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Merged
JeffBezanson merged 5 commits into from
Nov 25, 2014
Merged

itrunc -> trunc, etc, fix Int128 vs float comparisons #9133

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aebf40f
itrunc -> trunc, etc, improve iround
simonbyrne Nov 23, 2014
634b9e1
implement float <-> 128-bit int conversions in Julia
simonbyrne Nov 24, 2014
4d54390
fix 32bit shift error
simonbyrne Nov 25, 2014
a39a9dd
make integer checks explicit
simonbyrne Nov 25, 2014
1661d84
NEWS item
simonbyrne Nov 25, 2014
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implement float <-> 128-bit int conversions in Julia
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@simonbyrne
simonbyrne committed Nov 25, 2014
commit 634b9e1a90749462b52b3c6afa949780143d4af4
99 changes: 95 additions & 4 deletions base/float.jl
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Original file line number Diff line number Diff line change
Expand Up @@ -5,19 +5,81 @@ for t in (Bool,Char,Int8,Int16,Int32,Int64,UInt8,UInt16,UInt32,UInt64)
end

for t1 in (Float32,Float64)
for st in (Int8,Int16,Int32,Int64,Int128)
for st in (Int8,Int16,Int32,Int64)
@eval begin
convert(::Type{$t1},x::($st)) = box($t1,sitofp($t1,unbox($st,x)))
promote_rule(::Type{$t1}, ::Type{$st} ) = $t1
end
end
for ut in (Bool,Char,UInt8,UInt16,UInt32,UInt64,UInt128)
for ut in (Bool,Char,UInt8,UInt16,UInt32,UInt64)
@eval begin
convert(::Type{$t1},x::($ut)) = box($t1,uitofp($t1,unbox($ut,x)))
promote_rule(::Type{$t1}, ::Type{$ut} ) = $t1
end
end
end

promote_rule(::Type{Float64}, ::Type{UInt128}) = Float64
promote_rule(::Type{Float64}, ::Type{Int128}) = Float64
promote_rule(::Type{Float32}, ::Type{UInt128}) = Float32
promote_rule(::Type{Float32}, ::Type{Int128}) = Float32

function convert(::Type{Float64}, x::UInt128)
x == 0 && return 0.0
n = 128-leading_zeros(x) # ndigits0z(x,2)
if n <= 53
y = ((x % UInt64) << (53-n)) & 0x000f_ffff_ffff_ffff
else
y = ((x >> (n-54)) % UInt64) & 0x001f_ffff_ffff_ffff # keep 1 extra bit
y = (y+1)>>1 # round, ties up (extra leading bit in case of next exponent)
y &= ~UInt64(trailing_zeros(x) == (n-54)) # fix last bit to round to even
end
reinterpret(Float64,((n+1022)<<52) % UInt64 + y)
end

function convert(::Type{Float64}, x::Int128)
x == 0 && return 0.0
s = ((x >>> 64) % UInt64) & 0x8000_0000_0000_0000 # sign bit
x = abs(x) % UInt128
n = 128-leading_zeros(x) # ndigits0z(x,2)
if n <= 53
y = ((x % UInt64) << (53-n)) & 0x000f_ffff_ffff_ffff
else
y = ((x >> (n-54)) % UInt64) & 0x001f_ffff_ffff_ffff # keep 1 extra bit
y = (y+1)>>1 # round, ties up (extra leading bit in case of next exponent)
y &= ~UInt64(trailing_zeros(x) == (n-54)) # fix last bit to round to even
end
reinterpret(Float64, (s | ((n+1022)<<52) % UInt64) + y)
end

function convert(::Type{Float32}, x::UInt128)
x == 0 && return 0f0
n = 128-leading_zeros(x) # ndigits0z(x,2)
if n <= 24
y = ((x % UInt32) << (24-n)) & 0x007f_ffff
else
y = ((x >> (n-25)) % UInt32) & 0x00ff_ffff # keep 1 extra bit
y = (y+one(UInt32))>>1 # round, ties up (extra leading bit in case of next exponent)
y &= ~UInt32(trailing_zeros(x) == (n-25)) # fix last bit to round to even
end
reinterpret(Float32,((n+126)<<23) % UInt32 + y)
end

function convert(::Type{Float32}, x::Int128)
x == 0 && return 0f0
s = ((x >>> 96) % UInt32) & 0x8000_0000 # sign bit
x = abs(x) % UInt128
n = 128-leading_zeros(x) # ndigits0z(x,2)
if n <= 24
y = ((x % UInt32) << (24-n)) & 0x007f_ffff
else
y = ((x >> (n-25)) % UInt32) & 0x00ff_ffff # keep 1 extra bit
y = (y+one(UInt32))>>1 # round, ties up (extra leading bit in case of next exponent)
y &= ~UInt32(trailing_zeros(x) == (n-25)) # fix last bit to round to even
end
reinterpret(Float32, (s | ((n+126)<<23) % UInt32) + y)
end

