Questions tagged [floating-point]
Floating point arithmetic: number formats, instruction sets, software and hardware implementations.
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Looking for early examples of extended precision by interpretation
The other day I came across a clever way of implementing variable-length extended precision, dated 1967 (on the BESM-6, apparently as part of the system software available at the time of introduction ...
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Is there any DOS game before Quake era (1996) that makes heavy use of the FPU?
Quake was one of the earliest DOS games to show most gamers the importance of having a fast FPU to play with. Were there any other games (probably 3D) before Quake that started using the FPU?
For ...
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What floating point libraries were written to meet the IEEE 754 standard before it was accepted in 1985?
The IEEE 754 floating point arithmetic working group began in 1977 and was formally accepted in 1985. One of the original driving factors of the standard itself was Intel who wanted a standard to go ...
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PDP-8 floating point numbers
I'm trying to find a single clear statement of the limits to the numbers represented in the PDP-8's three-word format.
I found the original documents on this, but they are, ahem, not exactly ...
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Why was BASIC's INT() a floor, and not a truncate?
Reading over some older bits I've collected over the years, it appears that some early BASICs used a truncate for their INT function, but this was standardized on floor.
Any ideas why? Poking about I ...
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Examples of floating-point numbers that don’t round-trip losslessly through text conversion in Microsoft BASIC
For a long time I thought it was kind of crazy that 8-bit Microsoft BASIC stores numeric constants in ASCII and has to parse them into its 32- or 40-bit floating point format at runtime. Why not parse ...
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Looking for help understanding a 'Reciproot' routine on the Manchester Mark I (1951)
I'm hoping to understand a routine written for the Manchester Mark I [NOTE: a comment from Raffzahn suggests this may be the Ferranti (wikipedia link) and not the Manchester Mark I] which computes ...
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What is the earliest use in C of indexing the bits of a float or double to sample a table lookup?
One common way to produce an approximation of a function like the logarithm or the exponential is to precompute a table of values (a lookup table) for the output or some intermediate stage of the ...
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Was the design of the PDP-11 Floating Point Processor responsible for C's willingness to do arithmetic on floats at double precision?
The Wikipedia page on PDP-11 architecture has a very interesting bullet point in the section on the Floating Point Processor extension to the basic architecture:
full floating point operations on ...
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How is FSTSW AX implemented on the 80286/80287?
The x87 instruction set does not support direct transfers between general purpose registers and floating point registers. This is mainly a consequence of the 8087/80287/80387 being a separate chip ...
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How robust was floating point format output in pre-IEEE systems?
Most pre-IEEE floating point formats that used biased exponent and a 2's-complement mantissa without a hidden bit, were asymmetric. That is, there was a representable negative value which had no ...
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Did the ARM-1 really outperform the 387?
According to a comment on https://news.ycombinator.com/item?id=31985142
The first benchmarks indicated the plain Archimedes had higher FP throughput than a 16MHz 386 with a 387.
The original ...
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Did any hardware-supported floating-point format ever fast-track integers?
The floating-point format on the ZX Spectrum has the unusual feature of special-casing small integers: Why does Sinclair BASIC have two formats for storing numbers in the same structure?
There are ...
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Who were the members of the IEEE 754 working group?
The IEEE 754 working group began meeting in 1977, produced a draft standard for floating-point arithmetic by the beginning of the eighties, and had it formally ratified in 1985, by which time it was ...
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Did any PC software floating point use non-IEEE format?
During the 1980s, prior to the 486 (well, strictly speaking, prior to the discontinuing of the 486SX in the nineties), IBM PCs and compatibles had hardware floating point only in the form of an ...
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