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Topic: Floating point unit


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In the News (Sat 23 Mar 19)

  
  Floating Point Unit - Wikipedia
Typical operations are floating point arithmetic (such as addition and multiplication), but some systems may be capable of performing exponential or trigonometric calculations as well (such as square roots or cosines).
In some computer architectures, floating point operations are handled completely separate from integer operations, with dedicated floating point registers and independent clocking schemes.
Floating point addition and multiplication operations are typically pipelined, but more complicated operations, like division, may not be, and some systems may even have a dedicated floating point divider circuit.
wikipedia.findthelinks.com /fp/FPU.html   (165 words)

  
 Floating point unit - Wikipedia, the free encyclopedia
In the past, some systems have implemented floating point via a coprocessor rather as an integrated unit; in the microcomputer era, this was generally a single microchip, while in older systems it could be an entire circuit board or a cabinet.
In the 1980s, it was common in IBM PC/compatible microcomputers for the FPU to be entirely separate from the CPU, and typically sold as an optional add-on.
Starting with the 80486, in x86 chips the floating point unit was integrated with the CPU, something true for almost all later x86-architecture processors.
en.wikipedia.org /wiki/Floating_point_unit   (693 words)

  
 Floating point computation unit having means for rounding the floating point computation result - Patent 4468748
A floating point computation unit for use in a data processing system in which the mantissa processing means provides an overall computation result a portion of which represents the desired mantissa result.
2 of the floating point unit of the invention.
MV/8000 unit, the operations for both the arithmetic logic unit and the floating point unit are cycled twice for each microinstruction (a first half-cycle and a second half-cycle) and the CSM, FPUD and EXT fields define the sources of control during each of the half-cycles.
www.freepatentsonline.com /4468748.html   (3186 words)

  
 Art of Assembly: Chapter Fourteen
If our floating point calculation is limited to three significant digits during computation, we would have had to truncate the last digit of the smaller number, obtaining 1.68e1 which is even less correct.
When Intel planned to introduce a floating point coprocessor for their new 8086 microprocessor, they were smart enough to realize that the electrical engineers and solid-state physicists who design chips were, perhaps, not the best people to do the necessary numerical analysis to pick the best possible binary representation for a floating point format.
Although single precision floating point numbers are perfectly suitable for many applications, the dynamic range is somewhat small for many scientific applications and the very limited precision is unsuitable for many financial, scientific, and other applications.
webster.cs.ucr.edu /AoA/DOS/ch14/CH14-1.html   (3947 words)

  
 Floating point unit for calculating A=XY+Z having simultaneous multiply and add - Patent 4969118
A floating point unit may be required to perform various mathematical operations on floating point numbers such addition, subtraction, multiplication and division.
Floating point notation can also be used with numbers to other bases, and in the case of high speed digital computers, floating point numbers are in binary.
Thus a binary number of the form 101.011 could be written as a floating point number of the form 0.101011.times.2.sup.3 where the mantissa is 0.101011, the exponent is 3, the radix, or base is 2, and the point is referred to as a binary point instead of a decimal point.
www.freepatentsonline.com /4969118.html   (3640 words)

  
 Intel Floating Point: Another Stack Code Example   (Site not responding. Last check: 2007-10-19)
The floating point instruction set uses the register array as a stack, but it also allows you to reference any register in the stack, not just the top.
Floating point values (float and double) are pushed onto the stack frame just like integers.
A floating point function return value is left on the top of the register stack, that is, in ST(0).
www.mathcs.sjsu.edu /faculty/kirchher/CS140/IntelFloatingPoint.html   (733 words)

  
 Embedded Pentium® Processor Family Technical Information Center - Floating-Point Unit   (Site not responding. Last check: 2007-10-19)
Like the general-purpose registers in the processor's integer unit, the contents of the FPU data registers are unaffected by procedure calls, or in other words, the values are maintained across procedure boundaries.
A pointer to the FPU data register that is currently at the top of the FPU register stack is contained in bits 11 through 13 of the FPU status word.
Note that the FPU's word-integer data type is identical to the word-integer data type used by the processor's integer unit and the short-integer format is identical to the integer unit's doubleword-integer data type.
www.engr.udayton.edu /faculty/jloomis/ece314/notes/fpu/fpu.html   (7054 words)

  
 Floating Point : Java Glossary
By floating point I refer generically to the code written to use the primitives double and float and the wrapper classes Double and Float.
In most computers, floating point arithmetic is usually much slower than integer arithmetic, though on the Pentium it is usually faster because the integer unit was not given the same care as the floating point unit.
Floating point is slower still when you consider the overhead of converting between the combined int/floating point stack in the JVM and the separate stacks in the Pentium hardware.
www.mindprod.com /jgloss/floatingpoint.html   (1691 words)

