https://github.com/jeffreysarnoff/ieeefloats.jl
Standard conformant constants for Float64, Float32, Float16
https://github.com/jeffreysarnoff/ieeefloats.jl
ieee-754 ieee754 julia
Last synced: about 1 year ago
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Standard conformant constants for Float64, Float32, Float16
- Host: GitHub
- URL: https://github.com/jeffreysarnoff/ieeefloats.jl
- Owner: JeffreySarnoff
- License: mit
- Created: 2017-12-08T06:06:53.000Z (over 8 years ago)
- Default Branch: master
- Last Pushed: 2020-03-07T10:04:40.000Z (over 6 years ago)
- Last Synced: 2025-02-11T10:32:13.046Z (over 1 year ago)
- Topics: ieee-754, ieee754, julia
- Language: Julia
- Size: 127 KB
- Stars: 3
- Watchers: 3
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
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README
# IEEEFloats.jl
### IEEE754-2019 structural introspection for Float8, Float16, Float32, Float64, Float128
#### Copyright © 2015-2020 by Jeffrey Sarnoff. This work is released under The MIT License.
----
[](https://travis-ci.org/JeffreySarnoff/IEEEFloats.jl) [](https://codecov.io/gh/JeffreySarnoff/IEEEFloats.jl)
----
```julia
IEEEFloat == Base.IEEEFloat == Union{Float16, Float32, Float64}
@inline bitwidth(::Type{T}) where T<:IEEEFloat = sizeof(T) * 8
# precision, significand_bits and exponent_bits are unchanged
precision(::Type{T}) where T<:IEEEFloat = Base.Math.precision(T)
significand_bits(::Type{T}) where T<:IEEEFloat = Base.Math.significand_bits(T)
exponent_bits(::Type{T}) where T<:IEEEFloat = Base.Math.exponent_bits(T)
# exponent_max (Emax in the standard) is an IEEE754-2008 standard term;
# The standard tabulates its values (see Table 3.2 on page 8).
# Julia had defined it in a nonstandard manner. This is conformant:
exponentmax(Float64) == 1023
exponentmax(Float32) == 127
exponentmax(Float16) == 15
# exponent_min (Emin) is another standard term
# it is fully determined by exponent_max:
# exponent_min(T) = 1 - exponent_max(T)
exponentmin(Float64) == -1022
exponentmin(Float32) == -126
exponentmin(Float16) == -14
# exponent_bias (bias) is defined equal to exponent_max
exponentbias(Float64) == 1023
exponentbias(Float32) == 127
exponentbias(Float16) == 15
# The value Julia has called exponent_max does not appear
# in the standard (nor do its values). It is a useful quantity
# (Emax + 1) that we rename `exponent_field_max`.
exponentfieldmax(Float64) == 1024
exponentfieldmax(Float32) == 128
exponentfieldmax(Float16) == 16
```
## all values
```julia
precision(Float16) = 11
precision(Float32) = 24
precision(Float64) = 53
significand_bits(Float16) = 10
significand_bits(Float32) = 23
significand_bits(Float64) = 52
exponent_bits(Float16) = 5
exponent_bits(Float32) = 8
exponent_bits(Float64) = 11
exponentmax(Float16) = 15
exponentmax(Float32) = 127
exponentmax(Float64) = 1023
exponentmin(Float16) = -14
exponentmin(Float32) = -126
exponentmin(Float64) = -1022
exponentbias(Float16) = 15
exponentbias(Float32) = 127
exponentbias(Float64) = 1023
exponentfieldmax(Float16) = 16
exponentfieldmax(Float32) = 128
exponentfieldmax(Float64) = 1024
# intfloatmax(FloatNN) is the most positive IntNN I where FloatNN(I-1) is representable
# intfloatmin(FloatNN) is the most negative IntNN I where FloatNN(I+1) is representable
intfloatmax(Float16) = Int16(2048)
intfloatmax(Float32) = Int32(16777216)
intfloatmax(Float64) = Int64(9007199254740992)
intfloatmin(Float16) = Int16(-2048)
intfloatmin(Float32) = Int32(-16777216)
intfloatmin(Float64) = Int64(-9007199254740992)
# floatintmax(FloatNN) is FloatNN(intfloat_max(FloatNN))
# floatintmin(FloatNN) is FloatNN(intfloat_min(FloatNN))
floatintmax(Float16) = Float16(2048)
floatintmax(Float32) = Float32(16777216)
floatintmax(Float64) = Float64(9007199254740992)
floatintmin(Float16) = Float16(-2048)
floatintmin(Float32) = Float32(-16777216)
floatintmin(Float64) = Float64(-9007199254740992)
```