#convert(::Type{Float16}, x::Float32) = box(Float16,fptrunc(Float16,x))
convert(::Type{Float16}, x::Float64) = convert(Float16, convert(Float32,x))
convert(::Type{Float32}, x::Float64) = box(Float32,fptrunc(Float32,x))
Expand All @@ -44,19 +106,48 @@ float32(x) = convert(Float32, x)
float64(x) = convert(Float64, x)
float(x) = convert(FloatingPoint, x)

for Ti in (Int8, Int16, Int32, Int64, Int128)
for Ti in (Int8, Int16, Int32, Int64)
@eval begin
unsafe_trunc(::Type{$Ti}, x::Float32) = box($Ti,fptosi($Ti,unbox(Float32,x)))
unsafe_trunc(::Type{$Ti}, x::Float64) = box($Ti,fptosi($Ti,unbox(Float64,x)))
end
end
for Ti in (UInt8, UInt16, UInt32, UInt64, UInt128)
for Ti in (UInt8, UInt16, UInt32, UInt64)
@eval begin
unsafe_trunc(::Type{$Ti}, x::Float32) = box($Ti,fptoui($Ti,unbox(Float32,x)))
unsafe_trunc(::Type{$Ti}, x::Float64) = box($Ti,fptoui($Ti,unbox(Float64,x)))
end
end

function unsafe_trunc(::Type{UInt128}, x::Float64)
xu = reinterpret(UInt64,x)
k = int(xu >> 52) & 0x07ff - 1075
xu = (xu & 0x000f_ffff_ffff_ffff) | 0x0010_0000_0000_0000
if k <= 0
UInt128(xu >> -k)
else
UInt128(xu) << k
end
end
function unsafe_trunc(::Type{Int128}, x::Float64)
copysign(unsafe_trunc(UInt128,x) % Int128, x)
end

function unsafe_trunc(::Type{UInt128}, x::Float32)
xu = reinterpret(UInt32,x)
k = int(xu >> 23) & 0x00ff - 150
xu = (xu & 0x007f_ffff) | 0x0080_0000
if k <= 0
UInt128(xu >> -k)
else
UInt128(xu) << k
end
end
function unsafe_trunc(::Type{Int128}, x::Float32)
copysign(unsafe_trunc(UInt128,x) % Int128, x)
end


# matches convert methods
# also determines floor, ceil, round
trunc(::Type{Signed}, x::Float32) = trunc(Int,x)
Expand Down
13 changes: 11 additions & 2 deletions base/int.jl
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Expand Up @@ -179,20 +179,29 @@ rem{T<:Integer}(x::T, ::Type{T}) = x
rem(x::Integer, ::Type{Bool}) = ((x&1)!=0)
mod{T<:Integer}(x::Integer, ::Type{T}) = rem(x, T)

for to in (Int8, Int16, Int32, Int64, Int128)
for to in (Int8, Int16, Int32, Int64)
@eval begin
convert(::Type{$to}, x::Float32) = box($to,checked_fptosi($to,unbox(Float32,x)))
convert(::Type{$to}, x::Float64) = box($to,checked_fptosi($to,unbox(Float64,x)))
end
end

for to in (UInt8, UInt16, UInt32, UInt64, UInt128)
for to in (UInt8, UInt16, UInt32, UInt64)
@eval begin
convert(::Type{$to}, x::Float32) = box($to,checked_fptoui($to,unbox(Float32,x)))
convert(::Type{$to}, x::Float64) = box($to,checked_fptoui($to,unbox(Float64,x)))
end
end

for Ti in (Int128,UInt128)
for Tf in (Float32,Float64)
@eval function convert(::Type{$Ti},x::$Tf)
isinteger(x) || throw(InexactError())
trunc($Ti,x)
end
end
end

convert(::Type{Signed}, x::UInt8 ) = convert(Int8,x)
convert(::Type{Signed}, x::UInt16 ) = convert(Int16,x)
convert(::Type{Signed}, x::UInt32 ) = convert(Int32,x)
Expand Down