** Ivy Bridge processors and newer

References

External links

* New Bulldozer and Piledriver Instruction

* DirectX math F16C and FMA

* AMD64 Architecture Programmer's Manual Volume

* AMD64 Architecture Programmer's Manual Volume

* AMD64 Architecture Programmer's Manual Volume

* AMD64 Architecture Programmer's Manual Volume

* AMD64 Architecture Programmer's Manual Volume

* IA32 Architectures Software Developer Manua

{{Multimedia extensions, state=uncollapsed X86 instructions AMD technologies