  
 Floating Point Unit Design
The floating point unit consists of a four stage pipelimne with a one entry instruction queue.
The FPU class is the top-level class, serving as the shell for instances of the FPULoadWB, FPUnitRegs, and FPUPipeline classes.
Since the logic of the various pipeline stages was not discussed in great detail in any of the references used in coding the FPU, the FPU may need to be modified to reflect a greater knowledge and accuracy in the future.
www.cs.utexas.edu /users/chris/ppc/fpu_design.html   (1808 words)

  
 Floating Point Unit - Unofficial BOINC Wiki   (Site not responding. Last check: 2007-10-19)
That portion of the computer that does the operations on Floating Point Numbers.
Floating point numbers give us a good dynamic range and a reasonable representation of numbers.
The portion of the Central Processing Unit (CPU) that performs the manipulation of these values and performs the mathematical operations of these values is called the Floating Point Unit, or FPU for short.
boinc-wiki.ath.cx /index.php?title=FPU   (340 words)

  
 History of the PowerPC Architecture
Utilization of the load-store unit’s three reservation station entries averages 1.36 to 1.73 entries for integer benchmarks and 0.98 to 2.26 entries for floating-point benchmarks.
Unlike the other execution units, the load-store unit does not deallocate a reservation station entry as soon as an instruction is issued.
For each execution unit, the overall execution latency is the actual execution time of an instruction plus the waiting time in the reservation stations.
www.cs.pitt.edu /~alanjawi/p620.html   (1130 words)

  
 CMOS floating-point unit for the S/390 Parallel Enterprise Server G4
The G4 FPU executes the most common floating-point instructions in a pipelined fashion with a throughput of one per cycle, and the infrequent operations are executed in a nonpipelined mode.
Thus, the G4 FPU chip implements a very aggressive division algorithm which is quadratically converging, and eliminates the remainder comparison in half of the cases.
Since the G4 FPU can be considered a peripheral unit which is not aware of the global central processor state, it was best to implement a feed-forward pipeline so as not to become instruction-starved or data-starved.
www.research.ibm.com /journal/rd/414/schwarz.html   (7457 words)

  
 The S/390 G5 floating-point unit
Both the execution unit (E-unit) and the instruction unit (I-unit) are duplicated on chip and execute on the same instruction stream, and the results are compared by the recovery unit and L1 cache unit.
Since the FXU and FPU cannot execute in parallel, the FXU is used for the starting of floating-point instructions to access data from the register files and align storage data for the FPU.
The primary difference between this diagram and one for the G4 FPU is the addition of feedback paths in the FS1 cycle for binary format conversion and the addition of the FS5 stage for rounding.
www.research.ibm.com /journal/rd/435/schwarz.html   (7160 words)

  
 BDTI - GPP: Motorola/IBM PowerPC 604/604e
The floating-point unit is capable of operating on either 64-bit (double-precision) or 32-bit (single-precision) operands with no difference in speed, except for division operations which take longer for 64-bit operands.
The floating-point unit is pipelined and performs all operations with a latency of three clock cycles and a throughput of one clock cycle.
Since the complex integer unit can perform multiplications with single-cycle throughput (assuming at least one operand is 16 bits in length) and the simple integer units can perform additions in the same clock cycle, single-cycle integer MAC throughput is theoretically possible on the PowerPC 604.
www.bdti.com /products/reports_gpp604.htm   (1814 words)

  
 FPU (Floating Point Unit) Definition
Stands for "Floating Point Unit." The first computer processors were far better at dealing with integers than with real numbers (a.k.a.
So a separate FPU processor was developed to handle the floating point calculations.
While the first floating point units used to be manufactured as individual chips, they are now typically integrated into the CPU.
www.techterms.org /definition/fpu   (121 words)

  
 EETimes.com - Floating point unit added to Coldfire with enhanced core
With many embedded applications dealing with streaming multimedia data forms, floating point and an enhanced MAC unit were clear options.
The FPU is a 64-bit double-precision implementation of the MC68060 floating point instruction set, and is IEEE-754 standard compliant with a software assist.
The FPU module supports concurrent execution between the operand execution pipeline on the 4e core and and FPU.
www.eetimes.com /story/OEG20001017S0041   (1028 words)

  
 THE SPARC ARCHITECTURE
The SPARC architecture's definition includes the IU (Integer Unit) which is the CPU, the FPU (Floating Point Unit) and the CP (CoProcessor) which is optional for the user.
The floating-point unit (FPU) is tightly coupled to the integer pipeline and is capable of seamlessly executing a floating-point memory event and a floating-point operation.
The FPU performs all floating-point operations and implements a 3-entry floating-point instruction queue to re duce the impact of bottlenecks at the IU and improve overall performance.
www.cs.wisc.edu /~fischer/cs701.f03/sparc.htm   (1389 words)

  
 Floating Point
It explains the binary representation of these numbers, how to convert to decimal from floating point, how to convert from floating point to decimal, discusses special cases in floating point, and finally ends with some C code to further one's understanding of floating point.
The single precision floating point unit is a packet of 32 bits, divided into three sections one bit, eight bits, and twenty-three bits, in that order.
The answer is that there are special cases of floating point numbers, specifically when the exponent field is all 1 bits (255) or all 0 bits (0).
www.cs.cornell.edu /~tomf/notes/cps104/floating.html   (2287 words)

  
 Floating Point
Make sure that everything is consistently compiled for hardware floating point, especially if you've assembled your toolkit yourself, or are using an 8xx toolkit to compile for the 8260.
Programs compiled for hardware floating point can still run on a CPU without an FPU, provided the kernel is built with the floating point instruction emulator.
In general, you're better off choosing one or the other, and choosing hardware floating point with kernel instruction emulation is much easier to get working correctly.
penguinppc.org /embedded/howto/floating.html   (337 words)

  
 What is floating-point number? - A Word Definition From the Webopedia Computer Dictionary
The term floating point is derived from the fact that there is no fixed number of digits before and after the decimal point; that is, the decimal point can float.
If the programmer is not careful, small discrepancies in the approximations can snowball to the point where the final results become meaningless.
FPUs are also called math coprocessors and numeric coprocessors.
www.webopedia.com /TERM/F/floating_point_number.html   (432 words)

  
 IBM eServer z990 floating-point unit, The IBM Journal of Research and Development - Find Articles
The floating-point unit (FPU) of the IBM z990 eServer(TM) is the first one in an IBM mainframe with a fused multiply-add dataflow.
The z990 FPU had a variety of predecessors: the 1996 G3 FPU [4], the 1997 G4 FPU [5, 6], the 1998 G5 FPU [7, 8], the 1999 G6 FPU, and the 2000 z900 FPU [9].
Compared with them, the main z990 FPU goals were to optimize for BFP and have a fast multiply-adcl execution in order to support the increase in new zSeries workloads, particularly those utilizing Linux**.
www.findarticles.com /p/articles/mi_qa3751/is_200405/ai_n9388219   (866 words)

  
 Minature Introduction - Using and Abusing PowerPC Floats
In the past, most programmers could not assume that the floating point unit was part of the standard architecture.
This is not a problem with the branch unit, but takes some planning with the integer and floating unit.
This is the conversion from integer to float...
www.lightsoft.co.uk /PD/rob/ppcfloat.html   (1542 words)

  
 VHJ: Boosting the VIA C3's Floating Point Performance
When a floating point exception is unmasked, an error condition will then trigger an exception that the programmer must code for.
All that is necessary to mask FPU exceptions is to initialize the floating point unit once prior to entering the code block that exercises the FPU.
If floating point errors are expected within your code and cannot be "debugged away," error conditions can be checked for by polling the floating point status word.
www.vanshardware.com /articles/2004/03/040331_C3Fpu/040331_C3Fpu.htm   (666 words)

  
 Floating point instructions
You have the ability to convert integers to your implementation-defined 'floating point' and perform basic mathematics with them (most usually fixed point), but you cannot interact with a floating point co-processor and do things the 'native' way.
FP units can be software implementations such as the FPEmulator modules, hardware implementations such as the FP chip (and support code), or a combination of both.
This could be modified to multiply two floating point numbers, and give a floating point response, but as it is only a short example, it will simply use two integers.
www.heyrick.co.uk /assembler/fpops.html   (3039 words)

  
 Fractal eXtreme: x86 and Infinity
Floating point math is described by IEEE 754-185 and IEC-559.
Denormals are special floating point numbers that are not normalized - instead of being 1.x times the exponent they are 0.x times the exponent.
Their non-standard format causes difficulty for many floating point units, and was the cause of much wrangling when IEEE 754 was being worked on.
www.cygnus-software.com /papers/x86andinfinity.html   (1235 words)

  
 floating point unit - a Whatis.com definition
A floating point unit (FPU), also known as a math coprocessor or numeric coprocessor, is a specialized coprocessor that manipulates numbers more quickly than the basic microprocessor circuitry.
The FPU does this by means of instructions that focus entirely on large mathematical operations.
A floating point number is a binary number carried out to a specific number of digits, and containing a radix (or decimal) point somewhere in the digit sequence.
whatis.techtarget.com /gDefinition/0,294236,sid1_gci213965,00.html   (312 words)

  
 What is FPU? - A Word Definition From the Webopedia Computer Dictionary
Short for floating-point unit, a specially designed chip that performs floating-point calculations.
Computers equipped with an FPU perform certain types of applications much faster than computers that lack one.
Floating-point units are also called numeric coprocessors, math coprocessors, and floating-point processors.
www.webopedia.com /TERM/F/FPU.html   (115 words)

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